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University of Groningen
Immediate dental implant placement in the aesthetic zoneSlagter, Kirsten Willemijn
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Immediate dental implant placement
in the aesthetic zone
Kirsten Slagter
Thesis
The research presented in this thesis was performed at the Department of Oral and
Maxillofacial Surgery, University Medical Center Groningen, The Netherlands.
This research project was supported by:
Nobel Biocare Services AG, Zurich, Switzerland (materials grant: 2009-851)
Nobel Biocare c/o Medicim NV, Mechelen, Belgium
Publication of this thesis was supported by:
Buijs Tandartsen (www.buijstandartsen.nl)
DENK RUIM OVER INTERIEUR (www.denkruim.nl)
Dental Clinics (www.dentalclinics.nl)
Gjald Accountancy en AFAS Dienstverlening (www.gjald.nl)
Gronings Tandtechnisch Laboratorium (www.gtl.nl)
Koninklijke Nederlandse Maatschappij tot bevordering der Tandheelkunde (www.knmt.nl)
Nobel Biocare Nederland BV (www.nobelbiocare.nl)
Nederlandse Vereniging voor Mondziekten, Kaak- en Aangezichtschirurgie (www.nvmka.nl)
Nederlandse Vereniging voor Orale Implantologie (www.nvoi.nl)
Tandartspraktijk Reijenburg (H.H. Slagter, de Reijenburg 31 te Veldhoven)
Tandprothetische Praktijk Wietse Molenaar (www.wietsemolenaar.nl)
Zheng (Zheng, Stoeldraaierstraat 11 te Groningen)
University of Groningen (www.rug.nl)
Bookdesign: Sythe Veenje, Buro.Baum
Printed by: Drukkerij van der Eems, Heerenveen
ISBN: 978-90-367-8725-3
ISBN e-pub: 978-90-367-8724-6
© Kirsten Slagter, 2016
All rights reserved. No part of this publication may be reported or transmitted, in any form or
by any means, without prior permission of the author.
Immediate dental implant placement in the aesthetic zone
Proefschrift
ter verkrijging van de graad van doctor aan deRijksuniversiteit Groningen
op gezag van derector magnificus prof. dr. E. Sterken
en volgens besluit van het College voor Promoties.
De openbare verdediging zal plaatsvinden op
woensdag 6 april 2016 om 16.15 uur
door
Kirsten Willemijn Slagter
geboren op 3 juli 1983
te Utrecht
Promotores Prof. dr. G.M. Raghoebar
Prof. dr. H.J.A. Meijer
Prof. dr. A. Vissink
BeoordelingscommissieProf. dr. M.S. Cune
Prof. dr. G.J. Meijer
Prof. dr. E.B. Wolvius
ParanimfenDr. N.A. Bakker
Dr. Y.C.M. de Waal
6
1
7
1General introduction
8
General Introduction
Failing or missing teeth in the aesthetic zone require a predictable treatment strategy1. Single-tooth dental
implant placement in the aesthetic zone is a highly reliable treatment option for replacing a failing tooth or
missing tooth.2,3 There is a growing tendency in this zone to place single-tooth dental implants immediately
after extraction of a failing tooth in the fresh extraction socket4, 5 as an alternative to early (<8 weeks after
tooth extraction) or delayed placed implants (>8 weeks after tooth extraction). Presumably, this tendency
is related to evolving society factors, with more demanding patients and a wish for direct and better
aesthetic results. Innovations in implant surfaces and designs have facilitated the possibilities for such
an approach.6 There is insufficient evidence, however, which approach immediate, early or delayed placed
dental implants, are in favour for which specific treatment strategy in the aesthetic zone.7
The presence of sufficient bone volume is the most important prerequisite to achieve primary stability
of the dental implant, especially in case of immediate implant placement in an extraction socket. 1 A
successful aesthetic outcome is suggested to be dependent on establishment of an optimal three-
dimensional implant position within the available bone dimensions and the maintenance of adequate
buccal bone along the implant axis.8,9 The size of the bony defect after extraction can be a considerable
aesthetic risk for immediately placed implants. The combination of buccal extraction socket defects
and thin overlying soft tissues is a considerable aesthetic risk for maintaining an acceptable long-term
aesthetic outcome for immediately placed implants, despite ideal placement and synchronous hard or
soft tissue grafting procedures.10 A delayed approach with hard or soft tissue grafting in the event of an
osseous defect presenting on the labial bony plate was therefore recommended. Recently, due to altering
techniques, a favourable treatment outcome of immediate implant placement in extraction sockets
with labial plate dehiscences was reported.11-13 This means that an intact buccal plate is not essential for
immediate implant placement. To what extent the bony defect affects the treatment outcome remains
unclear.
Regarding replacing a missing tooth (delayed implant placement), immediate provisionalization (<24
hours after implant placement) is not less favourable than conventional provisionalization for single-
tooth implants.14 For a failing tooth (immediate implant placement), it is assumed that immediate
provisionalization results in better aesthetice results compared to conventional provisionalization.4, 5
However, the exact effect of immediate provisionalization combined with immediate implant placement
requires further research.
There are several outcome measures to assess the treatment outcome of single-tooth dental implants.
The outcome measure implant survival seems to be hardly affected by timing of implant placement relative
to tooth extraction.3 Thus, as timing of implant placement seems not to be a major factor determining
implant survival, the focus in outcome measures shifted towards the dynamics of hard and soft peri-
implant tissues. Establishment and maintenance of healthy hard and soft peri-implant tissues are crucial,
particularly in the aesthetic zone. 15-18
1
9
Peri-implant bone preservation is thought to be a key factor determining the outcome of peri-implant
hard tissues as Marginal Bone level (MBL) and amount of Buccal Bone Thickness (BBT).19 MBL can be
detected with a standardized method on conventional radiographs.20 The lack of data regarding BBT is
probably related to frequently encountered difficulties in standardization of the measurements. Cone-
beam computed tomography (CBCT) has proven to be a useful tool that has been successfully employed
for various dental procedures.21 The availability of an accurate and reliable imaging modality is clinically
important in terms of postoperative monitoring of bone volume stability and assessing the best treatment
approach.22 For example, to assess the minimum BBT at time of implant placement to predict the aesthetic
outcome and the long-term stability.19,23,24
Besides peri-implant hard tissues, the outcome of peri-implant soft tissues are essential in the aesthetic
zone. It is suggested that timing of implant placement and provisionalization affects peri-implant soft
tissues16,25 by increasing a risk for recession and thereby influence the aesthetic and patient-centered
outcome. The aesthetic result is mainly determined by the shape of healthy pink soft peri-implant tissues
and the contour and colour of the definitive crown. Therefore several aesthetic indexes (e.g. ICAI26 and PES/
WES27) have been developed to objectify the aesthetic outcome. Patient-centered outcomes are outcomes
that are based on the care experience viewed through the eyes of patients and focus on outcomes
important to patients such as quality of life. For patient-centered outcomes, Visual Analogue Scales
(VAS)28 and the Oral Health Impact Profile (OHIP)29 are commonly applied. For immediate dental implant
placement in the aesthetic zone, no randomized clinical trials depending on the size of the bony defect
after extraction, assessing the full panel of outcome measures, including changes in the hard and soft
tissue dimensions, implant survival, aesthetic evaluation and patient-centered outcome in the aesthetic
zone, have been published yet.
10
General aim and outline of the thesis
The general aim of the research described in this thesis was to assess the 1-year treatment outcome
of immediate dental implant placement in the aesthetic zone. The treatment outcome consisted out of
changes in hard and soft tissue dimensions, implant survival, aesthetic evaluation and patient-centered
outcome.
The specific aims were:
- a systematic review on the currently available literature assessing implant survival, peri-implant
hard and soft tissues, aesthetic outcome and patient-centered outcomes in the aesthetic zone after
immediate placement of dental implants;
- to perform a randomized controlled trial to assess whether the 1-year outcome of immediate dental
implant placement and immediate provisionalization was non-inferior to immediate dental implant
placement and delayed provisionalization in extraction sockets with labial bony defects of <5 mm;
- to perform a randomized controlled trial to assess whether the 1-year outcome of immediate dental
implant placement and delayed provisionalization is non-inferior to delayed dental implant placement
and delayed provisionalization in extraction sockets with labial bony defects of ≥5 mm;
- to develop a reproducible method based on 3D image diagnostic and treatment planning software
programs for buccal bone measurements at dental implants on CBCTs;
- to assess the amount of BBT of immediate and delayed placed dental implants in the aesthetic zone.
1
11
References
1. Kan JY, Rungcharassaeng K. Site development for
anterior single implant esthetics: the dentulous site.
Compend Contin Educ Dent 2001;22(3):221-6, 228,
230-1.
2. Esposito M, Grusovin MG, Polyzos IP, Felice P,
Worthington HV. Timing of implant placement after
tooth extraction: immediate, immediate-delayed or
delayed implants? A Cochrane systematic review. Eur J
Oral Implantol 2010;3(3):189-205.
3. Lang NP, Pun L, Lau KY, Li KY, Wong MC. A
systematic review on survival and success rates of
implants placed immediately into fresh extraction
sockets after at least 1 year. Clin Oral Implants Res
2012;23 Suppl 5:39-66.
4. De Rouck T, Collys K, Cosyn J. Single-tooth replacement
in the anterior maxilla by means of immediate
implantation and provisionalization: a review. Int J
Oral Maxillofac Implants 2008;23(5):897-904.
5. Slagter KW, den Hartog L, Bakker NA, Vissink A, Meijer
HJ, Raghoebar GM. Immediate placement of dental
implants in the esthetic zone: a systematic review and
pooled analysis. J Periodontol 2014;85(7):e241-50.
6. Eghbali A, De Bruyn H, De Rouck T, Cleymaet R, Wyn
I, Cosyn J. Single implant treatment in healing versus
healed sites of the anterior maxilla: a clinical and
radiographic evaluation. Clin Implant Dent Relat Res
2012;14(3):336-346.
7. Esposito M, Grusovin MG, Polyzos IP, Felice P,
Worthington HV. Interventions for replacing missing
teeth: dental implants in fresh extraction sockets
(immediate, immediate-delayed and delayed
implants). Cochrane Database Syst Rev 2010;(9)
(9):CD005968.
8. Buser D, Martin W, Belser UC. Optimizing esthetics for
implant restorations in the anterior maxilla: anatomic
and surgical considerations. Int J Oral Maxillofac
Implants 2004;19 Suppl:43-61.
9. Grunder U, Gracis S, Capelli M. Influence gingival
dynamics after immediate tooth replacement and
guided bone regeneration: 1-year results. J Oral
Maxillofac Surg 2007;65(7 Suppl 1):13-19.
10. Kan JY, Rungcharassaeng K, Sclar A, LozadaJL.Effects
of the facial osseous defect morphology on gingival
dynamics after immediate tooth replacement and
guided bone regeneration: 1-year results. J Oral
Maxillofac Surg 2007;65(7 Suppl 1):13-19.
11. Noelken R, Kunkel M, Wagner W. Immediate implant
placement and provisionalization after long-axis root
fracture and complete loss of the facial bony lamella.
Int J Periodontics Restorative Dent 2011;31(2):175-183.
12. da Rosa JC, Rosa AC, da Rosa DM, Zardo CM.
Immediate Dentoalveolar Restoration of compromised
sockets: a novel technique. Eur J Esthet Dent
2013;8(3):432-443.
13. Sarnachiaro GO, Chu SJ, Sarnachiaro E, Gotta SL,
Tarnow DP. Immediate Implant Placement into
Extraction Sockets with Labial Plate Dehiscence
Defects: A Clinical Case Series. Clin Implant Dent Relat
Res 2015; Apr 27. [Epub ahead of print]
14. den Hartog L, Raghoebar GM, Stellingsma K, Vissink
A, Meijer HJ. Immediate non-occlusal loading of single
implants in the aesthetic zone: a randomized clinical
trial. J Clin Periodontol 2011;38(2):186-194.
15. den Hartog L, Slater JJ, Vissink A, Meijer HJ, Raghoebar
GM. Treatment outcome of immediate, early and
conventional single-tooth implants in the aesthetic
zone: a systematic review to survival, bone level,
soft-tissue, aesthetics and patient satisfaction. J Clin
Periodontol 2008;35(12):1073-1086.
16. Cosyn J, Hooghe N, De Bruyn H. A systematic review
on the frequency of advanced recession following
single immediate implant treatment. J Clin Periodontol
2012;39(6):582-589.
12
17. Jung RE, Zembic A, Pjetursson BE, Zwahlen M, Thoma
DS. Systematic review of the survival rate and the
incidence of biological, technical, and aesthetic
complications of single crowns on implants eported in
longitudinal studies with a mean follow-up
of 5 years. Clin Oral Implants Res 2012;23 Suppl
6:2-
18. Hammerle CH, Araujo MG, Simion M, Osteology
Consensus Group 2011. Evidence-based knowledge on
the biology and treatment of extraction sockets. Clin
Oral Implants Res 2012;23 Suppl 5:80-82.
19. Merheb J, Quirynen M, Teughels W. Critical buccal
bone dimensions along implants. Periodontol 2000
2014;66(1):97-105.
20. Meijndert L, Meijer HJ, Raghoebar GM, Vissink A. A
technique for standardized evaluation of soft and hard
peri-implant tissues in partially edentulous patients. J
Periodontol 2004;75(5):646-651.
21. Sennerby L, Andersson P, Pagliani L, et al. Evaluation
of a Novel Cone Beam Computed Tomography Scanner
for Bone Density Examinations in Preoperative 3D
Reconstructions and Correlation with Primary Implant
Stability. Clin Implant Dent Relat Res 2015;17(5):844-
53.
22. El Nahass H, Naiem SN. Analysis of the dimensions
of the labial bone wall in the anterior maxilla: a cone-
beam computed tomography study. Clin Oral Implants
Res 2015;26(4):e57-61.
23. Klinge B, Flemmig TF, Working Group 3. Tissue
augmentation and esthetics (Working Group 3). Clin
Oral Implants Res 2009;20 Suppl 4:166-170.
24. Teughels W, Merheb J, Quirynen M. Critical horizontal
dimensions of interproximal and buccal bone around
implants for optimal aesthetic outcomes: a systematic
review. Clin Oral Implants Res 2009;20 Suppl 4:134-
145.
25. Lin GH, Chan HL, Wang HL. The Effect of Currently
Available Surgical and Restorative Interventions on
Reducing Mid-facial Mucosal Recession of Single-
Tooth Immediate Placed Implants: A Systematic
Review. J Periodontol 2014;85(1):92-102.
26. Meijer HJ, Stellingsma K, Meijndert L, Raghoebar GM.
A new index for rating aesthetics of implant-supported
single crowns and adjacent soft tissues--the Implant
Crown Aesthetic Index. Clin Oral Implants Res
2005;16(6):645-649.
27. Belser UC, Grutter L, Vailati F, Bornstein MM Weber HP,
Buser D. Outcome evaluation of early placed maxillary
anterior single-tooth implants using objective esthetic
criteria: a cross-sectional, retrospective study in 45
patients with a 2- to 4-year follow-up using pink and
white esthetic scores. J Periodontol 2009;80(1):140-
151.
28. Gallagher EJ, Liebman M, Bijur PE. Prospective
validation of clinically important changes in pain
severity measured on a visual analog scale. Ann
Emerg Med 2001;38(6):633-638.
29. van der Meulen MJ, John MT, Naeije M, Lobbezoo F.
Developing abbreviated OHIP versions for use with
TMD patients. J Oral Rehabil 2012;39(1):18-27.
1
13
14
2
15
2Immediate placement of dental
implants in the aesthetic zone:
a systematic review and pooled analysis.
This chapter is an edited version of the manuscript:Slagter KW, den Hartog L, Bakker NA, Vissink A, Meij er HJ, Raghoebar GM.
Immediate placement of dental implants in the esthetic zone: a systematic review and pooled analysis. J Periodontol 2014;85:e241-50.
16
Abstract
Background:
Research interest on immediate placement of dental implants has shifted from
implant survival towards optimal preservation of soft and hard tissues. The aim was to
systematically assess the condition of implant survival, peri-implant hard and soft tissue
changes, aesthetic outcome and patient satisfaction of immediately placed single-tooth
implants in the aesthetic zone.
Material and methods:
MEDLINE, EMBASE and CENTRAL databases were searched for publications up to June
2013. Studies reporting on implant survival, changes in hard and soft peri-implant tissues,
aesthetic outcome and patient satisfaction were considered. A pooled analysis was
performed to identify factors associated with survival and peri-implant tissue changes
after immediate implant placement.
Results:
34 studies were considered eligible. Immediate placement of single tooth implants in
the aesthetic zone was accompanied by excellent one year implant survival (97.1%,
95% Confidence Interval (CI) 0.958-0.980). Mean marginal peri-implant bone loss was
0.81±0.48 mm, mean loss of interproximal peri-implant mucosa level was 0.38±0.23 mm
and mean loss of peri-implant midfacial mucosa level was 0.54±0.39 mm. Regression
analysis revealed that delayed provisionalization (OR 60.22, 95%CI 8.36-434.04, p<0.001),
use of a flap (OR 20.34, 95%CI 10.52 -39.65, p<0.001) and use of a connective tissue graft
(OR 4.56, 95%CI 1.72-12.08, p< 0.001) were associated with marginal peri-implant bone
level change >0.50 mm. Due to underreporting, aesthetic and patient satisfaction did not
allow for reliable analysis.
Conclusion:
Immediate placement with immediate provisionalization of dental implants in the
aesthetic zone results in excellent short-term treatment outcome in terms of implant
survival, and minimal change of peri-implant soft and hard tissue dimensions.
2
17
Introduction
Single-tooth implant placement in the aesthetic zone is a highly reliable treatment option for replacing a
failing tooth.1-3 Yet, the research interest has shifted from implant survival towards optimal preservation of
soft and hard peri-implant tissues.3,4 Moreover, attention has shifted to aesthetic outcomes and patient-
centered outcomes of single-tooth implant placement..5-7
The aesthetic outcome is determined to a large extent by healthy and stable peri-implant tissues as well
as the implant crown. Several aesthetic indexes, such as the Implant Crown Aesthetic Index (ICAI)6, the
pink esthetic score (PES) and the white esthetic score (WES)7 have been developed in order to objectify the
aesthetic outcome, while for patient-centered outcomes, the Oral Health Impact Profile (OHlP)5 has been
developed. There is a growing tendency to place implants immediately after extraction often combined
with immediate provisionalization.2 This tendency is probably amongst others a result of evolving society
factors, more demanding patients and the wish for quick results. However, it is suggested that timing
of implant placement and timing of provisionalization influences peri-implant soft and hard tissues8-11
thus challenging the aesthetic and patient-centered outcome. According to some recent studies, implant
survival seems to be hardly affected by timing of implant placement relative to tooth extraction.1-3
In terms of hard and soft tissue changes, no definitive conclusions have been drawn from the available
literature so far. However, the focus of recent systematic reviews is on specific aspects of peri-implant
tissues after immediate implant placement. E.g., in the study by Lang et al.12, implant survival and success
rates were the only parameters measured, while in the studies of Lin et al.13 and Cosyn et al.9 only recession
of soft tissues was observed.
A systemic review of all identified variables affecting the treatment outcome of immediate implant
placement is to the best of our knowledge not available in the international literature. Therefore, the aim of
the present study was to perform a systematic review on the currently available literature assessing implant
survival, peri-implant hard and soft tissues, aesthetic outcome and patient outcomes in the aesthetic zone
after immediate placement of endosseous dental implants. In addition, a pooled analysis of the included
studies was performed to identify factors possibly associated with the aforementioned outcome variables.
Material and methods
Search strategy
Three electronic databases were considered by two reviewers (K.S. and L.H.): MEDLINE (PubMed), CENTRAL
(Cochrane Central Register of Controlled Trials) and EMBASE. No language restriction was applied.
Databases were scrutinized for studies published up to the 1st of June 2013. The search strategy is outlined
in Table 1.
Study selection
Titles and abstracts of the identified publications were screened. Full-text articles were obtained for all
potentially relevant studies and eligibility assessment was performed by two independent reviewers
(K.S. and L.H.). In addition, references of the selected publications and previously published reviews
18
relevant to the present review were searched for eligible studies. In case of disagreement between the
two reviewers, consensus was reached by discussion with the senior author (G.R.). To ensure that no
patients were analyzed twice in the pooled analysis, studies in which the same patients were analyzed with
different follow-ups, leading to different publications, the study with the longest follow-up was selected for
definitive analysis.
Inclusion criteria
Prospective studies with a follow-up period of at least one year or observational studies with implants
placed in the aesthetic zone with a follow-up of at least one year (in function) were considered. The
aesthetic zone was defined from second premolar to second premolar. The adjacent teeth needed to be
natural. Case reports were considered, but excluded if <10 cases were evaluated. Treatments should have
been carried out with single titanium or ceramic endosseous implants. Single tooth implants should have
been placed immediately. Immediate implant placement was defined as implant placement immediately
following extraction of a tooth. At least one of the following factors needed to be reported: implant
survival, marginal peri-implant bone level change, change in peri-implant soft tissue, or aesthetic outcome
assessed by means of an objective index or patient questionnaire at last follow-up. There were no language
restrictions.
Quality assessment
Methodological quality was assessed by two reviewers (K.S. and L.H.) using specific study-design related
forms designed by the Dutch Cochrane Collaboration. The two observers independently assessed the
included articles8,10,11,15-49 based on the recommended approach for assessing risk of bias in Cochrane
reviews (Table 2).
Data extraction
The data that was extracted and re-organized is presented in Table 3.
Data regarding the following outcome variables (if present) were assessed:
- implant survival
- change in marginal peri-implant bone level (MBL) (the mean reported MBL was used, in studies with
mesial/distal MBL, the mean of the two was calculated and used for analysis)
- change in interproximal peri-implant mucosal level (IML; the mean reported IML was used, in studies
with mesial/distal IML, the mean of the two was calculated and used for analysis)
- change in midfacial peri-implant mucosal level (MML), Papilla index4, width of keratinized mucosa or
gingival index, bleeding index14, plaque index14, mean probing depth
- aesthetics assessed by means of an objective index6, 7
- patient satisfaction, assessed using an Oral Health Impact Profile (OHIP) index⁵, Visual Analogue
Scale (VAS) or questionnaire.
2
19
Table 1. Search strategy.
MEDLINE
([MeSH terms / all subheadings] Dental Implants OR [MeSH terms / all subheadings] Dental Implantation OR
dental implant[tiab] OR dental implants[tiab] OR dental implantation[tiab] OR endosseous dental implantation[tiab] OR endosseous implantation[tiab] OR endosseous implant[tiab] OR single tooth[tiab] OR single teeth[tiab] OR single implant[tiab] OR single implants[tiab] OR single crown[tiab] OR single crowns[tiab] OR single restoration[tiab] OR single restorations[tiab])
AND
(aesthetic[tiab] OR esthetic[tiab] OR anterior[tiab] OR front[tiab] OR incisor[tiab] OR incisors[tiab] OR canine[tiab] OR canines[tiab] OR cuspid[tiab] OR cuspids[tiab] OR bicuspid[tiab] OR bicuspids[tiab] OR premolar[tiab] OR premolars[tiab])
AND (immediate[tiab] OR direct[tiab]
EMBASE
‘tooth implant’/exp OR ‘tooth implantation’/exp OR
‘dental implant’:ab,ti OR ‘dental implants’:ab,ti OR dental implantation:ab,ti OR ‘endosseous dental implantation’:ab,ti OR ‘endosseous implantation’:ab,ti OR ‘endosseous implant’:ab,ti OR ‘single tooth’:ab,ti OR ‘single teeth’:ab,ti OR ‘single implant’:ab,ti OR ‘single implants’:ab,ti OR ‘single crown’:ab,ti OR ‘single crowns’:ab,ti OR ‘single restoration’:ab,ti OR ‘single resto-rations’:ab,ti
AND
aesthetic:ab,ti OR esthetic:ab,ti OR anterior:ab,ti OR front:ab,ti OR incisor:ab,ti OR incisors:ab,ti OR canine:ab,ti OR canines:ab,ti OR cuspid:ab,ti OR cuspids:ab,ti OR bicuspid:ab,ti OR bicuspids:ab,ti OR premolar:ab,ti OR premolars:ab,ti
AND immediate:ab,ti OR direct:ab,ti
AND [embase]/lim
Cochrane
#1 search [MeSH terms / all subheadings] Dental Implants
#2 search [MeSH terms / all subheadings] Dental Implantation
#3 search ‘dental implant’ OR ‘dental implants’ OR dental implantation OR ‘endosseous dental implantation’ OR ‘endosseous implantation’ OR ‘endosseous implant’ OR ‘single tooth’ OR ‘single teeth’ OR ‘single implant’ OR ‘single implants’ OR ‘single crown’ OR ‘single crowns’ OR ‘single restoration’ OR ‘single restorations’
#4 aesthetic OR esthetic OR anterior OR front OR incisor OR incisors OR canine OR canines OR cuspid OR cuspids OR bicuspid OR bicuspids OR premolar OR premolars
#5 immediate OR direct
#6 search (#1 OR #2 OR #3) AND #4 AND #5
20
Table 2. Summary of risk of bias of included studies
AuthorsAdequate sequence generation?
Allocation conceal-ment?
Blinding?
Incomplete outcome data addressed?
Free of selective reporting?
Free of other bias?
Risk of Bias
Lindeboom et al. 18 + + + + + + Low
Crespi et al.19 - - - + - ? High
Palattella et al.11 + + + + + + Low
De Rouck et al.22 + + + + + + Low
Block et al.20 ? + - + + - Medium
Raes et al.21 + - - + + + Low
Wöhrle23 NA NA NA ? - ? High
Groisman et al.24 NA NA NA ? - ? High
Norton25 NA NA NA ? ? ? High
Tsirlis26 NA NA NA ? ? ? High
Barone et al.27 NA NA NA - - ? High
Ferrara et al.28 NA NA NA - - ? High
Canullo et al.29 NA NA NA - - ? High
Covani et al. 30 NA NA NA + + ? Medium
Kan et al.31 NA NA NA + ? ? Medium
Cornelini et al.32 NA NA NA ? - ? High
Lops et al.33 NA NA NA + + ? Medium
Romeo et al.34 NA NA NA + ? ? High
Cordaro et al.36 NA NA NA + + ? Medium
Canullo et al. 37 NA NA NA + ? ? High
Crespi et al.38 NA NA NA + ? ? High
Cooper et al.39 NA NA NA + - ? High
Tortamano et al.40 NA NA NA + ? ? High
Valentini et al.41 NA NA NA + + ? Medium
Brown and Payne 42 NA NA NA + + ? Medium
Chung et al.43 NA NA NA + + ? Medium
Cosyn et al.8 NA NA NA + + ? Medium
Kan et al.44 NA NA NA + + ? Medium
Malchiodi et al.45 NA NA NA - + ? High
Pieri et al.46 NA NA NA + + ? Medium
Tsuda et al.47 NA NA NA + + ? Medium
Cabello et al.48 NA NA NA + + ? Medium
Cosyn et al.10 NA NA NA + + + Low
Grandi et al.49 NA NA NA + + ? Medium
2
21
Statistical analysis
Pooled analysis
In order to perform a pooled data analysis and to identify potential predictive factors for the outcome
variables, all available study data were re-organized in a new data set. From the included manuscripts, all
available data were individualized after extraction. As such, raw data was obtained from these studies.
Fields that could not be individualized were left empty and censored in the analysis accordingly. All
analyses that could be performed were conducted on an individual patient level. The following predictors
were considered:
1. age, 2. sex, 3. timing of provisionalization (immediate or delayed,) 4. flap (yes or no), 5. connective
tissue graft (yes or no), 6. grafting material (autograft, allograft, xenograft with or without (non) resorbable
membrane), 7. biotype (thick or thin), 8. primary stability (divided in three groups: ≤25, 25-35, ≥35 N/cm), 9.
duration of temporary provisionalization (months), 10. material definitive restoration (ceramic or porcelain
fused to metal (PFM)), 11. screw- or cement-retained definitive crown.
Antibiotic use and the use of mouth rinse were not considered, as either all patients received antibiotics or
mouth rinse, or data were not reported.
95% confidence intervals (95%CI) of the survival proportion were calculated using the Wilson procedure
without continuity correction. It turned out that only data on implant survival and MBL could be
meaningfully combined into the pooled data analysis. Regarding the other variables, insufficient data was
available. Risk factors (Odds Ratio, OR) for implant survival (yes/no) were analyzed by multiple binary
logistic regression analysis. All factors with a p-value <0.10 were considered in the multiple model using a
backward elimination strategy. MBL was categorized into two groups: ≤0.50 mm and >0.50 mm bone loss.
