id journal iv 2008

Cranio-maxillofacial

Implant Directions®

Vol.3 N° IV December 2008

Published by IF Publishing, Germany

Case RepoRt »ReplaCement of a maxillaRy dentuRe, extRaCtion of Residual teeth and implant boRne ReConstRuCtion in an immediate load pRotoCol

CRitiCal appRaisal »the effeCt of inteR-implant distanCe on the

height of inteR-implant bone CRest

evidenCe RepoRt »effeCt of diabetes mellitus on dentalimplants suRvival and CompliCations

liteRatuRe analysis »effeCts of Radiation theRapy in CRaniomaxillofaCial

and dental implantssummaRy of findings an impliCations

ReseaRCh in Context - paRt vii »aRe the diffeRenCes between two study gRoups

Real and appliCable CliniCally oR is it possible pos-sibly they aRe simply due to ChanCe?

CiRCulaR »full mouth Rehabilitation -

fRom extRaCtion to full aRCh bRidges in just one day

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Editorial board

Editor-in-chief Dr. Werner Mander, [email protected]

Managing editor Dr. Sigmar Kopp, [email protected]

Coordinating editorN. N., Switzerland

Editorial board (in alphabetic order)Prof. Dr. Volker Bienengräber, GermanyHenri Diederich med.dent, LuxemburgDr. Yassen Dimitrov, BulgariaZa. Stephan Haas, GermanyProf. Dr. Vitomir S. Konstantinovic, SerbiaCarlos Mendez, SpainDr. Richard Musicer, USADr. Gerald Schillig, GermanyDr. Katrin Tost, Greece

Evidence reports and Critical AppraisalsIF Research & Evidence Dept. Single Issue Price Euro 30 Annual SubscriptionEuro 120

Copyright Copyright ©2008 byInternational Implant FoundationDE- 80802 Munich / Germanywww.implantfoundation.org

[email protected]

CMF.Impl.dir.ISSN 1864-1199e-ISSN 1864-1237

Disclaimer

HazardsGreat care has been taken to maintain the accuracy of the informa-tion contained in this publication. However, the publisher and/or the distributer and/or the editors and/or the authors cannot be held re-sponsible for errors or any consequences arising from the use of the information contained in this publication. The statements or opinions contained in editorials and articles in this publication are solely those of the authors thereof and not of the publisher, and/or the distributer, and/or the IIF.The products, procedures and therapies described in this work are hazardous and are therefore only to be applied by certified and trained medical professionals in environment specially designed for such pro-cedures. No suggested test or procedure should be carried out un-less, in the user‘s professional judgment, its risk is justified. Whoever applies products, procedures and therapies shown or described in this publication will do this at their own risk. Because of rapid advances in the medical sience, IF recommends that independent verification of diagnosis, therapies, drugs, dosages and operation methods should be made before any action is taken. Although all advertising material which may be inserted into the work is expected to conform to ethical (medical) standards, inclusion in this publication does not constitute a guarantee or endorsement by the publisher regarding quality or value of such product or of the claims made of it by its manufacturer.

Legal restrictionsThis work was produced by IF Publishing, Munich, Germany. All rights reserved by IF Publishing. This publication including all parts thereof, is legally protected by copyright. Any use, exploitation or commercializa-tion outside the narrow limits set forth by copyright legislation and the restrictions on use laid out below, without the publisher‘s consent, is illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, scanning or duplication of any kind, translation, preparation of microfilms, electronic data processing, and storage such as making this publication available on Intranet or Internet. Some of the products, names, instruments, treatments, logos, desi-gns, etc. reffered to in this publication are also protected by patents and trademarks or by other intellectual property protection laws« (eg. «IF«, «IIF« and the IF-Logo) are registered trademarks even though spe-cific reference to this fact is not always made in the text. Therefore, the appearance of a name, instrument, etc. without desi-gnation as proprietary is not to be construed as a representation by publisher that it is in the public domain.Institutions‘ subscriptions allow to reproduce tables of content or pre-pare lists of Articles including abstracts for internal circulation within the institutions concerned. Permission of the publisher is required for all other derivative works, including compilations and translations. Per-mission of the publisher is required to store or use electronically any material contained in this journal, including any article or part of an article. For inquiries contact the publisher at the adress indicated.

CMF.Impl.Dir. Vol. IV 2008 161

Typical contents in ID

Evidence Reports summarize the latest «Hot Topics» from relevant journals putting similar studies «side-by-side». This unique presentation of studies allows you to compare and contrast the patient populations, the treatment interventions, and the quality of the scientific methods. The «evidence-based bottom line» is presented with an overall summary statement at the beginning. Clinical notes by implantologists with special expertise on the topic complete the Evidence Re-port by providing their expert clinical opinion. ID is an implantology publication that provides atten-tion to detail in balancing science with clinical opinion in such a clear, concise, and visually-friendly presentation.

Literature Analyses provide you with an in-depth look at the research on a given topic. A «Literature Analysis» is a critical review of the literature on the epidemiology, treatment methods, and prognosis for implant-related topics or conditions. Literature Analyses are broader than «Evidence Reports» and are written to serve as a reference tool for implantologists to help them make decisions regarding how to manage patients, to assist them in evaluating needs for future research, and to use the material for future presentations.

Critical Appraisals summarize the findings from important papers used for clinical decision making or marketing by implant companies. In addition to the summary, the study‘s methods and clinical conclusions are critically reviewed in an effort to challenge the implantology community into not accepting everything that is published, while fostering alternative explanations and ideas.

Case reports give implantologists the opportunity to publish on unique patients using innovative or alternative methods for treating challenging patient conditions.

Research in Context is a helpful «what is» section to consult if you’ve ever read a study and asked «what is a p-value» or any other research method question. It assists clinicians with the critical evaluation of the literature by briefly describing relevant aspects of research methods and statistical analysis that may bias results and lead to erroneous conclusions.

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Case Report

Replacement of a maxillary denture, extraction of residual teeth and implant borne recon-struction in an immediate load protocol

AUTHOR:Dr. Stefan IhdeGommiswald Dental ClinicDorfplatz 118737 Gommiswald, SwitzerlandE-mail: [email protected]

ABSTRACT

For many patients removable upper dentures are acceptable, as long as it is possible to leave parts of the palatum free from an un-desireable denture plate and a long as the dentures are not overly mobile. When the last teeth are lost, the patients expect a fast solution, they try to avoid full dentures. They consider full dentures outdated.Dental implantology provides the desired solu-tion. In the case shown here the residual teeth were extracted and replaced by basal implants. Both types of basal implants were used: lateral implants and screw-type implants. Due to the surface properties and the reduced diameter of the basal implants the extraction sockets could be equipped immediately after the extraction.The first fixed restauration was incorporated on day two after the operation. The use of basal implants with thin, polished vertical implant portions allows immediate reconstruction even after extractions and in unfavourable bone situations. Cortial bone areas may be reached with basal implants in several areas of the jaw bone.

INTRODUCTION

In the last decades intricate connection ele-ments between anchouring teeth and have been developed. The disadvantage of those dentures is that the teeth included into these construc-tions are overloaded and that they must provide strong retention for the crowns carrying con-nection elements. The fixed & removable recon-struction in the case shown here had been in-corporated shortly before the patient requested our help, Fig. 1: the bridges in the upper jaw had become loose several times, because the retention was to small for the masticatory load. We did not see any possibility to re-cement the bridges with permanent success. After discuss-ing several treatment alternatives, the patient decided for a reconstruction on implants.

MATERIAL & METHOD

In local anaesthesia the extraction of all re-maining teeth in the upper jaw was attempted. Both canines resisted a complete extraction: only part by part was taken out until only very little access to the root was given. In this situa-tion we decided to open a large vestibular flap. Using the FG-vertical cutter for basal implants a vertical cut through the vestibular cortical to the root was made and the root of both canines were cut into two halves. After this the two root-haölve were taken out easily. With a 9mmd contra-angle cutter (with inter –disk-distance of 5mm) two horizontal slots were prepared. The Crestal slot was enlagened to 10 mmd, the bas-al slot was enlargened to 15 mmd. After prepar-


ing the implant bed in this way a XBBS 14/10 H6 double-BOI-Implant was inserted from the lat-eral. The alveolus of the centrals were equipped with BCS 3.5 17 mm implants. Those implante engaged into the resistant bone of the anterior alveolar spine. The area of the 1st premolars was equipped with a BCS 3.5 23 mm and also the area of the 2nd Promolar received a basal screw implant. In order to extend the support of the bridge to the first molar we inserted two long basal implants BCS 3.5 23 in an oblique manner in front of the sinus. Those two implant bypassed the other implants on the palatal side of the alveolar crest. (Fig. 2) We did not observe and contacts between the

implants during insertion. The intention was, to ensure cortical anchorage of the basal screw implants in the cortical bone provided by the floor of the nose and the sinus respectively. Both distal implant were equipped with cemented an-gulation adapters immediately after the place-ment. Following to the setting of the cement, the distally projecting parts of the implant heads were cut of with a herd metal cutter on the tur-bine. Impression caps were placed onto the 10 anterior implants. An impression was taken im-mediately and a temporary bridge was inserted. During the next day the metal frame was tried in and at the end of the following day the metal-to plastic-bridge was incorporated using tempo-rary cement.

RESULTS

The unfavorable situation of the masticatory system of this patient was changed into a stable, implant-borne bridge within 48 hours. The heal-ing occurred uneventful, the situation remained stable and no changes in the temporary bridge were necessary. The patients expectations had been met completely.

RESULTS

Traditional concepts in implantology include wide diameter implants and an unloaded, most-ly covered healing time after placements into sockets. Conventional screw tye implants seem unpractical for applications in extraction cases in combination with open healing protocols. The reason is, that their surface is sand-blasted and/or etched, and provides considerable retention for bacteria. Hence traditional protocols with these implants include a covered healing time, allowing the woven bone to close the socket in a sterile environment.Our concept becomes possible through using

appropriate implants with the following features: thin, polished vertical parts, without threads or other retentive elements near the location of the potential bacterial attack. This demand is ful-filled by both types of basal implants used here; laterally inserted BOI®-implants, and vertically in-serted BCS implants.

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For safe immediate loading protocols today two concepts are used widely:

One concept (shown here) includes cortical & macro-mechanical anchorage of implants. The cortical bone is known to be quite resis-tant to resorption (because it is required for structural reasons) and due to its high de-gree of mineralization this bone is prepared for carrying large loads. This concepts ap-plies the strategy of orthopaedic surgeons & the principles of fracture treatment. When chosing the best implants, the width of the bone is considered (for lateral implants) and the distance between the alveolar crest and the opposing cortical is considered (for basal screw implants). Integration along the verti-cal implant part is not essential for the suc-cess of the implant, but of course osseo- in-tegration will occur over time also along the vertical implant parts.

The second concept includes corticalisation of spongeous bone through with conical im-plants providing 1retentive threads. Cortical-ized (compressed ) bone looses the capabil-ity of the initiation of osteonal remodeling. Hence the compressed bone areals may not be origin of new osteons but only the target. The implants used for this concepts must either provide a surface enlargening (sand-blasting) or large retentive elements (e.g. thread) or a combination of both. The width of the implant is chosen according to the available bone (between 3 and 5 mm) and the length of the implant varies between 10 and 15 mm in most cases.

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In extraction cases the lateralization of bone is not an option in the crestal part of the alveoli, because this would require the invol-vement of implants with overly large diame-ters. Also the usage of implants with rough surfaces adds risks to the procedure, if the sockets remains open because the implants are loaded immeditely. For this reason we prefer to use implants anchoured in cortical areals: this offers sa-fety both with respect to infections and with respect of loss of stability during early func-tion. In our view, to avoid early infection of the extraction socket, implants exposed to the unsterile oral environment should be machin-ed (polished) at least in the crestal portion of the implant. To prevend peri-implantitis, the mucosal penetration diameter must be as thin as possible.This design contradicts the traditional concept of creating an “emerging profile” for the im-plant crown. In our view the introduction of the “emerging profile-concept” is a blessing only in selected cases, e.g. when enough vertical and horizontal bone is available and where teeth have remained adjacent to the implant. The teeth help to maintain the vertical bone level in those cases. Our concept however, is appli-cable and successful in all cases and it avoids risky augmentations.Immediate implant placement in extraction cases leads occasionally to the requirement of re-basing the bridge after several weeks: the shrinkage of the gums can`t be anticipa-ted completely in the design of the bridge, and remodeling will also reduce the vertical and horizontal bone height. Therefore the cemen-


tation should be done with temporary cement (e.g. Temp Bond®). In some cases the venee-ring needs to be replaced completely after the bone and the soft tissues have healed. If the same metal framework is used for the “second bridge” we can be sure, that the frame will sit tension-free (passive) on the implants.

CONCLUSION

The patients demand for immediate restoration after extractions can be met by using lateral and basal implants. Depending on the situation after the extraction, either basaly anchoured screw im-plants (BCS) or bi-cortically anchoured lateral im-plants (BOI) may be used alone or in combination. Our concept does not include any augmentation. If vertical bone is missing, we use the horizontal bone supply and keep the implant anchoured in the lateral cortical walls of the mandible or in the lateral walls of the maxilla, the palatal wall of the alveolar crest of the maxilla, the lateral and/or basal borders of the maxillary sinus or in the lat-eral cortical walls of the nasal cavity.

Figure 1. Preoperative panoramic view of the dentition in upper and lower jaw. The remaining teeth did not provide enough reten-tion for the blocks of crowns holding the denture. Both molars were mobile. Severe intra-bony infections with suppuration and pronounced bone loss around the left canine were diagnosed immediately before the implant placement.

Fig. 2: Postoperative panoramic view of the same patient after placement of implants and cementing angulation-adapter on the distal implants. Note that the anterior segment of the maxilla need strong support by the implants, because the anterior man-dibular dentition will be supported strongly by the two anterior implants.

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Fig. 3. 10 weeks postoperatively the gums appeared well healed and infection free. All extraction sockets had closed uneventfully.

Fig. 5. Intra-oral view, 10 weeks after implant placement. No request from the patient to replace this bridge for a ceramic bridge without pink base.

Fig. 4. The metal-to-plastic bridge placed on the second day after implant placement.


Evidence Report

Title: The influence of inter-implant distance upon dental implant outcomes

EVIDENCE REPORT PURPOSE

In dental implantology, the establishment of a supracrestal soft tissue seal for protection of the osseointegration is considered to be impor-tant for the success of the treatment. Because the bone crest constitutes the base for the soft tissue seal, alterations in the peri-implant bone level will affect the position of the soft tissue margin, which in turn may have a significant im-pact on the aesthetic outcome of the implant therapy. It has been suggested that both verti-cal and lateral bone loss at implants could have an effect on the level of the bone crest and soft tissue between two implants.

OBJECTIVE

To critically summarize the recently published literature examining the influence of inter-im-plant distance upon outcomes of intraoral den-tal implants.

SUMMARY

One study reported a greater mean crestal bone loss for implants with ≤ 3mm distance between compared to implants that were > 3mm apart. Another study reported that crestal bone loss was related to a decreased inter-implant distance. One other study found that, when the tooth/implant or inter-implant distance was ≤ 2.5 mm, dental papilla was ab-sent. Studies were of moderate to poor quality so conclusions based on reported differences should be considered with caution. However, this particular study question is a finite one that would unlikely be assessed in a higher quality study, at least as a primary objective. This Evi-dence Report, therefore, provides some insight into this interesting clinical question. Additional methodologically rigorous comparative stud-ies with comparable characteristics between groups should be considered to better evaluate the effect of inter-implant distance upon dental implant treatment outcomes.

SAMPLING

A MEDLINE search was performed to identify recent human studies published between Janu-ary 2000 and June 2008 examining the influ-ence of inter-implant distance upon intraoral dental implant treatment outcomes. Four ar-ticles evaluated the treatment comparison of interest and are included in this report, Table 1.

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Terms Hits Reviewed

Search dental implants OR dental implantation, endosseous [MeSH]

17,556

Search (dental implants OR dental implantation, endosseous [MeSH]) AND (implant distance OR thin OR platform switch), Limits ENGLISH, Human, Literature containing Abstracts

121 4

Bibliographies from existing literature 0 0

Total Reviewed 4

Table 1. Medline Search Summary

Common Outcome MeasuresVertical bone lossLateral bone lossSoft-tissue parameters

InterventionsStudies that evaluated outcomes of inter-im-

plant distance for intraoral dental implants were described as follows. All details regarding im-plant type are reported if reported by the author. If implant type is not reported, author failed to report it in the text of the manuscript:

Lee (2005)Fifty-two patients who had implant-supported, fixed prostheses in posterior sites for more than 12 months underwent evaluation of in-terproximal papillae between two adjacent implants. Subjects had various implant types, designs and surfaces (turned, titanium diox-ide-blasted, and acid-etched).

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Gastaldo (2004)Interproximal sites between adjacent im-plants (group 1) and between a tooth and an implant (group 2) were evaluated in 48 pa-tients who had implant-supported, fixed pros-theses for a minimum of 18 months and a maximum of 6 years.

Cardaropoli (2003)In a retrospective study, 28 partially dentate patients had been fitted with partial fixed prostheses supported by 3 standard Brane-mark implants and underwent post-treat-ment follow-up at 1 and 3 years.

Tarnow (2000)In a radiographic study, radiographic mea-surements were taken between 1 and 3 years after implant exposure in 36 patients who had 2 adjacent machined titanium im-plants separated by different distances.

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Author(year)

Study Design Population Diagnostic Cha-racteristics

Follow-up: % LoE*

Lee (2005) Case series N=52; Ninter = 72

female: 42.3%

age: 52.4 (40-62) yrs

Partially edentu-lous, rehabilita-ted with imp-lant-supported, fixed prosthesis

N/A Poor

Gastaldo (2004)

Case series N=48

female: 58.3%

age: 45 (19-72) yrs

Partially edentu-lous, rehabilita-ted with imp-lant-supported, fixed prosthesis

N/A Poor

Cardaropoli

(2003)

Retrospective Cohort

N=28; Npros=35

female: 64.3%

age: 65 (48-81) yrs

Partially eden-tulous in lateral jaw, rehabilita-ted with imp-lant-supported, fixed prosthesis

3 years: NR Moderate

Tarnow

(2000)

Case series N=36

female: NR

age: NR

Two adjacent implants sepa-rated by diffe-rent distances

N/A Poor

Table 2. Studies evaluating the influence of inter-implant distance upon outcomes for intraoral dental implants

N=number of subjects; Ninter=number of interproximal sites; Npros=number of prostheses

*Level of Evidence (LoE) is based on study design and methods (Very high, High, Moderate, and Poor)

†NR (not reported) = for follow-up rate either not reported or precise follow-up rate could not be determined since the initial number of eligible patients or number lost to follow-up were not provided.

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Study design and methods Lee (2005) Gastaldo (2004)

Cardaropoli (2003)

Tarnow (2000)

1. What type of study design? Case Series Case Series Retrospec-tive Cohort

Case Series

2. Statement of concealed allocation?* N/A N/A N/A N/A3. Intention to treat?* N/A N/A N/A N/A4. Independent or blind assessment? NO NO NO NO5. Complete follow-up of >85%? NR NR NR NR6. Adequate sample size? YES YES YES YES7. Controlling for possible confounding? YES NO YES NOLEVEL OF EVIDENCE Poor Poor Moderate Poor

* Applies to randomized controlled trials only

Table 3. Evaluation of articles studying inter-implant distance upon outcomes for intraoral den-tal implants

RESULTSInter-implant Bone LossVertical bone loss

Mean crestal bone loss for implants with a 3mm or less distance between (n=25) them was 1.04mm, while mean crestal bone loss for implants that were more than 3.0mm apart (n=11) was 0.45mm (Figure 1; no sig-nificance statistics presented) [Tarnow].

The mean distance from the base of the con-tact point to the inter-implant crestal bone was 4.7 ± 1.2mm [Lee].

For tooth/implant units after 3 years, the mean marginal bone loss at the tooth was 0.4 ± 1.0mm, at the implant was 0.5 ± 1.2mm, and at the mid-proximal bone crest level was 0.3 ± 0.5mm [Cardaropoli].

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For tooth/implant units after 3 years, multi-ple regression analysis with respect to verti-cal bone loss at the mid-proximal bone crest level revealed a significant association with bone level change at the tooth site (p<.01) [Cardaropoli].

For implant/implant units after 3 years, the mean marginal bone loss at the proximal im-plant surfaces facing the implant/implant unit was 0.7 ± 0.6mm and 0.6 ± 0.8mm. At the mid-proximal bone crest, there was a mean reduction of 0.5 ± 0.5mm [Cardarop-oli].

For implant/implant units after 3 years, mul-tiple regression analysis revealed that a loss of mid-proximal bone crest level was related to decreased horizontal inter-implant dis-tance (p<.05) [Cardaropoli].

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Lateral bone lossThe lateral distance from the implant to the crest of the ridge ranged from 1.34 to 1.40 ± 0.60mm [Tarnow].

For implant/implant units after 3 years, the mean lateral bone loss was 0.3 ± 0.4mm and 0.4 ± 0.5mm for the anterior and poste-rior implant sites, respectively [Cardaropoli].

Interproximal soft-tissue parametersThe mean length of the papilla from the crestal bone to the tip of the papilla was 3.3 ± 0.5mm. The width of keratinized mucosa from the mucogingival junction to the tip of the interproximal papilla between adjacent implants was 4.5 ± 1.7mm. The mean dis-tance from the base of the contact point to the inter-implant crestal bone was 4.7 ± 1.2mm. The mean horizontal distance be-tween adjacent implants was 3.1 ± 0.5mm [Lee].

In a multiple regression analysis, the mean length of the papilla from the crestal bone to the tip of the papilla was directly related to the width of keratinized mucosa from the mucogingival junction to the tip of the inter-proximal papilla between adjacent implants (p=.001) [Lee].

For the tooth/implant interproximal region, when the distance from the base of the contact point to the bone crest was from 3-5mm, the papilla was present 80-100% of the time (p<.05). The papilla filled the entire

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proximal space when this vertical distance was 3 and 4mm [Gastaldo].

When the tooth/implant distance was 3 to 4mm, the papilla was present 75-88% of the time (p<.05, Figure 2). When this distance was ≤2.5mm, the papilla was present 0% of the time, independent of the distance from the base of the contact point to the bone crest (p<.05) [Gastaldo].