For this outcome variable, also univariate binary logistic regression analysis was applied. Multivariable
regression analysis was not performed, as too few variables were available. Regarding IML and MML, too
few data was available to perform a regression analysis. A p-value <0.05 mm was considered to indicate
statistical significance. Missing data were censored in all analysis. All data analysis was performed with the
IBM SPSS, version 20.0.
Results
Study inclusion
The MEDLINE, EMBASE and Cochrane CENTRAL searches resulted in 993, 273 and 130 hits, respectively.
Figure 1 outlines the flow chart according to the PRISMA statement. After extracting duplicate citations,
637 publications remained to be screened. After screening of titles and abstracts, 98 publications were
selected for full-text analysis. Screening of bibliographies of relevant reviews and selected publications
revealed no additional publications. Of the 98 publications, 61 were excluded after full-text analysis and
quality assessment. Two disagreements occurred which were easily resolved in a consensus meeting. This
led to 38 studies available for initial analysis. Four studies15-17,35 were excluded from the pooled analysis
as the same patient population was described (only the study with the longest follow-up was used). In the
final pooled analysis, 34 studies were considered eligible for pooled analysis (Tables 2 and 3). Of these, 5
were RCTs11,18-20,22, 1 CT21 and 28 were observational studies8,10,23-34,36-49 .
22
Tabl
e 3.
Cha
ract
eris
tics
of in
clud
ed s
tudi
es.
auth
ors
stud
y de
sign
setti
ng
follo
w-
up (m
)
patie
nts
follo
wed
impl
ants
(m
ax/m
an)
mea
n ag
e (y)
mal
eim
plan
t sys
tem
(ty
pe)
diam
eter
(m
m)
test
gr
oup
type
of
plac
e-m
ent
type
of
prov
ision
al-
izatio
n
fem
ale
leng
th
(mm
)co
ntro
l gr
oup
Lind
eboo
m e
t al.
18*
RCT
Inst
1250
50 (5
0/0)
39.9
( 16
.2)
25De
ntsp
ly
(Fria
lit-2
-Syn
chro
)3.
8-6.
525
IPDP
r39
.5 (1
2.9)
25NR
25DP
DPr
Cres
pi e
t al.
19*
RCT
Inst
2440
40 (4
0/0)
45.5
9 (2
4-62
)10
Swed
en &
Mar
tina
(Out
link)
3.75
-5.0
20IP
IPr
10
48.8
3 (2
7-68
)6
1320
IPDP
r14
Pala
ttel
la e
t al.
11*
RCT
Inst
2416
18 (1
8/0)
35 (2
1-49
)6
Stra
uman
n
(Tap
ered
Effe
ct)
4.1
9IP
IPr
1010
-12
9EP
IPr
De R
ouck
et a
l. 22
* RC
TIn
st12
4949
(49/
0)55
(13)
11No
bel B
ioca
re
(Nob
el re
plac
e)
4.3
or 5
.024
IPIP
r13
52 (1
2)12
10-1
625
IPDP
r13
Bloc
k et
al.
20*
RCT
Inst
2455
55 (5
5/0)
65.0
(49-
80)
14Bi
omet
3i (
Certa
in
Impl
ant)
NR26
IPIP
r15 10
11.5
-13
29DP
IPr
16
Raes
et a
l. 21
*CT
Inst
1248
48(4
8/0)
40 (1
9-75
)21
Astra
Tech
O
sseo
spee
d4.
0-5.
025
IP
IPr
2711
-17
23DP
IPr
Wöh
rle23
O
SPr
iv18
1414
(14/
0)NR
NRSt
eri-O
ss (R
epla
ce)
NRNA
IPIP
r
Groi
sman
et a
l. 24
O
SIn
st24
9292
(92/
0)NR
NRNo
bel B
ioca
re
(Rep
lace
)
3.5,
4.3,
5.
0,6.
0NA
IPIP
r13
,16
2
23
Nort
on25
*O
SPr
iv20
.325
28 (2
8/0)
48.2
(27-
72)
10
Astra
Tech
(NR)
4.5
or 5
.0NA
IP
(n=1
6)IP
r15
11-1
7
Tsirl
is26
*O
SIn
st24
4343
(43/
0)20
-60
NR3i
(NT
Oss
eotit
e)3.
8-6.
5NA
IP
(n=2
8)IP
r13
Baro
ne e
t al. 2
7 O
SIn
st12
1818
(13/
5)22
-60
6Sw
eden
&M
artin
a (P
rem
ium
)>3
.75
NAIP
IPr
12>1
3
Ferr
ara
et a
l. 28
O
SIn
st30
3333
(33/
0)24
-58
16De
ntsp
ly (F
rialit
-2-)
3.8,
4.5,
5.5
NAIP
IPr
1713
or 1
5
Canu
llo e
t al.
29
OS
Priv
229
10 (1
0/0)
45.9
(33-
69)
2De
fcon
(TSA
TM
Serie
s 5
Defc
on)
6.0
NAIP
IPr
713
Cova
ni e
t al.
30
OS
Priv
1210
10(1
0/0)
42-5
55
Swed
en&
Mar
tina
(NR)
3.75
or 4
.0NA
IPDp
r5
13 o
r 15
Kan
et a
l. 31
O
SIn
st12
2323
(23/
0)39
.5 (2
5-63
)NR
Nobe
l Bio
care
(R
epla
ce S
elec
t)NR
NAIP
Ipr
Corn
elin
i et a
l. 32
OS
Priv
1234
34 (2
7/7)
43 (2
1-62
)19
Stra
uman
n (N
R)4.
8NA
IPIP
r15
10 o
r 12
Lops
et a
l. 33
O
SIn
st12
4646
(32/
14)
47.2
(18-
71)
25As
traTe
ch
(Oss
eosp
eed)
3.5,
4,4.
5NA
IPDP
r21
9,11
,13
Rom
eo e
t al.
34O
SIn
st12
4848
(20/
28)
46 (1
8-63
)22
Stra
uman
n
(sta
ndar
d pl
us T
E)3.
3,4.
1,4.8
NAIP
DPr
2610
or 1
2
Cord
aro
et a
l. 36
OS
Priv
18NR
30 (N
R)NR
NRSt
raum
an
(TE
impl
ants
)NR
NAIP
DPr
Canu
llo e
t al.
37
OS
Priv
3625
25 (2
5/0)
55 (1
3.5)
51
(7.7
) 14
Swed
en&
Mar
tina
(Glo
bal I
mpl
ants
)5.
5NA
IPIP
r9
13
Cres
pi e
t al.
38
OS
Inst
2430
30 (3
0/0)
51.2
(34-
71)
12Sw
eden
&M
artin
a (S
even
)3.
75 o
r 5.0
NAIP
DP
r18
13
Coop
er e
t al.
39*
OS
Inst
1213
915
7 (1
57/0
)45
.1 (1
4.2)
22As
traTe
ch
(Oss
eosp
eed)
3.5,
4.0,
4.
5,5.
0NA
IP
(n=5
5)IP
r33
11-1
9
24
Tort
aman
o et
al.
40
OS
Inst
1812
12 (1
2/0)
22-5
43
Stra
uman
n4.
8NA
IPIP
r9
12
Vale
ntin
i et a
l. 41
*O
SIn
st12
4043
(43/
0)NR
NRAs
tra Te
ch (T
iO-
blas
t)4,
4.5,
5NA
IP
(n=2
0)
IPr
9,11
,13
Brow
n an
d Pa
yne
42
OS
Inst
1227
28 (2
8/0)
47.1
(21-
71)
9So
uth
Impl
ants
(C
o-Ax
is)
4 or
4.7
NAIP
IPr
1813
or 1
5
Chun
g et
al.
43
OS
Inst
1210
10 (8
/2)
52.1
(22.
7-67
.1)
6Bi
omet
3i (
Oss
eo-
tite
Prev
ail)
3.25,4
.0,5.
0NA
IPIP
r4
13 o
r 15
Cosy
n et
al.
8 O
SIn
st36
3030
(30/
0)54
(24-
76)
14No
bel B
ioca
re
(Rep
lace
TiU
nite
)4.
3 or
5.0
NAIP
IPr
1613
or 1
6
Kan
et a
l. 44
O
SIn
st48
3535
(35/
0)36
.5 (1
8-65
)8
Nobe
l Bio
care
(R
epla
ce)
3.75
NAIP
IPr
2713
,15,
18
Mal
chio
di e
t al.
45
OS
Inst
3658
64 (6
4/0)
39.9
(19-
78)
32NR
(Fas
t bon
e
rege
nera
tion
co
ated
impl
ants
)
3.25
-4.9
NAIP
IPr
2610
-16
Pier
i et a
l. 46
OS
Inst
1240
40 (4
0/0)
4614
Bios
park
(Sam
o Sm
iler I
mpl
ants
)NR
NAIP
IPr
2
Tsud
a et
al.
47
OS
Inst
1210
10 (1
0/0)
48 (3
5-70
)4
Astra
Tech
(O
sseo
spee
d)4.
0-5.
0NA
IPIP
r6
13-1
7
Cabe
llo e
t al.
48
OS
Priv
1214
14 (1
4/0)
52 (3
4-71
)7
Stra
uman
n (T
L RN.
NN
and
BL N
C and
RC)
NRNA
IPIP
r7
Cosy
n et
al.
10
OS
Priv
1222
22 (2
2/0)
50 (2
7-74
)12
Nobe
l Bio
care
(N
obeA
activ
)NR
NAIP
IPr
10
Gran
di e
t al.
49
OS
Inst
1236
36 (3
6/0)
37.4
(35-
60)
16JD
enta
l Car
e (JD
E-vo
lutio
n)3.
7,4.
3,5
NAIP
IPr
208-
15
* on
ly im
med
iate
impl
ants
acc
ount
ed in
poo
led
anal
ysis
Stud
y des
ign:
RCT
rand
omize
d co
ntro
lled
trial
, CT
Cont
rolle
d tri
al, O
S =
obse
rvat
iona
l stu
dy; S
ettin
g: In
st=
Inst
itutio
n, P
riv=
Priv
ate
prac
tice;
Follo
w up
: m=m
onth
s;
Impl
ants
: max
=max
illa,
man
=man
dibu
la; M
ean
age:
y=ye
ar; N
R= N
ot R
epor
ted;
mm
=mill
imet
er; T
est g
roup
/con
trol g
roup
: NA=
Not
App
licab
le; T
ype
of p
lace
men
: IP
= Im
med
iate
Pla
cem
ent,
DP=D
elay
ed P
lace
men
t, EP
=Ear
ly P
lace
men
t; Ty
pe o
f pro
visi
onal
izatio
n: IP
r= Im
med
iate
Pro
visi
onal
izatio
n, D
Pr=
Dela
yed
Prov
isio
naliz
atio
n.
2
25
Tabl
e 3.
(con
tinue
d)
auth
ors
reas
on e
xtra
ctio
n
antib
iotic
s
mou
th-
rinse
flap
con-
nect
ive
tissu
e gr
aft
graf
ting
mat
eria
l (T
G/CG
)
biot
ype
prim
ary
stab
ility
(N
/cm
)
dura
tion
tem
pora
ry
prov
isio
n-al
izat
ion
(m
onth
s)
defin
itive
pr
ovis
ion-
aliz
atio
n-m
ater
ial
(PFM
/Cer
)
reta
ined
de
finiti
ve
prov
isio
n-
aliz
atio
n (c
em/s
crew
)
Lind
eboo
m e
t al.
18pe
ri-ap
ical
pat
holo
gyye
s 60
0 m
gye
s
6dye
sNR
Aut
+Bio
GNR
≥25
6NR
cem
Cres
pi e
t al.
19tra
uma,
end
odon
tic
failu
re ,
carie
s,
perio
dont
al fa
ilure
yes
1g
prio
r and
2x
for 1
w
yes
2x
d
15d
yes
in
CG
NRNR
NR≥2
53
PFM
cem
Pala
ttel
la e
t al.
11
root
frac
ture
n=2
en
dodo
ntic
failu
re n
=6
carie
s n=
5 pe
riodo
ntal
failu
re n
=1
agen
esis
n=4
yes
1 g 2
x fo
r 5d
yes
1wye
sNR
NRNR
35NR
PFM
n=1
6
Cer n
=2ce
m/s
crew
De R
ouck
et a
l. 22
toot
h fra
ctur
e n=
14
endo
dont
ic fa
ilure
/ca
ries
n=16
ro
ot re
sorp
tion
n=4
pe
riodo
ntal
failu
re n
=15
yes
500
mg
prio
r and
3x
for 5
d
yes
2xd
2w
yes
NR
BioO
thic
k≥3
56
PFM
cem
BioO
+B
ioG
Bloc
k et
al.
20NR
yes
7dNR
yes
in
CG
NRye
s,
othe
rNR
NR4
PFM
cem
Raes
et a
l. 21
fract
ure
n=13
ca
ries/
endo
dont
ic
failu
re n
=17
root
reso
rptio
n n=
6
perio
dont
al fa
ilure
n=4
ag
enes
is n
=8
yes
500
mg
1h
preo
p an
d 3x
for 5
d
yes
2x 1w
IN n
=9IN
Noth
ick/
thin
NR2
Cer
cem
26
Wöh
rle23
NRNR
NRye
s NR
NRNR
456
NRNR
Groi
sman
et a
l. 24
NRye
s 7d
yes
15
dNR
NRAu
tNR
NR6
Cer
NR
Nort
on25
heal
ed s
ite a
nd
traum
a
root
fract
ure
en
dodo
ntic
failu
re
perio
dont
al fa
ilure
ag
enes
is
yes
3g p
rior
and
250
mg
3x
for 5
d
yes
1wIN
NRNR
NR
254.
5PF
M a
nd
Cer
NR
Tsirl
is26
heal
ed s
ite n
=15
othe
r rea
sons
NR
NRNR
yes
NRot
her+
Bi
oG n
=10
NRNR
6NR
NR
Baro
ne e
t al.
27
NRye
s
1h p
reop
2g
and
1.5g
mg
post
op
yes
2xd
3wno
NRno
NRNR
6PF
MCe
m
Ferr
ara
et a
l. 28
root
frac
ture
yes
1g 2
xd fo
r 1w
yes
1wNR
NRAu
tNR
NR
6PF
MNR
Canu
llo e
t al.
29NR
yes
1g
yes
2wno
NRBi
oO
if ga
p >1
mm
thick
n=
6/
thin
n=3
32-4
54
Cer
NR
Cova
ni e
t al.
30
NRye
s 50
0 m
g 4x
for 4
d ye
sno
yes
NRNR
NR6
NRNR
Kan
et a
l. 31
NRye
sye
sye
s IN
n=
15ye
s IN
n=
11Au
t or
BioO
thic
k n=
10/
thin
n=1
3NR
6PF
MCe
m
Corn
elin
i et a
l. 32
root
frac
ture
, end
-od
ontic
failu
re, c
arie
s,
perio
dont
al fa
ilure
yes
fo
r 8d
yes
2xd
for
2wye
sye
s n=
17Bi
oG IN
NRNR
6NR
NR
Lops
et a
l. 33
endo
dont
ic, c
arie
s le
sion
s, ro
ot o
r cro
wn
fract
ures
NRNR
yes
NRNR
thic
kNR
5PF
MCe
m
2
27
Rom
eo e
t al.
34
endo
dont
ic, c
arie
s le
sion
s, ro
ot o
r cro
wn
fract
ures
NRNR
yes
NRNR
thick
n=
35
thin
n=1
4 n=
9 ex
cl
NR5
PFM
Cem
Cord
aro
et a
l. 36
NR
NRNR
yes
NRNR
thic
k n=
16/
thin
n=1
3NR
NRNR
NR
Canu
llo e
t al.
37
root
frac
ture
n=8
en
dodo
ntic
failu
re/
carie
s n=
17
yes
2g
+ 1g
1h p
rior
chx
0.12
%
2wno
NRot
her I
N
thic
k n=
6/
thin
n=4
th
ick
n=7/
th
in n
=8
32-4
53
PFM
Cem
Cres
pi e
t al.
38
peri-
apic
al p
atho
logy
n=
15
root
frac
ture
s/ c
arie
s n=
15
yes
1g 2
xd fo
r 1w
yes
2x fo
r 15
dye
sNR
NRNR
>25
6PF
MCe
m
Coop
er e
t al.
39
NRIN
yes
yes
in
n=15
NRNR
NR<5
03
Cer
Cem
Tort
aman
o et
al.
40
root
h fra
ctur
e n=
7 en
dodo
ntic
failu
re n
=2
root
reso
rptio
n n=
2
caire
s= n
=1
NRNR
nono
noNR
yes
1.5
PFM
Scre
w
Vale
ntin
i et a
l. 41
Trau
ma,
frac
ture
, en
dodo
ntic
failu
re,
carie
s
Infe
cted
site
n=1
8 ye
s 1g
/14
dye
sye
sNR
BioO
n=
17
NR≥4
03
NRCe
mNo
Infe
ctio
n n=
25
yes1
g/7d
BioO
+ Bi
oG n
=26
Brow
n an
d Pa
yne42
endo
dont
ic fa
ilure
n=3
ca
ries
n=5
toot
h fra
ctur
e n=
19
agen
esis
n=1
yes
only
pre
-op
yes
noNR
NRNR
20-4
52
Cer
Scre
w
28
Chun
g et
al.
43NR
yes
post
- op
yes
2wNR
NRBi
oONR
≥30
6PF
Mce
m/s
crew
Cosy
n et
al.
8
fract
ure
n=10
ca
ries/
endo
dont
ic
failu
re n
=9
root
reso
rptio
n n=
4
perio
dont
al fa
ilure
n=7
yes
1h p
reop
500
mg
and
3x fo
r 5d
yes
2wye
sNR
BioO
norm
al/
thic
k>3
56
PFM
Cem
Kan
et a
l. 44
to
oth
fract
ure
n=15
en
dodo
ntic
failu
re n
=12
root
reso
rptio
n n=
8
yes
500
mg
4xd
yes
noNR
BioO
an
d/or
Bi
oG
n=3
thic
k n=
14/
thin
=21
NR6
PFM
Cem
Mal
chio
di e
t al.
45
traum
a, to
oth/
root
fra
ctur
es, c
arie
s, e
nd-
odon
tic fa
ilure
, roo
t re
sorp
tion,
per
iodo
n-ta
l fai
lure
s,
yes
3g1h
prio
r and
8h
afte
r
yes
prio
r an
d 2x
d af
ter
nono
Aut
thic
k/th
inye
s6
PFM
and
Ce
rCe
m
Pier
i et a
l. 46
ro
ot fr
actu
re, e
nd-
odon
tic fa
ilure
, car
ies,
pe
riodo
ntal
failu
re
yes
2g 1
h pr
ior a
nd
2xd
for1
w
yes
1wno
NRAu
t+
BioO
NR40
4PF
M a
nd
Cer
NR
Tsud
a et
al.
47
NRye
sye
s 2w
yes
yes
BioO
NR25
-35
6Ce
rCe
m
Cabe
llo e
t al.
48fra
ctur
e/no
ferru
le n
=3
carie
s/en
dodo
ntic
n=1
0 in
tern
al re
sopt
ion
n=1
yes
500-
750
mg/
8h/7
d
yes
2x 10
d no
nono
URNR
4PF
M a
nd
Cer
scre
w/c
em
Cosy
n et
al.
10fra
ctur
e n=
11
carie
s n=
9
root
reso
rptio
n n=
2
yes
1,00
mg
2x fo
r 4d
yes
noIN
BioO
NR≥3
56
Cer
cem
/scr
ew
Gran
di e
t al.
49
toot
h fra
ctur
e n=
9 ca
ries
n=14
en
dodo
ntic
failu
re n
=9
perio
dont
al fa
ilure
n=4
yes
1g 1h
prio
r an
d 2x
for 6
d
yes
2x 3
d pr
ior
+ 2x
2w
nono
BioO
NR70
.55
(35-
80)
4PF
Mce
m/s
crew
UR =
Und
er re
porte
d, IN
= If
nec
essa
ry, T
G =
Test
Gro
up, C
G= C
ontro
l Gro
up, A
ntib
iotic
s: D
= d
ays,
W =
wee
k, M
g =
mill
igra
m, G
= g
ram
, Pre
-op
= pr
e op
erat
ive,
Gra
ft-in
g m
ater
ial:
Aut =
Aut
ogen
ou, B
ioG
= Bi
o Gu
ide,
Gei
stlic
h Bi
omat
eria
ls, B
ioO
= B
io O
ss, G
eist
lich
Biom
ater
ials
, Prim
ary
stab
ility
: N/c
m =
New
ton/
cent
imet
ers,
Defin
i-tiv
e pr
ovis
iona
lizat
ion
mat
eria
l: PF
M =
Por
sela
in Fu
sed
Met
al, C
er =
Cer
amic
, Ret
aine
d de
finiti
ve p
rovi
sion
aliz
atio
n: ce
m =
cem
ente
d, s
crew
= s
crew
ed.
2
29
UR =
Und
er re
porte
d, IN
= If
nec
essa
ry, T
G =
Test
Gro
up, C
G= C
ontro
l Gro
up, A
ntib
iotic
s: D
= d
ays,
W =
wee
k, M
g =
mill
igra
m, G
= g
ram
, Pre
-op
= pr
e op
erat
ive,
Gra
ft-in
g m
ater
ial:
Aut =
Aut
ogen
ou, B
ioG
= Bi
o Gu
ide,
Gei
stlic
h Bi
omat
eria
ls, B
ioO
= B
io O
ss, G
eist
lich
Biom
ater
ials
, Prim
ary
stab
ility
: N/c
m =
New
ton/
cent
imet
ers,
Defin
i-tiv
e pr
ovis
iona
lizat
ion
mat
eria
l: PF
M =
Por
sela
in Fu
sed
Met
al, C
er =
Cer
amic
, Ret
aine
d de
finiti
ve p
rovi
sion
aliz
atio
n: ce
m =
cem
ente
d, s
crew
= s
crew
ed.
Tabl
e 3.
(con
tinue
d)
auth
ors
impl
ant
surv
ival
m
argi
nal b
one
loss
ch
ange
in in
ter-
prox
imal
muc
osal
le
vel (
mm
)
chan
ge in
m
idfa
cial
m
ucos
al
leve
l
(mm
)
papi
lla in
dex
0/1/
2/3/
4 M
/D
ging
iva
inde
x
0/1/
2/3
or
KM (m
m)
blee
ding
in
dex
0/1/
2/3
or
scor
e (%
)_
plaq
ue
inde
x
0/1/
2/3
or
scor
e (%
)
prob
ing
dept
h
(mm
)
aest
hetic
s
patie
nt
satis
fac-
tion
(%
)M
ean
(sd)
M/D
(s
d)M
ean
(sd)
M/D
(s
d)
Lind
eboo
m
et a
l. 18
920.
51
M 0
.49
(0.1
1)/
D 0.
53
(0.1
2)NR
NR
0/0/
5/18
/0
NRNR
NRNR
NRNR
100
0.52
M 0
.52
(0.1
6)/
D 0.
52
(0.1
4)
0/0/
7/18
/0
Cres
pi e
t al
. 19
100
1.02
(0
.53)
M 0
.93
(051
)/
D 1.
10
(0.2
7)NR
NRNR
NR7
7NR
NRNR
100
1.16
(0
.51)
M 1.
16
(0.3
2)/
D 1.
17
(0.4
1)
Pala
ttel
la
et a
l. 11
100
0.54
(0
.51)
NR
NR
-0.8
(0
.7)
0/3/
8/7/
0
NRNR
NRNR
NRNR
100
0.46
(1
.01)
NR-0
.6
(0.6
)0/
2/7/
9/0
30
De R
ouck
et
al.
22
960.
86
M 0
.92
(0.4
9)/
D 0.
79
(0.5
4)
0.38
M 0
.44
(0.7
7)/
D 0.
31
(0.8
1)
0.41
(0
.75)
NRNR
40(1
3)16
(15)
3.6
(0.6
1)
NR
VAS
93 (8
2-10
0)
920.
97
M 0
.96
(0.2
5)/
D 0.
97
(0.3
5)
0.48
M 0
.43
(0.4
2)/
D 0.
53
(0.5
5)
1.16
(0
.66)
36(1
3)
17(1
8)3.
27 (0
.53)
VA
S 91
(80-
96)
Bloc
k et
al
. 20
872.
45
M 2
.81
(1.1
3)/
D
2.08
(0
.81)
NR
0.75
NRNR
NRNR
NRNR
NR
972.
57
M 2
.79
(0.9
8)/
D 2.
34
(0.5
7)
0.75
Raes
et
al. 21
940.
85
(0.6
4)NR
0.16
+0.0
7 (0
.99)
/ 0.
38
(1.2
1)D
0.12
(0
.78)
NRNR
83/1
7/0/
085
/11/
4/0
NR
PES/
WES
10
.33
(2.2
9)/
7.2
(2.0
4)
OHI
P 69
.67
(0.6
2)
100
0.65
(0
.79)
NR0.
45
+0.3
(1
.38)
M/
+0.6
(0
.87)
D
1.00
(1
.15)
PES/
WES
10
.35
(1.5
8)
/7.0
0 (2
.37)
OHI
P 67
.39
(6.2
1)
100
0.56
(0
.44)
NR0.
38
+0.6
1 (0
.87)
M/
0.14
(0
.47)
D
0.49
(0
.82)
PES/
WES
10
.11
(1.9
0)
/7.2
2 (1
.86)
OHI
P 68
.00
(4.5
8)
2
31
Wöh
rle23
10
0NR
UR
Not m
ore
>1.0
NRUR
>1
.0 in
n=
2NR
NRNR
NRNR
NRNR
Groi
sman
et
al.
2494
NR
n=85
No
t mor
e >2
.0
n=1
4.0
UR
n=3
>2
.0NR
0/2/
2/82
/0NR
NRNR
NRNR
NR
Nort
on25
96
.40.
24
(nr)
NRNR
NRNR
NRNR
NRNR
NRNR
Tsirl
is26
100
0.75
(1
.05)
NRNR
NRNR
NRNR
NR0.
3 (0
.2)
NRNR
Baro
ne e
t al
. 27
951.
4
(0.3
)NR
NRNR
NR3.
3 (0
.5)
6167
1.6
(0.8
)NR
NR
Ferr
ara
et
al. 28
97
URNR
NRNR
NRNR
NRNR
NRNR
SAQ
Canu
llo e
t al
. 2910
00.
78
(0.3
6)M
0.5
7/
D 1.
01+0
.25
+0.2
NRNR
NRNR
2.8
NRNR
Cova
ni e
t al
. 3010
01.
5
(0.5
)NR
NRNR
NR4.
1 (0.
5)NR
NR3.
0 (0
.8)
NRNR
Kan
et
al. 31
100
UR (n
ot
>1.0
0)NR
NRUR
(n=8
<1
.5)
NRNR
NRNR
NRNR
NR
Corn
elin
i et
al.
3210
00.
7
(nr)
NRUR
(0.2
-0.8
5)NR
0/0/
41/2
7/0
NRNR
NRNR
NRNR
Lops
et
al. 33
10
0DM
NRNR
NRUR
45/1
/0/0
NRNR
NRNR
NR
Rom
eo e
t al
. 3410
0DM
NRNR
NRUR
NRNR
NRNR
NRNR
32
Cord
aro
et
al. 36
97
0.54
(0
.33)
n=15
NRNR
<1 n
=12
>1<2
n=
13
>/ n
=4
NR
3.47
(0
.99)
20
UR
2.57
(0
.87)
n=
15NR
NR0.
63
(0.5
3)n=
14
2.57
(0
.93)
212.
88
(1.0
1)
n=14
Canu
llo e
t al
. 3710
0
0.34
(0
.07)
n=15
NRNR
NRNR
0.98
(0
.11)
1.67
(0
.3)
0.61
(0
.08)
2.80
(0
.21)
NRNR
0.55
(0
.09)
n=10
Cres
pi e
t al
. 38
100
0.86
(0
.54)
n=15
NR0.
20
(0.1
3)NR
0.25
(0
.18)
NR3.
67
(0.6
1)0.
77
(0.3
3)0.
74
(0.2
9)2.
05
(0.6
6)NR
NR0.
82
(0.5
2)n=
15
Coop
er e
t al
. 3994
.51.
18
(1.1
9)NR
UR-0
.35
(0.8
9)NR
DR *
NRNR
NRNR
NR
Tort
aman
o et
al.
4010
0DM
URNR
NRNR
NRNR
NRNR
NRNR
Vale
ntin
i et
al.