For implant/implant interproximal regions, when the distance from the base of the con-tact point to the bone crest was 3mm only, the papilla was present 100% of the time (p<.05). The papilla filled the entire proximal space when this vertical distance was 3mm [Gastaldo].

When the inter-implant distance was 3 to 4mm, the papilla was present 70-80% of the time (p<.05, Figure 2). When this distance was ≤2.5mm, the papilla was present 0% of the time, independent of the distance from the base of the contact point to the bone crest (p<.05) [Gastaldo].

Methodological considerationsOne study was a retrospective cohort study with a rating of moderate (low quality co-hort), while the remaining studies were case series studies with a poor level of evidence rating. No high quality randomized con-trolled trials or high quality cohort studies were identified in the literature.

However, this particular study question is a

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finite one that would unlikely be assessed in a higher quality study, at least as a primary objective. This Evidence Report, therefore, provides some insight into this interesting clinical question.

In general, these studies provided outcomes that were unique to each study and, there-fore, were not comparable.

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REFERENCES

Studies Study 1

Lee D-W, Park K-H, Moon I-S (2005)Dimension of keratinized mucosa and the interproximal papilla between adjacent implantsJ Periodontol 76:1856-60.

Study 2Gastaldo JF, Cury PR, Sendyk WR (2004)Effect of the vertical and horizontal distances between adjacent implants and between a tooth and an

implant on the incidence of proximal papillaJ Periodontol 75:1242-6.

Study 3Cardaropoli G, Wennstrom JL, Lekholm U (2003) Peri-implant bone alterations in relation to inter-unit distancesClin Oral Impl Res 14:430-36.

Study 4Tarnow DP, Cho SC, Wallace SS (2000)The effect of inter-implant distance on the height of inter-implant bone crestJ Periodontol 71:546-9.

Only one study [Cardaropoli] reported sub-ject follow-up since the remaining studies were case series (cross-sectional) studies. This study did not provide a follow-up rate, though an 85% follow-up rate is necessary to ensure valid results.

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1.04

0.45

0.0

0.2

0.4

0.6

0.8

1.0

1.2

n=36 [Tarnow]

Mea

n C

rest

al B

on

e L

oss

(m

m)

� 3mm

> 3mm

Figure 1. Inter-implant Mean Crestal Bone Loss

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Figure 2. Percent of Papillae Present/Absent by Inter-implant or Tooth/Implant Distance

0.0% 0.0%

82.0% 81.0%

71.0%

0.0%

88.0%83.0%

75.0%

56.0%

100.0%

29.0%

100.0%

12.0%17.0%

25.0%

44.0%48.0%

0.0%

100.0%

52.0%

19.0%

100.0%

18.0%

0%

20%

40%

60%

80%

100%

2 2.5 3 3.5 4 4.5 2 2.5 3 3.5 4 4.5

Inter-implant or Tooth/Implant Distance (mm), n=48 [Gastaldo]

Per

cen

t o

f P

apill

ae P

rese

nt/

Ab

sen

t (%

)

% of papilla present

% of papilla absent


Critical Appraisal

REFERENCE:

Tarnow DP, Cho SC, Wallace SS. The effect of inter-implant distance on the height of inter-implant bone crest. J Periodontol. 2000 Apr; 71(4):546-9.

PERFORMING CLINIC:

Department of Implant Dentistry, New York University College of Dentistry, New York, USA.

AUTHORS’ SUMMARY:

There is a lateral component to the bone loss around implants in addition to the more com-monly discussed vertical component. The clini-cal significance of this phenomenon is that the increased crestal bone loss would result in an increase in the distance between the base of the contact point of the adjacent crowns and the crest of bone. This could determine whether the papilla was present or absent between 2 im-plants as has previously been reported between 2 teeth. Selective utilization of implants with a smaller diameter at the implant-abutment inter-face may be beneficial when multiple implants are to be placed in the esthetic zone so that a minimum of 3 mm of bone can be retained be-tween them at the implant-abutment level.

STUDY OBJECTIVES:

To evaluate the lateral dimension of the bone loss at the implant-abutment interface and to determine if this lateral dimension has an effect on the height of the crest of bone between adja-cent implants separated by different distances.

STUDY DESIGN:

Case series consisting of 36 patients (age and gender not reported) who were part of a longitu-dinal study (no reference) at the New York Uni-versity Department of Implant Dentistry.

INCLUSION/EXCLUSION CRITERIA:

• Patients who had previously received 2 adja-cent machined titanium implants who had ra-diographs between 1 and 3 years after implant placement.

STUDY METHODS:

• Radiographic measurements were taken at a minimum of 1 and a maximum of 3 years after implant exposure to determine bone loss. • Lateral bone loss was measured from the

crest of bone to the implant surface. • Crestal bone loss was also measured from a

line drawn between the tops of the adjacent im-plants. The data were divided into 2 groups, based on the inter-implant distance at the implant shoul-der (either greater than or less than 3mm).

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RESULTS:

• Lateral bone loss was 1.34 mm (SD = 0.36mm) from the mesial implant shoulder to the bone crest and 1.40 mm (SD = 0.60) from the distal implant shoulder to the bone crest be-tween the adjacent implants, Table. • Crestal bone loss was 0.45 mm for implants

> 3mm apart.• Crestal bone loss was 1.04 mm for implants

≤ 3mm apart.

Bone loss (mm)

LateralDistance A

(n=36)Distance B (n=36)

Mean (± SD) 1.34 ± .36 1.40 ± .60

Crestal Mean vertical crestal bone loss

≤ 3mm (n=25)

1.04

> 3mm (n=11)

0.45

CONCLUSIONS PROVIDED BY AUTHORS:

The study demonstrates a trend of increased crestal bone loss as inter-implant distance de-creases. Selective utilization of implants with a smaller diameter at the implant-abutment inter-face may be beneficial when multiple implants are to be placed in the esthetic zone so that a minimum of 3mm of bone can be retained be-tween them at the implant-abutment level.

REVIEWER’S EVALUATION:

Methodological Principle

Randomized design NO

Independent or blind assessment NO

Adequate sample size NO

Appropriate analysis NO

Appropriate measures

Radiological analysis YES

1. WHAT WERE THE STUDY’S METHODOLO GICAL STRENGTHS?

• Clearly defined objective.• There were no other strengths identified.


3. HOW MIGHT THE FINDINGS FROM THIS CRITICAL APPRAISAL BE APPLIED TO PA- TIENT CARE?

The authors used implants whose maximum collar diameter equals the maximum thread diameter. This is an untypical type of implant. Most of the implants available are of the Tulip-type (Straumann, SSO, STc, STO, etc.) or have at least some difference between collar-diam-eter and thread-width. We must doubt strongly, that the results are applicable to all types and designs of implants.

The authors should have registered the width of the bone at baseline. This way bone loss in sagitally reduced ridges could have been distin-guished from wide ridges. We have to assume from the experience we have today, that the width of the ridge is a determining factor for bone loss around implants.

Furthermore the author should have made sure, that they work with a coherent study group: individuals “having two adjacent implants pres-ent”, are not a coherent group, as a number of factors can influence the result:

- Next to the implants may be teeth which main-tain the vertical level of bone well

- Next to the implant may be bone turning to atrophy, which by itselve leads to bone loss

-Bone loss in different regions varies

1. WHAT WERE THE STUDY’S METHODOLO GICAL LIMTATIONS?

• The authors did not provide basic patient de-mographic data such as age and gender.• The authors did not provide basic general

health or comorbidity data that may influence crestal bone loss. Examples may include smok-ers, patients who are diabetic, or patients with bone conditions.• The authors report that radiographs were

performed between 1 and 3 years after implant placement; however, did report means or control for these differences when comparing crestal bone loss. Is it possible that 3 years could be significantly different than 1 year?• The sample size was very small. The authors

compared 25 subjects (≤ 3mm) to 11 subjects (>3mm) and concluded that distance between implants is associated with crestal bone loss. They did not report the variability of these find-ings (i.e., standard deviation, see table) and therefore we cannot calculate whether these differences were statistically significant.• The authors did not report any analytical com-

parisons with p-values or confidence intervals. They only reported the mean crestal loss for the two categories. Again, this difference may be the result of chance with such a small sample size and no statistical analysis.• Lastly, even if a statistical analysis was per-

formed that demonstrated these changes in crestal bone loss as significant, the author did not report and therefore could not have con-trolled for other factors that might influence crestal bone loss such as age, bone conditions, smokers, or other comorbidities.

178

4. WERE ALL IMPORTANT ASSESSMENTS PERFORMED? IF NOT, WHAT ASSESS- MENTS SHOULD BE CONSIDERED

Measuring distances “A”, “B”, and “C” are not clinically relevant outcomes, as implant loss oc-curs anyway in this type (design) of implants. The cases should have been grouped differently so that the result could be matched to the remain-ing dentition.

The diameter and type of the implants used should have been mentioned. The “results” are limited to these implants.

5. ARE THERE ALTERNATIVE EXPLANATI- ONS FOR THE FINDINGS OBSERVED IN THIS STUDY?

It seems that the authors have assumed, that bone loss occurs anyway in the implants used and that the bone loss will reach the first thread and stop there. This is the case for formerly sold Branemark implants etc.The vertical crest height (“C” in the graphs of

the authors) does not play any role under these circumstances. The authors should have pro-longed the observation period to distinguish cas-es showing really progressing bone loss from typical bone loss.

6. HOW MIGHT THE FINDINGS BE APPLIED TO PATIENT CARE?

It is not possible to draw any conclusion to pa-tient care. Especially the results may not be used to draw any conclusion on cases with thin diam-eter implants (e.g. less than 3.7 mm), to implant without crestal widening (e.g. not to KOS-im-plants) or to implants showing no threads along the crestal part of the bone (e.g. BCS-implants or thin necked basal implants).Note also that the effect of reduced distance

between endosseous parts of implants (screw threads or disk plates) was not investigated and conclusions may not be drawn to those implant types.

The results may also not be applied to implant without threads: bone loss in threaded implants is known to stop are slow down at the first tread. Patterns of bone loss in non-threaded implants have not been investigated yet.


Evidence Report

Effect of diabetes mellitus on dental implants survival and complications

EVIDENCE REPORT PURPOSE

Diabetes mellitus is a group of metabolic disorders characterized by an increase in plasma glucose levels. The resulting hyperglycemia is caused by a defect in insulin secretion, insulin action, or both.Chronically high levels of plasma glucose may be associated with a wide range of systemic compli-cations such as retinopathy, nephropathy, neu-ropathy, micro- and macrovascular disease, and altered wound healing. In implantology, microvas-cular disease may contribute to delayed wound healing, reversed bone turnover, and increased susceptibility to infection

OBJECTIVE

To critically summarize the recently published lit-erature examining implant survival and other out-comes in studies comparing patients with and without diabetes mellitus.