41
100
n=10
1,20
n=
10
M 1,
03
(0,9
5)/
D 1,
41
(1,0
2)
n=10
NRNR
2.81
(0.5
)NR
NRNR
NRNR
NR
100
n=10
0,93
n=
10
M 0
,87
(1,1
3)/
D 0,
99
(0,9
9)n=
10
2
33
Brow
n an
d Pa
yne
4292
.9+0
.2
(0.6
)NR
NR0.
2 (0
.99)
M 0
/2/1
8/7/
0 D
0/2/
/12/
13NR
NRNR
NRNR
NR
Chun
g et
al
. 4390
0.31
(0
.34)
NRNR
0.05
(3
.67-
0.94
/ 3.
72/
1.03
)
M 0
/0/1
/8/0
D
0/1/
1/6/
0NR
NRNR
NRNR
NR
Cosy
n et
al
. 896
1.00
(1
.13
M/
0.86
D)NR
NRNR
NRNR
NRNR
PES/
WES
10
.48
(2.4
7)/
8.17
(1
.52)
NR
Kan
et
al. 44
100
0.68
M 0
.72
(0.2
7)/
D 0.
63
(0.2
1)
0.22
M 0
.22
(0.3
4)/
D
0.21
(0
.41)
1.13
(0
.87)
NRNR
NRNR
NRNR
NR
Mal
chio
di
et a
l. 45
100
0.8
(0.6
)NR
0.7
M 0
.6
(0.5
)/
D 0.
8 (0
.6)
0.5
(0
.6)
DRNR
NRNR
NRNR
NR
Pier
i et
al. 46
94.7
n=
20
0.20
(0
.17)
n=20
NR
0.26
n=
20
M 0
.24
(0.2
1)/
D 0.
28
(0.1
9)n=
20
0.61
(0
.54)
n=20
3.86
(0.7
2)n=
20
NRNR
NRNR
NRNR
100
n=20
0.51
(0
.24)
n=20
0.33
n=
20
M 0
.33
(0.1
9)/
D 0.
33
(0.2
3)n=
20
0.73
(0
.52)
n=20
3.84
(0.5
7)n=
20
Tsud
a et
al
. 4790
-0.1
4 (0
.33)
NR
NR2.
25
(1.2
1)NR
NRNR
NRNR
NRNR
34
Cabe
llo e
t al
. 4810
0NR
NR0.
58
M 0
.36
(0.6
)/
D 0.
8 (0
.96)
0.45
(0
.25)
NRUR
NRNR
NRNR
NR
Cosy
n et
al
. 1095
.20.
1 (0.
5)NR
0.35
M 0
.2
(0.5
)/
D 0.
5 (0
.5)
0.2
(0.4
)NR
NRNR
NRNR
NR
PES/
WES
12
.15
(0.9
9)/
8.63
(1
.07)
Gran
di e
t al
. 4997
.20.
51NR
NRNR
NRNR
NRNR
NRNR
NR
DM =
Diff
eren
t Mea
sure
men
ts, I
N =
If Ne
sces
sary
, sd
= st
anda
rd d
evia
tion,
M =
mes
ial,
D =
dist
al, m
m =
mill
imet
er, S
AQ =
Sel
f Adm
inis
tere
d Q
uest
ionn
aire
2
35
36
Figure 1. Flow chart of study selection procedure according to the PRISMA statement.
MEDLINE = 993 EMBASE = 273
COCHRANE = 130 1,396 records identified
through database searching
No additional records identified through other
sources
637 records after duplicates removed
338 records screened
98 full-text articles assessed for eligibility
38 studies included in quantitative synthesis
34 studies included in quantitative synthesis (pooled analysis)
4 studies excluded because the same
patients were studied
4 studies excluded because the same
patients were studied
240 records excluded
Identification
Screening
Eligibility
Included
2
37
Statistical analysis
Pooled analysis
In order to perform a pooled data analysis and to identify potential predictive factors for the outcome
variables, all available study data were re-organized in a new data set. From the included manuscripts, all
available data were individualized after extraction. As such, raw data was obtained from these studies.
Fields that could not be individualized were left empty and censored in the analysis accordingly. All
analyses that could be performed were conducted on an individual patient level. The following predictors
were considered:
1. age, 2. sex, 3. timing of provisionalization (immediate or delayed,) 4. flap (yes or no), 5. connective
tissue graft (yes or no), 6. grafting material (autograft, allograft, xenograft with or without (non) resorbable
membrane), 7. biotype (thick or thin), 8. primary stability (divided in three groups: ≤25, 25-35, ≥35 N/cm), 9.
duration of temporary provisionalization (months), 10. material definitive restoration (ceramic or porcelain
fused to metal (PFM)), 11. screw- or cement-retained definitive crown.
Antibiotic use and the use of mouth rinse were not considered, as either all patients received antibiotics or
mouth rinse, or data were not reported.
95% confidence intervals (95%CI) of the survival proportion were calculated using the Wilson procedure
without continuity correction. It turned out that only data on implant survival and MBL could be
meaningfully combined into the pooled data analysis. Regarding the other variables, insufficient data was
available. Risk factors (Odds Ratio, OR) for implant survival (yes/no) were analyzed by multiple binary
logistic regression analysis. All factors with a p-value <0.10 were considered in the multiple model using a
backward elimination strategy. MBL was categorized into two groups: ≤0.50 mm and >0.50 mm bone loss.
For this outcome variable, also univariate binary logistic regression analysis was applied. Multivariable
regression analysis was not performed, as too few variables were available. Regarding IML and MML, too
few data was available to perform a regression analysis. A p-value <0.05 mm was considered to indicate
statistical significance. Missing data were censored in all analysis. All data analysis was performed with the
IBM SPSS, version 20.0.
38
Table 4. Characteristics of included studies.
N (median) % (range)
Total number of implants assessed 985 100
Survival of implants 956 97
Age of patients (46) (35-65)
Sex • Male • Female • NR
985 361 364 260
100 36.6 37.0 26.4
Mean follow up (months) (18) (12-48)
Provisionalization • Immediate • Delayed
985 752 233
100 76.3 23.7
Antibiotic use • Yes • No • NR
985 752 0 233
100 76.3 0 23.7
Mouth rinse use • Yes • No • NR
985 875 0 110
100 88.8 0 11.2
Flap • Yes • No • NR
985 355 384 246
100 36.0 39.0 25.0
Connective tissue graft • Yes • No • NR
985 40 90 855
100 4.1 9.1 86.8
Grafting material • Autogenous • BioOss • BioOss + Bioguide • Autogenous+ BioOss • Autogenous+ BioGuide • Other • No • NR
985 192 158 34 64 25 86 89 337
100 19.5 16.0 3.5 6.5 2.5 8.7 9.0 34.2
2
39
Biotype • Thick • Thin • NR
985 222 30 732
100 22.5 3.0 74.3
Primary Stability (Ncm) • ≤25 • 25<>35 • ≥35 • NR
985 111 64 306 481
100 11.3 6.5 31.1 48.8
Mean duration of temporary provi-sionalization (months) (6) (2-6)
Definitive crown material • Ceramic • PFM • NR
985 220 490 275
100 22.3 49.7 27.9
Type of definitive crown • Cement-retained • Screw-retained • NR
985 602 41 342
100 61.1 4.2 34.7
NR = not reported
40
Table 5. Risk factors for implant survival and marginal bone level change >0.50 mm.
implant survival marginal bone level change >0.50 mm
OR CI (95%) P OR CI (95%) P
Provisionalization (reference: immediate) 1.50 0.57-3.99 0.41 58.03 8.05-418.41 0.00
Flap 0.83 0.33-2.06 0.69 19.87 10.21-38.66 0.00
Connective tissue graft 0.89 0.08-10.07 0.92 4.56 1.72-12.08 0.002
Material (reference: autogenous) • BioOss • BioOss + Bioguide • Autogenous+ BioOss • Autogenous+ BioGuide • Other • No
1.33 0.70 2.74 0.50 1.20 1.89
0.43-4.15 0.14-3.43 0.34-22.33 0.1-2.50 0.31-4.65 0.39-9.09
0.78 0.62 0.66 0.35 0.40 0.79 0.3
0.25 NA 0.00 NA 0.24 NA
0.12-0.50 NA NA NA 0.51 NA
0.012 0.00 NA NA NA NA NA
Biotype (reference: thick) 1.20 0.14-10.00 0.87 4.23 0.26-70.16 0.32
Primary stability (ref ≤25 N/cm) • 25<>35 • ≥35
0.57 0.49
0.08-4.14 0.11-2.26
0.66 0.58 0.36
0.01 0.17
0.01-0.04 0.08-0.34
0.00 0.00 0.00
Material Definitive crown (reference: ceramic) 2.12 0.95-4.72 0.07 1.29 0.81-2.05 0.28
Way of connecting Definitive Provisionalization (reference: cement-retained)
0.50 0.11-2.26 0.37 0.01 0.00-0.03 0.00
OR = Odds Ratio CI = Confidence Interval
2
41
Results
Study inclusion
The MEDLINE, EMBASE and Cochrane CENTRAL searches resulted in 993, 273 and 130 hits, respectively.
Figure 1 outlines the flow chart according to the PRISMA statement. After extracting duplicate citations,
637 publications remained to be screened. After screening of titles and abstracts, 98 publications were
selected for full-text analysis. Screening of bibliographies of relevant reviews and selected publications
revealed no additional publications. Of the 98 publications, 61 were excluded after full-text analysis and
quality assessment. Two disagreements occurred which were easily resolved in a consensus meeting. This
led to 38 studies available for initial analysis. Four studies15-17,35 were excluded from the pooled analysis
as the same patient population was described (only the study with the longest follow-up was used). In the
final pooled analysis, 34 studies were considered eligible for pooled analysis (Tables 2 and 3). Of these, 5
were RCTs11,18-20,22, 1 CT21 and 28 were observational studies8,10,23-34,36-49 .
Patient characteristics
In the pooled analysis of 34 studies, 985 implants in 979 patients were analyzed. Characteristics are shown
in Table 4. Median age in the studies considered was 46 years (range 35-65 years). Median follow-up was
18 months (range 12-48 months). Most patients underwent immediate provisionalization (76.9%).
Risk factors for implant survival
Out of 985 implants, 956 survived (97.1%, 95%CI 0.958-0.980) (Table 4). After multiple analysis (Table 5),
no variables were significantly associated with survival.
Risk factors for changes in marginal peri-implant bone level (MBL)
A mean marginal bone loss of 0.81±0.48 mm was identified after at least 12 months follow-up. Univariate
regression analysis (Table 5) showed that delayed provisionalization was significantly associated with
bone loss >0.50 mm (OR 60.2, 95%CI 8.36-434.04, p<0.001). Also, the use of a flap (OR 20.3, 95%CI 10.52-
39.65, p<0.001) and connective tissue graft (OR 4.56, 95%CI 1.72-12.08, p< 0.001) were both significantly
associated with marginal bone loss >0.50 mm. In addition, primary stability of >25 N/cm (25-35 N/cm: OR
0.01, 95%CI 0.01-0.04, p<0.001, >35N/cm: (OR 0.16, 95%CI 0.08-0.34, p<0.001) and the use of a screw-
retained instead of a cement-retained provisional crown (OR 0.01,95%CI 0.00-0.04, p<0.001) were both
strongly associated with marginal peri-implant bone loss <0.50 mm.
Mean changes in peri- implant soft tissue
Mean loss of interproximal (IML) and midfacial mucosa level (MML) was 0.38±0.23 mm and 0.54±0.39 mm
after at least 12 months follow-up, respectively.
42
Discussion
Survival of immediately placed implants was excellent with 97% after at least one year follow-up and
comparable with previously published survival rates.12 Timing of provisionalization was not associated with
outcome in terms of implant survival. These are important results, underlining the advantage of immediate
provisionalization as survival rates of implants were not inferior to those of delayed provisionalization.
Regarding risk factors for MBL, immediate provisionalization was associated with bone level change of
<0.50 mm, which is, to our opinion, a clinically relevant observation. From this, it may be concluded that
micromotion is possibly not as important as previously thought in terms of MBL loss. Furthermore, the
use of a flap and connective tissue graft was also significantly associated with a MBL change of >0.50
mm, thereby confirming a recent observation that the use of a flap should be avoided when possible.27
When an implant site does not need a complementary connective tissue graft during the installation of
the dental implant, favorable conditions are probably already present. It is hypothesized that immediate
provisionalization, as was performed in the majority of cases included in this review, without a flap or
connective tissue graft, is associated with less MBL. In future studies, not only MBL should be taken
into account, but also buccal bone level (BBL) change. The presence or absence of buccal bone may
influence final outcome. The pre-operative surgical site is not always suitable for immediate placement
and provisionalization as well as that there are clinical conditions in which immediate placement is not
an optimal treatment option, e.g. in (severely) inflamed areas or in medically compromised patients. In
such cases, the surgical site is usually optimized by the use of a flap or connective tissue graft or special
precautions have to be taken. However, the reasons for extraction of the tooth to be replaced were mostly
underreported. Obviously, the pre-operative condition of the peri-implant tissues is of critical importance
for the definitive result of the implant. The mean calculated MBL is in line with other studies17,21,22, as well as
the calculated interproximal mucosa level (IML) and midfacial mucosa level (MML)16,17.
It was not possible to analyze the role of antibiotics and mouth rinse in this study as antibiotics were used
in all included studies or its use was not reported. In addition, the included studies used different types
and schedules of antibiotics. Whether or not to use antibiotics in single implant placement obviously is
an important topic of discussion as the use of antibiotics in a healthy population has never proven its
benefits.50 Further research regarding the need for antibiotics when placing implants in healthy subjects is
warranted.
Some limitations of the present study have to be addressed. It was not possible to analyze all data on an
individual patient base, as a lot of data were not available in the studies considered eligible for this review.
Regarding MBL, a cut-off value of 0.50 mm was taken. One could discuss whether this is appropriate. It
was not possible to use it as a continuous variable as differences were too small to perform a reliable
regression analysis. Also, as individual patient data were not available, a cut-off value on basis of the
results could not be calculated. In the literature, no studies have been performed in this way, so this item
is open for discussion. To our opinion, a cut-off value of 0.50 mm makes sense as only this difference in
height is possible to measure in clinical practice and can be seen on plain dental radiographs. As multiple
analysis could not be performed, we cannot exclude that some variables significant after univariate
analysis, are not associated with MBL if correction had been possible. Also, as measurements of mucosal
2
43
level changes were not standardized, the reported data in the included studies have to be interpreted
carefully, as it is not always clear how measurements took place.
Another important issue is the patient population studied. Individual patient factors such as presence of
diabetes or other co-morbidities are very relevant in clinical practice, but medically compromised patients
had been excluded in all included studies to obtain “clean results”. The same holds true for smoking
(only non-smoking patients were included in the various studies). For clinical practice, these factors are
important when it comes to implant survival rates and dimensions of the hard and soft tissues in the
aesthetic zone. The results of the present study which is based on a systematic review of the available
literature should, therefore, be interpreted with caution. Nevertheless, the present results may have
some important implications for clinical practice. An important current issue is the gaining interest in
patient satisfaction. In view of this, immediate placement and provisionalization in the aesthetic zone
has some important advantages: the patient immediately benefits from this treatment method which can
substantially have a positive impact on the patient’s quality of life. Thus, aesthetic indexes and patient
satisfaction scales have to be applied, in addition to the already used treatment outcome parameters,
in future studies assessing the treatment outcome of immediate placement of dental implants in the
aesthetic zone.
Conclusion
Immediate placement with immediate provisionalization of dental implants in the aesthetic zone results in
an excellent short-term treatment outcome in terms of implant survival and minimal change of peri-implant
soft and hard tissue dimensions.
44
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48
3
49
3Feasibility of immediate placement
of single-tooth implants in
the aesthetic zone:
a 1-year randomized controlled trial.
This chapter is an edited version of the manuscript:Slagter KW, Meij er HJ, Bakker NA, Vissink A, Raghoebar GM.
Feasibility of immediate placement of single-tooth implants in the aesthetic zone: a 1-year randomized controlled trial. J Clin Periodontol 2015; 42: 773–782.
50
Abstract
Aim:
to assess whether outcome of immediate implant placement and immediate
provisionalization after one year was non-inferior to immediate implant placement and
delayed provisionalization regarding Marginal Bone Level (MBL).
Materials and Methods:
Forty patients with a failing tooth in the aesthetic zone were randomly assigned
for immediate implant placement with immediate (n=20) or delayed (n=20)
provisionalization. Follow-up was at 1 month and after one year. The study was powered
to detect a difference in MBL of <0.9 mm. Apart from MBL, soft tissue peri-implant
parameters, aesthetic indexes and patient satisfaction were assessed. (www.isrtcn.com:
ISRCTN57251089)
Results:
After one year, MBL changes were 0.75±0.69 mm mesially and 0.68±0.65 mm distally
for the immediate group and 0.70±0.64 and 0.68±0.64 mm for the delayed group,
respectively. Regarding differences in means, non-inferiority was observed after 1 year
(mesially: Immediate vs. Delayed: difference in mean 0.08 mm (95%CI -0.38 to 0.53,
p=0,71), distally: Immediate vs. Delayed: difference in mean 0.09 mm (95%CI-0.37 to 0.56
mm, p=0.66)). No significant differences in the other outcome variables were observed.
Conclusion:
This study showed that immediate placement and immediate provisionalization was non-
inferior to immediate placement with delayed provisionalization. In addition, although not
powered for these outcome variables, no clinically relevant differences in other outcomes
were observed.
3
51
Introduction
Traditionally, placement and restoration of dental implants is a process involving a long period1, therefore
the quest for a shorter treatment period is imminent. Currently, there is a growing tendency to place single
tooth implants in the aesthetic zone immediately after extraction of a failing tooth, preferably combined
with immediate provisionalization.2,3 This tendency is probably related to evolving society factors, with
more demanding patients and a wish for direct treatment. Innovations in implant surfaces and designs
have facilitated the possibilities for such an approach.4 In view of these developments, immediate
placement and provisionalization of implants is nowadays presumed to be a reliable treatment option for
single tooth implants in the aesthetic zone.5,6
In line with this presumption, in a systematic review and pooled analysis7, it was demonstrated that
immediate placement with immediate provisionalization of dental implants in the aesthetic zone resulted
in an excellent short-term treatment outcome in terms of implant survival. Besides implant survival,
establishment and maintenance of healthy hard and soft peri-implant tissues are crucial too, particularly in
the aesthetic zone.8,9 Therefore, the interest in hard and soft tissue dynamics related to immediate single
tooth implant placement in the aesthetic zone increased.10,11
To objectively rate implant-based aesthetics, a number of aesthetic indexes has been developed including
the Implant Crown Aesthetic Index (ICAI)12; the pink aesthetic score (PES)13, and the white aesthetic score
(WES)14,15. To rate the opinion of the patients themselves patient-centered outcomes as the Visual Analogue
Scale (VAS)16 and Oral Health Impact Profile (OHIP)17 have been developed.
Inherent to the shift in interest to patient-centered outcomes, few studies have yet been conducted in
which outcome measures are systematically assessed.18,19 Currently, to the best of our knowledge, no
randomized clinical trials assessing the full panel of outcome measures, including changes in the hard
and soft tissue dimensions, implant survival, aesthetic evaluation and patient-centered outcome in the
aesthetic zone, have been published. Therefore, the aim of this randomized controlled trial was to assess
whether outcome of immediate implant placement and immediate provisionalization after one year was
non-inferior to immediate implant placement and delayed provisionalization regarding MBL. Our null
hypothesis stated that the difference in means of MBL between the two treatment groups would be greater
or equal to 0.9 mm. Soft peri-implant tissues, aesthetics and patient-centered outcomes in the aesthetic
zone were also assessed.
Materials and methods
Study design
All consecutive patients (age ≥ 18 year) with a failing tooth in the maxillary aesthetic zone (incisor, canine
or first premolar) referred to the department of Oral and Maxillofacial Surgery between January 2010 and
January 2012 for single tooth implant treatment, were considered if adequate oral hygiene and sufficient
space were present and when eligible asked to participate in this randomized clinical trial (Figure 1 and
2). The size of the bone defect was assessed after extraction of the failing tooth. The shape of the osseous
defect was checked by a bone sounding technique with a periodontal probe at the midfacial, the mesial,
52
and distal aspect of the failing tooth, and the mesial and distal aspect of the immediately adjacent teeth.
The patient was only included in the present study if the buccal socket wall had a bony defect of <5 mm in a
vertical direction. For allocation to a group determined by the bony defect, a computerized random number
generator was used. A research-nurse not involved in the study blindly allocated the patients to:
- Group A : immediate placed implant (NobelActive, Nobel Biocare AB, Goteborg, Sweden) and
immediate provisionalization;
- Group B: immediate placed implant (NobelActive, Nobel Biocare AB, Goteborg, Sweden) and delayed
provisionalization.
Informed consent was obtained from all patients. The study was approved by the local medical ethical
committee (NL32240.042.10) and registered in a trial register (www.isrtcn.com: ISRCTN57251089).
Surgical protocol
Preoperatively, patients started prophylactic antibiotic therapy (amoxicillin 500mg t.i.d. for 7 days
or clindamycin 300mg q.i.d. in case of amoxicillin allergy). Oral disinfection composed of a 0.2%
chlorhexidine mouthwash, twice daily for 7 days.
All surgeries were performed under local anesthesia. First, the attached periodontal ligament from the
failing tooth was carefully detached by an incision in the sulcus. Periotomes were used to extract the failing
tooth atraumatically. No mucoperiosteal flap was raised. The implant site was prepared on the palatal side
of the alveolus following the protocol of the manufacturer using a surgical template based on the ideal
position of the prospective implant crown. The last used burr, depending on the diameter of the implant,
was placed in the prepared alveolus. The remaining space between the burr and the peri-implant bone was
locally augmented. As grafting material, autogenous bone from the retromolar–ramus area was gathered
using a bonescraper (Bonescraper, Biomet 3i, Warsaw, Indiana, USA) 1:1 mixed with anorganic bone
(Geistlich Bio-Oss, Geistlich Pharma AG, Wolhusen, Switzerland). Regarding the corono-apical position of
the implants, the shoulder of the implant was placed at a depth of 3 mm apical to the most apical aspect of
the prospective clinical crown, with help of a surgical template.
Group A : immediate placed implant and immediate provisionalization
An implant-level impression was made immediately after implant placement. After the impression, a
corresponding healing abutment was placed. In the dental laboratory, a screw-retained provisional crown
was fabricated by means of an engaging temporary abutment and composite. The provisional restoration
was free from centric and eccentric contacts with the antagonist teeth. Approximately 6 hours following
implant placement, the healing abutment was removed, and the provisional crown was screwed directly
onto the implant with 20 Ncm by a manual torque wrench (Manual Torque Wrench Prosthetic; Nobel Biocare
AB).
Group B: immediate placed implant and delayed provisionalization.
immediately after implant placement a corresponding cover screw was placed. Following a standard
protocol20 for an optimal aesthetic outcome, a free oval full thickness soft-tissue graft was punched and
harvested from the palatal mucosa. The diameter of the punch was 2 mm larger than the socket access.
3
53
Figure 1. Cohort flow diagram.
Enrollment Assessed for eligibility (n=40)
Excluded (n=0) • Not meeting inclusion criteria (n=0) • Declined to participate (n=0) • Other reasons (n=0)
Allocated to intervention (n=20) • Received allocated intervention (n=20) • Did not receive allocated interven tion (give reasons) (n=0)
Lost to follow-up (give reasons) (n=1, patient did not show up at appointments) Discontinued intervention (give reasons) (n=0)
Analysed (n=19) • Excluded form analysis (give reasons) (n=0)
Allocated to intervention (n=20) • Received allocated intervention (n=20) • Did not receive allocated interven tion (give reasons) (n=0)
Lost to follow-up (give reasons) (n=0) Discontinued intervention (give reasons) (n=0)
Analysed (n=20) • Excluded form analysis (give reasons) (n=0)
Randomized (n=40)
Allocation
Follow-Up
Analysis
54
That 2 mm of epithelium was removed from soft tissue graft. The 2 mm zone of the soft tissue graft denuded
from epithelium was located beneath the mucosa at the recipient site. This was done to facilitate closure
and healing of the grafted area. The graft was sutured with Ethilon 5-0 (Johnson & Johnson, Amersfoort, The
Netherlands) on top of the reconstructed socket. During the three months osseointegration phase, patients
were allowed to wear a removable partial denture not interfering with the wound. After three months,
the implant was uncovered by a small incision at the site of the cover screw, followed by an implant-level
impression according to the procedure described in group A. All surgical procedures were performed by one
experienced oral and maxillofacial surgeon (GR).
Prosthetic protocol
A final open tray impression using polyether impression material (Impregum Penta, 3M ESPE, Seefeld,
Germany) was taken at implant level after a provisional phase of 3 months in both groups. In the dental
laboratory, a digital design of the definitive crown was made to the desired form of the abutment. The digital
design was used to retrieve individualized zirconia abutments (NobelProcera, Nobel Biocare AB). Depending
on the location of the screw access hole, the final crown was either a cemented-retained or screw-retained
zirconia crown (Procera, NobelBiocare AB). Abutment screws were torqued with 32 Ncm. Cement-retained
crowns were cemented with glass ionomer cement (Fuji Plus, GC Europe, Leuven, Belgium). All prosthetic
procedures were performed by one experienced prosthodontist (HM).
Outcome measures
Primary outcome measure of this study was the change in marginal peri-implant bone level (MBL) proximal
to the implant, 12 months after placement of the definitive crown on the mesial and the distal site.
Secondary outcome measures included implant survival, change in interproximal peri-implant mucosa
(IML) and change in midfacial peri-implant mucosal level (MML) as compared with the gingival level of
the pre-operative failing tooth. Furthermore, papilla volume, biotype prior to removal of the tooth, health
of keratinized gingiva, amount of plaque, amount of bleeding and pocket probing depth were assessed.
Aesthetic outcome was assessed by means of objective indexes (ICAI, PES/WES). Patients’ satisfaction was
assessed using the Oral Health Impact Profile (OHIP) index and the Visual Analogue Scale (VAS) on a 0-10
scale.
Radiographic assessments
To calculate changes in MBL, a standardized digital peri-apical radiograph was taken with an individualized
aiming device21, pre-operatively (Tpre), immediately following implant placement (baseline, T0), one month
(T1), and twelve months (T12) after definitive crown placement. The vertical distance from the shoulder
of the implant to the first-bone-to-implant contact was measured at the distal and mesial site of the
implant. The radiographs of T1 and T12 were analyzed using the known implant diameter as a reference.
The manufacturer provided the exact dimension of the implants used. Measurements were independently
performed by two examiners (KS and Harry Slagter), after which the average of both measurements was
used.
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55
Survival rate
Survival rate was defined as the percentage functional implants one year after definitive crown placement
in both groups. The criteria for successful osseointegration according to Smith & Zarb (1989) were adapted.
Photographic assessments
Before implant placement (Tpre) and after placement of the definitive crown standardized digital
photographs (Nikon D300s, Nikon Corporation,Yurakucho, Tokyo, Japan) were taken at T1 and T12 using
a technique as described earlier.21 A manual periodontal probe (Williams Color-Coded probe; Hu-Friedy,
Chicago, IL, USA) was held in close proximity and parallel to the long axis of the adjacent tooth. The known
dimensions of the periodontal probe allowed for calibration of the photographs. Full screen analysis of the
photographs was performed using a digital picture editing program (Keynote, Apple Inc, Cupertino, CA,
USA). The changes in IML and in MML were compared with the original gingival level of the failing tooth.
These measurements were independently performed by two examiners (KS and Harry Slagter) after which
the average of both measurements was used.
Clinical assessments
The following clinical variables were assessed at T1 and T12 both at the implant and adjacent teeth before
implant placement (Tpre) and after finalization of the definitive crown:
- Papilla volume: assessing the mesial and distal papilla adjacent to the implant using the papilla
index22;
- Amount of plaque: assessed at four sites per implant/adjacent tooth (mesial, buccal, distal and
palatinal) using the modified plaque index23;
- Amount of bleeding: using the modified sulcus bleeding index23;
- Gingiva: using the gingival Index24;
- Probing pocket depth: assessed at four sites per implant/adjacent tooth (mesial, buccal, distal and
palatinal) using a manual periodontal probe (Williams Color-Coded probe; Hu-Friedy, Chicago, IL, USA)
measuring to the nearest 1 mm.
All data were retrieved by one blinded examiner (KS).
Aesthetic assessments
The aesthetic outcome was assessed on standardized digital photographs (Nikon D300s, Nikon
Corporation) taken at Tpre and T1, and T12 in both groups. An additional photograph was taken of implant
crowns replacing the lateral or canine capturing the contra lateral tooth. Peri-implant mucosa and implant
crown aesthetic outcomes were determined using ICAI12 and PES-WES14. Measurements were independently
performed by two examiners (KS and Diederik Hentenaar).
Patients’ satisfaction
Patients’ satisfaction was assessed at T1 and T12 using the validated OHIP-14 questionnaire.17 Overall
satisfaction compared to Tpre was questioned using a 100-mm VAS scale.16
56
Figure 2A. Schedule of visits and procedures study group A: immediate placement and
immediate provisionalization.
Inclusion
Prosthetic phase
Healing phase
Follow-up phase
Pre-operative TPre
Screening and Measurements
Extraction &
Implant placement
& Immediate
provisionalization
Definitive crown and Follow-up
Follow-up
Day 0 (T0)
3 months (T3)
12 months (T12)
15 months (T15)
3
57
Figure 2B. Schedule of visits and procedures study group A: immediate placement and
delayed provisionalization.
Inclusion
Prosthetic phase
Healing phase
Follow-up phase
Pre-operative TPre
Screening and Measurements
Extraction &
Implant placement
& Delayed
provisionalization
Second phase surgery
& Provisional crown
Definitive crown and Follow-up
Follow-up
Day 0 (T0)
3 months (T3)
6 months (T6)
12 months (T12)
18 months (T18)
58
Statistical analysis
For determination of the sample size, G*power version 3.1 was used.25 A radiographic MBL of <0.9 mm (SD
1 mm) after 12 months of definitive crown placement was regarded as a relevant difference between study
groups5. With an expected effect-size of 0.9 mm, an alpha of 0.05 and a power of 0.80, 38 patients were
required, 19 in each group. 40 patients were included to deal with possible redrawal.
Shapiro-Wilk test, together with normality plots were used to assess normal distribution of the continuous
variables. Differences between groups were evaluated by one-way analyses of variance (ANOVA) for
continuous data and by Fisher’s exact test or chi-Square test for categorical data. Regarding MBL, T-tests
for equality of means with associated confidence intervals (CI) were calculated. If the difference of 0.9
did not pass the 95% CI borders, non-inferiority was considered established. In case of uncertainty of
the significance because of the relatively small number of patients analysed and the large number of
outcomes, Bonferroni correction was considered in case of a p-value 0.01<>0.05. Inter- and intra-examiner
measurements were repeated twice by two independent observers in a random order. A p-value of 0.05 was
considered to indicate statistical significance. All analyses were performed using SPSS (PASW Statistics
20.0, SPSS Inc.; IBM Corporation, Chicago, IL, USA).
Results
Inter- and intra-observer correlation
Measurements were repeated twice by two independent observers in a random order. For the radiographic
assessment, the interobserver intraclass correlation coefficient was 0.88 (95CI 0.83-0.92). The intraobserver
intraclass correlation coefficient was 0.89 (95CI 0.83- 0.97) for observer one and 0.83 (95CI 0.80-0.95) for
observer two. For the photographic assessment, the interobserver intraclass correlation coefficient was
0.93 (95CI 0.88-0.98). The intra-observer intraclass correlation coefficient was 0.93 (95CI 0.87- 0.96) for
observer one and 0.90 (95CI 0.88-0.96) for observer two. For ICAI and PES-WES, the interobserver intraclass
correlation coefficient were 0.88 (95CI 0.77-0.94) and 0.87 (95CI 0.75 -0.94), respectively. The reliability from
all different assessments proved to be acceptable.
Patients
Baseline and clinical characteristics of groups A (n=20) and B (n=20) as well as details on surgical and
prosthetic procedures are depicted in Table 1 and Figures 3 and 4. One patient in group B was lost to follow
up immediately after definitive crown placement. All patients received their assigned treatment.
Change in marginal bone level
Table 2 shows the mean MBL changes at the mesial and distal site after twelve months in relation to the time
point of connecting the definitive crown. Regarding differences in means, non inferiority was observed (at a
level of 0.9 mm), both after 3 months (mesially: Group A vs. B: difference in mean 0.02 mm (95%CI -0.42 to
0.46 mm, p=0.64, distally: Group A vs. B: difference in mean 0.06 mm (95%CI -0.40 to 0.52 mm, p=0.66) as
well as after 1 year (mesially: Group A vs. B: difference in mean 0.08 mm (95%CI -0.38 to 0.53 mm, p=0.71,
distally: Group A vs. B: difference in mean 0.09 mm (95%CI -0.37 to 0.56 mm, p=0.66).To analyze the uneven
3
59
Table 1. Baseline characteristics and treatment specifications per study group.
Variable Group A (n=20)
Group B (n=20)
Mean age ±sd (range) 39.4±16.9 (19-70) 42.3±14.2 (23-66)
Male/female 5/15 8/12
Implant site location I1/I2/C 7/8/5 13/6/1
Cause of tooth loss • Fracture (crown or root) • Agenesis • Caries • Endodontic failure • Periodontal failure • Root resorption
7 6 0 2 0 5
10 0 1 6 0 3
Bone defect mean±sd (mm) 3.40±1.19 4.21±1.08
Length implant (mm) 13/15/18 2/16/2 2/9/9
Diameter (mm) 4.3/ 3.5 12/8 15/5
Type of final restoration • Screw-retained • Cement -retained
14 6
12 8
60
distribution of the agenesis patients (6 vs. 0, see Table 1) additional analyses were performed, comparing
both groups with the agenesis patients excluded, as well as an a analysis in group A comparing the
differences between the agenesis patients and other patients, showing no significant differences between
both groups (data not shown).
Survival rate
No implants were lost during the study resulting in an implant survival rate of 100% at one year after
placement of the definitive crown for both groups.
Change in interproximal and midfacial peri-implant mucosal level
Table 2 shows the soft tissue level changes from the pre-operative situation up to 12 months after
placement of the definitive crown at the mesial, distal and mid-facial site. Again, the largest IML change
was observed early after placement of the definitive crown, with an observed statistical significant,
persisting difference with regard to the mesial papilla in both groups (0.89±0.46 mm (immediate) and
0.32±0.43 mm (delayed), p<0.001). Between the 1 and 12 months evaluation, only minor, non-significant
changes were observed with regard to IML and MML.
Clinical outcome
The health of the keratinized gingiva remained stable, and the plaque and bleeding indexes remained low
throughout the study period (Table 3). Even at one year of follow-up no plaque was seen in both groups.
Pocket probing depth remained stable for both groups on all four measured sites: mesial, distal, buccal
and palatal.
Aesthetic assessments
The ICAI and PES/WES scores are shown in Table 2. After one year, an acceptable clinical ICAI and PES/
WES outcome was seen in 94% patients of both groups A and B. The total aesthetic outcome was mainly
influenced by the appearance of the implant crown (WES) and to a lesser extent by the peri-implant mucosa
(PES). A positively significant difference in aesthetic outcome was measured over time within each group.
No significant difference was measured between both groups.
Patients’ satisfaction
At the first follow-up visit after definitive crown placement, no significant differences between both
groups were observed. After one year, however, VAS scores were 8.2±0.9 and 9.1±0.8 for groups A and B,
respectively (p<0.002). Regarding the OHIP-14 (Table 4), no statistical significances were observed between
both groups one year after definitive crown placement.
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61
Table 2. Changes regarding marginal bone level, marginal soft tissue level and aesthetic evaluation from pre-operative (Tpre), one month (T1) to 12 months (T12) after definitive crown placement.
Tpre Tpre P-value T1 T1 P-value T12 T12 P-value
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Variable
Group A
Group B
Group A
Group B
Group A
Group B
Marginal bone level in mm(±sd)
Mesial of implant 0.70 (±0.67)
0.68 (±0.64) 0.92 0.75
(±0.69)0.68 (±0.65) 0.73
Distal of implant 0.69 (±0.71)
0.64 (±0.63) 0.80 0.70
(±0.64)0.68 (±0.64) 0.68
Marginal soft tissue level changes in mm (±sd)
Mesial of implant 0.90 (±0.45)
0.44 (±0.45) 0.003 0.89
(±0.46)0.32 (±0.43) 0.001
Distal of implant 0.44 (±0.45)
0.78 (±0.67) 0.54 1.00
(±0.58)0.79 (±0.66) 0.33
Mid-facial of implant 1.15 (±0.81)
0.78 (±0.86) 0.18 0.95
(±0.62)0.85 (±0.86) 0.71
PES 7.00 (2.05)
6.90 (1.32) 0.63 7.80
(1.66)7.40 (1.59) 0.71 7.50
(1.59)7.40 (1.46) 0.79
WES 5.00 (2.33)
5.40 (1.65) 0.70 7.99
(1.73)7.60 (1.09) 0.68 8.10
(0.90)7.90 (1.08) 0.79
PES/WES 11.60 (3.33)
11.10 (3.46) 0.43 16.20
(2.20)15.10 (1.71) 0.38 15.80
(2.05)15.30 (2.11) 0.50
ICAI 9.6 (06.54)
14.10 (8.57) 0.23 3.80
(2.18)6.20 (3.94) 0.35 4.20
(2.38)5.2 (4.10) 0.37
62
Figure 3. Immediate implant treatment with immediate provisionalization.
a Clinical situation pre-operative.
b. Pre-operative radiograph.
c. Clinical situation post-operative after one year.
d. Post-operative radiograph after one year.
3b
3a
3c
3b
3d
3
63
Figure 4. Immediate implant treatment with delayed provisionalization.
a Clinical situation pre-operative.
b. Pre-operative radiograph.
c. Clinical situation post-operative after one year.
d. Post-operative radiograph after one year.
3b
4a
4c
4b
4d
64
Table 3. Clinical outcome measures from pre-operative to 12 months after definitive crown placement.
Tpre Tpre P-value T1 T1 P-value T12 T12 P-value
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Variable
Group A
Group B
Group A
Group B
Group A
Group B
Papilla volume (papilla index 0/1/2/3/4)
Mesial 1.95 (1.10)
1.95 (0.85) 0.99 2.16
(0.83)2.37 (0.60) 0.38 2.35
(0.81)2.67 (0.77) 0.23
Distal 2.05 (0.99)
1.68 (0.67) 0.19 2.37
(0.76)2.00 (0.67) 0.12 2.45
(0.76)2.28 (0.75) 0.49
Health of gingiva (gingival index (0/1/2/3)
0.00 (0.00)
0.00 (0.00) NA 0.90
(0.31)0.79 (0.42) 0.35 0.80
(0.70)0.94 (0.24) 0.41
Amount of plaque (plaque index)
0.10 (0.31)
0.05 (0.23) 0.59 0.00
(0.00)0.05 (0.23) 0.31 0.00
(0.00)0.00 (0.00) NA
Bleeding after probing (bleeding index)
0.75 (0.55)
0.68 (0.58) 0.71 0.60
(0.60)0.47 (0.61) 0.52 0.25
(0.44)0.22 (0.43) 0.85
Pocket probing depth (mm)
Mesial 2.70 (0.80)
2.44 (0.71) 0.31 3.50
(0.83)3.21 (0.71) 0.25 2.95
(0.76)3.11 (0.32) 0.41
Distal 2.85 (1.09)
2.61 (0.70) 0.43 3.15
(0.49)3.21 (0.92) 0.80 3.05
(0.61) 3.50 (0.71) 0.41
Buccal 1.60 (0.75)
1.89 (0.96) 0.31 2.65
(1.42)2.79 (0.86) 0.72 3.05
(0.83)3.00 (0.59) 0.83
Palatal 1.65 (0.81)
2.06 (0.80) 0.13 2.30
(0.66)2.79 (0.42) 0.18 2.90
(0.55)2.89 (0.32) 0.94
NA = not applicable
3
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66
Table 4. OHIP scores from one month to one year of functioning.
Mean OHIP-14 Group A Group B
T0 –T1 P-value
Group A Group B
T1-T12 P-value
Variable
never/hardly ever/occasionally/fairly often/very often
never/hardly ever/occasionally/fairly often/very often
Question 1 Have you had trouble pronouncing any words because of problems with your teeth, mouth or dentures?
0/18/0/2/0 0/17/0/2/0 0.96 0/20/0/0/0
0/17/2/0/0 0.20
Question 2 Have you felt that your sense of taste has worsened because of problems with your teeth, mouth or dentures?
0/20/0/0/0 0/16/3/0/0 0.06 0/16/1/3/0
0/16/2/0/0 0.29
Question 3 Have you had a painful aching in your mouth?
0/15/2/3/0 0/14/2/3/0 0.90 0/20/0/0/0
0/17/2/0/0 0.60
Question 4 Have you found it uncomfortable to eat any foods because of problems with your teeth, mouth or dentures?
0/14/2/4/0 0/11/6/2/0 0.99 0/15/4/1/0
0/15/3/1/1 0.43
Question 5 Have you been self-conscious of your teeth, mouth or dentures?
0/14/3/2/1 0/15/2/2/0 0.22 0/13/4/3/0
0/16/2/1/0 0.65
Question 6 Have you felt tense because of problems with your teeth, mouth or dentures?
0/18/2/0/0 0/15/2/2/0 0.75 0/17/2/1/0
0/14/3/1/1 0.45
Question 7 Has your diet been unsatisfactory because of problems with your teeth, mouth or dentures?
0/19/1/0/0 0/18/0/1/0 0.33 0/14/4/1/0
0/15/4/0/0 0.29
Question 8 Have you had to interrupt meals because of problems with your teeth, mouth or dentures?
0/14/4/1/1 0/17/1/1/0 0.37 0/15/4/1/0
0/16/3/0/0 0.94
Question 9 Have you found it difficult to relax because of problems with your teeth, mouth or dentures?
0/14/1/5/0 0/17/1/1/0 0.38 0/13/4/3/0
0/15/2/2/0 0.54
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Question 10 Have you been a bit embarrassed because of problems with your teeth, mouth or dentures?
0/14/1/5/0 0/13/3/3/0 0.47 0/17/2/1/0
0/13/3/1/1 0.54
Question 11 Have you been a bit irritable with other people because of problems with your teeth, mouth or dentures?
0/16/2/2/0 0/17/2/0/0 0.37 0/14/4/1/0
0/15/2/2/0 0.39
Question 12 Have you had difficulty doing your usual jobs because of problems with your teeth, mouth or dentures?
0/18/2/0/0 0/17/2/0/0 0.23 0/15/4/1/0
0/15/3/1/0 0.61
Question 13 Have you felt that life in general was less satisfying because of problems with your teeth, mouth or dentures?
0/18/2/0/0 0/17/2/0/0 0.21 0/13/4/3/0
0/15/3/1/0 0.38
Question 14 Have you been totally unable to function because of problems with your teeth, mouth or dentures?
0/19/0/1/0 0/17/2/0/0 0.21 0/18/2/0/0
0/17/2/0/0 0.29
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Discussion
The present study showed that immediate placement and immediate provisionalization was not inferior to
immediate placement with delayed provisionalization with the difference in means of MBL between the two
treatment groups being smaller <0.90 mm, thereby rejecting the null-hypothesis. Only some statistically
significant differences were observed in VAS-score and mesial IML after one year. These differences were
not regarded clinically relevant.
Peri-implant hard and soft tissue dimensions
The results of the present study are in line with other clinical studies26-28 on immediate placement in
the aesthetic zone with regard to change in MBL. In a recent systematic review, a mean MBL change of
0.81±0.48 mm was reported.⁷ These results were based on 43 studies reporting on immediate placement
of single tooth implants in the aesthetic zone. This study is in line with these findings with a reported MBL
change after one year of 0.75±0.69 mm mesially and 0.68±0.65 mm distally for the immediate group and
0.70±0.64 mm and 0.68±0.64 mm for the delayed group). In this systematic review, a change of IML of
0.38±0.23 mm and a mean change of MML of 0.54±0.39 mm was reported, the mean change of IML and
MML reported in this study was within this range.⁷
It has been described that immediate implant placement is associated with an increased risk for recession
of the peri-implant tissues.9,29 In this study, in our opinion, recession of peri-implant tissues was still
clinically acceptable after one year (IML of 1.00±0.58 mm and MML 0.95±0.62 mm). The observed
significant difference between groups A and B with regard to the mesial IML, probably can be explained
by the absence of immediate support by a provisional crown in group B as well as the use of a removable
denture. Theoretically, after placement of a provisional crown, peri-implant tissues have the possibility to
gain height due to support of the provisional crown.
Clinical outcome
We reported a 100% survival rate of immediately placed implants in the aesthetic zone, comparable with
known numbers.5,7,30 With regard to the papilla volume, we showed that papilla volume gained after one
year. This phenomenon has also been demonstrated in studies involving conventional22,31 and immediate
implant placement.26,28 In this study, pocket probing depths and the health of the keratinized gingiva
remained stable throughout the study period, while the plaque and bleeding indexes remained low in both
groups.
Aesthetic assessments
PES/WES scores did not differ statistically between both groups and were comparable to the aesthetic
results published in the literature regarding single tooth implants in the aesthetic zone.14,32-34 This is an
important observation, as the present study specifically assessed differences in the aesthetic zone.
Obviously further improvement of the aesthetic results is always desirable.
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69
Patients’ satisfaction
Over the last years, there is an increasing focus on patient-reported outcome measures within the field
of implant dentistry.35 Immediate placement and provisionalization are known to be associated with high
subjective satisfaction rates.36 This is in line with the patients’ satisfaction perceived by the patients in
this study. Regarding the OHIP-14, no significant differences were observed between these groups during
the entire follow-up, again in line with other studies.32,37 The significant difference after one year in the VAS
score, though, is not considered to be a clinically relevant difference as more than a 13 point difference on
the 100-point VAS is needed to obtain a clinically relevant difference.38 In addition, the observed difference
might be explained by the fact that patients in group A were satisfied immediately, as provisionalization
was performed the same day, while the other patients had to deal with a removable denture for three
months making them even more satisfied with the final results as they had experienced the misery of
wearing a removable denture for three months.
Limitations of the study
Some limitations have to be addressed. First, and most important, regarding the non-inferiority design we
have to admit that the chosen maximal difference in means of <0.9 mm is debatable. In retrospect, a (much)
smaller difference in means would have been better to prove non-inferiority. For now, we can only conclude
that immediate provisionalization is not inferior to delayed provisionalization when considering a margin
<0.9 mm as equal. However, because the data shows that the difference in MBL between both groups in
fact is much smaller, it is reasonable to assume that with a smaller difference in means (and thus a larger
sample size), immediate provisionalization would also be non-inferior to delayed provisionalization. On
basis of these results (comparable results for both treatment designs), it also can be presumed that any
difference observed between both treatments when increasing the sample size will be clinically rather
irrelevant. Regarding the other outcome parameters we can only conclude that it seems that there is
not a large difference between both groups. However, as this study was not powered do detect relevant
differences for these outcome measures, no firm conclusions can be drawn from these observations.
The second limitation is directly linked to the imbalance between both groups after randomization. All
agenesis patients (n=6) were allocated to group A after randomization. Taking a closer look at these
patients, no significant differences were present between agenesia patients and patients with a failing
tooth for other reasons allocated to group A. It is therefore unlikely that this imbalance between both
groups influenced our results.
In this study a maximum bony defect of 5 mm was used. However, it is difficult to measure the bony defect
when the tooth is still in situ. The reasons of tooth loss can be very diverse, so randomization took only
place on the bony defect. Given the seemingly favourable outcomes of immediate placement in this study,
immediate placement in a larger bony defect should certainly be considered in future studies.
Conclusion
The present study showed that immediate placement and immediate provisionalization was non-inferior
compared with immediate placement with delayed provisionalization regarding MBL at a level <0.9 mm. The
outcome is hampered by the large margin for differences in means taken for non-inferiority. In this respect,
further research in larger groups of patients is warranted to monitor the outcome measures, also on the
long-term.
70
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12. Meijer HJ, Stellingsma K, Meijndert L, Raghoebar
GM. A new index for rating aesthetics of
implant-supported single crowns and adjacent
soft tissues - the Implant Crown Aesthetic Index.
Clin Oral Implants Res 2005;16(6):645-649.
13. Furhauser R, Florescu D, Benesch T, Haas R,
Mailath G, Watzek G. Evaluation of soft tissue
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patients with a 2- to 4-year follow-up using
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2009;80(1):140-151.
15. Buser D, Halbritter S, Hart C, et al. Early implant
placement with simultaneous guided bone
regeneration following single-tooth extraction
in the esthetic zone: 12-month results of a
prospective study with 20 consecutive patients.
J Periodontol 2009;80(1):152-162.
16. Carlsson AM. Assessment of chronic pain. I.
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17. van der Meulen MJ, John MT, Naeije M,
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18. De Rouck T, Collys K, Cosyn J. Immediate
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2011;38(4):385-394.
20. Raghoebar GM, Slater JJ, Hartog L, Meijer
HJ, Vissink A. Comparison of procedures for
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2009;38(7):736-743.
21. Meijndert L, Meijer HJ, Raghoebar GM, Vissink
A. A technique for standardized evaluation
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partially edentulous patients. J Periodontol
2004;75(5):646-651.
22. Jemt T. Regeneration of gingival papillae after
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Restorative Dent 1997;17(4):326-333.
23. Mombelli A, van Oosten MA, Schurch E,Jr, Land
NP. The microbiota associated with successful
or failing osseointegrated titanium implants.
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25. Faul F, Erdfelder E, Buchner A, Lang AG.
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26. Lindeboom JA, Frenken JW, Dubois L, Frank M,
Abbink I, Kroon FH. Immediate loading versus
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Oral Maxillofac Surg 2006;64(6):936-942.
27. Crespi R, Cappare P, Gherlone E, Romanos
GE. Immediate versus delayed loading of
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Implants 2008;23(4):753-758.
28. Palattella P, Torsello F, Cordaro L. Two-year
prospective clinical comparison of immediate
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29. Chen ST, Buser D. Clinical and esthetic
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sites. Int J Oral Maxillofac Implants 2009;24
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30. Esposito M, Grusovin MG, Polyzos IP, Felice P,
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31. Henriksson K, Jemt T. Measurements of soft
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32. Raes F, Cosyn J, De Bruyn H. Clinical, Aesthetic,
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Loaded Single Implants in the Anterior Maxilla:
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Healed Ridges, and Grafted Sites. Clin Implant
Dent Relat Res 2012;
33. den Hartog L, Raghoebar GM, Slater JJ,
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34. Santing HJ, Raghoebar GM, Vissink A, den
Hartog L, Meijer HJ. Performance of the
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consecutive patients. Clin Oral Implants Res
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36. Hartlev J, Kohberg P, Ahlmann S, Andersen
NT, Schou S, Isidor F. Patient satisfaction and
esthetic outcome after immediate placement
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involving a definitive individual abutment. Clin
Oral Implants Res 2014;25(11):1245-1250.
37. Raes F, Cooper LF, Tarrida LG, Vandromme H, De
Bruyn H. A case-control study assessing oral-
health-related quality of life after immediately
loaded single implants in healed alveolar
ridges or extraction sockets. Clin Oral Implants
Res 2012;23(5):602-8.
38. Gallagher EJ, Liebman M, Bijur PE. Prospective
validation of clinically important changes in
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scale. Ann Emerg Med 2001;38(6):633-638.
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4Immediate single-tooth implant
placement in bony defects in the
aesthetic zone:
a 1-year randomized controlled trial.
This chapter is an edited version of the manuscript:Slagter KW, Meij er HJ, Bakker NA, Vissink A, Raghoebar GM.
Immediate single-tooth implant placement in bony defects in the esthetic zone: a 1-year randomized controlled trial. Journal of Periodontology.
Epub ahead of publication. 2016;15:1-15.
76
Abstract
Aim:
To assess whether outcome of immediate implant placement in the aesthetic zone in bony
defects was non-inferior to delayed implant placement after one year regarding marginal
bone level (MBL).
Materials and Methods:
Forty patients with a failing tooth in the aesthetic zone and a labial bony defect of ≥5 mm
after removal of a tooth were randomly assigned for immediate (n=20) or delayed (n=20)
implant placement. Second stage surgery and provisionalization occurred after three
months healing. Follow-up was at 1 month and 1 year after definitive crown placement.
The study was powered to detect a difference in MBL of >0.9 mm. Buccal bone thickness,
soft tissue peri-implant parameters, aesthetic indexes and patients’ satisfaction were also
assessed.
Results:
One year after definitive crown placement, MBL level loss was 0.49±0.46 mm mesially
and 0.49±0.46 mm distally for the immediate group and 0.45±0.41 mm and 0.68±0.64
mm for the delayed group, respectively. Regarding differences in means, non-inferiority
was observed after 1 year (mesially: immediate vs. delayed: difference in mean 0.04 mm
(95%CI -0.22 to 0.30 mm, p=0.40, distally: immediate vs. delayed: difference in mean 0.21
mm (95%CI -0.10 to 0.51 mm, p=0.58). No significant differences in the outcome variables
were observed.
Conclusion:
Immediate implant placement with delayed provisionalization was non-inferior to delayed
implant placement with delayed provisionalization in labial bony defects of ≥5 mm
regarding change in MBL. Although not powered for other outcome variables, no clinically
relevant differences were observed in these variables.
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Introduction
The survival of immediately placed and provisionalized implants in the aesthetic zone is very high.1,2,3
However, it is not just implant survival that determines the success of an implant treatment as implant
treatment in the aesthetic zone is also in need of a favourable hard and soft peri-implant tissue outcome.4,5
A recent randomized clinical trial6 verified this for marginal bone level (MBL) in extraction sockets with
no bony defects and showed that indeed the MBL outcome is favourable too. Although unknown to what
extent the peri-implant soft tissues react on missing support of hard peri-implant tissues, it has been
hypothesized that the risk on developing facial gingival recession is low when the bone labially from the
implants has no dehiscences and a sufficient thickness at implant placement.7 In this respect, it was
reported that large U- and UU-shaped defects are accompanied by more gingival recession 1-year after
immediate tooth replacement, reason why Kan et al8 recommended a delayed approach, viz. to combine
implant placement with hard and/or soft tissue grafting when a labial bone defect is present at implant
placement. Recently, however, it was reported that newer techniques allow for a favorable treatment
outcome of implants placed in fresh extractions sockets with labial plate dehiscences.9-11 Thus, an intact
labial plate is presumably not essential to allow for immediate implant placement with a favorable
outcome. No studies yet assessed the treatment outcome of implants placed in fresh extraction sockets
with labial plate dehiscences in the aesthetic zone in a prospective, randomized clinical trial design.
Therefore, the aim of this randomized controlled trial was to assess whether the 1 year treatment outcome
of immediate implant placement and delayed provisionalization is non-inferior regarding change in
marginal bone level (MBL) to delayed implant placement and delayed provisionalization in case of implant
placement in fresh extraction sockets with labial bony defects of ≥5 mm in the aesthetic zone.
Materials and methods
Study design
Between January 2010 and January 2012 all eligible consecutive patients >18 years with a failing tooth in
the maxillary aesthetic zone (incisor, canine or first premolar) referred for single tooth implant treatment
were asked to join this randomized clinical trial. Pre-operative, a cone beam computed tomography
(CBCT)-scan was made to assess whether there was sufficient bone on the palatal side to place an implant
as for primary stability of the implant sufficient palatinal bone is necessary in case of labial dehiscence.
Patients were excluded from participation in this study when they met one or more of the following criteria:
inadequate oral hygiene, insufficient mesio-distal width for implant placement, periodontal disease,
smoking, ASA (American Society of Anesthesiologists) score ≥II12, and a bony defect of <5 mm in vertical
direction of the labial socket wall after removal of the tooth. The size of the bony defect was determined
after extraction of the failing tooth. The shape of the osseous defect was assessed by a bone sounding
technique with a periodontal probe at the buccal, the mesial, and distal aspect of the failing tooth, and the
mesial and distal aspect of the immediately adjacent teeth.
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For allocation to either group a computerized random number generator was used. A research-nurse not
involved in the study blindly allocated the patients to (Figure 1 and 2):
- An immediate group: immediate placed implant (NobelActive, Nobel Biocare AB, Goteborg, Sweden)
and delayed provisionalization;
- A delayed group: delayed placed implant (NobelActive, Nobel Biocare AB, Goteborg, Sweden) and
delayed provisionalization.
Informed consent was obtained from all patients. The study was approved by the local medical ethical
committee (NL32240.042.10) and registered in a trial register (ISRCTN57251089).