SUMMARY

There was a trend towards lower implant survival rates for subjects with diabetes mellitus compared to nondiabetic subjects. One study found increased implant survival rates in diabetic patients (1) when 0.12% chlorhexidine digluconate was used at the time of implant placement compared to not, (2) when pre-operative antibiotics were used compared to not, and(3) when hydroxyapatite (HA) coated im-plants were used compared to non-HA implants.Studies found significantly greater levels of peri-im-plant bone loss in (a) patients with diabetes com-pared to nondiabetics and (b) patients with poor diabetic control compared to those who were well-controlled. Further, there was a significantly great-er prevalence of peri-implantitis in poorly-controlled diabetics compared to well-controlled individuals.Post-operative complications were also greater in poorly-controlled diabetics compared to those with good control, though the prevalences were not sig-nificantly different between these two groups. Addi-tional methodologically rigorous comparative stud-ies are needed to better evaluate the treatment outcomes of dental implants in relation to diabetes; however, these findings should be considered when treating patients with diabetes.

SAMPLING

A MEDLINE search was performed to identify recent studies published between January 2000 and Sep-tember 2008 examining the effect of diabetes mel-litus on dental implant treatment outcomes. From a list of 16 articles, 3 included implant treatment outcomes that met our criteria and are included in this report, Table 1.

180

Table 1. Medline Search SummaryTerms Hits Reviewed

Search dental implants OR dental implantation, endosseous [MeSH] 17,913

Search (dental implants OR dental implantation, endosseous [MeSH]) AND [diabetes OR diabetes mellitus]), Limits ENGLISH, Human, Literature containing Abstracts

52 2

Search (dental implants OR dental implantation, endosseous [MeSH]) AND [diabetes OR diabetes mellitus] AND comparative studies), Limits ENGLISH, Human, Literature containing Abstracts

8 1

Total Reviewed 3

COMMON OUTCOME MEASURES:

• Implant survival• Implant survival, categorized• Peri-implant bone resorption• Peri-implantitis• Post-operative complications

INTERVENTIONS:

Dental implants were placed in subjects de-scribed as follows:

Tawil (2008)• Forty-five Type 2 diabetic patients with a glyco-

sylated hemoglobin (HbA1c) value ≤ 7.2% during the perioperative period were matched by age, gender and type of implant to 45 consecutively treated nondiabetic patients. Individuals were followed prospectively for 1 to 12 years.

Morris (2000)• In a retrospective study, 255 implants were

placed in individuals with Type 2 diabetes, and 2632 implants were placed in patients without diabetes. Implant outcomes were followed for 3 years after implantation.

Accursi (2000) (within Elsubeihi & Zarb 2002)• In a retrospective study, 15 medically con-

trolled diabetes mellitus patients were matched to 2 non-diabetic control subjects by age, sex, location of implants, type of prosthetic restora-tion, opposing dentition, and duration of edentu-lism. Individuals were followed for 1 to 17 years, and implant survival in diabetic patients (n=59 implants) was compared with that of non-diabet-ics (n=111 implants).


Note:Glycosylated hemoglobin values reflect average

blood sugar levels for the 2- to 3- month period before the blood test. Levels from 4% to 7% in-dicate well-controlled diabetes, and levels above approximately 7% indicate poor control.


Author

Study Design PopulationDiagnostic Characteri-

stics

Diabetes(year)

Follow-up (%)

Diabetes Mellitus

No Diabe-tes

LoE†

(Group A) (Group B)Tawil Prospective

cohortN = 90 Indication for

dental implant placement

N=45; Ni=255

n=45; Ni=244

1-12 years (mean 42.4

months): NR*

Moderate

-2008 female: 37% age: diabetics

= 64.7 (43-84) yrs; nondiabetics = 59.6 (29-

85) yrs

Morris (2000)

Retrospective N = 663 Indication for dental implant

placement

N=NR; Ni=255

N=NR; Ni=2632

3 years: NR* Moderate

cohort female: 5.9%

age: NR

Accursi (2000)

Retrospective N = 45 Indication for dental implant

placement

N=15; Ni=59 N=30; Ni=111

1-17 years: NR*

Moderate

cohort female: NR‡

age: NR‡

N = Number; Ni = Number of implants; NR = Not Reported†Level of Evidence (LoE) is based on study design and methods (Very high, High, Moderate, and Poor)*NR (not reported) = for follow-up rate either not reported or precise follow-up rate could not be determined since the initial number of eligible patients or number lost to follow-up were not provided.‡ = Subjects with diabetes were age- and sex-matched to 2 control subjects without diabetes.

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Study design and methods

Tawil (2008)

Morris (2000)

Accursi (2000)

1. What type of study design?

Prospective Cohort



2. Statement of concealed allocation?*

N/A N/A N/A

3. Intention to treat?*

N/A N/A N/A

4. Independent or blind assessment?

NO NO NO

5. Complete follow-up of >85%?

NR NR NR

6. Adequate sample size?

NO YES NO

7. Controlling for possible confounding?

YES NO YES

LEVEL OF EVIDENCE

Moderate Moderate Moderate

* Applies to randomized controlled trials onlyNR = not reported

RESULTS

Overall implant survival (Figure 1)

There was a trend for lower survival rates in those subjects with diabetes.• Overall implant survival for Type 2 diabetic sub-

jects was 97.6%, while that of nondiabetics was 99.6% (p>.05) in a study in which subjects were followed for 1 to 12 years. [Tawil]• At 3 years, subjects with Type 2 diabetes dem-

onstrated a survival rate of 92.2% and those without diabetes had a survival rate of 93.2%; p>.05. However, in a multivariate regression, diabetes (p<.05) and health status (p<.02) were significant factors influencing implant survival. [Morris]• In a retrospective study in which individuals

were followed for 1 to 17 years, subjects with di-abetes experienced a 93.2% survival rate, while those without diabetes had a survival of 94.6%; p>.05. [Accursi].

Implant survival, by treatment (Figure 2)

• When 0.12% chlorhexidine digluconate (CHX) was used at the time of implant placement in Type 2 diabetics, there was a significantly greater im-plant survival rate at 3 years compared to Type 2 diabetics on whom CHX was not used (95.6% vs. 86.5%; p<.05). In non-diabetic subjects, there was an increased, though non-significant, survival rate in those with CHX compared to those with-out CHX (94.3% vs. 91.8%, p>.05). [Morris]• Pre-operative antibiotic usage in Type 2 diabet-

ics provided a significant improvement in implant survival at 3 years (97.1% vs. 86.6%; p<.05). In


non-diabetics, there was an increased though non-significant implant survival rate in individuals in whom pre-operative antibiotics were used com-pared to those without pre-operative antibiotics at 3 years (95.1% vs. 90.6%, p>.05). [Morris]• The use of hydroxyapatite (HA) coated im-

plants compared to non-HA coated implants sig-nificantly improved implant survival in both Type 2 diabetics (97.9% vs. 84.7%; p<.05) and non-diabetics (96.7% vs. 87.2%; p<.05). [Morris]

Peri-implant bone loss

• One study reported a significantly greater mean loss of crestal bone height in the first year in subjects with medically controlled diabe-tes compared to those without diabetes (-0.25 ± 0.07mm vs. -0.06 ± 0.03 mm, respectively; p<.05) [Accursi].• Another study found significantly greater peri-

implant bone loss in Type 2 diabetic patients with poor diabetic control (HbA1c levels ≥ 7%) com-pared to those with good control (HbA1c levels < 7%) (-0.24 ± 0.28 mm vs. -0.5 ± 0.7 mm, re-spectively; p=.01). [Tawil]

Peri-implantitis (Figure 3)

• In Type 2 diabetics with different levels of dia-betic control, there was a significantly greater prevalence of peri-implantitis in patients with HbA1c levels ≥ 7% compared to those with levels < 7% (30.4% vs. 0%, p=.05). [Tawil]

Post-operative complications (Figure 3)

• In Type 2 diabetics with different levels of dia-betic control, there was a greater prevalence of post-operative complications in patients with HbA1c levels ≥ 7% compared to those with lev-els < 7%, though the difference was not statisti-cally significant, likely due to small sample sizes (52.2% vs. 27.3%, p>.05). [Tawil]prevalence of peri-implantitis in patients with HbA1c levels ≥ 7% compare

Methodological considerations

• All studies reviewed were cohort studies with a rating of moderate (low quality cohort) level of evidence. No very high quality randomized con-trolled trials or high quality cohort studies were identified in the literature.• All of the studies had small sample sizes, and

two of the studies [Tawil, Accursi] had sample sizes that were likely inadequate to show a differ-ence between the study groups, especially when samples were stratified into subgroups.• Since multiple implants in the same subject

are not statistically independent, either one im-plant should be chosen per patient or statistical analysis should account for multiple implants per patient. Only one of the studies reviewed [Tawil] accounted for multiple implants in the same sub-ject, but only for complication rates.• None of the studies reported a follow-up rate

or provided data adequate enough to calculate the follow-up rate. A follow-up rate of ≥85% is necessary to ensure valid study results.

184

REFERENCES

Studies

Study 1Tawil G, younan R, Azar P, Sleilati G (2008)Conventional and advanced implant treatment

in the type II diabetic patient: surgical protocol and long-term clinical results.Int J Oral Maxillofac Implants 23:744-52.

Study 2Morris HF, Ochi S, Winkler S (2000) Implant survival in patients with type 2 diabetes:

placement to 36 months.Ann Periodontol 2000;5:157-65.

Study 3Accursi GE (2000)Treatment outcomes with osseointegrated

Branemark implants in diabetic patients: a retro-spective study [thesis]. Toronto (ON): University of Toronto.

In: Elsubeihi ES, Zarb GA. Implant prosthodon-tics in medically challenged patients: The Univer-sity of Toronto experience. J Can Dent Assoc 2002;68(2):103-8.


Figure 1. Cumulative overall survival rates for dental implants by diabetic status.*

97.6%92.2% 93.2%93.2% 94.6%

99.6%

0%

20%

40%

60%

80%

100%

1-12 years, n=90 [Taw il]

3 years, n=663 [Morris]

1-17 years, n=45 [Accursi]

Cu

mu

lati

ve S

urv

ival

Rat

es (

%))

Diabetes

No Diabetes

p>0.05 p>0.05p>0.05

Statistical significance noted on graphs if provided by author* n=number of subjects

Dowell S, Oates TW, Robinson M (2007)

Implant Success in people with Type 2 diabetes mellitus with varying glycaemic control – a pilot study; J Am Dent Assoc , 138: 355-361 (None of the implants places was lost during the observa-tion period)

Behnke A., Behnke N., Hoedt B., Wagner W. (1998)

Diabetes mellitus – ein Risikofaktor für enossale Implantate im zahnlosen Unterkiefer?Dtsch Zahnärztl. Z. 5:332-329 (Controlled clini-

cal study. Article in German: within a 5-year obser-vation period implants placed in the anterior region of the mandible showed higher survival rate in dia-

betic patients (94,6%), compared to healthy sub-jects(91,6); the amount of bone resoption along the vertical axis of the implants was slightly higher (1.3mm) in diabetic patients, compared to healthy subjects (1mm), and the amount of resorption de-pended on duration of the diabetic condition.

Tawil G, Younan R et al; (2008)

A study on diabetic patients (Type II) showed that there is no statistic correlation between the group with well adapted hbA1c < 7%) compared to less well adapted HbA1c (7-9 %). However HbA1c values vorrelated to Plaque-Index and Bleeding Index BOP.Int. J Oral Maxillofac Implants (2008) 23: 744-752

186

Figure 2. Cumulative survival rates for dental implants by diabetic patients by treatment.*

95.6% 97.1% 97.9%

86.6%84.7%86.5%

0%

20%

40%

60%

80%

100%

CHX vs. no CHX atplacement

Pre-operative antibioticsvs. none

HA coated implants vs.non-HA implants

Diabetic Patients, number of implants=255 [Morris]

Cu

mu

lati

ve S

urv

ival

Rat

es (

%))

p<0.05 p<0.05p<0.05

Statistical significance noted on graphs if provided by author* blue indicates treatment, burgundy indicates no treatment or non-standard treatment

Figure 3. Post-operative soft tissue parameters of dental implants in diabetic patients by level of diabetic control.*

Statistical significance noted on graphs if provided by author* n=number of diabetic subjects

30.4%

52.2%

27.3%

0.0%0%

20%

40%

60%

80%

100%

Peri-implantitis, n=45 [Tawil] Post-op complications, n=45 [Tawil]Pre

vale

nce

of

So

ft T

issu

e P

aram

eter

s (%

)

HbA1c � 7%

HbA1c < 7%

p=0.05

p>0.05


Literature Analysis

A “Literature Analysis” is a critical review of the literature on the epidemiology, treatment methods, and prognosis for implant-related topics or conditions. Literature Analyses are broader than “Evidence Reports” (also published in each issue of Implant Directions) which focus on one specific treatment inter-vention by comparing and contrasting only 3 to 5 high quality articles in greater depth.

Literature Analyses are written to serve as a refer-ence tool for implantologists:

To help them make decisions regarding how to manage patients;To assist them in evaluating needs for future research;To use the material for future presentations.

This literature analysis on the effects of radiation therapy is the second of two parts. Part I evalu-ated and reported on ANIMAL studies. This analy-sis (Part II) will be published in the next edition of Implant Directions and will evaluate and report on HUMAN studies.

PurposeThe purpose of this Literature Analysis was to

systematically search the literature to identify key articles in an effort to evaluate the effects of radiation therapy on craniomaxillofacial and dental implants. Part I of this literature analysis addressed the following objectives:

Provide an overview of implantology in irradi-ated craniomaxillofacial bone.

•

•

•

1.

Summarize dental implant failure from ANI-MAL studies with respect to the following:a. Irradiated versus non-irradiated boneb. Dosing of radiationc. Implant typesd. Timing of radiatione. Hyperbaric Oxygen TherapySummarize the quality of the literature on ANIMAL studies and recommended future studies.

This edition (Part II) will address the following objec-tives:

.Summarize craniomaxillofacial (CMF) and dental implant failure from HUMAN with re-spect to the same parameters as reported in ANIMAL STUDIES.Summarize complications from HUMAN studies associated with implants in irradi-ated bone in CMF and dental implants.Summarize quality of literature on HUMAN studies and recommended future studies.Discuss the role of BOI in the treatment of patients with irradiated bone.

The search methods and an overview of implants in irradiated bone are reported in the last edition of Implant Directions.

Summary of human studies on craniofacial implants in irradiated bone An attempt was made to address the following

categories by relying only on studies that made appropriate comparisons (i.e., cohort studies and case series with historical controls): irradi-ated versus non-irradiated bone, dosing of radia-

2.

3.

1.

2.

3.

4.

188

tion, timing of radiation, implant location, implant types, and HBO therapy. Studies were of poor (case series) to moderate (cohort studies) qual-ity so conclusions should be made with caution, Table 1. Rates of failure are reported by implant location in the table so a single study may ap-pear more than once in the table.

Irradiated versus non-irradiated bone When comparing rates of implant failure in ir-

radiated versus non-irradiated bone in CF appli-cations, the risk of implant failure in irradiated bone was as high as 12 times greater than that for non-irradiated bone.1-5 The increased risk was statistically significant in seven compari-sons, however, only two were data from cohort studies (i.e., made the comparison in the same study population).1, 2 Stronger associations were seen in case series compared to histori-cal controls. Survival rates were based on as little as one year and as much as 5 years after implantation.

Dosing of radiation Few studies were identified evaluating radiation

dose in CF applications. One study reported no difference in failure based on dose (< 50 versus ≥ 50 Gy) in orbital implants, however the sample size was relatively small.6 Cumulative radiation effect (CRE) as a measure of dose (≤30) was sig-nificantly related to implant failure in one prog-nostic study.7 Radiation dose (above CRE30) was the only factor associated with implant fail-ure (p=0.05) in this study.

Timing of radiation Schoen evaluated failure rates based on wheth-

er the implants were placed prior to or after ir-radiation.8 The sample sizes were too small to effectively determine the effects of timing or the risks associated with radiation prior to or after implant placement. No other studies were iden-tified.

Implant locationLocation of CF implants may influence the sur-

vival rate. Numbers cited in the literature for im-plant survival in non-irradiated bone by location are as follows: mastoid region, >95%; orbital im-plants, 35-91%; nasal implants, 71-81%.9 No significant differences were seen for implants in other CF locations. Several studies reported a tendency toward higher failure rate in the or-bital area due to thin bone in this region,1, 10, 11 while others did not find any statistical differ-ence between orbital implant success and other craniofacial implants, whether in irradiated or non-irradiated bone.5-9 A review of patient data over a 25-year period comparing implant suc-cess in irradiated and non-irradiated popula-tions indicated that implant location was not a factor in survival, with the possible exception of orbital implants which may show a trend toward lower survival rates (p=0.055), and gingival im-plants which may have a higher survival rate (p=0.05).7

Implant types No studies attempting to compare different

types of CF implants in irradiated bone were identified precluding any conclusions regarding superiority of one CF implant type over another.


HBO therapyOne study was identified evaluating the effect

of HBO therapy in irradiated bone.4 Failure was significantly less common (RR=0.15; 95% CI 0.7, 0.30) among radiotherapy patients treated with HBO compared with those who had radio-therapy but no HBO. There was no difference in failure rates comparing non-irradiated patients and those who had radiation and HBO.

Summary of human studies on dental im-plants in irradiated bone An attempt was made to address the same

categories of treatment effects reported in the CF section, Table 2.

Irradiated versus non-irradiated bone The proportion of studies that reported statis-

tically significant differences between irradiated bone and non-irradiated bone in the dental im-plant studies was far less than reported in the CF studies. Further the relative risks were not nearly as high. Of the eight studies that com-pared rates of implant failure in irradiated and non-irradiated bone, only three reported sta-tistically significant differences. The risk of im-plant failure in irradiated bone was between 2-3 times greater than that for non-irradiated bone in these studies. In CF studies, the relative risk was as high as 12. Moy reported nearly a 3 times greater risk of implant failure in irradiated versus non-irradiated bone (RR= 2.73; 1.10, 6.81); however, after adjusting for diabetes and smoking status, the RR was still significant but less than two (RR= 1.87; no confidence interval was provided).12 Raw data was not available so we did not present it in Table 3; however, the

author produced the RRs and adjusted RRs that we report here.

Dosing of radiation Visch et al 13 compared survival rates at 10-

years in patients receiving a dose either less than or greater than or equal to 50Gy. Lower radiation dose (<50Gy) was significantly associ-ated with improved implant survival compared with higher doses (≥50 Gy). This difference was greater than two-fold (RR = 0.49; 95% CI 0.29, 0.81). A review article noted that no failures were observed with radiation doses lower than 45Gy. 14

Timing of radiation Several studies compared failure rates for im-

plants placed at varying intervals post-irradia-tion. No differences were seen when comparing placement less than or more than one year after radiation in one study. 13 Another study found no differences in timing but the number of subjects and implants was small.15 One study observed that only the time interval between implant placement and the abutment operation showed significance, where patients receiving implant placement and abutment <4 months apart did significantly worse than those with the abut-ment procedure >4 months from time of implant (p=0.0001). 16 A second study agreed with this finding, noting that significantly more mandibu-lar reconstruction plates were lost when radia-tion was administered during the perioperative period, defined as within 12 weeks of implant surgery.15 A third study did not observe a sta-tistically significant difference in survival rates between implants inserted less than or greater

190

than one year post-irradiation.13 A review article comparing failure rates for implants placed ei-ther pre- or post- irradiation showed that failure rates were similar between the two groups and not statistically significant (5.4% and 3.2%, re-spectively).14

Implant locationImplant failure in irradiated maxillary bone was

twice that of non-irradiated maxillary bone based on one study where the comparison could be made.17 Complications based on radiation status were not well reported and generally not sepa-rated out in those studies reporting complica-tions, making definitive statements about com-plications, including osteoradionecrosis difficult. Mandibular implants were significantly less likely to fail compared with maxillary implants. 13 An adjusted RR of 1.79 (p = 0.001, no CI provided) for implant failure in the maxilla compared with that in the mandible was reported (all bone). One study showed a survival rate of 59% in the max-illa, 85% in the mandible. (p=0.001).13 In a com-parison of total implant locations, high implant failures were seen after high dose radiotherapy and a long time after irradiation. All craniofacial regions were affected, but the highest implant failures were seen in frontal bone, zygoma, man-dible, and nasal maxilla. Lowest implant failures were seen in oral maxilla.7 A review article noted that implant location resulted in significant differ-ences in failure rates, with mandibular implants failing less than maxillary implants (4.4% and 17.5%, respectively; OR=4.63; 95% CI: 2.25 to 9.49).14

HBO therapy Two studies attempting to evaluate the effect

of HBO therapy as an adjunct to irradiation for dental implants in irradiated bone were identi-fied. 18, 19 Based on the criteria that the patient is expected to experience difficulty during osseo-integration, Granstrom et al proposed the use of HBO therapy as potentially beneficial.18 They reported from a multivariate analysis of 671 ir-radiated implants that HBO therapy improved implant survival with significance at the p<0.001 level (study in press). Conversely, Donoff et al contend that our understanding of wound heal-ing is incomplete and constantly changing in the light of new research, and that our incomplete knowledge precludes any reliable conclusions regarding the necessity for HBO therapy.19

Summary of complications associated with implants in irradiated bone in human studies Complication rates based on radiation status

were not well described in any of the compara-tive studies. Failure to report complications should not be construed as meaning that none were present. Briefly, in the CF studies reviewed, several studies reported no complications,8, 9 one study reported a low rate of osteoradione-crosis (4.7% (n=5/107)),7 and grade 1-3 tissue reactions were observed in patients receiving radiotherapy (P<0.001 to 0.05).7, 8

For the dental implant studies, August et al reported the following early complications in an oral cancer population:20 soft tissue overgrowth around pins (22.2% (n=4/18)), tongue ulcer-ations (11.1% (n=2/18)), and intraoral wound dehiscence(11.1% (n=2/18)). Late complica-tions included orocutaneous fistula formation


(16.6% (n=3/18)), submental erythema (11.1% (n=2/18)), persistent tissue overgrowth around pins (5.6% (n=1/18)). Soft tissue ulcers have also been noted.21, 22

Radiation scatteringImplants placed before radiation therapy may

cause scattering, resulting in a decreased dose delivered to the tumour and increased exposure to soft tissue and bone adjacent to the implant. 8 Implants of a higher atomic number mate-rial cause a greater back-scatter dose factor (BSDF), though the range is small (a few milli-metres). Additionally, lower energy photons, i.e. 60Co, caused greater backscatter than higher energy photons.23, 24 A study of simulated head and neck radiotherapy showed that highest dose enhancement occurs at a distance of 0 mm from the bone-implant interface in all locations and implant materials studied. Transmandibular implants (high gold content, gold-copper-silver alloy) had scatter up to 1mm from the bone-implant interface. No significant difference was noted in buccal, lingual, mesial or distal direc-tions. Hydroxyapatite-coated titanium implants demonstrated the best results.25 An additional study of titanium implants in mandible confirmed that the risk of radionecrosis from backscatter is slightly but not significantly higher with post-implantation radiotherapay.24

A dosimetric evaluation of the effect of pre-viously placed dental implants during radio-therapy concluded that the risk of osteora-dionecrosis to the mandible is slightly but not significantly affected by the scattered dose in the radiation field exposed to 3 different radia-tion beams.24Granstrom et al recommend that

if irradiation is to be performed post-implanta-tion, all prostheses, frameworks and abutments should be removed prior to irradiation. Fixtures should be left intact but covered with skin or mu-cosa, as removal of osseointegrated implants is itself a potentially damaging procedure.3

Quality of literature and need for future re-search

In general, the quality of studies comparing im-plant failure/success and complication rates in irradiated versus non-irradiated bone is poor. For animal studies, no studies evaluated all im-portant parameters such as timing, histomor-phometric, biomechanical, and histological mea-surements in the same study using irradiated bone with a non-irradiated control leg. Further-more, few animal studies were designed to com-pare implant types in irradiated bone.