Surgical protocol
Preoperatively, patients started prophylactic antibiotic therapy (amoxicillin 500mg t.i.d. for 7 days or
clindamycin 300mg q.i.d. in case of amoxicillin allergy). Oral disinfection consisted of a 0.2% chlorhexidine
mouthwash, twice daily for 7 days. All surgeries were performed under local anesthesia and performed
by the same experienced oral and maxillofacial surgeon (GR). In all cases, the failing teeth were removed
with a sulcular incision, careful detachment of the periodontal ligament and use of periotomes. After
removal of the tooth, the alveolus was meticulously cleansed and any alveolar debridement was removed
with a sterile gauze. If the sterile gauze was still contaminated, more cleaning took place. Before implant
placement, bone grafts were harvested from the maxillary tuberosity with the use of chisels. The wound of
the bone graft in the tuberosity region was closed with Vicryl 4-0 (Ethicon, Johnson&Johnson, Amersfoort,
The Netherlands).
Immediate placement group:
The implant site was prepared on the palatal side of the alveolus following the protocol of the manufacturer
using a surgical template based on the ideal position of the prospective implant crown. The last used burr,
depending on the diameter of the implant, was placed in the prepared alveolus. Next, the tuberosity bone
graft was shaped with the use of a forceps to match the labial bony defect. The bone graft was placed in the
extraction socket, with the cortical side facing the periosteum, under the periosteum covering the labial
plate defect. A mixture of autologous bone and Bio-Oss® (Geistlich, Wolhusen, Switzerland) spongiosa
granules (0.25-1.0 mm) was thightly packed into the remaining space between the burr and the bone
graft. Regarding the corono-apical position of the implants (NobelActive, Nobel Biocare AB, Goteborg,
Sweden) the shoulder of the implant was placed at a depth of 3 mm apical to the most apical aspect of
the prospective clinical crown, with help of the surgical template. Immediately after implant placement a
corresponding cover screw was placed. To achieve an optimal aesthetic outcome, next a soft tissue graft,
harvested from tuberosity region where the bone graft was taken from, was placed on top of the bone graft
and implant according to the method described in detail by Raghoebar et al.13 The wound was closed with
Ethilon 5-0 (Ethicon, Johnson&Johnson, Amersfoort, The Netherlands).
During the three months osseointegration phase, patients were allowed to wear a removable partial
denture not interfering with the wound. After three months, the implant was uncovered by a small
incision at the site of the cover screw, followed by an implant-level impression according to the procedure
described in the prosthetic protocol section.
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Figure 1. Cohort flow diagram.
Enrollment Assessed for eligibility (n=40)
Excluded (n=0) • Not meeting inclusion criteria (n=0) • Declined to participate (n=0) • Other reasons (n=0)
Allocated to intervention (n=20) • Received allocated intervention (n=20) • Did not receive allocated interven tion (give reasons) (n=0)
Lost to follow-up (give reasons) (n=0) Discontinued intervention (give reasons) (n=0)
Analysed (n=20) • Excluded form analysis (give reasons) (n=0)
Allocated to intervention (n=20) • Received allocated intervention (n=20) • Did not receive allocated interven tion (give reasons) (n=0)
Lost to follow-up (give reasons) (n=0) Discontinued intervention (give reasons) (n=0)
Analysed (n=20) • Excluded form analysis (give reasons) (n=0)
Randomized (n=40)
Allocation
Follow-Up
Analysis
80
Figure 2A. Schedule of visits and procedures study group immediate placement and
delayed provisionalization.
Inclusion
Prosthetic phase
Healing phase
Follow-up phase
Pre-operative TPre
Screening and Measurements
Extraction &
Implant placement
& Delayed
provisionalization
Second phase surgery
& Provisional crown
Definitive crown and Follow-up
Day 0 (T0)
3 months (T3)
6 months (T6)
12 months (T12)
Follow-up
18 months (T18)
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Figure 2b. Schedule of visits and procedures study group delayed placement and
delayed provisionalization.
Inclusion
Prosthetic phase
Healing phase
Pre-operative TPre
Screening and Measurements
Extraction &
Guided Bone Regeneration
Implant placement
Second phase surgery
& Provisional crown
Definitive crown and Follow-up
Day 0 (T0)
3 months (T3)
6 months (T6)
9 months (T9)
12 months (T12)
Follow-up
21 months (T21)
18 months (T18)
Follow-up phase
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Delayed placement group:
The alveolus was locally augmented with the same procedure as described for the immediate group,
with exception of placement of an implant. After 3 months a pedicled mucoperiosteal flap was raised to
expose the maxilla, after which the NobelActive implant was placed according to the requirements of the
manufacture using a surgical template. The implants were placed, comparable to the implants placed in the
immediate placement group, 3 mm below the cervical junction of the adjacent teeth. The wound was primary
closed with Ethilon 5-0 (Ethicon, Johnson&Johnson, Amersfoort, The Netherlands). After three months
the implant was uncovered following the same procedure as described for the immediate group, again
followed by an implant-level impression. Patients were allowed to wear a removable partial denture until the
provisionalization took place.
Prosthetic protocol
An implant-level impression was made immediately after uncovering the implant. After the impression was
taken, a corresponding healing abutment was placed. A screw-retained provisional crown composed of
an engaging temporary abutment and composite was then fabricated in the dental laboratory. This same
day, the provisional crown was fastened directly onto the implant with 20 Ncm by a manual torque wrench.
A final open tray impression using polyether impression material (Impregum Penta, 3M ESPE, Seefeld,
Germany) was taken at implant level after a provisional phase of 3 months in both groups. In the dental
laboratory, one lab technician made the digital design of the definitive crown to the desired form of the
abutment. This digital design was used to retrieve individualized zirconia abutments (NobelProcera, Nobel
Biocare AB, Goteborg, Sweden). Depending on the location of the screw access hole, the final crown was
either cement-retained or screw-retained. Abutment screws were torqued with 32 Ncm. Cement-retained
crowns were cemented with glass ionomer cement (Fuji Plus, GC Europe, Leuven, Belgium). All prosthetic
procedures were performed by a single experienced prosthodontist (HM).
Outcome measures
Primary outcome measure of this study was the change in marginal peri-implant bone level (MBL) proximal
to the implant, from placement of the implant to one month (T1) after connecting the definitive crown and
from placement of the implant to one year (T12) after connecting the definitive crown.
Secondary outcome measures included buccal bone thickness (BBT), implant survival, change in
interproximal peri-implant mucosa (IML) and midfacial peri-implant mucosal level (MML) as compared
with the gingival level of the pre-operative failing tooth. Furthermore, papilla volume, health of keratinized
gingiva, amount of plaque, amount of bleeding and pocket probing depth were assessed. Aesthetic
outcome was assessed by means of objective indices (Implant Crown Aesthetic Index (ICAI)14, the pink
esthetic score (PES)15 and the white esthetic score (WES).16,17 Patients’ satisfaction was assessed using the
Oral Health Impact Profile (OHIP) index18 and the Visual Analogue Scale (VAS)19 on a 0-10 scale.
Radiographic assessments
To calculate changes in MBL, one month (T1) and one year (T12) after placement of the definitive crown,
a standardized digital peri-apical radiograph was taken with an individualized aiming device20, pre-
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operatively (Tpre), immediately following implant placement (baseline T0), one month (T1), and twelve
months (T12) after definitive crown placement. The vertical distance from the shoulder of the implant to the
first-bone-to-implant contact was measured at the distal and mesial site of the implant. The radiographs of
T1 and T12 were analyzed using the manufacturer-provided implant diameter as a reference. Measurements
were performed independently by two examiners (KS and Harry Slagter), after which the average of both
measurements was used.
To calculate buccal bone thickness (BBT) labial of the implant, one month (T1) and one year (T12) after
placement of the definitive crown a CBCT scan was made. The scanner (iCAT 3D exam scanner,KaVo Dental
GmbH, Biberach, Germany) was validated for measuring bone thickness by Fourie et al.21 To allow for
reproducible measurements, a CBCT imaging and software protocol was developed and validated.22 Area
of interest was the distance from the central axis of the implant to the outer contour of the buccal bone
at the neck of the implant. Buccal bone thickness measurements (in mm) were performed calculating the
distance to the buccal bone outline minus the radius of the interior contour of the implant (as provided by
the implant company). Measurements were performed independently by two examiners (KS and HM), after
which the average of both measurements was used.
Survival rate
Survival rate was defined as the percentage of functional implants one year after definitive crown
placement. The criteria for successful osseointegration according to Smith & Zarb (1989) were adapted.
Photographic assessments
Before implant placement (Tpre) at T1 and at T12, standardized digital photographs (Nikon D300s, Nikon
Corporation,Yurakucho, Tokyo, Japan) were taken using a technique as described earlier.17 A manual
periodontal probe (Williams Color-Coded probe; Hu-Friedy, Chicago, IL, USA) with known dimensions was
held in close proximity and parallel to the long axis of the adjacent tooth to calibrate the photographs. Full
screen analysis of the photographs was performed using a digital picture editing program (Keynote, Apple
Inc, Cupertino, CA, USA). The changes in IML and in MML were compared with the original gingival level
of the failing tooth. These measurements were independently performed by two examiners (KS and Harry
Slagter) after which the average of both measurements was used.
Clinical assessments
The following clinical variables were assessed at T1 and T12 at the implant and adjacent teeth before
implant placement (Tpre):
- Papilla volume: assessing the mesial and distal papilla adjacent to the implant using the papilla
index23;
- Amount of plaque: assessed at four sites per implant/adjacent tooth (mesial, buccal, distal and
palatinal) using the modified plaque index24;
- Amount of bleeding: using the modified sulcus bleeding index24;
- Gingiva: using the gingival Index25;
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- Probing pocket depth: assessed at four sites per implant/adjacent tooth (mesial, buccal, distal and
palatinal) using a manual periodontal probe (Williams Color-Coded probe; Hu-Friedy, Chicago, IL, USA)
measuring to the nearest 1 mm. All data were recorded by a single one blinded examiner (KS).
Aesthetic assessments
The aesthetic outcome was assessed on standardized digital photographs (Nikon D300s, Nikon
Corporation,Yurakucho, Tokyo, Japan taken at Tpre and T1, and T12 in both groups. An additional
photograph was taken of implant crowns replacing the lateral of canine capturing the contra lateral tooth.
Peri-implant mucosa and implant crown aesthetic outcomes were determined using ICAI14 and PES-WES.16,17
Measurements were performed independently by two examiners (KS and Diederik Hentenaar).
Patients’ satisfaction
Patients’ satisfaction was surveyed at T1 and T12 using the validated OHIP-14 questionnaire. Overall
satisfaction was assessed using a 100-mm visual analogue scale (VAS).
Statistical analysis
For determination of the sample size, G*power version 3.1 was used.26 A radiographic change in MBL of
>0.9 mm (SD 1 mm) after 12 months of definitive crown placement was regarded as a relevant difference
between study groups.1 With an expected effect-size of 0.9 mm, an alpha of 0.05 and a power of 0.80,
38 patients were required, 19 in each group. 40 patients were included to account for anticipated drop-
out rate. Shapiro-Wilk test, together with normality plots were used to assess normal distribution of
the continuous variables. Differences between groups were evaluated by one-way analyses of variance
(ANOVA) for continuous data and by Fisher’s exact test or chi-Square test for categorical data. Regarding
MBL, T-tests for equality of means with associated confidence intervals (CI) were calculated. If the
difference of 0.9 did not pass the 95% CI borders, non-inferiority was considered established. In case of
uncertainty of the significance because of the relatively small number of patients analysed and the large
number of outcomes, Bonferroni correction was considered in case of a p-value 0.01<>0.05. A p-value of
0.05 was considered to indicate statistical significance. All analyses were performed using SPSS (PASW
Statistics 20.0, SPSS Inc.; IBM Corporation, Chicago, IL, USA).
Results
Inter-and intra-observer correlation
The inter- and intra-observer correlations for both the radiographic and photographic measurements were
very high. For details see Slagter et al.6
Patients
Baseline characteristics and treatment specifications of the immediate group (n=20) and delayed group
(n=20) are shown in Table 1 and Figure 3 and 4. All patients received their assigned treatment (Figure 1).
No extensive bleedings at the donor and receptor site were observed.
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Table 1. Baseline characteristics and treatment specifications per study group.
Variable Immediate group (n=20)
Delayed group (n=20)
Age Mean±SD Range
43.7 ±13.9 18-63
48.6 ±16.4 20-72
Gender Male Female
11 9
7 13
Cause of tooth loss
Fracture (crown or root) Agenesis Caries Endodontic failure Periodontal failure Root resorption
9 0 0 8 0 3
9 0 1 5 2 3
Bone defect Mean±SD (mm) 8.35 ±2.18 8.65 ±1.76
Implant locationIncisor 1 Incisor 2 Canine
12 5 3
14 6 0
Implant length13 mm 15 mm 18 mm
1 12 7
6 10 4
Implant diameter 3.5 mm 4.3 mm
5 15
5 15
Type of final restoration Screw-retained Cement-retained
14 6
12 8
86
Three patients (immediate: group 1; delayed: group 2) had an antral perforation due to harvesting
the tuberosity bone. The wound overlying the antral perforation was primary closed and healing was
uneventful. Wound healing at the grafting/implantation site was undisturbed with the exception of
one patient (group 2) in whom a small bone sequester had to be removed. After removal of the bone
sequester, wound healing was uneventful and the remaining bone was sufficient for implant placement. No
complications were observed during the follow up.
Marginal bone level
MBL loss at the mesial and distal site after 1 month and 12 months after placement of the definitive crown
was comparable for both treatment approaches (Table 2). Non-inferiority for the change in MBL between
the groups was observed, both for the 1 month (mesially: immediate group vs. delayed group: difference in
mean 0.04 mm (95%CI-0.24- to 0.23 mm, p=0.83, distally: 0.23 mm (95%CI-0.84 to 0.54 mm, p=0.70) and
1 year (mesially: 0.04 mm (95%CI -0.22 to 0.30, p=0.40, distally: 0.21mm (95%CI -0.10 to 0.51 mm, p=0.58)
time point.
Buccal bone level
Mean buccal bone thickness at the neck of the implant 1 month and 12 months after placement of the
definitive crown is shown in Table 2. Buccal bone thickness did not change between between T1 and T12.
Survival rate
One year implant survival rate was 100% in both groups.
Interproximal and midfacial peri-implant mucosal level
IML and MML, did not change significantly between with time in both groups (Table 2).
Clinical outcome
Plaque, bleeding and gingival indexes as well as the pocket probing depth were low and remained low
throughout the study period (Table 3).
Aesthetic assessments
At the 1-year evaluation, no significant differences in ICAI as well as PES/WES were seen between the
groups (Table 2). The aesthetic outcome was mainly dependent on the appearance of the implant crown
and less by the aspect of the peri-implant mucosa, and did not differ between the groups.
Patients’ satisfaction
OHIP-14 scores did not differ between the groups (Table 4; p>0.05). Overall satisfaction scores one year
after placement of the crown were 8.4±1.4 and 8.1±1.3 for the immediate and delayed group, respectively.
4
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Table 2. Changes regarding marginal bone level, marginal soft tissue level and aesthetic evaluation from pre-operative (Tpre), one month (T1) to 12 months (T12) after definitive crown placement.
Tpre Tpre P-value T1 T1 P-value T12 T12 P-value
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Mean (sd)
Variable
Group A
Group B
Group A
Group B
Group A
Group B
Marginal bone level in mm(±sd)
Mesial of implant 0.49 (±0.46)
0.45 (±0.41) 0.79 0.56
(±0.39)0.51 (±0.43) 0.74
Distal of implant 0.71 (±0.51)
0.48 (±0.47) 0.15 0.74
(±0.51)0.54 (±0.45) 0.18
BBTchanges in mm Buccal of implant (mean ±sd)
1.01 (±0.55)
0.79 (±0.46) 0.19 1.00
(±0.47)0.71 (±0.28) 0.07
Marginal soft tissue level changes in mm (±sd)
Mesial of implant 0.15 (±0.18)
0.18 (±0.16) 0.73 0.15
(±0.16)0.15 (±0.16) 0.99
Distal of implant 0.17 (±0.16)
0.23 (±0.17) 0.32 0.18
(±0.18)0.21 (±0.17) 0.53
Mid-facial of implant 0.13 (±0.28)
0.30 (±0.49) 0.20 0.15
(±0.28)0.34 (±0.55) 0.17
PES 7.00 (2.10)
6.90 (1.30) 0.63 7.80
(1.66)7.40 (1.59) 0.71 7.50
(1.59)7.40 (1.46) 0.79
WES 5.00 (2.33)
5.40 (1.65) 0.70 7.99
(1.73)7.60 (1.09) 0.68 8.10
(0.90)7.90 (1.08) 0.79
PES/WES 10.68 (3.40)
11.10 (3.46) 0.43 16.20
(2.20)15.10 (1.71) 0.38 15.80
(2.05)15.30 (2.11) 0.50
ICAI 9.60 (6.54)
14.10 (8.57) 0.23 3.80
(2.18)6.20 (3.94) 0.35 4.20
(2.38)5.2 (4.10) 0.37
88
3b
3a
3c
3b
3d
Figure 3. Immediate implant treatment with delayed provisionalization.
a Clinical situation pre-operative.
b. Pre-operative radiograph.
c. Clinical situation post-operative.
d. Post-operative radiograph.
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4a
4c
4b
4d
Figure 4. Delayed implant treatment with delayed provisionalization.
a Clinical situation pre-operative.
b. Pre-operative radiograph.
c. Clinical situation post-operative.
d. Post-operative radiograph.
90
Table 3. Clinical outcome measures pre-operative (Tpre), and one month (T1) and 12 months (T12) after definitive crown placement.
Tpre Tpre P- value T1 T1 P-
value T12 T12 P- value
Variable
Immediate group
Delayed group
Immediate group
Delayed group
Immediate group
Delayed group
Papilla index: 0/1/2/3/4
Mesial (#patient) 0/7/2/11/0 2/6/6/6/0 0.17 1/5/3/11/0 2/8/4/6/0 0.45 0/3/8/9/0 0/6/5/9/0 0.43
Distal (#patient) 0/7/5/8/0 2/6/6/6/0 0.53 1/5/8/6/0 5/6/5/4/0 0.28 0/3/8/9/0 0/7/7/6/0 0.32
Gingival index: 0/1/2/3 (#patient)
19/1/0/1 17/1/1/1 0.55 18/2/0/0 20/0/0/0 0.35 18/2/0/0 20/0/0/0 0.24
Plaque index: 0/1/2/3 (#patient)
18/2/0/0 20/0/0/0 0.47 20/0/0/0 20/0/0/0 NA 18/1/1/0 20/0/0/0 0.35
Bleeding index: 0/1/2/3 (#patient)
9/9/2/0 9/6/3/2 0.39 11/7/1/0 12/8/0/0 0.59 11/9/0/0 15/5/0/0 0.16
Pocket depth in mm
Mesial (mean ±sd) 3.0±1.7 3.3± 1.7 0.51 3.1± 0.6 3.2± 0.7 0.80 3.3±0.7 3.6±0.8 0.27
Distal (mean ±sd) 3.3±1.1 3.6±1.6 0.43 3.6±0.7 3.3±0.7 0.25 3.5±0.8 3.8±0.8 0.33
Buccal (mean ±sd) 1.6±0.8 2.3±1.2 0.10 2.8±0.8 3.3±0.9 0.17 3.2±0.8 3.3±0.7 0.53
Palatal (mean ±sd) 2.2±0.9 2.9±1.9 0.12 2.8±0.4 2.9±0.6 0.76 2.7±0.6 3.1±0.5 0.09
4
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92
Table 4. Oral Health Impact Profile18scores at baseline (T1) and one year (T12) of functioning.
Mean OHIP-14 T1 P-value T12 P-value
Immediate group Delayed group
Immediate group Delayed group
Variable
never/hardly ever/occasionally/fairly often/very often
never/hardly ever/occasionally/fairly often/very often
Question 1 Have you had trouble pronouncing any words because of problems with your teeth, mouth or dentures?
0/17/3/0/0 0/14/5/1/0 0.41 0/19/1/0/0
0/16/3/1/0 0.32
Question 2 Have you felt that your sense of taste has worsened because of problems with your teeth, mouth or dentures?
0/18/2/0/0 0/16/2/2/0 0.35 0/19/1/0/0
0/18/1/1/0 0.60
Question 3 Have you had a painful aching in your mouth?
0/11/7/2/0 0/9/10/1/0 0.59 0/9/9/2/0
0/10/8/2/0 0.95
Question 4 Have you found it uncomfortable to eat any foods because of problems with your teeth, mouth or dentures?
0/12/7/1/0 0/11/5/4/0 0.34 0/16/3/1/0
0/16/2/2/0 0.77
Question 5 Have you been self-conscious of your teeth, mouth or dentures?
0/10/4/4/2 0/11/4/5/0 0.54 0/13/4/3/0
0/15/3/1/0 0.53
Question 6 Have you felt tense because of problems with your teeth, mouth or dentures?
0/12/5/3/0 0/14/3/3/0 0.72 0/11/5/4/0
0/16/1/3/0 0.15
Question 7 Has your diet been unsatisfactory because of problems with your teeth, mouth or dentures?
0/17/3/0/0 0/16/4/0/0 0.68 0/19/1/0/0
0/16/4/0/0 0.17
Question 8 Have you had to interrupt meals because of problems with your teeth, mouth or dentures?
0/18/2/0/0 0/18/2/0/0 1.00 0/18/2/0/0
0/20/0/0/0 0.24
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Question 9 Have you found it difficult to relax because of problems with your teeth, mouth or dentures?
0/14/1/5/0 0/17/2/1/0 0.38 0/16/3/1/0
0/17/3/0/0 0.60
Question 10 Have you been a bit embarrassed because of problems with your teeth, mouth or dentures?
0/15/5/0/0 0/13/6/1/0 0.54 0/17/2/1/0
0/13/3/1/1 0.54
Question 11 Have you been a bit irritable with other people because of problems with your teeth, mouth or dentures?
0/16/2/2/0 0/17/2/0/0 0.37 0/15/5/0/0
0/16/2/2/0 0.19
Question 12 Have you had difficulty doing your usual jobs because of problems with your teeth, mouth or dentures?
0/11/7/1/1 0/12/7/1/0 0.79 0/17/3/0/0
0/16/3/1/0 0.60
Question 13 Have you felt that life in general was less satisfying because of problems with your teeth, mouth or dentures?
0/14/4/1/0 0/15/3/2/0 0.68 0/18/1/1/0
0/18/1/1/0 1.00
Question 14 Have you been totally unable to function because of problems with your teeth, mouth or dentures?
0/19/1/0/0 0/20/0/0/0 0.31 0/19/0/1/0
0/17/3/0/0 0.13
94
Discussion
The present study showed that immediate placement with delayed provisionalization was not inferior
to delayed placement with delayed provisionalization at a level of >0.9 mm MBL. Although not a priori
powered to compare the other outcome variables, no clinically relevant differences were observed
regarding clinical, esthetic and patient-reported outcomes too. Immediate placement offers a shorter
treatment time due to the lower number of surgical procedures by combining extraction, implant
placement, and bone grafting in one operative procedure.27-29
Clinical outcomes
Change in MBL in this study is considerably less than the generally accepted magnitude of up to 1 mm for
the first year after implant placement described in the systematic review of Lang et al.1 and the 0.81±0.48
mm according to the systematic review of Slagter et al.3 concerning immediate implant placement. It has
to be mentioned that MBL loss usually predominantly occurs during the first year after immediate implant
placement and hardly progresses thereafter.1 Thus, the 1-year results are considered to reflect the level
of MBL related to a specific treatment in healthy subjects, a result that supports the immediate implant
placement approach.
A successful aesthetic outcome is presumably dependent on establishment of an optimal three-
dimensional implant position within the available bone dimensions as well as the maintenance of
adequate buccal bone over the buccal implant surface.30,31 In the present study, the buccal bone thickness
appeared at least to be stable up to 1 year after implant placement and provisionalization in both patient
groups and was thus considered to be independent of timing of implant insertion. Literature regarding
BBT is scarce. Comparison with other studies, although measured in a different study design, learned that
in the present study BBT after 1 year for immediate placed implants was more than the value of 0.16 mm
thickness reported in the immediate implant group of Raes et al.32 but less than the 2.12 mm BBT reported
by Degidi et al.33 For the delayed placed implants, BBT in the present study was more than the 0.20 mm
reported by Raes et al.32
Regarding the peri-implant soft tissues, the phenomenon biotype has been reported to affect the aesthetic
result.34 Possibly the thickness of the mucosa can positively influence the stability of the peri-implant soft
tissues. In future studies, the effect of biotype on treatment outcome should be an integral part of the
treatment design.
Aesthetic assessments
Although not upfront powered, the PES/WES and ICAI scores were comparable for the studied approaches
and were comparable to results published in the literature regarding immediately and delayed placed
single tooth implants placed in the aesthetic zone.16,35,36 The scores of the pink component of PES/WES
and ICAI were favorable and comparable for the immediate and delayed approaches, again supporting
immediate placement of implants in larger bony defects when primary stability of the implant can be
achieved.
4
95
Patients’ satisfaction
In the field of implant dentistry there is an increasing focus on patient-reported outcome measures.37
Immediate placement with immediate provisionalization is associated with high satisfaction rates.38 This
is in line with the satisfaction perceived by patients with immediate implant placement in this study.
Regarding the OHIP-14, no differences were observed between both groups during the entire follow-up,
again in line with other studies regarding immediate implant placement.39,40 The two protocols, while
yielding comparable results in terms of clinical outcomes and patient satisfaction, differed considerably
in time to teeth and the number of scheduled visits (Figure 2), with the immediate implant placement
reducing both the time and visit number to final restoration.
Limitation
The procedure to replace a failing tooth in the aesthetic zone with a bony defect with an immediate implant
is a complex procedure. Raghoebar et al13 showed that gingival mid-labial aesthetics most benefitted from
a full thickness palatal graft compared to a connective tissue graft or closing with a membrane. Due to the
complexity of this procedure, to achieve an optimal result it was recommended that the surgery should be
done by experienced surgeons.13 Therefore, in the current study all surgeries were performed by one single
experienced surgeon. The latter approach compromises the applicability of the reported approach for
general applications.
Conclusion
Immediate placement with delayed provisionalization is non-inferior regarding a change in MBL of >0.9
mm to delayed placement with delayed provisionalization in labial bony defects of ≥5 mm in the aesthetic
zone after a 1-year follow-up. In addition, although not powered for these outcome variables, no clinically
relevant differences in other outcomes were observed.
96
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5Inter- and intraobserver
reproducibility of buccal bone
measurements at dental implants
with cone beam computed
tomography in the aesthetic region.
This chapter is an edited version of the manuscript:Slagter KW, Raghoebar GM, Vissink A, Meij er HJA.
Inter- and intra-observer reproducibility of buccal bone measurements at dental implants with cone beam computed tomography in the esthetic region.
International Journal of Implant Dentistry 2015, 1:8; doi:10.1186/s40729-015-0007-1.
102
Abstract
Background:
Sufficient buccal bone is important for optimal aesthetic results of implant treatment in
the anterior region. It can be measured with cone beam computed tomography (CBCT),
but background scattering and problems with standardization of the measurements are
encountered. The aim was to develop a method for reliable, reproducible measurements on
CBCTs.
Materials and Methods:
Using a new method, buccal bone thickness was measured on 10 CBCTs at 6 positions
along the implant axis. Inter- and intra-observer reproducibility was assessed by repeated
measurements by two examiners.
Results:
Mean buccal bone thickness measured by observer one and two was 2.42 mm (sd:0.50) mm
and 2.41 mm (sd:0.47), respectively. Interobserver intraclass correlation coefficient was 0.96
(95%CI 0.93-0.98). The mean buccal bone thickness of the first measurement and the second
measurement of observer one was 2.42 mm (sd:0.50) and 2.53 mm (sd:0.49), respectively,
with an intra-observer intraclass correlation coefficient of 0.93 (95%CI 0.88-0.96). The mean
buccal bone thickness of the first measurement and the second measurement of observer
two was 2.41 mm (sd:0.47) and 2.52 mm (sd:0.47), respectively, with an intra-observer
intraclass correlation coefficient of 0.96 (95%CI 0.93-0.97).
Conclusion:
Applying the methods used in this study, CBCTs are suitable for reliable and reproducible
measurements of buccal bone thickness at implants.