For HUMAN studies, most were of poor to mod-erate quality. The majority of comparisons be-tween irradiated bone and non-irradiated bone were with historical controls. However, a pro-spective study comparing patients who do and do not get irradiated in the same consecutive patient population may be difficult to perform. No studies were designed to compare implant types in irradiated bone. This may be the focus for future research.

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We recommend the following two studies for future research and publication:

1. A well-designed animal study with ad-equate sample size that compares different im-plant types in irradiated and non-irradiated bone. This study should assess the following important parameters with respect to the implants evalu-ated:a. Timing of radiationb. Histomorphometric characteristicsc. Biomechanical characteristicsd. Histological characteristics

2. A well designed HUMAN observational cohort study that follows a group of similar pa-tients during the same time period. This should be a population of patients who do and do not undergo radiation. Furthermore, this should be a large enough population with enough im-plantologists that more than one implant type is used in both irradiated and non-irradiated bone. This will allow for the comparison of implants in irradiated and non-irradiated bone with respect to the following outcomes:a. Time to loadingb. Implant failurec. Complicationsd. Implant functione. Overall quality of life

Role of BOI in the treatment of patients with irradiated bone

The following key findings from this literature overview make BOI a potential solution for the management of patients with irradiated bone:

Patients are at greater risk of implant fail-ure.Patients typically undergo multiple proce-dures and very prolonged waiting times be-fore loading their implants.No implants have been identified from the literature superior for treating patients with irradiated bone.If animal studies are successful, this may be an area of indication for BOI to market itself and find its way into the US market.Furthermore, if BOI appears indicated for pa-tients with irradiated bone then it may also be assumed it is indicated for all indications of “poor” bone quality or quantity.

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2.

3.

4.

5.


Table 1: Summary of studies comparing implantation in irradiated versus non-irradiated bone: Cra-niofacial applications.Studies Study Design Implant Loca-

tionOutcome Irradiated Non-irradiated Effect Size RR

(CI)*

Roumanas1 Cohort All Implant Failure 40% (14/35) 12% (21/172) 3.3 (1.9, 5.8)*

Albrekteson2 Case series All Implant Failure 15% (4/34) 1.5% (6/389) 9.5 (3.1, 29.6)*

Granstrom7 Case series All Implant Failure 23%(147/631) 12% (76/614) 1.9 (1.5, 2.4)*

Granstrom4 Case series All Implant Failure 54% (79/147) 12%(12/101) 4.5 (2.6, 7.9)*

Wolfaardt5 Case series All No Osseointe-gration

30.5% (44/144)

2.5% (31/1221)

12.0 (7.9, 18.4)*

Roumanas1 Cohort Various CF Implant Failure 30% (3/10) 27% (9/33) 1.1 (0.37, 3,3)

Wolfaardt5 Case series Nasal No Osseointe-gration

20% (2/10) 17% (9/53) 1.18 (0.29, 4.66)

Roumanas1 Cohort Auricular Implant Failure 0%(0/6) 4.5 % (5/111) Incalculable

Wolfaardt5 Case series Mastoid No Osseointe-gration

0%(0/10) 1.7% (9/516) Incalculable

Schoen8 Cohort Orbit Implant Failure 11% (4/35) 0% (0/14) Incalculable

Toljanic6 Case series Orbit Implant Failure 34% (31/92) 24% (21/89) 1.4 (0.89, 2.29)

Wolfaardt5 Case series Orbit No Osseointe-gration

49% (40/81) 6.1% (7/115) 8.1 (3.8, 17.2)*

Roumanas1 Cohort Orbit Implant Failure 59% (11/19) 25% (7/28) 2.3 (1.1, 4.9)*

Rad + HBO Non-Irradiated

Granstrom26 Case series All Implant Failure 8.1% (8/99) 13.5% (12/89) 0.60 (0.26, 1.4)

Rad + HBO RAD only

Granstrom26 Case series All Implant Failure 8.1% (8/99) 54% (79/147) 0.15 (0.7, 0.30)*

Rad after Imp-lant

Non-irradiated

Schoen8 Cohort Orbit Implant Failure 14% (2/14) 0% (0/14) Incalculable

Rad prior to Implant

Non-irradiated

Schoen8 Cohort Orbit Implant Failure 9.5% (2/21) 0% (0/14) Incalculable

Rad after Imp-lant

Rad prior to Implant

Schoen8 Cohort Orbit Implant Failure 14% (2/14) 9.5% (2/21) 1.5 (0.23, 9.4)

< 50 Gy** ≥ 50 Gy

Toljanic6 Case series Orbit Implant Failure 17% (2/12) 16% (10/61) 1.0 (0.25, 4.1)

*Indicates statistically significant findings. Cohort studies compare patients in the same treatment population. Case series compared results to historical controls.

**Gy= Grey

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Table 2. Summary of studies comparing implantation in irradiated versus non-irradiated bone: Den-tal applications.

Studies Study Design Implant Location Outcome Irradiation Non-irradiation Effect Size RR (CI)*

Weischer21 Cohort Mandible Implant Failure 13.7% (10/73) 5.7% (5/87) 2.4 (0.85, 6.6)

Wound distur-bance

4.8% (4/83) 0 (0/92) Incalculable

Peri-implant inflam-mation

22.2% (4/18) 9.0% (2/22) 2.4 (0.50, 11.9)

Weischer22 Cohort Mandible Implant Failure 7.0% (4/57) 6.3% (3/48) 1.1 (0.26, 4.8)

Landes27 Cohort Mandible Implant Failure 1.4% (1/72) 0% (0/42) incalculable

Schepers28 Cohort Mandible Implant Failure 3.3% (2/61) 0% (0/78) incalculable

Esser29 Case series Implant Failure 16.6% (29/221) 9.9% (7/71) 1.3 (0.81, 2.02)

Osteoradione-crosis

3.4% (2/58) NR Incalculable

Soft Tissue Ne-crosis

3.4% (2/58) NR Incalculable

Cao17 Cohort Maxilla Implant Failure 51% (27/53) 22% (17/78) 2.3 (1.4, 3.8)*

Osteoradione-crosis

0 (0/53) 0 (0/78) 1.0

Ryu15 Case series Mandible Implant Failure 30.6% (11/36) 9.1% (1/11) 3.4 (1.49, 23.2)*

Osteomyelitis or necrosis

11.1% (4/36) 0 (n=0/11) Incalculable

Chronic Pain 2.7% (1/36) 9.1% (n=1/11) 0.31 (0.02, 4.5)

Complications 30.6% (11/36) 27% (n=3/11) 1.1 (0.38, 3.3)

Landes27 Cohort Mandible Peri-implant inflam-mation

3.2% (5/155) 2.2% (3/134) 1.4 (.35, 5.9)

< 1yr post IR ≥ 1 year post IR

Visch13 Cohort HA-Titan screw Implant Failure 16.5 %(n=29/175)

12.9% (n=35/271)

1.3 (0.81, 2.02)

< 50 Gy* Dose ≥50 Gy Dose

Implant Failure 9.2% (19/207) 18.8% (45/239) 0.49 (0.29, 0.81)*

10yr post IR

Mandible Maxilla

Implant Failure 9.2% (31/338) 30.6% (33/108) 0.30 (0.19, 0.47)*

IR > 10 mos post implant

IR ≤ 12 wks post implant

Implant Failure 0% (n=0/10) 42.3% (n=11/26) Incalculable

Osteomyelitis or necrosis

0 (n=0/10) 15.4% (n=4/26) Incalculable

Chronic Pain 0 (n=0/10) 3.8% (n=1/26) Incalculable

Complications 20% (n=2/10) 35% (n=9/26) 0.58 (0.15, 2.2)

Indicates statistically significant findings**Gy= Grey NR=not reported

IR = irradiation


APPENDIX IIREFERENCES:

Roumanas, E. D., Freymiller, E. G., Chang, T. L. et al.: Implant-retained prostheses for facial defects: an up to 14-year

follow-up report on the survival rates of implants at UCLA. Int J Prosthodont, 15: 325, 2002

Albrektsson, T., Branemark, P. I., Jacobsson, M. et al.: Present clinical applications of osseointegrated percutaneous

implants. Plast Reconstr Surg, 79: 721, 1987

Granstrom, G., Tjellstrom, A., Albrektsson, T.: Postimplantation irradiation for head and neck cancer treatment. Int

J Oral Maxillofac Implants, 8: 495, 1993

Granstrom, G., Tjellstrom, A., Branemark, P. I.: Osseointegrated implants in irradiated bone: a case-controlled study

using adjunctive hyperbaric oxygen therapy. J Oral Maxillofac Surg, 57: 493, 1999

Wolfaardt, J. F., Wilkes, G. H., Parel, S. M. et al.: Craniofacial osseointegration: the Canadian experience. Int J Oral

Maxillofac Implants, 8: 197, 1993

Toljanic, J. A., Eckert, S. E., Roumanas, E. et al.: Osseointegrated craniofacial implants in the rehabilitation of orbital

defects: an update of a retrospective experience in the United States. J Prosthet Dent, 94: 177, 2005

Granstrom, G.: Osseointegration in Irradiated Cancer Patients: An Analysis With Respect to Implant Failures. Jour-

nal of Oral and Maxillofacial Surgery, 63: 579, 2005

Schoen, P. J., Raghoebar, G. M., van Oort, R. P. et al.: Treatment outcome of bone-anchored craniofacial prostheses

after tumor surgery. Cancer, 92: 3045, 2001

Scolozzi, P., Jaques, B.: Treatment of midfacial defects using prostheses supported by ITI dental implants. Plast

Reconstr Surg, 114: 1395, 2004

Tolman, D. E., Taylor, P. F.: Bone-anchored craniofacial prosthesis study: irradiated patients. Int J Oral Maxillofac

Implants, 11: 612, 1996

Tolman, D. E., Taylor, P. F.: Bone-anchored craniofacial prosthesis study. Int J Oral Maxillofac Implants, 11: 159,

1996

Moy, P. K., Medina, D., Shetty, V. et al.: Dental implant failure rates and associated risk factors. Int J Oral Maxillofac

Implants, 20: 569, 2005

Visch, L. L., van Waas, M. A., Schmitz, P. I. et al.: A clinical evaluation of implants in irradiated oral cancer patients. J

Dent Res, 81: 856, 2002

Colella, G., Cannavale, R., Pentenero, M. et al.: Oral implants in radiated patients: a systematic review. Int J Oral Maxil-

lofac Implants, 22: 616, 2007

Ryu, J. K., Stern, R. L., Robinson, M. G. et al.: Mandibular reconstruction using a titanium plate: the impact of radiation

therapy on plate preservation. Int J Radiat Oncol Biol Phys, 32: 627, 1995

Wagner, W., Esser, E., Ostkamp, K.: Osseointegration of dental implants in patients with and without radiotherapy.