5
103
Introduction
Single-tooth implant placement in the aesthetic zone is a highly reliable treatment option for replacing a
failing tooth.1-4 Yet, research interest has shifted from implant survival towards optimal preservation of soft
and hard peri-implant tissues.5-7 Especially in the aesthetic region, buccal bone and its preservation is one
of the key factors in aesthetic outcome.8 Computerized tomography (CT) scans and cone beam CTs (CBCTs)
are commonly used for presurgical planning and to predict bone density and potential stability of dental
implants.9 Next to this, CTs and CBCTs also allow for measuring bone at dental implants during follow-
up.10,11 The quality and accuracy of a three-dimensional (3D) model derived from a (CB)CT is dependent on
scanner related factors such as type of scanner, field of view (FoV), artifacts and voxel size.12 In addition,
patient related factors such as patient position and metal artifacts13, and operator related factors as the
segmentation process or interpretation of the (CB)CT are of influence.14 It has been reported that buccal
bone thickness at implant sites can be measured with CBCT, but background scattering and problems with
standardization of the measurements are frequently encountered.15 In view of the aforementioned, there is
need for a reliable, reproducible method to facilitate measurements. The use of 3D image diagnostic and
treatment planning software programs in combination with software programs for tracking and registration
of the exact position of existing dental implants in radiographs can be of help.16
The aim of the current study was to develop a reproducible method based on 3D image diagnostic and
treatment planning software programs for buccal bone measurements at implants on CBCTs.
Materials and Methods
Ten patients with a dental implant in the aesthetic zone (region 13 to 23) were included. Patients were part
of a randomized controlled trial on aesthetics; the study was approved by the local Medical Ethic Board
(METC 2010.246) as well as that written informed consent was obtained from all patients. The CBCT scans
were made with an iCAT 3D exam scanner (KaVo Dental GmbH, Biberach, Germany), which scanner was
validated for measuring bone thickness by Fourie et al.17 The method error of this scanner is very small,
i.e. 0.05 mm (95 CI 0.03-0.07). The standard used voxel size was 0.30 and FoV was 100 x100 mm on the
CBCT scans. Bone measurements at implants on the CBCT scans was done using 3D image diagnostic and
treatment planning software (Nobelclinician, version 2.1 (Nobel Biocare - Guided Surgery Center, Mechelen,
Belgium). A novelty is that this program, regularly used pre-operatively, was employed to measure the
buccal bone thickness (in mm), after implant surgery. To allow for reproducible measurements, a CBCT
imaging and software protocol was developed.
104
Table 1. Flow diagram of CBCT imaging and measurements to calculate bone thickness buccally of implants.
CBCT of patient
Determination and registration of position of implant with MIRIT
Measurements from central axis of planning implant to outer contour of buccal bone with Measurement
Tool in Nobelclinician
Import of patient DICOM-file and implant DICOM-file into Maxilim
Alignment of planning implant and registered implant with Research Tool
in Nobelclinician
Import of patient DICOM-file into Nobelclinician
Calculation of buccal bone thickness by substraction of radius of implant
5
105
CBCT imaging and software protocol
Acquired CBCT Digital Imaging and Communications in Medicine (DICOM) datasets were transferred to a
computer. The CBCT images were exported in DICOM multi-file format and imported into Maxilim, version
2.3 (Medicim, Sint-Niklass, Belgium). Maxilim is a medical image computing program assessing the
patients head anatomy and is used for diagnostics and preoperative planning of maxillofacial surgery. The
input information for Maxilim is a 3D dataset, often (CB)CT data. The DICOM files of all patients were set
continuously on Hounsfield Unit (HU) isovalue 280. The implant used was set on HU isovalue 130. With
Multimodality Image Registration using Information Theory (MIRIT), which has an accuracy of a subvoxel,
the exact position of the implant could be recognized, determined and implemented in the patients DICOM
files16. The MIRIT procedure is based on recognizing image similarities. The degree of similarity between
intensity patterns in two images is determined and, consequently, the recognized image is registered
automatically into one coordinate system. Image similarities are broadly used in medical imaging to
enhance diagnostics. In the software program Nobelclinician, the patients DÌCOM files were opened with
the same HU isovalue of 280. An extra research tool was added to this software program by the program
makers, so that the DICOM file from Maxilim was recognized by this program and the exact position of the
implant, as determined in Maxilim, could be aligned with a planning implant in NobelClinician. Due to
the alignment of a planning implant (with a known configuration) and an actual inserted implant into one
image, measurements could take place at the exact buccal midline of the implant (Figure 1). The display of
the implant and surrounding structures was set on bone value, so that the outline of the bony structures
could be seen and measured. The buccal bone measurements at midline of the implant were performed
with the standard provided measurement tools in the software program of Nobelclinician.
Measuring procedure
The implant and patient dataset were exactly aligned by the MIRIT method, so that the distance from the
central axis of the implant to the outer contour of the buccal bone could be measured. Area of interest
was the upper 5mm section of the implant, beginning at the neck of the implant towards the apical
direction. Exact dimensions along the implant axis of each implant configuration used in the study was
provided by the manufacturer. Buccal bone measurements (in mm) were performed calculating the
distance to the buccal bone outline minus the radius of the interior contour of the implant. These buccal
bone measurements were done for 5 mm at each millimeter along the axis, beginning at the neck of the
implant (Figure 2). Measurements were repeated twice (with time interval to prevent recollection) by two
independent operators (HM and KS) in a random order. Flow diagram of the consecutive steps has been
depicted in Table 1.
Statistical analysis
Continuous variables were expressed as a mean with standard deviation. Interobserver and intra-observer
variability was assessed using two-way mixed intraclass correlation coefficient single measures analysis18.
All analyses were performed using SPSS software (version 20.0).
106
Figure 1. Due to the alienation of the patients` DÌCOM fi les by MIRIT, the exact position of the implant was defi ned. As
such, the measurements could take place in the exact correct buccal direction.
Figure 1. Due to the alienation of the patients` DÌCOM fi les by MIRIT, the exact position of the implant was defi ned. As such, the measurements could take place in the exact correct buccal direction.
Figure 2. Measurements were performed at each millimeter along the axis of the implant for
5mm, beginning at the neck of the implant.
5
107
Results
The mean buccal bone thickness measured by observer one and two was 2.42 mm (sd:0.50) and 2.41
mm (sd:0.47), respectively. Interobserver intraclass correlation coefficient was 0.96 (95%CI 0.93-0.98).
The mean buccal bone thickness of the first measurement and the second measurement of observer one
was 2.42 mm (sd:0.50) and 2.53 mm (sd:0.49), respectively, with an intra-observer intraclass correlation
coefficient of 0.93 (95%CI 0.88-0.96). The mean buccal bone thickness of the first measurement and the
second measurement of observer two was 2.41 mm (sd:0.47) and 2.52 mm (sd:0.47), respectively, with
an intra-observer intraclass correlation coefficient of 0.96 (95%CI 0.93-0.97).
Discussion
Intra-observer and interobserver agreement was very high with measurements on CBCTs of bone buccally
of dental implants. Apparently, the method is clear and measurements can be performed reproducibly.
Moreover, measurements are not observer dependent, meaning that results of different observers in
different studies can be compared with each other. In previous studies buccal bone thickness was
also measured, but the exact position of these measurements at the surface of the implant was not
determined by 3D image-based diagnostic and treatment planning software programs.10,11,15 It is important
to perform measurements of bone thickness at the same position at implants to make comparison in
time possible. Because of the cylindrical contour of the implant, thickness of bone can vary considerably
in the mesio-distal direction. The combination of the software programs MIRIT (for determination and
registration of the implant position in Maxilim) and Research Tool in Nobelclinician (for alignment of
planning implant and registered implant) makes the method reproducible.
Scattering of the titanium dental implant makes it difficult to perform measurements from the bone-
to-implant boundary to the buccal outer contour of the bone19. The combination of Research Tool in
Nobelclinician (exact positioning of the planning implant) and Measurement Tool in Nobelclinician
(for measurements from central axis of the implant) makes it possible to bypass the scattering area.
Measurements are corrected by subtraction of the known radius of implant, resulting in the actual
thickness of bone. Measurements are not directly possible in NobelClinician, because the image
recognizing program MIRIT can only be executed in the configuration of Maxilim. It would be desirable if
the total procedure could be carried in one program, being NobelClinician.
Conclusions
When applying 3D image-based software programs according to the set-up used in this study, CBCTs are
suitable for reliable and reproducible measurements of buccal bone thickness at implants.
108
List of abbreviations
CBCT: Cone Beam Computed Tomography
CT: Computerized Tomography
FoV: Field of View
3D: three-Dimensional
DICOM: Digital Imaging and Communications in Medicine
HU: Hounsfi eld Unit
MIRIT: Multimodality Image Registration using Information Theory
5
109
References
1. Den Hartog L, Slater JJ, Vissink A, Meijer
HJ, Raghoebar GM. Treatment outcome of
immediate, early and conventional single-tooth
implants in the aesthetic zone: a systematic
review to survival, bone level, soft-tissue,
aesthetics and patient satisfaction. J Clin
Periodontol. 2008;35:1073-86.
2. De Rouck T, Collys K, Cosyn J. Single-tooth
replacement in the anterior maxilla by means of
immediate implantation and provisionalization:
a review. Int J Oral Maxillofac Implants.
2008;23:897-904.
3. Esposito M, Grusovin MG, Polyzos IP, Felice P,
Worthington HV. Timing of implant placement
after tooth extraction: immediate, immediate-
delayed or delayed implants? A Cochrane
systematic review. Eur J Oral Implantol.
2010;3:189-205.
4. Jung RE, Zembic A, Pjetursson BE, Zwahlen M,
Thoma DS. Systematic review of the survival
rate and the incidence of biological, technical,
and aesthetic complications of single crowns on
implants reported in longitudinal studies with
a mean follow-up of 5 years. Clin Oral Implants
Res. 2012;23( Suppl 6):2-21.
5. Hammerle CH, Araujo MG, Simion M, Osteology
Consensus Group 2011. Evidence-based
knowledge on the biology and treatment of
extraction sockets. Clin Oral Implants Res.
2012;23(Suppl 5):80-2.
6. Botticelli D, Berglundh T, Lindhe J. Hard-tissue
alterations following immediate implant
placement in extraction sites. J Clin Periodontol.
2004;31:820-8.
7. Jemt T. Regeneration of gingival papillae after
single-implant treatment. Int J Periodontics
Restorative Dent. 1997;17:326-33.
8. Meijer HJ, Stellingsma K, Meijndert L, Raghoebar
GM. A new index for rating aesthetics of implant-
supported single crowns and adjacent soft
tissues - the Implant Crown Aesthetic Index. Clin
Oral Implants Res. 2005;16:645-9.
9. Sennerby L, Andersson P, Pagliani L, Giani C,
Moretti G, Molinari M, Motroni A. Evaluation
of a Novel Cone Beam Computed Tomography
Scanner for Bone Density Examinations in
Preoperative 3D Reconstructions and Correlation
with Primary Implant Stability. Clin Implant Dent
Relat Res. 2015;17(5):844-53.
10. Kan JY, Roe P, Rungcharassaeng K, Patel RD, Waki
T, Lozada JL, Zimmerman G. Classification of
sagittal root position in relation to the anterior
maxillary osseous housing for immediate
implant placement: a cone beam computed
tomography study. Int J Oral Maxillofac Implants.
2011;26:873-6.
11. Miyamoto Y, Obama T. Dental cone beam
computed tomography analyses of
postoperative labial bone thickness in maxillary
anterior implants: comparing immediate and
delayed implant placement. Int J Periodontics
Restorative Dent. 2011;31:215-25.
12. Kamburoglu K, Murat S, Kilic C, Yuksel S,
Avsever H, Farman A, et al. Accuracy of
CBCT images in the assessment of buccal
marginal alveolar peri-implant defects: effect
of field of view. Dentomaxillofac Radiol.
2014;43:20130332.
13. Ritter L, Mischkowski RA, Neugebauer J,
Dreiseidler T, Scheer M, Keeve E, Zöller JE. The
influence of body mass index, age, implants,
and dental restorations on image quality
of cone beam computed tomography. Oral
Surg Oral Med Oral Pathol Oral Radiol Endod.
2009;108:e108-16.
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14. Besimo CE, Lambrecht JT, Guindy JS. Accuracy of
implant treatment planning utilizing template-
guided reformatted computed tomography.
Dentomaxillofac Radiol. 2000;29:46-51.
15. Roe P, Kan JY, Rungcharassaeng K, Caruso JM,
Zimmerman G, Mesquida J. Horizontal and
vertical dimensional changes of peri-implant
facial bone following immediate placement
and provisionalization of maxillary anterior
single implants: a 1-year cone beam computed
tomography study. Int J Oral Maxillofac
Implants. 2012;27:393-400.
16. Maes F, Collignon A, Vandermeulen D, Marchal
G, Suetens P. Multimodality image registration
by maximization of mutual information. IEEE
Trans Med Imaging. 1997;16:187-98.
17. Fourie Z, Damstra J, Schepers RH, Gerrits PO,
Ren Y. Segmentation process significantly
influences the accuracy of 3D surface
models derived from cone beam computed
tomography. Eur J Radiol. 2012;81:e524-30.
18. Shrout PE, Fleiss JL. Intraclass correlations:
uses in assessing rater reliability. Psychol Bull.
1979;86:420-8.
19. Parsa A, Ibrahim N, Hassan B, Syriopoulos K,
van der Stelt P. Assessment of metal artefact
reduction around dental titanium implants
in cone beam CT. Dentomaxillofac Radiol.
2014;43:20140019.
5
111
112
6
113
6Buccal bone measurements at dental
implants the aesthetic region:
a 1 year follow-up cone -beam
computed tomography study.
This chapter is an edited version of the manuscript: KW Slagter, GM Raghoebar, NA Bakker, A Vissink, HJA Meij er.
Buccal bone measurements at dental implants the aesthetic zone: a 1 year follow-up cone beam computed tomography study. Submitted.
114
Abstract
Background: Sufficient buccal bone thickness (BBT) is important for optimal aesthetic results of implant
treatment in the aesthetic zone. BBT measurements can be done with cone beam computed
tomography (CBCT), but studies are scarce.
Aim:To assess the mean amount of BBT as a function of time after implant placement and relate
it to immediate and delayed placed implants in the aesthetic zone with a 1 year follow-up
using CBCT-scans.
Materials and Methods: After 1 month and 1 year of definitive crown placement, BBT was measured on CBCTs of
80 patients, part of 2 randomized clinical trials. Patients were divided in 4 study groups
according bony defect (<5 or ≥5 mm) and timing of implant placement (immediate or
delayed). Area of interest was the upper 5mm section of the implant, beginning at the neck
of the implant towards the apical direction and measured in steps of 1 mm along the axis of
the implant).
Results:BBT 1 year after placement of the definitive crown, varied for the immediate placed
implants of study group 1 from 1.52(sd:0.89) to 2.04(sd:0.77) mm (i.e., at the level of the
upper 5 mm of the implant); for study group 2 from 1.08(sd:0.55) to 1.44(sd:0.72) mm and
for study group 3 from 1.00(sd:0.47) to 1.29(sd:0.72) mm. BBT varied from 0.71(sd:0.28)
to 0.92(sd:0.57) mm for the delayed placed implants in study group 4. Mean loss of BBT
between 1 month and 1 year was negigible and independent of the size of the buccal bone
defect (<5 or ≥5 mm) prior to implant insertion and timing of implant insertion.
Conclusion:BBT at dental implants in the aesthetic zone measured on CBCTs, appears to be stable
for immediate and delayed placed implants after placement of the definitive crown,
independent of the size of buccal bone defect prior to implant insertion and timing of
provisionalization.
6
115
Introduction
Single-tooth immediate implant placement in the aesthetic zone is a highly reliable treatment option
for replacing a failing tooth.1-3 Particularly in the aesthetic zone, establishment and maintenance of
healthy peri-implant hard and soft tissues is crucial.4,5 The presence of sufficient bone volume is the most
important prerequisite to achieve primary stability in case of immediate implant placement in an extraction
socket. Peri-implant bone preservation could be considered as one of the key factors in aesthetic
outcome.6 The morphological assessment of bone volume is of great interest to clinicians. In the literature
there is insufficient evidence to set a threshold for minimum buccal bone thickness to ensure the aesthetic
outcome and the long-term stability.6-8 In the aesthetic zone there is data of buccal bone dimensions at
different apical positions when the tooth is still in situ.9 Mean buccal bone thickness (BBT) varied from
0.6 mm to 0.8 mm, measured at different locations at central incisors and lateral incisors.9 The lack of
clinical data regarding bone thickness at buccal aspect of dental implants is probably related to frequently
encountered difficulties in standardization of the measurements. Cone-beam computed tomography
(CBCT) has proven to be a useful tool that has been successfully employed for various dental procedures.10
The choice of an accurate and reliable imaging modality is clinically important in terms of postoperative
monitoring of bone volume stability and to choose an adequate treatment approach.9 The CBCT might be
used for evaluation of implant buccal bone dimension.11-13 The use of 3D image diagnostic and treatment
planning software programs in combination with software programs for tracking and registration of the
exact position of existing dental implants in radiographs can be of help. In view of the aforementioned,
there is need for more studies which measure BBT at single tooth implants in the aesthetic zone on CBCT-
scans. To the best of our knowledge, no clinical trials yet assessed the amount of implant buccal bone
with a reproducible measure method on CBCT-scans at different apical positions along the implant axis.
It is therefore not known how reliable the CBCT-scan is to assess BBT as a function of time after implant
placement in the aesthetic zone.
The aim of the present study was to assess the mean buccal bone thickness (BBT) as a function of time and
relate it to immediate and delayed placed implants in the aesthetic zone in after 1 month and 1 year follow-
up using CBCT-scans.
Material and methods
To measure BBT on a CBCT-scan were 80 patients included with an immediate or delayed placed implant in
the aesthetic region (region 13 to 23) of the maxilla (Figure 1). Patients were part of two randomized clinical
trials. Both trials14,15 were approved by the local Medical Ethic Board (METC 2010.246) and registered in
a trial register (www.isrtcn.com: ISRCTN57251089) as well as that written informed consent was obtained
from all patients. Patients were divided according the bony defect after removal of the failing tooth before
implant placement. Due to sample size calculation, the two trials consisted each out of 20 patients per
study group, with a total of 4 study groups (3 study groups with immediate implant placement and 1 study
group with delayed implant placement).
116
Figure 1. Cohort flow diagram.
Enrollment Assessed for eligibility (n=80)
Excluded (n=0) • Not meeting inclusion criteria (n=0) • Declined to participate (n=0) • Other reasons (n=0)
Allocated to intervention (n=40) • Received allocated intervention (n=40) • Did not receive allocated interven tion (give reasons) (n=0)
Lost to follow-up (give reasons) (n=1, patient did not show up at appointments) Discontinued intervention (give reasons) (n=0)
Analysed (n=39) • Excluded form analysis (give reasons) (n=0)
Allocated to intervention (n=40) • Received allocated intervention (n=40) • Did not receive allocated interven tion (give reasons) (n=0)
Lost to follow-up (give reasons) (n=0) Discontinued intervention (give reasons) (n=0)
Analysed (n=40) • Excluded form analysis (give reasons) (n=0)
Randomized (n=80)
Allocation
Follow-Up
Analysis
6
117
A research-nurse not involved in the study blindly allocated by a computerized random number the
patients in:
Study A with patients with a buccal bony defect of <5 mm:
- Group 1 (n=20) : immediate placed implant (NobelActive, Nobel Biocare AB, Goteborg, Sweden) and
immediate provisionalization;
- Group 2 (n=20): immediate placed implant (NobelActive) and delayed provisionalization.
Study B with patients bony defect of ≥5 mm:
- Group 3 (n=20): immediate placed implant (NobelActive) and delayed provisionalization;
- Group 4 (n=20): delayed placed implant (NobelActive) and delayed provisionalization.
For the present study to measure changes in the BBT at the level of implants as a function of time, CBCT
scans were made after one month and 1 year after placement of the definitive crown (iCAT 3D exam
scanner,KaVo Dental GmbH, Biberach, Germany). This scanner was validated for measuring bone thickness
by Fourie et al.16 The method error of this scanner is very small, i.e. 0.05 mm (95 CI 0.03-0.07). The standard
used voxel size was 0.30 and FoV was 100 x100 mm on the CBCT scans. Bone measurements at implants
on the CBCT-scans were done using 3D image diagnostic and treatment planning software (Nobelclinician,
version 2.1 (Nobel Biocare - Guided Surgery Center, Mechelen, Belgium). To allow for reproducible
measurements, a CBCT imaging and software protocol was developed and validated.17
Measuring procedure
Acquired CBCT Digital Imaging and Communications in Medicine (DICOM) datasets were transferred to a
computer. The CBCT images were exported in DICOM multi-file format and imported into a medical image
computing program, Maxilim, version 2.3 (Medicim, Sint-Niklass, Belgium). With Multimodality Image
Registration using Information Theory (MIRIT), which has an accuracy of a subvoxel, the exact position of
the implant could be recognized, determined and implemented in the patients DICOM files.18 The implant
and patient dataset were exactly aligned by the MIRIT method, so that the distance from the central axis
of the implant to the outer contour of the buccal bone could be measured. Area of interest was the upper
5 mm section of the implant, beginning at the neck of the implant towards the apical direction. Exact
dimensions along the implant axis of each implant configuration used in the study was provided by the
manufacturer. Buccal bone measurements (in mm) were performed calculating the distance to the buccal
bone outline minus the radius of the interior contour of the implant. These buccal bone measurements
were done for 5 mm at each millimeter along the axis beginning at the neck of the implant (M0) towards
apical (M1,M2,M3,M4,M5) (Figure 2). Measurements were done (with time interval to prevent recollection)
by two independent operators (HM and KS) in a random order. This after validation of the measurement
procedure17 and an interobserver intraclass correlation coefficient of 0.96 (95%CI 0.93-0.98) and an
intra-observer intraclass correlation coefficient of 0.93 (95%CI 0.88-0.96) for examiner one and an intra-
observer intraclass correlation coefficient of 0.96 (95%CI 0.93-0.97) for examiner two.
118
Figure 2a. Measurements were performed at each millimeter along the axis of the implant for 5 mm,
beginning at the neck of the implant.
Figure 2b. Actual measurements beginning at the neck of the implant of the axis of the implant for 5
mm towards apical.
6
119
Statistical analysis
Friedman’s test was used to compare between bone thickness measurements at diff erent levels. In
case of uncertainty of the signifi cance because of the relatively small number of patients analysed and
the large number of outcomes, Bonferroni correction was considered in case of a p-value 0.01<>0.05. A
p-value of 0.05 was considered to indicate statistical signifi cance. All analyses were performed using
SPSS (PASW Statistics 20.0, SPSS Inc.; IBM Corporation, Chicago, IL, USA).
Results
One patient from study group 2 did not show up at appointments and was therefore excluded from
the study, which lead to evaluation of CBCT’s of 79 patients. Baseline charasteristics and treatment
specifi cations are presented in Table 1. The mean and standard deviation values of buccal bone thickness
(BBT) at diff erent levels 1 year after defi nitive crown placement are presented per study and study group
in Table 2.
In study A, with bony defects of <5 mm, the BBT in mm varied at the diff erent apical positions between
1.58(0.55)- 2.12(0.78) in group 1 (immediate placement and immediate provisonalization) and 1.10(0.70)-
1.46(0.82) in group 2 (immediate placement and delayed provisonalization) after 1 month with a
signifi cant diff erence at M1,M2,M3 and M4 (1-4mm apical). After 1 year the BBT in mm varied between
1.52(0.89)- 2.04(0.77) in group 1 and 1.08(0.55)- 1.44(0.72) in group 2 with a signifi cant diff erence at
M1,M2 and M3.
In study B, with bony defects of ≥5 mm, the BBT in mm varied at the diff erent apical positions between
1.11(0.65)-1.29(0.60) in group 3 (immediate placement and delayed provisonalization) and 0.79(0.46)-
0.93 (0.59) in group 4 (immediate placement and delayed provisonalization) after 1 month with a
signifi cant diff erence at M1. After 1 year the BBT in mm varied between 1.00(0.47) – 1.29 (0.72) in group 3
and 0.71(0.28) – 0.92 (0.57) in group 4 with a signifi cant diff erence at M0 (neck) and M1.
120
Table 1. Baseline characteristics and treatment specifications per study group.
Variable
Immediate
Group 1 (n=20)
Immediate
Group 2 (n=20)
Immediate
Group 3 (n=20)
Delayed
Group 4 (n=20)
Age Mean ± SD Range
39.4±16.9 19-70
42.3±14.2 23-66
43.7 ±13.9 18-63
48.6 ±16.4 20-72
Gender Male Female
5 15
8 12
11 9
7 13
Implant location
Incisor 1 Incisor 2 Canine
7 8 5
13 6 1
12 5 3
14 6 0
Table 2. Buccal bone measurements and changes after 1 month and 1 year.
Group 1 (n=20)
Group 2 (n=19)
Level of sign.
Group 3 (n=20)
Group 4 (n=20)
Level of sign.
Measurements 1 month
Mean (sd) in mm
Mean (sd) in mm
Mean (sd) in mm
Mean (sd) in mm
M0 (at neck) 1.84 (0.91) 1.27 (0.82) 0.06 1.01 (0.55) 0.79 (0.46) 0.19
M1 2.05 (0.80) 1.39 (0.94) 0.03* 1.29 (0.60) 0.88 (0.57) 0.03*
M2 2.12 (0.78) 1.46 (0.82) 0.02* 1.19 (0.61) 0.93 (0.59) 0.18
M3 2.08 (0.63) 1.39 (0.76) 0.01* 1.26 (0.61) 0.92 (0.62) 0.08
M4 1.89 (0.54) 1.31 (0.75) 0.01* 1.25 (0.67) 0.85 (0.66) 0.06
M5 1.58 (0.55) 1.10 (0.70) 0.07 1.11 (0.65) 0.82 (0.71) 0.18
Measurements 1 year
M0 (at neck) 1.52 (0.89) 1.28 (0.85) 0.41 1.00 (0.47) 0.71 (0.28) 0.07
M1 1.94 (0.79) 1.37 (0.78) 0.04* 1.25 (0.53) 0.81 (0.46) 0.01*
M2 2.04 (0.74) 1.44 (0.72) 0.02* 1.28 (0.67) 0.92 (0.57) 0.08
M3 1.91 (0.64) 1.39 (0.63) 0.02* 1.29 (0.72) 0.90 (0.55) 0.06
M4 1.66 (0.71) 1.24 (0.58) 0.07 1.24 (0.70) 0.85 (0.58) 0.06
M5 1.57 (0.90) 1.08 (0.55) 0.43 1.14 (0.66) 0.77 (0.59) 0.06
6
121
Discussion
A successful aesthetic outcome is suggested to be dependent on establishment of an optimal 3D implant
position within the available bone dimensions and the maintenance of adequate buccal bone over the
buccal implant surface19,20 but the amount of buccal bone is not known. The position of the implant in
relation to the bucco-oral dimension of the alveolar ridge is thought to influence the degree of bone
remodeling following implant placement.21 When there is no buccal bone present due to a bony defect
after extraction, the position and depth of the placed implant could be different compared to an intact
extraction socket or healed site. In the study of El Nahass and Naiem (2015) a mean buccal bone thickness,
in relation to natural incisors still in situ, of 0.57 mm and 0.84 mm was found in the first 4 mm towards
apically. This means that due to the surgical procedure with the slightly palatal placement of the implant
and augmentation of the buccal space in the extraction socket between implant and buccal wall, more
thickness of buccal bone is present at dental implants compared to natural teeth.
The reason behind the 6 measurements (M0-M5) performed after 1 month and 1 year after placement
of the definitive crown is to investigate the buccal bone thickness at different apical positions, clinically
relevant with dental implants in the aesthetic zone. No measurements for BBT at different positions along a
dental implant are known in the literature. Although measured in a different study design, a mean value of
0.16 (0.21) mm BBT is found in an immediate implant group of Raes et al.22 and 2.12 (0.92) mm BBT found
by Degidi et al.23 These numbers are in line for the immediate placed implants in this study. For delayed
placed implants, only a mean amount of 0.20 (0.22)mm is described by Raes et al.22 This number is lower
then the mean amount of BBT in this study.
Loss of buccal bone is inevitable, mainly as a consequence of the disappearance of bundle bone. Therefore
information on the original buccal bone contour prior to removal of the tooth should be provided to
measure the amount of change before and after implant placement. On post-operative CBCTs it is not
known how much of the original contour has been changed after dental implant treatment. It would be
interesting to include preoperative dimensions on CBCT-scans in relation to the actual position of the
placed implant on a post-operative CBCT’scan. More insight would be gained on alterations in BBT due
to the surgical procedure and occurring during the follow-up period. Consequently, implant positioning
in relation to the bucco-oral dimensions of the alveolar ridge, which is thought to influence the degree of
bone remodeling, could then be evaluated.6
Limitations of the study
Some limitations have to be addressed. The interpretation of the buccal bone adjacent to dental implants
on the resolution of the CBCT is insufficient in comparison with light microscopy.11 In the case of very thin
buccal bone, CBCT images seem not always reliable due to background scattering and problems with
standardization of the measurements.22,24,25 The quality and accuracy of a three-dimensional (3D) model
derived from a CBCT is dependent on scanner related factors such as type of scanner, field of view (FoV),
artifacts and voxel size.12 In addition, patient related factors such as patient position and metal artifacts26,
and operator related factors as the segmentation process or interpretation of the CBCT are of influence.27
122
Conclusion
Buccal Bone Thickness at dental implants in the aesthetic zone measured on CBCTs, appears to be stable
for immediate and delayed placed implants after placement of the definitive crown, independent of the
size of buccal bone defect prior to implant insertion and timing of provisionalization.
6
123
References
1. Esposito M, Grusovin MG, Polyzos IP, Felice P,
Worthington HV. Timing of implant placement
after tooth extraction: immediate, immediate-
delayed or delayed implants? A Cochrane
systematic review. Eur J Oral Implantol 2010
Autumn;3(3):189-205.
2. Lang NP, Pun L, Lau KY, Li KY, Wong MC. A
systematic review on survival and success
rates of implants placed immediately into fresh
extraction sockets after at least 1 year. Clin Oral
Implants Res 2012 Feb;23 Suppl 5:39-66.
3. Slagter KW, den Hartog L, Bakker NA, Vissink
A, Meijer HJ, Raghoebar GM. Immediate
placement of dental implants in the esthetic
zone: a systematic review and pooled analysis.
J Periodontol 2014 Jul;85(7):e241-50.
4. den Hartog L, Slater JJ, Vissink A, Meijer
HJ, Raghoebar GM. Treatment outcome of
immediate, early and conventional single-tooth
implants in the aesthetic zone: a systematic
review to survival, bone level, soft-tissue,
aesthetics and patient satisfaction. J Clin
Periodontol 2008 Dec;35(12):1073-1086.
5. Cosyn J, Hooghe N, De Bruyn H. A systematic
review on the frequency of advanced recession
following single immediate implant treatment. J
Clin Periodontol 2012 Jun;39(6):582-589.
6. Merheb J, Quirynen M, Teughels W. Critical
buccal bone dimensions along implants.
Periodontol 2000 2014 Oct;66(1):97-105.
7. Klinge B, Flemmig TF, Working Group 3. Tissue
augmentation and esthetics (Working Group
3). Clin Oral Implants Res 2009 Sep;20 Suppl
4:166-170.
8. Teughels W, Merheb J, Quirynen M. Critical
horizontal dimensions of interproximal and
buccal bone around implants for optimal
aesthetic outcomes: a systematic review. Clin
Oral Implants Res 2009 Sep;20 Suppl 4:134-
145.
9. El Nahass H, Naiem SN. Analysis of the
dimensions of the labial bone wall in the
anterior maxilla: a cone-beam computed
tomography study. Clin Oral Implants Res 2015
Apr;26(4):e57-61.
10. Sennerby L, Andersson P, Pagliani L, Giani
C, Moretti G, Molinari M, et al. Evaluation of
a Novel Cone Beam Computed Tomography
Scanner for Bone Density Examinations
in Preoperative 3D Reconstructions and
Correlation with Primary Implant Stability. Clin
Implant Dent Relat Res 2015 Oct;17(5):844-53.
11. Razavi T, Palmer RM, Davies J, Wilson R, Palmer
PJ. Accuracy of measuring the cortical bone
thickness adjacent to dental implants using
cone beam computed tomography. Clin Oral
Implants Res 2010 Jul;21(7):718-725.
12. Kamburoglu K, Murat S, Kilic C, Yuksel S,
Avsever H, Farman A, et al. Accuracy of
CBCT images in the assessment of buccal
marginal alveolar peri-implant defects:
effect of field of view. Dentomaxillofac Radiol
2014;43(4):20130332.
13. Ritter L, Elger MC, Rothamel D, Fienitz T,
Zinser M, Schwarz F, et al. Accuracy of peri-
implant bone evaluation using cone beam CT,
digital intra-oral radiographs and histology.
Dentomaxillofac Radiol 2014;43(6):20130088.
14. Slagter KW, Meijer HJ, Bakker NA, Vissink
A, Raghoebar GM. Feasibility of immediate
placement of single-tooth implants in the
aesthetic zone: a 1-year randomized controlled
trial. J Clin Periodontol 2015 Jun 26. doi:
10.1111/jcpe.12429. [Epub ahead of print]
15. Slagter KW, Meijer HJ, Bakker NA, Vissink
A, Raghoebar GM. Immediate placement of
single-tooth implants in the esthetic zone: a
1-year randomized controlled trial. J Periodontol
2016;15:1-15.
124
16. Fourie Z, Damstra J, Schepers RH, Gerrits PO, Ren
Y. Segmentation process significantly influences
the accuracy of 3D surface models derived from
cone beam computed tomography. Eur J Radiol
2012 Apr;81(4):e524-30.
17. Kirsten W Slagter, Gerry M Raghoebar,
Arjan Vissink, Henny J A Meijer. Inter- and
intraobserver reproducibility of buccal bone
measurements at dental implants with cone
beam computed tomography in the esthetic
region. International Journal of Implant Dentistry
2015, 1:8.
18. Maes F, Collignon A, Vandermeulen D, Marchal
G, Suetens P. Multimodality image registration
by maximization of mutual information. IEEE
Trans Med Imaging 1997 Apr;16(2):187-198.
19. Buser D, Martin W, Belser UC. Optimizing
esthetics for implant restorations in the anterior
maxilla: anatomic and surgical considerations.
Int J Oral Maxillofac Implants 2004;19
Suppl:43-61.
20. Grunder U, Gracis S, Capelli M. Influence of the
3-D bone-to-implant relationship on esthetics.
Int J Periodontics Restorative Dent 2005
Apr;25(2):113-119.
21. Qahash M, Susin C, Polimeni G, Hall J, Wikesjo
UM. Bone healing dynamics at buccal peri-
implant sites. Clin Oral Implants Res 2008
Feb;19(2):166-172.
22. Raes F, Renckens L, Aps J, Cosyn J, De Bruyn
H. Reliability of circumferential bone level
assessment around single implants in healed
ridges and extraction sockets using cone
beam CT. Clin Implant Dent Relat Res 2013
Oct;15(5):661-672.
23. Degidi M, Daprile G, Nardi D, Piattelli A. Buccal
bone plate in immediately placed and restored
implant with Bio-Oss((R)) collagen graft: a 1-year
follow-up study. Clin Oral Implants Res 2013
Nov;24(11):1201-1205.
24. Naitoh M, Nabeshima H, Hayashi H, Nakayama
T, Kurita K, Ariji E. Postoperative assessment
of incisor dental implants using cone-beam
computed tomography. J Oral Implantol
2010;36(5):377-384.
25. Roe P, Kan JY, Rungcharassaeng K, Caruso JM,
Zimmerman G, Mesquida J. Horizontal and
vertical dimensional changes of peri-implant
facial bone following immediate placement
and provisionalization of maxillary anterior
single implants: a 1-year cone beam computed
tomography study. Int J Oral Maxillofac Implants
2012 Mar-Apr;27(2):393-400.
26. Ritter L, Mischkowski RA, Neugebauer J,
Dreiseidler T, Scheer M, Keeve E, et al. The
influence of body mass index, age, implants,
and dental restorations on image quality of
cone beam computed tomography. Oral Surg
Oral Med Oral Pathol Oral Radiol Endod 2009
Sep;108(3):e108-16.
27. Besimo CE, Lambrecht JT, Guindy JS. Accuracy of
implant treatment planning utilizing template-
guided reformatted computed tomography.
Dentomaxillofac Radiol 2000 Jan;29(1):46-51.
6
125
126
7
127
7General discussion
&
Conclusions
128
General Discussion and Conclusions
The PhD research described in this thesis was performed to provide evidence for the use of immediately
placed dental implants and/or provisionalization in the aesthetic zone. At the start of this PhD project in
2009, studies with immediate implant placement were scarce. Based on the studies performed in this
PhD study one could say in general that the 1-year results of immediately placed dental implants and/or
provisionalization in the aesthetic zone are comparable and very promising.
Current knowledge
A Cochrane review on replacement of a single tooth with an immediate, early or delayed implant in a
fresh extraction socket after tooth extraction evaluated success, complications, aesthetics and patient
satisfaction among immediate, early and delayed implants and whether and when augmentation
procedures are necessary and which is the most effective augmentation technique.1 The authors
concluded that there was insufficient evidence to determine the possible advantages and disadvantages
of immediate, early (immediate-delayed) and delayed implants. However, the authors mentioned
that immediate and early (immediate-delayed) implants may be at a higher risk of implant failure and
complications than delayed implants, while the aesthetic outcome might be better when placing implants
just after tooth extraction. Moreover, there is yet insufficient evidence whether placement of implants in
fresh extraction sockets have to be combined with augmentation procedure as well as which augmentation
techniques is superior when indicated.
A systematic review was performed specifically assessing the clinical outcome of immediate placed
implants in the aesthetic zone.2 This review (Chapter 2) learned that timing of provisionalization was not
associated with outcome in terms of implant survival, which allows for immediate provisionalization after
immediate implant placement. Regarding risk factors for change in marginal bone level (MBL), immediate
provisionalization was associated with less bone loss, which is, to our opinion, a clinically relevant
observation. Furthermore, the use of a flap and connective tissue graft was significantly associated with
more bone loss. Unfortunately, the few included randomized clinical studies were based on short-term
results (1 year), and studies with a longer follow-up period are needed to predict the aesthetic outcome on
the long term. In future, we will report on the long-term results of our randomized clinical trials.
In future trials, not only interproximal bone level dimensions should be taken into account, but also buccal
bone level and buccal bone thickness. Loss of buccal bone after removal of a tooth is inevitable but there
is insufficient evidence to set a threshold for minimum buccal bone thickness needed buccally of the
implant to ensure the aesthetic outcome and the long-term stability.3-5 For example, most studies do not
investigate the size of the bony defect after extraction. However, it has been hypothesized that an intact
labial bony plate of the failing tooth might minimize facial gingival recession.6 Recently, due to altering
techniques, the literature also reports a favourable treatment outcome of immediate implant placement in
extraction sockets with buccal plate dehiscences.7-9 Thus, probably an intact buccal plate is not essential
for immediate implant placement if the implant can be placed with sufficient primary stability. The current
lack of clinical data regarding bone thickness at the buccal aspect of dental implants is probably related
7
129
to frequently encountered difficulties in how to reliably measure buccal bone thickness. A method was
introduced to reliably measure buccal bone thickness after implant placement (Chapter 5), but still no
reliable method is available to measure buccal bone thickness before implant placement.
Besides clinical and radiographic outcomes of the peri-implant tissues, aesthetic evaluation and patient-
centered outcomes are gaining interest in the literature.10-12 The combination of unfavourable bony
defects after extraction and thin overlying soft tissues are a considerable aesthetic risk for maintaining
an acceptable long-term aesthetic outcome for immediately placed implants despite ideal placement and
synchronous hard or soft tissue grafting procedures.6 The aesthetic result is mainly determined by the
shape of these pink soft peri-implant tissues and the contour and colour of the definitive crown.
Immediate placement and provisionalization in the aesthetic zone has some important advantages for
the patient: the patient immediately benefits from this treatment method which can substantially have
a positive impact on the patient’s quality of life. Thus, patient satisfaction scales have to be applied,
in addition to the already used treatment outcome parameters and aesthetic indexes in future studies
assessing the treatment outcome of immediate placement of dental implants in the aesthetic zone (see
Chapters 3 and 4). An aesthetic evaluation by professionals and a patient-centered outcome on quality of
life should be a requirement for publications on single tooth replacement in the aesthetic zone.
Clinical outcome
Survival
In both clinical trials (Chapters 3 and 4) the survival rate of the immediate placed implants was 100%.
Survival rate was defined as the percentage of functional implants one year after definitive crown
placement. This is consistent with the one-year survival rates of around 98% in the literature.1,13 In a
systematic review13, factors were analyzed: reasons for extraction, antibiotic use, position of implant
(anterior vs. posterior, maxilla vs. mandible) and type of loading. Only the regimen of antibiotic use
reduced the survival rate significantly because provision of antibiotics may have helped to prevent post-
operative infection.
Peri-implant hard tissue dimensions
The presence of sufficient bone volume is the most important prerequisite to achieve primary stability in
case of immediate implant placement in an extraction socket. The size of the bony defect after extraction is
considered a considerable aesthetic risk for immediately placed implants despite ideal placement.14 Thus,
peri-implant bone preservation is thought to be a key factor determining the outcome of peri-implant hard
tissues as Marginal Bone level (MBL) and the amount of Buccal Bone Thickness (BBT).4
In two clinical studies (Chapter 3 and 4) the outcome of single-tooth implants in the aesthetic zone were
assessed. Patients were divided according to buccal bony defects of <5 mm and ≥5 mm. Unfortunately,
in the literature, yet no publications are available indicating the effect of the size of the bony defects
on treatment outcome. Although, not supported by evidence, recent studies report that buccal plate
dehiscences possibly not influence the outcome of immediate implant placement.7-9 To achieve primary
stability in case of immediate implant placement in an extraction socket is leading regarding a favourable
130
outcome, but it is not an easy procedure. Due to the complexity of the surgery (bone augmentation and soft
tissue grafting in the same operation) the studies in this thesis focused only on the treatment outcome of
immediate placement.
Marginal Bone level
Marginal Bone Level (MBL) change was the primary outcome measure for both clinical studies. MBL led to
comparable outcomes in all patient groups subject to evaluation of immediate and delayed placement and
independent of the size of buccal bone defect prior to implant insertion and timing of provisionalization.
The change in MBL in this study is considerably less than the generally accepted magnitude of up to 1
mm for the first year after immediate implant placement described in the literature.2,13 MBL loss usually
predominantly occurs during the first year after immediate implant placement and hardly progresses
thereafter.13 Changes in MBL will probably not progress after this first year, but a longer follow-up period is
needed.
Change in Buccal Bone level
A successful aesthetic outcome is suggested to be dependent on establishment of an optimal three-
dimensional implant position within the available bone dimensions and the maintenance of adequate
Buccal Bone Thickness (BBT) along the implant axis.15,16 If there is no buccal bone present due to a bony
defect after extraction, the position and depth of the placed implant could be different compared to
an intact extraction socket or healed site. In the present clinical studies, BBT at dental implants in the
aesthetic zone, measured on CBCTs, appeared to be stable after 1 year, irrespective whether immediate
or delayed implant placement used, and independent of size of defect, timing of implant insertion and
provizionalisation. Still the interpretation of BBT adjacent to dental implants on the resolution of the
CBCT is insufficient in comparison with light microscopy.17 In the case of very thin buccal bone, CBCT
images seem not always reliable due to background scattering and problems with standardization of
the measurements.18-20 The quality and accuracy of a three-dimensional (3D) model derived from a CBCT
is dependent on scanner related factors such as type of scanner, field of view (FoV), artifacts and voxel
size.21,22 In addition, patient related factors such as patient position and metal artifacts23, and operator
related factors as the segmentation process or interpretation of the CBCT are of influence.24 Although
precise BBT measurements on CBCT scans rely on various factors, standardized measurements should be
an integral part of the treatment evaluation as the amount of BBT influences the treatment outcome.
Peri-implant soft tissues dimensions
It has been described that immediate implant placement is associated with an increased risk for recession
of peri-implant tissues.25,26 A midfacial recession of 1 mm is reported for the outcome of immediate implant
placement.25,26 Larger bony defects are accompanied by a higher frequency and magnitude of facial gingival
recession (>1.5 mm) 1-year after immediate tooth replacement.6 Recession of the peri-implant tissues in
our clinical studies were clinically acceptable after one year. Due to support of a provisional crown, peri-
implant tissues have the possibility to establish their form around an anatomically shaped crown. In the
aesthetic zone it is therefore a must to use a provisional crown before placement of the definitive crown.
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131
All other parameters as the health of the keratinized gingiva remained stable throughout the study period,
while the plaque and bleeding indexes remained low in all groups. Participating patients seem to be well
aware of the necessity of an adequate oral hygiene to keep healthy peri-implant tissues on the long term.
Good oral hygiene instructions by the treatment provider are therefore a must.
The health, shape and form of the soft peri-implant tissues mainly determine the aesthetic result. It is
therefore interesting that primary outcome measures in studies are particularly survival or the hard peri-
implant tissues (MBL). The reason could be because the hard tissue dimensions support to a large extent
the soft tissues. A shift towards outcome measures in soft peri-implant tissues is thought to be more
logical in the aesthetic zone.
Aesthetic assessments
The clinical studies (Chapter 3 and 4) specifically asses the differences in the aesthetic zone. Interestingly,
aesthetic scores did not differ between groups with regard to buccal bony defects of <5 mm or ≥5 mm. This
is an important observation as differences in treatment outcome could have been expected. The aesthetic
result is mainly determined by the shape of healthy pink soft peri-implant tissues and the contour and
colour of the definitive crown. The total aesthetic outcome in these clinical studies was mainly influenced
by the appearance of the implant crown (WES) and to a lesser extent by the peri-implant mucosa (PES).27
The PES/WES28 and ICAI29 scores were comparable to results published in the literature regarding
immediately, early and delayed placed single tooth implants in the aesthetic zone.30-32
Patient-centered outcome
There is an increasing focus on patient-centered outcome measures within the field of implant dentistry.33
Immediate placement and provisionalization are known to be associated with high subjective satisfaction
rates.12,34 The Visual Analogue Scales (VAS)35 and the Oral Health Impact Profile (OHIP)36 scores are in line
with the patients’ satisfaction in our clinical studies. Regarding the OHIP-14, no differences were observed
between both studies of all four groups during the entire follow-up, again in line with other studies
regarding immediate implant placement.10,11 It seems that the advantage of immediate placement offering
a shorter treatment time due to the lower number of surgical procedures by combining extraction, implant
placement, and bone grafting in one operative procedure37 is experienced through the eyes of patients as a
contribution to quality of life.
132
Future perspectives
In the clinicial studies in this thesis patients were divided according to buccal bony defects of <5 mm or ≥5
mm. In the literature there is no division in the size or shape of bony defects.7,9,38 It is difficult to measure
the exact dimensions of a bony defect when the failing tooth is still in situ. The diverse various osseous
defects in the remaining alveolus after extraction can therefore pre-operatively not be predicted. It would
be interesting to include the pre-operative peri-implant bone dimensions of the CBCT scan in relation to
the actual position of the implant post-operatively. When information is available on the pre-operative BBT
prior to removal of the failing tooth, it could be measured how much of this contour has been changed after
dental implant treatment and what the influence is of the exact size and shape of the bony defect on the
treatment outcome of immediate implant placement in the aesthetic zone.
In the literature there is insufficient evidence to set a threshold for minimum BBT to ensure the aesthetic
outcome and the long-term stability.4,5 If standardized measurements are an integral part of the treatment
evaluation, insight would be gained on alterations in BBT due to the surgical procedure and the
remodeling process in the follow-up period. Not only BBT should be investigated with these standardized
measurements, also interproximal and palatinal peri-implant bone dimensions as well as changes in BBT
in the period between implant placement and provisionalization as this period was not assessed in the
current study.
In the systematic review2 timing of provisionalization was not associated with outcome in terms of
implant survival or changes in peri-implant hard and soft tissues. In the clinical study of buccal bony
defects of <5 mm immediate provisionalization was non-inferior to delayed provisionalization. In buccal
bony defects of ≥5 mm the results of immediate implant placement were very promising. In larger bony
defects in the aesthetic zone it would be therefore interesting to investigate if immediate implant
placement with immediate provisionalization is non-inferior to immediate implant placement with delayed
provisionalization.
The phenomenon biotype is gaining interest.39 A thick or thin biotype could be of influence on the final
aesthetic result. In the literature is described that biotype could be altered to gain more favourable
results.40,41 Possibly the thickness of the mucosa can positively influence the stability of the peri-implant
soft tissues. If pre- and post-operatively biotype is measured, possible alterations in the thickness of the
mucosa can be investigated. In future studies, the effect of biotype on treatment outcome in the aesthetic
zone should be an integral part of the treatment design.
Immediate single implant placement in the aesthetic zone shows good short-term results. The question
remains how the performance is on the long term. Further research in prospective studies on immediate
placed implants is warranted with a longer follow-up period than one year, preferably a follow-up of at
least five years. If these studies, which are expected to be available in the next five years, show that
immediate implant placement is stable on the long term, immediate implant placement should become the
first treatment option if there is a failing single tooth in the aesthetic zone. If the tooth is already missing,
the benefit of one operation combining implant placement and bone grafting in one operative procedure
should be the first treatment option.
7
133
Conclusions
Immediate placement and/or provisionalization of dental implants in the aesthetic zone results in an
excellent short-term treatment outcome in terms of survival, clinical outcome, aesthetic indexes and
patient-centered outcome. Prerequisite is, however, primary stability of the implant.
Specific conclusions are:
- immediate implant placement with immediate provisionalization is non-inferior to immediate
placement with delayed provisionalization in case of labial bony defects <5 mm;
- immediate implant placement with delayed provisionalization is non-inferior to delayed placement
with delayed provisionalization in case of labial bony defects ≥5 mm;
- buccal bone at dental implants in the aesthetic zone, measured on CBCTs, is stable in thickness
during the first year, irrespective of immediate or delayed placement as well as independent
of the size of buccal bone defect prior to implant insertion and timing of implant insertion and
provisionalization.
134
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soft tissue alterations and its relation to
gingival biotype. Clin Oral Implants Res
2013;24(10):1094-100.
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Notes
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8Summary
&
Samenvatting
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Summary
In the aesthetic zone, the tendency to place single-tooth dental implants immediately after extraction
of a failing tooth, preferably combined with immediate provisionalization, is growing. This tendency is
probably related to evolving society factors, with more demanding patients and a wish for direct result.
Chapter 1 describes the background of immediate dental implant placement in a fresh extraction socket in
the aesthetic zone and the shift towards the peri-implant hard and soft tissues instead of implant survival
as outcome measure. The general aim of the research described in this thesis was to assess the treatment
outcome of immediate dental implant placement in the aesthetic zone. The treatment outcome included
outcome measures as changes in the hard and soft tissue peri-implant tissues, implant survival, aesthetic
evaluation and patient reported outcome with a 1-year follow-up.
A systematic review was performed to systematically assess the clinical outcome of immediately placed
implants in the aesthetic zone (Chapter 2) after one year. Based on 43 studies reporting on immediate
placement of single tooth implants in the aesthetic zone, a pooled analysis was done. Survival of
immediately placed implants was excellent, being 97% after at least one year follow-up. A mean Marginal
Bone Level (MBL) of 0.81±0.48 mm loss was reported for the peri-implant hard tissues. For the peri-implant
soft tissues, a loss of Interproximal Mucosa Level (IML) 0.38±0.23 mm and a loss of Midfacial Mucosa Level
(MML) of 0.54±0.39 mm were reported. Overall, immediate placement with immediate provisionalization of
dental implants in the aesthetic zone results in excellent short-term treatment outcome in terms of implant
survival and minimal change of peri-implant hard and soft tissue dimensions.
A randomized clinical trial is described in Chapter 3 assessing the outcome of single-tooth implants in the
aesthetic zone in bony defects of <5 mm. In this study 40 patients with a failing tooth in the aesthetic zone
were randomly assigned for immediate placement with immediate provisionalization (n=20) or immediate
implant placement with delayed provisionalization (n=20). Follow-up was at 1 month and after 1 year after
placement of the definitive crown. The primary outcome measure was MBL change. Apart from MBL, survival,
soft tissue peri-implant parameters, aesthetic indexes and patient satisfaction were assessed. A MBL change
after one year of 0.75±0.69 mm mesially and 0.68±0.65 mm distally for the immediate group and 0.70±0.64
mm and 0.68±0.64 mm for the delayed group were found. Both study groups had a 100% survival rate.
Recession of the peri-implant tissues for the immediate group were clinically acceptable after one year (IML
of 1.00±0.58 mm and MML 0.95±0.62 mm). This randomized clinical trial showed that immediate placement
and immediate provisionalization was non-inferior regarding MBL to immediate placement with delayed
provisionalization. In addition no clinically relevant differences in other outcomes were observed.
In Chapter 4 a randomized clinical trial is described assessing the outcome of single-tooth implants in the
aesthetic zone in bony defects of ≥5 mm. In this study 40 patients with a failing tooth in the aesthetic zone
were randomly assigned for immediate implant placement with delayed provisionalization (n=20) or delayed
implant placement with delayed provisionalization (n=20). Follow-up was at 1 month and after 1 year after
placement of the definitive crown. The primary outcome measure was MBL change. Other
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outcome measures were survival, soft tissue peri-implant parameters, aesthetic indexes and patient
satisfaction. One year after definitive crown placement, MBL level loss was 0.49±0.46 mm mesially and
0.49±0.46 mm distally mm for the immediate group and 0.45±0.41 mm and 0.68±0.64 mm for the delayed
group. Recession of the peri-implant tissues was clinically acceptable after one year in both groups (IML
0.15±0.16 versus 0.21±0.27 mm and MML 0.15±0.16 versus 0.34±0.55 mm). This randomized clinical trial
showed that immediate placement with delayed provisionalization was non-inferior to delayed placement with
delayed provisionalization in labial bony defects of ≥5 mm. In addition, no clinically relevant differences in
other outcomes were observed.
The aim of the study described in Chapter 5 was to develop a method for reliable, reproducible buccal bone
thickness (BBT) measurements on cone beam computed tomography (CBCT)-scans. A novelty is that this
program, regularly used pre-operatively, was employed to measure the BBT (in mm), after implant surgery.
Inter- and intra-observer reproducibility was assessed by repeated measurements by two examiners on 10
CBCTs at 6 positions along the implant axis. Mean BBT measured by observers one and two was 2.42±0.50 mm
and 2.41±0.47 mm, respectively. Interobserver intraclass correlation coefficient was 0.96 (95%CI 0.93-0.98)
and an intraobserver intraclass correlation coefficient of 0.93 (95%CI 0.88-0.96) for observer one and an
intraobserver intraclass correlation coefficient of 0.96 (95%CI 0.93-0.97) for observer two, respectively. From
this study it can be concluded that CBCTs are suitable for reliable and reproducible measurements of buccal
bone thickness at implants. 1 year after definitive crown placement, BBT at dental implants in the aesthetic
zone measured on CBCT’s appears to be stable for immediate and delayed placed implants in the aesthetic
zone, independent of the size of buccal bone defect prior to implant insertion and timing of provisionalization.
The purpose of the study described in Chapter 6 was to assess BBT using CBCTs and relate it to immediate
and delayed placed implants in the aesthetic zone after 1 month and 1 year follow-up after definitive crown
placement. BBT was measured with the approach described in chapter 5 on CBCTs of 80 patients divided in
4 study groups according to the bony defect (<5 or ≥5 mm) and timing of implant placement (immediate or
delayed). For the purpose of this study, the area of interest in the aesthetic zone was the upper 5 mm section
buccal of the implant, beginning at the neck of the implant towards the apical direction and measured in
steps of 1mm along the axis of the implant. BBT 1 year after placement of the definitive crown, varied for the
immediate placed implants of study group 1 from 1.52±0.89 to 2.04±0.77 mm (i.e., at the level of the upper 5
mm of the implant); for study group 2 from 1.08±0.55 to 1.44±±0.72 mm and for study group 3 from 1.00±0.47
to 1.29±0.72mm. BBT varied from 0.71±0.28 to 0.92±0.57 mm for the delayed placed implants in study group
4. BBT at dental implants in the aesthetic zone measured on CBCTs, appears to be stable for immediate and
delayed placed implants after placement of the definitive crown, independent of the size of buccal bone
defect prior to implant insertion and timing of provisionalization.
Chapter 7 includes the discussion and conclusion of the outcomes of the research performed in this thesis.
The main conclusion is that immediate placement of dental implants in the aesthetic zone results in an
excellent short-term treatment outcome in terms of survival, clinical outcome, aesthetic indexes and patient
satisfaction. There is a need for long-term prospective studies with a follow-up of more >1 year.