Acta Oncol, 37: 693, 1998

Cao, Y., Weischer, T.: Comparison of maxillary implant-supported prosthesis in irradiated and non-irradiated pa-

tients. J Huazhong Univ Sci Technolog Med Sci, 23: 209, 2003

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Granstrom, G.: Placement of dental implants in irradiated bone: the case for using hyperbaric oxygen. J Oral Maxil-

lofac Surg, 64: 812, 2006

Donoff, R. B.: Treatment of the irradiated patient with dental implants: the case against hyperbaric oxygen treat-

ment. J Oral Maxillofac Surg, 64: 819, 2006

August, M., Bast, B., Jackson, M. et al.: Use of the fixed mandibular implant in oral cancer patients: a retrospective

study. J Oral Maxillofac Surg, 56: 297, 1998

Weischer, T., Mohr, C.: Ten-year experience in oral implant rehabilitation of cancer patients: treatment concept and

proposed criteria for success. Int J Oral Maxillofac Implants, 14: 521, 1999

Weischer, T., Schettler, D., Mohr, C.: Concept of surgical and implant-supported prostheses in the rehabilitation of

patients with oral cancer. Int J Oral Maxillofac Implants, 11: 775, 1996

Ravikumar, M., Ravichandran, R., Sathiyan, S. et al.: Backscattered dose perturbation effects at metallic interfaces

irradiated by high-energy X- and gamma-ray therapeutic beams. Strahlenther Onkol, 180: 173, 2004

Ozen, J., Dirican, B., Oysul, K. et al.: Dosimetric evaluation of the effect of dental implants in head and neck radio-

therapy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 99: 743, 2005

Wang, R., Pillai, K., Jones, P. K.: Dosimetric measurement of scattered radiation from dental implants in simulated

head and neck radiotherapy. Int J Oral Maxillofac Implants, 13: 197, 1998

Granstrom, G.: Radiotherapy, osseointegration and hyperbaric oxygen therapy. Periodontol 2000, 33: 145, 2003

Landes, C. A., Kovacs, A. F.: Comparison of early telescope loading of non-submerged ITI implants in irradiated and

non-irradiated oral cancer patients. Clin Oral Implants Res, 17: 367, 2006

Schepers, R., Slagter, AP, Kaanders, JH, van den Hoogen, FJ, Merkx, MA: Effect of postoperative radiotherapy on

the functional result of implants placed during ablative surgery for oral cancer. Int J Oral Maxillofac Surg, 35: 803,

2006

Esser, E., Wagner, W.: Dental implants following radical oral cancer surgery and adjuvant radiotherapy. Int J Oral

Maxillofac Implants, 12: 552, 1997without radiotherapy. Acta Oncol, 37: 693, 1998

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24.

25.

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29.


Research in Context – Part VII

Are the differences between two study groups real and applicable clinically or is it possible possibly they are simply due to chance?

Research in Context Question:

In the last edition of Implant Directions, we gave an overview of checking for appropriate analy-ses when critically reviewing a paper and con-sidering the authors conclusions. For example, were there appropriate analyses that included descriptive statistics, analytic statistics using the primary outcome, ample sample size, and adjustment of potential confounding variables?

We listed the following 4 questions that need to be considered when evaluating the statistical analyses used for testing the hypothesis:

Is the primary outcome used for the statis-tical analysis?Is any difference between the groups likely due to chance?Is the sample size large enough to test the hypothesis adequately?Are potentially confounding variables con-sidered in the analysis?

The first point is self-explanatory – the authors should include the primary outcome outlined by the study question in the statistical analyses and present these data. It is amazing to see how often an author list the study’s goal or objective but does not use an appropriate outcome mea-

1.

2.

3.

4.

sure to test this hypothesis. In a previous edi-tion of Implant Directions, we discussed in detail the importance of outcomes measures in dental implant research and how to go about choosing the right one.

The second point relates to the role of chance as an explanation for any observed difference between the study groups. When you look at statistical significance (which is the measure of probability that the results you achieved oc-curred by chance) remember that statistical sig-nificance depends on three parameters:

Sample size (the larger the sample size, the easier to demonstrate statistical signifi-cance; the smaller the sample size the pos-sibility that the observed difference is simply due to chance)Variability in patient response, either by chance or by non-random factors (the small-er the variability, the easier to demonstrate statistical significance)Effect size, or the magnitude of the observed effect between groups (the greater the size of the effect, the easier to demonstrate sta-tistical significance)

A real world example to address this issue is the published Critical Appraisal (CA) in this edi-tion of Implant Directions evaluating an article by Tarnow, et al. The authors compared pa-tients who had less than or equal to 3 millime-ters (mm) of distance between implants to pa-tients who had greater than 3 mm of distance between implants. They reported a mean of 1.04 mm vertical crestal bone loss in patients

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(n=25) who had less than or equal to 3 mm distance between implants and a mean of 0.45 mm vertical crestal bone loss in patients (n=11) who had greater than 3 mm between implants. This sample size is very small and therefore this mean difference could be due to chance alone. One would want a much larger sample to make a conclusive statement regarding the cause of crestal bone loss.

One way to determine this would be to compare the groups analytically using a t-test which would reveal whether or not this difference is statisti-cally significant (p<.05). This would require the mean values and the variability often reported in terms of the standard deviation. The authors failed to report the standard deviation of these findings. If the variability is small, then it is far more likely this difference is real than a result of chance. However, if the variability is high, with such a small sample size, these differences mean little and conclusions regarding the associ-ation of one factor (eg, lateral distance between implants) with another (eg, vertical crestal bone loss) are not warranted.

Lastly, if the differences are great, then fewer subjects are needed. For example, if the mean difference in crestal bone loss was 2 mm or more, then the difference is more likely to be real then a result of chance, assuming the vari-ability is not too large.

It is important when reading a paper that one does not trust the author’s conclusions without a critical review. Simple considerations such as those mentioned above, will go along way in help-

ing you make informed clinical decisions.

The effect of confounding on the comparison of two groups will be discussed in the next edi-tion of Implant Directions…


Circular

Full mouth rehabilitation - from extraction to full arch bridges in just one day

AUTHOR:Dr. Sigmar KoppNiklotstrasse 39D-18273 [email protected]

ABSTRACT

The demand of patients for fast and minimal invasive treatments must be the ruling guideline for development and choice of technologies in dental treatment. “primum non nocere” – as basic thought for every physical intervention is obvious. So every additional surgery and foreign material exposition needs a good justification. The immediate implant placement as well as the immediate loading of cortical anchoraged im-plants has been proofed to be a sufficient and enduring protocol.The in literature described high success rates

will here be supplemented by the description of the treatment steps, with the example of a 50 years old male patient, receiving the whole surgical treatment in a single day under local anaesthesia. The treatment from extraction of 9 teeth, via grinding of two residual teeth to in-sertion of 14 implants was finalised by fixation of two full arch plastic bridges. The cemented fixation of the permanent metal ceramic bridge was done 44 days later. The use of removable dentures on implants just to be able to remove

one implant after another without continuous redoing the prosthodontic work may be useful in traditional implants but is not necessary when basal implants are use. Such a procedure would even be contraindicated here because of the traction force transmission possible alone by really fixed prosthodontics. With the here pre-sented protocol the fast rehabilitation of the full mouth in physiological dimensions and relations may become more independent from well known compromised implant positioning by common surgical protocols.

KEYWORDS

Full arch bridge, immediate loading, immedi-ate function, immediate implant placement, full mouth rehabilitation

INTRODUCTION

Patients with the need of the remove of teeth having the choice between several treatment op-tions tend surely to fixed teeth as permanent re-habilitation, if some other factors are adequate. This means not the price in first stage but this factor is surely not unimportant at all. In times where even heart interventions are possible to be done in a matter of days and weeks, people may hardly agree to a mouth rehabilitation treat-ment lasting for month till years.This is not only a matter of functionless healing

periods and missing comfort but also of social compatibility. Just few people are able to inter-rupt their daily work for just an oral rehabilita-

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tion for more than few days. If they are compre-hensively informed about all options in today’s implantology nobody would ask for unnecessary bone build-ups or covered healing. So every den-tist and surgeon has to be aware of the com-plete clarification of facts to cooperate with a well informed patient and to avoid possible legal fighting after he has done his favourite tradition-al treatment, the patient would probably have rejected when fully informed about all modern alternatives. So the demand of patients for fast and minimal invasive treatments must be the ruling guideline for development and choice of technologies in dental treatment. “primum non nocere” – as basic thought for every physical intervention is obvious. Under this aspect every additional surgery and foreign material exposi-tion needs a good justification. The immediate implant placement as well as

the immediate loading of cortical anchoraged implants even immediately in infected extraction sites has been proofed to be a sufficient and en-during protocol with high success rates, mean-ing about 97% after 4.5 to 10 years.[1-7] Because basal implants are placed trans-osse-

ously and anchored in the basal, cortical bone they have immediate loading abilities.[3, 8, 9] Since at least the cortical walls are still present after extractions even if more basal of the extracted root, the option to use this support for implant anchorage is evident. The available amount of bone crestally to the base plate is of no impor-tance for this implant type, because primary stability is gained through cortical engagement of the base-plate. This qualifies those implants to be used in extraction sockets.[2, 3, 8, 10-16] BCS® screw implants are categorized as basal im-

plants, because they allow transmission of loads to the cortical bone areas near the apex of the implant (basal areas) or in thin high bone. Alike basal implant, their mucosal penetration diam-eter is thin and they are polished and provide reliable macro-retention.Histological studies have shown that basal im-

plants undergo a dual way of integration: ring areas in direct contact with the native bone may undergo primary integration through osteonal remodeling. In addition the void space left after insertion fill with blood which transforms to wo-ven bone first and undergoes osteonal remodel-ing later on. This dual modus of integration is well known from typical fracture healing. Clinical ex-perience shows that areas undergoing second-ary integration contribute to the long term sta-bility, but the cortical engagement even around empty sockets or the maxillary sinus is enough to support the bridge in the first crucial weeks after implant installation.[8] The fact that the nec-essary vertical bone amounts needed for place-ment of basal implants is 2-3 mm only, makes their use advisable even in those patients, who ,- after lengthy periodontal treatments-, provide a pronounced atrophy after the final extractions.Other than in axial (crestal) implantology, the

placement of an immediately loaded, fixed resto-ration is the typical prosthetic choice, since tele-scopes on basal implants are not indicated and the indication for bar restoration is rare.[8]


Statement of the problem

The aim of this publication is the presentation of the treatment steps from tooth extraction to fixation of bridges on basal implants (BOI®, BCS® brand, Ihde Dental; Switzerland).