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Samenvatting
Bij enkeltandsvervanging in de esthetische zone bestaat de tendens om na extractie van een niet te
behouden tand een implantaat te plaatsen in de extractiealveole, bij voorkeur in combinatie met een
tijdelijke kroon. Deze tendens past bij het huidige tijdsbeeld: veeleisende patiënten met de wens voor een
direct resultaat.
In hoofdstuk 1 wordt kort het hoe en waarom van het direct plaatsen van implantaten in de extractiealveole
in de esthetische zone beschreven. Ook wordt aandacht geschonken aan de verschuiving in de
uitkomstmaat voor het meten van succes van een implantaat, namelijk de verschuiving van het
overlevingspercentage van implantaten als voornaamste uitkomstmaat naar de conditie van de peri-
implantaire harde en zachte weefsels.
Het doel van het in dit proefschrift beschreven onderzoek was het evalueren van het behandelresultaat één
jaar na het direct plaatsen van implantaten in de extractiealveole van een enkel element in de esthetische
zone (enkeltandsvervanging). Als uitkomstmaten werden veranderingen in de harde en zachte weefsel
peri-implantaire weefsels, het overlevingspercentage van de implantaten, een objectieve beoordeling van
het esthetische resultaat en de beoordeling door de patiënt zelf gebruikt.
In hoofdstuk 2 wordt de uitkomst van een systematische literatuurstudie naar de klinische uitkomst van
direct geplaatste implantaten in de esthetische zone beschreven. Gebaseerd op 43 aan de kwaliteitscriteria
voldoende studies, waarin enkeltandsvervanging met direct geplaatste implantaten in de esthetische
zone werd beschreven, werd een gepoolde analyse uitgevoerd. Het overlevingspercentage van de in deze
regio direct geplaatste implantaten was uitstekend: 97% na ten minste één jaar follow-up. Het gemiddelde
verlies aan Marginaal Bot Niveau (MBN) bedroeg van 0,81 ± 0,48 mm, het gemiddelde verlies van het
Interproximale Mucosa Niveau (IMN) bedroeg 0,38 ± 0,23 mm en het gemiddelde verlies van het Midfaciale
Mucosa Niveau (MMN) 0,54 ± 0,39 mm. Op basis van de uitkomsten van de systematische literatuurstudie
werd geconcludeerd, dat het direct plaatsen bij enkeltandsvervanging in combinatie met een directe
tijdelijke kroon in de esthetische zone resulteert in uitstekende kortetermijn resultaten. De resultaten
betreffen zowel de conditie van de peri-implantaire harde en zachte weefsel als het overlevingspercentage
van de implantaten. De beschikbare gegevens waren onvoldoende om een uitspraak te doen over een
objectieve beoordeling van het te bereiken esthetische resultaat en de tevredenheid van de patiënt.
In hoofdstuk 3 wordt een gerandomiseerde klinische studie in de esthetische zone beschreven naar
het behandelresultaat van enkeltandsvervanging bij direct geplaatste implantaten in botdefecten van
<5 mm. In dit onderzoek werden 40 patiënten met een niet te behouden tand in de esthetische zone at
random in 2 groepen ingedeeld. Één groep: het direct plaatsen van een implantaat in de extractiealveole
met daarop direct een tijdelijke kroon (n=20) of één groep: het direct plaatsen van een implantaat in
de extractiealveole met daarop een conventionele tijdelijke voorziening (partiele plaatprothese; n=20).
Een veelheid aan uitkomstmaten werd één maand en één jaar na het plaatsen van de definitieve kroon
gemeten. De primaire uitkomstmaat was verandering in het MBN. Naast MBN, waren de uitkomstmaten het
overlevingspercentage van de implantaten, de conditie van de zachte peri-implantaire weefsels, de
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uitkomst van esthetische indexen en de mate van patiënttevredenheid. Één jaar na het plaatsen van de
definitieve kroon werd een MBN verlies van 0,75 ± 0,69 mm mesiaal en 0,68 ± 0,65 mm distaal van het
implantaat gemeten in de directe tijdelijke kroon groep en een verlies van 0,70 ± 0,64 mm mesiaal en 0,68
± 0,64 mm distaal in de groep die eerst was voorzien van een conventionele tijdelijke voorziening. Geen
enkel implantaat is in beide groepen verloren gegaan. Ook de mate van recessie van de peri-implantaire
weefsels één jaar na het plaatsen van de definitieve kroon bij de directe groep lag op een klinisch
aanvaardbaar niveau (IMN 1,00 ± 0,58 mm, MMN 0,95 ± 0,62 mm). Deze gerandomiseerde klinische
studie toonde aan, dat het direct plaatsen van een implantaat met daarop direct een tijdelijke kroon niet
onderdoet voor de uitkomst van het direct plaatsen van een implantaat met daarop een conventionele
tijdelijke voorziening wat betreft verandering in het MBN. Ook in de andere uitkomstmaten werden geen
klinisch relevante veranderingen gemeten.
In hoofdstuk 4 wordt een gerandomiseerde klinische studie in de esthetische zone beschreven aangaande
het behandelresultaat van solitair direct geplaatste implantaten in alveoles met botdefecten ≥ 5mm. In dit
onderzoek werden 40 patiënten met een niet te behouden tand in de esthetische zone gerandomiseerd
in 2 groepen: Of direct plaatsen van een implantaat in de extractiealveole (n=20) of het conventioneel
plaatsen van het implantaat na een genezingsperiode van 3 maanden (n=20). Wederom werd een
veelheid aan uitkomstmaten één maand en één jaar na het plaatsen van de definitieve kroon bepaald.
De primaire uitkomstmaat was verandering in het MBN. Naast MBN, werden als uitkomstmaten het
overlevingspercentage van de implantaten, de conditie van de zachte peri-implantaire weefsels, de
uitkomst van esthetische indexen en de mate van patiënttevredenheid bepaald. Eén jaar na het plaatsen
van de definitieve kroon bedroeg het MBN verlies 0,49 ± 0,46 mm mesiaal en 0,49 ± 0,46 mm distaal voor
de directe implantaat groep en 0,45 ± 0,41 mm en 0,68 ± 0,64 mm voor de conventionele implantaat groep.
In beide onderzoeksgroepen bleek de mate van recessie van de peri-implantaire weefsels op een klinisch
aanvaardbaar niveau te liggen (IMN 0,15 ± 0,16 versus 0,21 ± 0.27 mm en MMN 0,15 ± 0,16 versus 0,34
± 0.55 mm). In deze gerandomiseerde klinische studie werd aangetoond, dat de uitkomst van het direct
plaatsen van een implantaat in een extractie alveole niet onderdoet voor het conventioneel plaatsen van
het implantaat in geval van een labiaal botdefect ≥5 mm. Ook in de andere uitkomstmaten werden geen
klinisch relevante verschillen gemeten.
Het doel van de in hoofdstuk 5 beschreven studie was het ontwikkelen van een methode om betrouwbaar
en reproduceerbaar de buccale botdikte (BBD) te kunnen meten met behulp van zogenaamde
cone beam computed tomography (CBCT). Aangetoond werd dat middels het daartoe ontwikkelde
computerprogramma inderdaad de BBD (in mm) ter plaatse van het implantaat kan worden gemeten. De
inter- en intra-observator reproduceerbaarheid werd bepaald op basis van herhaalde metingen door twee
onderzoekers, namelijk op 6 posities buccaal langs de implantaat as op 10 CBCTs. De gemiddelde BBD
gemeten door onderzoekers één en twee bedroeg, respectievelijk, 2,42 ± 0,50 mm en 2,41 ± 0,47 mm. De
interobserver intraclass correlatiecoëfficiënt bedroeg 0,96 (95% BI 0,93-0,98). De intra-observer intraclass
correlatiecoëfficiënt bedroeg 0,93 (95% BI 0,88-0,96) voor onderzoeker één en 0,96 (95% BI 0,93-0,97)
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voor onderzoeker twee. Uit deze studie werd geconcludeerd dat CBCTs geschikt zijn voor het betrouwbaar
en reproduceerbaar meten van de BBD ter plaatse van implantaten.
Het doel van de in hoofdstuk 6 beschreven studie was: om de buccale botdikte (BBD) te meten met behulp
van CBCTs en de BBD te relateren aan direct en conventioneel geplaatste implantaten in de esthetische
zone tijdens één maand en één jaar follow-up. BBD werd gemeten op CBCTs met het in hoofstuk 5
beschreven en geteste softwareprogramma bij 80 patiënten verdeeld in 4 studiegroepen na leiding
van het botdefect na extractie(<5 or ≥5 mm) en het tijdstip van plaatsen (direct of conventioneel). Het
aandachtsgebied in de esthetische zone was de eerste 5 mm labiaal van het implantaat, te beginnen bij de
hals van het implantaat en werd gemeten met een interval van 1 mm parallel aan de as van het implantaat.
BBD (in mm) variëerde voor direct geplaatse implantaten van studiegroep 1 van 1.52±:0.89 tot 2.04±0.74
mm ter plaatse van de bovenste 5 mm van het implantaat; voor studiegroep 2 van 1.08±0.58 tot 1.44±0.72
mm en voor studiegroep 3 van 1.00±:0.47 tot 1.29±:0.72 mm. De BBD variëerde van 0.71±0.28 tot 0.92±0.57
mm voor de conventioneel geplaatste implantaten in studiegroep 4. BBD bij enkeltandsvervanging in
de esthetische zone is stabiel voor direct en conventioneel geplaatste implantaten en onafhankelijk van
de grootte van het buccale botdefect vóórafgaand aan het implanteren en het tijdstip van de tijdelijke
voorziening.
De overkoepelende discussie en conclussies uit dit promotieonderzoek worden beschreven in hoofdstuk
7. De belangrijkste conclusie is, dat bij enkeltandsvervanging in de esthetische zone het direct plaatsen
van tandheelkundige implantaten in een extractiealveole resulteert in uitstekende kortetermijn resultaten
(1-jaars resultaten). Wat betreft het overlevingspercentage van de implantaten, de conditie van de peri-
implantaire zachte en harde weefsels, de uitkomst van de esthetische indexen en de tevredenheid van
de patiënt. Of deze techniek ook op de lange termijn leidt tot goede uitkomsten, moet nog nader worden
onderzocht.
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9Dankwoord
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Dankwoord
De inhoud van dit proefschrift is naast ondersteuning van vele cappuccino’s, jazz en klassieke muziek
vooral tot stand gekomen door de hulp van vele verschillende personen. De tijd is gekomen voor het
schrijven van het dankwoord. Al typend heb ik geen idee waar en met wie ik moet beginnen. Het is slechts
een weergave van mijn idee over ieders rol in dit proefschrift. Martin Bril omschreef het treffend: “Geen
idee is ook een idee. Geen idee is het durven volgen van een enkel woord, een paar noten, een plotselinge
penseelstreek; geen idee is vertrouwen, en angst. Wat er in je zit, weet je pas als het er uit is.” Dat dit
proefschrift er nu uit is, had alleen gekund door ideeën, suggesties, interesse en tijd van een ieder die mijn
pad gekruist heeft de afgelopen jaren, waarvoor heel veel dank.
Een eerste dank gaat uit naar de patiënten die hebben geparticipeerd in het onderzoek. Dankzij hun tijd en
bereidwilligheid is de inhoud van dit proefschrift geworden tot wat het is.
Prof. dr. G.M. Raghoebar, hooggeleerde eerste promotor, beste Gerry. Naast een bekwaam chirurg, ben
je vooral een fijne begeleider. Jouw toegankelijkheid zorgde ervoor dat de lijnen kort bleven. Praktisch
gerichte oplossingen waren door jou toedoen altijd voor handen. Ik dank je voor de leerzame momenten
ten tijde van de chirurgie, maar vooral voor je begrip en interesse voor mijn activiteiten buiten het
onderzoek. Ik heb het persoonlijke contact als zeer plezierig ervaren. Hartelijk dank hiervoor!
Prof. dr. H.J.A. Meijer, hooggeleerde tweede promotor, beste Henny. Van mijn promotores heb ik met jou de
meeste tijd in auto’s en steden doorgebracht. Door jouw toedoen weet ik nu waar ik in Mechelen moet zijn
voor de juiste culinaire plekken. We zijn er ook samen achter gekomen waar je in Mechelen niet moet zijn
als je na werktijd de nooduitgang neemt en langs het spoor moet lopen om bij het hotel terug te komen.
Had me toch maar over het hek laten klimmen…Hartelijk dank voor je enthousiasme, organisatorische
talent, klinische ervaring en vooral het doen van vele CBCT metingen in dit onderzoek.
Prof. dr. A. Vissink, hooggeleerde derde promotor, beste Arjan. Jouw snelheid van werken en vermogen
om te schakelen zijn haast niet te bevatten. Jouw inzet om altijd het beste uit een manuscript te willen
halen bleef tot aan het allerlaatste toe 100 procent. Ik ben je hier erkentelijk voor, omdat op deze manier
een promovendus ook altijd het beste uit zichzelf leert halen. Vooral dank ik je voor je toegankelijkheid en
plezierige manier van samenwerken.
Prof. dr. M.S. Cune, prof. dr. G.J. Meijer en prof. dr. E.B. Wolvius, hooggeleerde leden van de
beoordelingscommissie. Dank voor uw bereidheid om zitting te nemen in de beoordelingscommissie en
voor de tijd die u hebt genomen om dit manuscript te beoordelen.
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Prof. dr. F.K.L. Spijkervet, geachte professor. Graag dank ik u voor de gelegenheid die u mij heeft
geboden om mijn promotieonderzoek te kunnen afronden op de afdeling Mondziekten-, Kaak- en
Aangezichtschirurgie van het Universitair Medisch Centrum Groningen. De open en prettige sfeer op de
afdeling is een stimulans voor het doen en voltooien van onderzoek.
Prof. dr. L.G.M. de Bont, geachte professor. Mijn dank voor de mogelijkheid die u mij heeft gegeven dit
promotieonderzoek te starten op de afdeling Mondziekten-, Kaak- en Aangezichtschirurgie.
Dr. N.A. Bakker, lieve Klaas. Niet genoeg etentjes om publicaties te vieren kunnen uitdrukken hoe
dankbaar ik je ben voor je steun en kennis, maar vooral voor je vriendschap. De steuntjes in mijn rug die
je hebt gegeven voor dit proefschrift zijn ontelbaar. Ik heb je leren kennen in 2002 tijdens mijn eerste
studieweek in Groningen. Wat hebben we leuke dingen ondernomen al die afgelopen jaren. Op de een
of andere manier maakte je het toch wel vaak spannend en heb ik regelmatig bijzondere situaties met
je meegemaakt. De afgelopen jaren zijn niet eenvoudig voor je geweest. Ik vind het fijn dat je ook deze
momenten met mij hebt willen delen, dit maakt voor mij onze vriendschap nog dierbaarder. Ik wens jou
en je gezin al het geluk van de wereld toe en dank je dat je vandaag mijn paranimf wilt zijn.
Dr. Y.C.M. de Waal, lieve Yvonne. Ook jou ken ik al sinds mijn eerste studieweek in Groningen. Naast een
geweldige collega ben je vooral een hele fijne en lieve vriendin. Ik ben blij dat we naast cappuccino’s,
wetenschappelijk onderzoek en congressen e.d. ook vooral andere dingen delen. Onze vriendschap is
de afgelopen jaren verdiept, door samen vreugdevolle momenten te delen, maar helaas ook verdrietige.
Ik kijk uit naar nieuwe leuke momenten samen met onze gezinnen. Ik vond het een eer jouw paranimf te
mogen zijn. Dank je wel dat jij vandaag mijn paranimf wilt zijn.
Mw. E. Wartena, beste Esther. Als ervaren onderzoeksassistente wist jij als geen ander hoe belangrijk
de logistiek en planning is bij patiënt- gebonden onderzoek. Ik ben je erg dankbaar voor je inzet en
ondersteuning door je snelle en zorgvuldige handelen. Jouw geheugen is fenomenaal. Aan de hand van
jouw patiënt omschrijving wist ik altijd exact wie er op de afspraak zou verschijnen. Daarnaast hartelijk
dank voor de leuke en gezellige samenwerking.
Mw. M.A. Bezema, mw. H.H. Kooistra-Veenkamp, mw. T.A.P. Schens-Mooi, mw I.J. Valkema, beste
Ans, Ria, Tally en Ingrid. Hartelijk dank voor jullie ondersteuning bij het behandelen van de
onderzoekspatiënten en zorgvuldige werk achter de schermen. Dankzij jullie kwamen de patiënten en
materialen ’s ochtends en ’s middags altijd weer op de juiste plaats terecht.
Mw. L.M.E. Kamstra-Dooper, mw. E.J.G. van Luijk-Voshaar, mw. A. van Oploo-Talens, mw. A. Poppinga,
mw. A. Prins-Schutter, mw. Y. Sanders-Niessen, beste Liliane, Emmy, Tiny, Anne, Anja en Yvonne.
Hartelijk dank voor al jullie tijd en het maken van de vele röntgenfoto’s en CBCT’s tijdens jullie drukke
programma. Een aantal van jullie heb ik zelfs tot aan jullie welverdiende pensioen vele verzoeken
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voorgelegd. Dank ook voor jullie interesse in mijn onderzoek en het feit dat jullie het belang van de patiënt
altijd voorop willen stellen.
Dhr. A.K. Wietsma en dhr. A. Beekes, beste Anne en Ashwin. Hartelijk dank voor het meedenken voor
praktische oplossingen omtrent tandtechnische vraagstukken en het vervaardigen van vele boormallen.
Fijn dat jullie ondanks jullie drukke programma altijd tijd voor mij wilden maken.
Dhr W. Van der Ven en dhr M. van der Veen, beste Menno en Wim. Veel dank voor jullie inzet en die van
jullie collega’s van het Gronings Tandtechnisch Laboratorium met betrekking tot het tandtechnische
aspect van dit onderzoek. Er zijn heel wat afdrukken de revue gepasseerd voor (tijdelijke) kronen en
andere benodigdheden. Jullie flexibiliteit en meedenken om een passende oplossing voor de patiënten
te bedenken heeft geleid tot grote tevredenheid van de patiënten. Hartelijk dank voor de goede
samenwerking.
Dhr M.F. de Wit en drs. J. van der Meer, beste Marnix en Joerd. Hartelijk dank voor het meedenken voor
mogelijkheden omtrent de CBCT’s. Joerd nog een extra dank voor alle heerlijke cappu’s!
Mw. N.E. Geurts-Jaeger, mw. L. Kempers, mw. A. de Vries, mw. S. Wiersema, dhr H.B. de Jonge en dhr. R.M.
Rolvink, beste Nienke, Lisa, Angelica, Fieke, Harry en Richard. Bedankt voor jullie secretariële, technische
en facilitaire ondersteuning. Hartelijk dank voor het meedenken en aandragen van oplossingen als deze
nodig waren.
Dr. L. den Hartog, beste Laurens. Mede dankzij jouw hulp, werd mijn eerste publicatie een feit. Ik dank je
voor je hulp en het meedenken omtrent dit onderzoek en voor de gezelligheid tijdens alle congressen.
C. Boven MSc, dr. F. Guljé , drs. C. Jensen, dhr D. Hentenaar, W. Van Nimwegen MSc, drs. C. Pol, dr. E.
Santing, drs. U. Schepke, dr. W. Slot, dr. C. Stellingsma, dr. G. Telleman, E. Zuiderveld MSc, beste Carina,
Felix, Charlotte, Diederik, Wouter, Christiaan, Eric, Ulf, Wim, Cees, Gerdien en Elise. Als implantologie tak
en mede-onderzoekers, dank ik jullie allen hartelijk voor de interesse in mijn onderzoek en de gezelligheid
tijdens de EAO congressen. Diederik, nogmaals dank voor alle esthetische metingen in de patiëntgebonden
onderzoeken!
Alle mede-onderzoekers en AIO’s van de afdeling Mondziekten-, Kaak- en Aangezichtschirurgie en in het
bijzonder Anne, Ferdinand, Joep, Lukas, Michiel, Nico, Petra, Rodney, Sebastiaan en Willem. Hartelijk dank
voor jullie belangstelling en leuke contacten rond diverse koffieautomaten en lunchtafels.
De administratie wil ik nog apart bedanken voor alle (telefonische) gesprekken en schriftelijke
administratie van de vele patiënten. En daarnaast alle niet met name genoemde medewerkers van de
afdeling Mondziekten-, Kaak- en Aangezichtschirurgie. Hartelijk dank voor de plezierige samenwerking.
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Alle collega’s van Tandartspraktijk de Reijenburg te Veldhoven. Dank voor jullie interesse en
belangstelling voor mijn werkzaamheden buiten en op onderzoeksgebied. Ook al reis ik vandaag de dag
minder vaak af naar het zonnige zuiden, het blijft altijd heel erg leuk om met jullie samen te werken.
Alle collega’s van Buijs Tandartsen te Groningen. Dank voor jullie interesse en ondersteuning bij al mijn
verzoeknummers voor diverse tandheelkundige werkzaamheden.
Alle collega’s van Dental Clinics Hardegarijp. Heel veel dank dat ik naast mijn promotieonderzoek, hier
met zoveel plezier kan werken. Elke pauze met jullie is een feest. Pini en alle collega’s, hartelijk dank
voor jullie interesse, begrip en de mogelijkheden die jullie boden om naast mijn werk, mijn onderzoek te
kunnen afronden.
Drs. E.W.J. de Boer, dr. D. Berghuis-Rickert en drs. J.M. Ijzerman-Schuurhuis. Lieve Esther, Daniela en
Marleen. Wat was en is het toch fijn om naast collega’s, ook kamergenoten met jullie te zijn. Naast de up’s
en down’s te delen op onderzoeksgebied, ben ik jullie zo dankbaar voor jullie oprechte interesse en hulp
wanneer nodig. Bovenal geniet ik van de gezellige momenten buiten het onderzoek om. Ik ben blij dat we
de moeite nemen af te spreken voor een update omtrent niet-gerelateerde onderzoeksonderwerpen. Dat
houden we erin!
Lieve Eva, dank je wel dat jij al jaren mijn coach bent en mij attendeert op de mooie wereld om ons heen.
Lieve tandheelkunde vriendinnetjes: Corine, Eefje, Iris, Nicole, Marjan en Marloes. Dankbaar ben ik dat
we naast de ervaringen over ons vak, vooral de ervaringen over andere zaken kunnen delen. Ik ben blij
dat we de tijd nemen om elkaar te blijven zien en op te zoeken, ook al zijn we inmiddels overal na ons
afstuderen door het land verspreid .
Lieve vrienden en vriendinnen: o.a Anouk, Charlotte, Danique, Dirk, Evelien, Jianhua, Maurits, Maria,
Marijke, Melanie en iedereen die weet dat zij tot dit rijtje behoren. Sommige van jullie ken ik al sinds mijn
jeugd, andere wat korter. Sommige van jullie zie ik vaak, andere minder frequent en andere vooral tijdens
de kerstdiners. Toch weet ik dat het bij elk van jullie goed zit en dat als we elkaar zien het leuk en gezellig
is. Daar ben ik jullie zeer dankbaar voor!
Lieve “party-nimfen”: Anne-Marie, Jorien, Mirjam en Wietse. Ik ben dankbaar voor de band die ik met
jullie elk afzonderlijk heb en alles wat ik met jullie deel en al meegemaakt heb. Jullie zijn fantastische
vrienden. Ik hoop op nog zoveel leuke ervaringen en momenten van samen zijn. Dank jullie wel voor al
het begrip en steun tijdens mijn afwezigheid op momenten waar ik verstek liet gaan om het afronden van
mijn proefschrift voor te laten gaan, hoewel ik graag bij jullie had willen zijn. Laten we gauw vele nieuwe
leuke momenten met elkaar gaan delen!
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Lieve Buijs familie. Lieve Aad & Heleen, dank voor het bijspringen de afgelopen jaren voor Mees als zijn
moeder weer eens achter de laptop zat. Maar vooral dank voor jullie interesse en betrokkenheid ten allen
tijde bij ons gezin. Janne & Kaman, Jauke & Minna, jullie zijn de beste schoonbroertjes en zusjes die ik me
kan wensen. Dank voor al jullie gezelligheid tijdens de Buijs bijeenkomsten.
Lieve Cathinka, fijn dat je als mijn peettante altijd zo geïnteresseerd in mij bent en dankbaar ben ik voor de
vele leuke trips die we hebben mogen en zullen ondernemen.
Lieve zusjes, Margit & Annique. Wat ben ik toch blij met jullie. Ik ben trots op dat een ieder van jullie het
pad kiest, dat bij haar past. Zo verschillend als we zijn, zo sterk is ook de band tussen ons! Waar jullie ook
gaan, ik zal er altijd voor jullie zijn en ik weet dat ik ook altijd bij jullie terecht kan.
Lieve mama, nu ik zelf moeder ben, begrijp ik waarom jij altijd zo je uiterste best hebt gedaan voor ons
alledrie. Al die uurtjes (sprookjes) voorlezen heeft ertoe geleid dat het lezen van al die wetenschappelijke
artikelen een stuk sneller ging. Daarnaast voel ik me gezegend dat je me zoveel talen, kennis en cultuur
hebt proberen bij te brengen, waardoor dit heeft geleid to vele verschillende interesses. Ik ben blij dat als
je op Mees past, hem ook zoveel probeert bij te brengen. Ik hoop op meer tijd samen om dit te kunnen
blijven delen.
Lieve papa, naast het plezier voor ons vak, hockey en kunst, delen wij vooral de liefde voor muziek en met
name de jazz. Aan de vele mooie herinneringen van geweldige concerten, springt vooral de road trip naar
Montreux en de bezoeken aan het North Sea Jazz eruit. Daarnaast ook zoveel dank voor het meten van
alle röntgenfoto’s. Je eerste schreden op wetenschappelijk gebied zijn nu in de literatuur vastgelegd. Het is
maar goed dat je zoveel geduld hebt, wat overigens al bleek tijdens de opvoeding van je drie dochters. Ik
ben zo blij dat jij nog steeds fit op het hockeyveld rondloopt en ik jou nu kan komen aanmoedigen in plaats
van andersom. Dankbaar ben ik voor de aanmoedigingen van jou en mama die ik mijn hele leven heb
gehad om te doen en te kiezen wat leuk is en goed voelt.
Lieve Jap, dat ik dit proefschrift heb afgerond, komt mede door jouw onvoorwaardelijke liefde en steun.
Als geen ander weet jij wat het is om een proefschrift te voltooien. Je bent en blijft de rust zelve als mijn
impulsiviteit weer eens met me aan de haal gaat. Toch weet jij altijd de balans in ons gezin te bewaren
en af en toe de juiste koerswijziging door te voeren. Ook al werken we beiden heel hard, ik ben blij dat
we proberen te genieten van wat er op ons pad komt, de vele mooie reizen en de leuke dingen die we
ondernemen, maar vooral van onze kleine Mees. De toekomst is ons allen onbekend, toch verheug ik me
op mijn toekomst met jou en ons gezin. Dank je wel voor je liefde, jouw eerlijkheid en oprechtheid. Ik hou
van je!
Lieve Mees, mama is zo blij en gelukkig met jou. De afgelopen jaren heb ik ontwikkelingen op allerlei
gebieden mogen meemaken, maar jij bent de grootste ontwikkeling en verrijking van mijn leven. Van jouw
komst heb ik misschien wel het meeste geleerd, waarvoor ik je heel erg dankbaar ben. Vanaf nu gaan we
nog meer plezier maken en samen spelen, joepie!
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Curriculum Vitae
Kirsten Slagter was born on July 3th 1983 in Utrecht, the Netherlands. After finishing
secondary school in 2001, she studied History of Art at the University of Connecticut,
Connecticut (USA). In 2002 she started studying Dentistry at the University of Groningen.
During her study, she was part of the board of the dental student faculty association
Archigenes and member of several committees. She did an internship for several months,
in 2007 at the University of the Western Cape, South Africa. In 2007 she graduated with the
distinction cum laude. After her graduation she worked as a volunteer in several countries
for dental health care organisations. Kirsten started in 2009 her PhD research project at
the University of Groningen and combined this with her work as general dental practitioner
in Groningen, Hardegarijp and Veldhoven. She participated in several committees for the
Royal Dutch Society for Dentistry (KNMT) and was a columnist (2007-2012) for the KNMT.
In 2013 she became a registered implantologist and is currently a member of the junior
committee of the Dutch Society of Oral Implantology (NVOI). Kirsten Slagter lives together
with Jappe Buijs and together they have a son Mees (2014).
Kirsten Slagter
Ubbo Emmiusingel 33
9711 BC Groningen
The Netherlands