MATERIALS AND METHODS

Surgical and prosthodontic procedure

The procedure will be explained by the example of a 50 years old man. The patient was referred because of our ability to use basal implants. The initial clinical view shown in figure 1 discloses not the whole extent of the problem as can be seen in the initial x-ray. (fig 2) Any functional use of his teeth for mastication was impossible. The whole construction was just a false front. Because of his business as boss in a big insurance company he could not abandon a healthy smile even if the health was gone for a long time. That’s why he chose the treatment in a single day by us with basal implants. After explanation of different op-tions he decided to get a full mouth reconstruc-tion on implants, even if the two lower canines were preserved.The whole surgical treatment in bouth jaws was

performed under local anaesthesis in about 4 hours. Initially all worthless teeth were removed. (fig 3). The lower canine were grinded for fit-ting the crowns in the desired bridge. Full thick-ness flaps were created and the alveolar bone cleansed mechanically. Disinfection of the site with Povodine-Iodine solution, used also in ortho-

paedic bone surgery, is recommended but was not performed here.[8, 13, 17] Using homologous cutters which are part of the system, an implant bed was prepare, using meticulously cooled an-gled hand pieces. BOI® implants must always be inserted bicortically, meaning that the base plate is inserted transosseously, usually approximately horizontal, anchored to both sides of the cortical bone in resorption free, basal bone areas. The implants were then inserted from the lateral as-pect with careful tapping action until full bi- or multicortical support is achieved, (fig 4).The presence of sufficient support should be

verified visually or manually by testing with the fingers. The implants may also be fixed horizon-tally by use of osteosythesis screws when pri-mary stability cannot be archived right away, e.g. when the implant bed is not congruent to the implant or the bone is extreme soft. This was here not necessary. In the region of the lower front teeth, were the bone was narrow BCS® were used. These are screwable basal implants or bicortical screws. They are often used when two cortical walls are tight together that bicorti-cal anchorage is possible. In this case we used BCS® in the lower front as well as in the tuber region. In the distal upper jaw we only use the angulated version BCSA® to avoid disparalleli-ties. They extraction sockets may be filled up by augmentation material for predictive bone re-modeling. Here we used NanoBone® (Artoss® Germany) as shown in figure 5. The application of a membrane may be helpful. The application of a chair side made fibrin membrane is to be seen in figure 6. The in literature described steps for production of these fibrin membranes will be shown here in a compact manner. 4] Pa-

202

tients blood will be taken. (figure 7) Few of it can be used for blending with NanoBone®. (figure 8) The blood will be centrifuged in glass vials by 2800 rpm for 12 minutes. (figure 9) The two fractures will be visible divided. (figure 10) The fibrin part may be easily taken by a surgical pin-cer. (figure 11) Than it must be put between sterile gauze com-

presses. (figure 12) Bigger membranes may be produced by layering is this step. This way wa-ter will be removed and a thin membrane shape gained. (figure 13) These membranes are also useful for primary sinus maxillaries perforation closure.When the membranes are in place tight su-

tures finish the surgical intervention. The length as well as the parallelism of the abutments has now to be adjusted. The immediate external splinting by temporary plastic bridges is absolute necessary. A panoramic X-ray assures the right position of the implant as well as the absence of plastic pressed in the sutures. (figure 14)That finishes the first treatment day. The pa-

tient leaves the office with full loadable tempo-rary bridges in correct inter maxillary position. When augmentation material is used, the pre-scription of antibiotics is recommended. The number and position of the implants in the lower jaw allows enough sustain even if the canines will have to get endodontic or final removal. The ex-traction may then be performed from lateral, so the bridge may survive the last included teeth.The impression for permanent metal based

bridges can be taken at the same session or later. One week later the sutures were removed. In this case the impression was taken 18 days later when the swelling of the gingiva was finally

gone and a stable red result evident. (figure 15) The technician work is sophisticated, but our technician has the experience of more than 50 full arch bridges of this kind. The extension to the distal jaw regions as well as the narrow width of the teeth for adequate force transmission is se-cured by the implant position. Especially when a treatment in booth jaws is possible, the general aspects of prosthodontics may be applicable. So physiological dimension and relations are reach-able. The correct inclination in the camper level is important. A well balanced chewing system is a good base for affordable longtime results. The CrCoMb frame can be casted in correct dimensions by the use of optimal steps. So we avoid disconnection as well as brazing, solder-ing, welding and lasing. We use a high tempera-ture ceramic for high brilliance. The layering is common known. To avoid nonphysiological long teeth a shield by gingiva colored ceramic may be used. This we do just in the anterior regions. In the distal part we prefer wider distance to the gingiva.This seems to be important for free flexion in

the bone as well as for the hygienic access. The vestibular shield should never become a hypo-mochlyon. This must be verified in every control session. We always go for a classic incisor-ca-nine-guidance. Due to the jaw atrophy pattern known from general prosthodontics a lateral cross-bite may result. An overbyte of 1mm as well as an overjet of 1mm should be aimed. (fig-ures 16-18)


Results

Figure 19 shows the permanent bridges in situ prior to small final grinding. Well balanced antagonistic contacts are important for func-tion and success. Normal lip line gives newer a view to the ceramic shield. An X-ray finalizes the whole treatment. With these materials and pro-tocol the fast and enduring treatment was final-ized within 44 days.

Discussion

We have observed and published a success rate of 98.1 % for basal implants in fresh extrac-tion sockets even after 4.5 years.[3] This number qualifies the here presented procedure and ma-terials for daily use. The lack of perioimplantitis on basal implant makes the indication group for fixed restorations even broader. The use of re-movable dentures on implants just to be able to remove one implant after another without con-tinuous redoing the prosthodontic work may be useful in traditional implants but is not necessary when basal implants are use. Such a procedure would even be contraindicated here because of the traction force transmission possible alone by really fixed prosthodontics. The here used procedure avoided even one single day of life without esthetic, phonetic and mastication, the basic aims of dental treatment. So the patient aims of fast and minimal invasive intervention are reached finally.

Conclusion

These results show that the immediate place-ment of basal implants even in infected extrac-tion sockets under real immediate prosthetic loading conditions is a safe and effective way of treatment. Waiting for the healing of the sockets after extractions does not improve the general high success rate of BOI® and BCS® implants and may be generally avoided. The presented treatment steps are safe and convenient. The safe insertion of basal implants especially in distal jaw regions brings the application of prov-en prosthodontical rules from bridges on teeth to the implant based rehabilitations.Every additional treatment step needs good rea-

son and explanation, because of this presented safe benchmark.

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Figure 1.The initial clinical view with periodontal involvement

Figure 2.The initial X-ray showing severe periodontal disease

Figure 3.All Teeth were remove in the same session when the implants were placed

Figure 5.Applicated NanoBone® for predictable bone remodeling

Figure 4.Implants in the extraction sockets

Figure 6.Application of an autologous fibrin membrane


Figure 7.Blood gaining from the patient

Figure 8.Mixed NanoBone® with patient blood

Figure 9.Centrifuge with correct adjustment

Figure 11.The fibrin fraction may be easily taken

Figure 10.Two fractures after centrifugal separation

Figure 12.Fibrin ready for pressing

206

Figure 13.Ready for use fibrin membrane

Figure 14.Control X-ray at the day of surgery

Figure 15.The situation 18 days after surgery when the impression was taken

Figure 17.View of the bridges from the left and the mild lateral cross bite

Figure 16.View of the bridges from the right and the free hygienic access in the distal region

Figure 18.The ceramic shield in the anterior region


Figure 19.The fixed bridges before final grinding

Figure 20.The lip line covering parts of the new bridges

Figure 21.The final X-ray with fixed bridges

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REFERENCES

1. Scortecci G: Immediate function of cortically anchored disk-design implants without bone augmentation in moderately to severely resorbed completely edentulous maxillae. J Oral Implantol 1999;25:70

2. Kopp S: Basal implants: a safe and effective treatment option in dental implantology. CMF Impl. Dir 2007;2:110

3. Kopp S, Kopp W: Comparison of immediate vs. delayed basal implants. J Maxillofac Oral Surg 2008;7:116

4. Ihde S: Principles of BOI. Springer-Verlag 2005

5. Ihde S, Konstantinvic, V., S.: Comparison and definition of pathological peri-implant symptoms and possible therapeutic measures with basal and crestal implants. Dent Implantol 2005;9:122

6. Ihde S, Eber M: Case report: restoration of edentulous mandible with 4 BOI implants in an immediate load procedure. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2004;148:195

7. Donsimoni J, M., Navarro, G., Gaultier, F., Dohan, D., : Les implants maxillo-faciaux à plateaux d`assise ; Concepts et technologies orthopédiques, réhabilitations, maxillomandibulaires, reconstructions maxillo-faciales, réhabilitation dentaires partielles, techniques de réintervention, méta-analyse 4ème partie : réhabilitations dentaires partielles. Implantodontie 2004;13:139

8. Ihde S: Principles of BOI. (ed. 1). Heidelberg: Springer, 2005

9. Kopp S: Implant based crowns in aesthetic challenging regions Arab Dental 2008;22:20

10. Ihde S: Restoration of the atrophied mandible using basal osseointegrated implants and fixed prosthetic superstructures. Implant Dent 2001;10:41

11. Ihde S: Sanierung mit basal osseointegrierten Implantaten. Colleg Magazin 1998;5:138

12. Ihde S, Mutter, E. : Versorgung von Freiendsituationen mit basalosseointegrierten Implantaten (BOI) bei reduziertem vertikalem Knochenangebot. Dtsch Zahnarztl Z 2003;58:94

13. Kopp S: „all on four“ - basal implants as solid base for circular bridges in high periodontal risk patients. CMF Impl. Dir 2007;2:105

14. Ihde SK: Fixed prosthodontics in skeletal Class III patients with partially edentulous jaws and age-related prognathism: the basal osseointegration procedure. Implant Dent 1999;8:241

15. Ihde S, Kopp S, Gundlach K, Konstantinovic VS: Effects of radiation therapy on craniofacial and dental implants: a review of the lite-rature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008

16. Kopp S: Radiological particularities in basal dental implants. Arab Dental 2008;20:24

17. Kopp S: Implantological treatment in a patient with hypodontia. CMF Impl. Dir 2007;2:147


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Each DVD contains approx. 20 minutes of oral surgery. With explanations in english and ger-man language.

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Guide for Authors

ID publishes articles, which contain information, that will improve the quality of life, the treatment outcome, and the affordability of treatments.The following types of papers are published in the journal: Full length articles (maximum length abstract 250 words, to-tal 2000 words, references 25, no limit on tables and figures). Short communications including all case reports (maximum length abstract 150 words, total 600 words, references 10, figures or tables 3) Technical notes (no abstract, no introduc-tion or discussion, 500 words, references 5, figures or tables 3). Interesting cases/lessons learned (2 figures or tables, legend 100 words, maximum 2 references).

Literature Research and Review articles are usually commissi-oned.Critical appraisals on existing literature are welcome.

Direct submissions to:[email protected] text body (headline, abstract, keywords, article, conclusion), tables and figures should be submitted as separate documents. Each submission has to be accompanied by a cover letter. The cover letter must mention the names, addresses, e-mails of all authors and explain, why and how the content of the article will contribute to the improvement of the quality of life of patients.

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