libro estetica
TRANSCRIPT
THE AmEricAnJOUrnAL OF
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Fall
• 2011 (1
–8
4)
VO
LUm
E 1 • Number 1
Volume 1 • Number 1 • Fall 2011
ISSN 2162-2833 (print)
ISSN 2162-2841 (online)
DENTISTRY
The American Journal of
Readers are invited to submit personal photographs for consideration for use in the journal. The number of photos may vary in each issue, but we hope the images will provide an interesting break between the outstanding papers within. This is an opportunity for you, the reader, to share with your colleagues some of the images you are proud of, that may otherwise never see the light of day. For this inaugural issue, we present images from Antelope Canyon, a slot canyon in northern Arizona, photo-graphed by Richard J. Simonsen (http://www.richardsimonsen.com). At certain times of the year and day, the sun may shine through from the slot above that communicates to the surface. Such canyons can be dangerous, as they fill with rainwater quickly in the event of a thunderstorm upstream, sometimes trapping those who choose to ignore nature’s warnings. It is the effect of the running water over millions of years that makes the unique patterns on the walls of the soft sandstone rock walls.
5 Editorial:Welcome aboard!
Richard J. Simonsen
10 Minimally Invasive Restorative Treatment of Hypoplastic Enamel in Anterior Teeth
Jussara Karina Bernardon
Renata Gondo
Luiz Narciso Baratieri
26 The Gray Zone Around Dental Implants: Keys to Esthetic Success
Iñaki Gamborena
Markus B. Blatz
48 Determining the Influence of Flowable Composite Resin Application on Cuspal Deflection Using a Computerized Modification of the Strain Gauge Method
Hamdi H. Hamama
Nadia M. Zaghloul
Ossama B. Abouelatta
Abeer E. El-Embaby
60 All-Ceramic Crowns and Extended Veneers in Anterior Dentition: A Case Report with Critical Discussion
Júnio S. Almeida e Silva
Juliana Nunes Rolla
Daniel Edelhoff
Élito Araujo
Luiz Narciso Baratieri
7
8
Guidelines for Authors
Mandatory Submission Form
ISSN 2162-2833 (print) ISSN 2162-2841 (online)
DENTISTRY
The American Journal of
Editor-in-ChiEf
Richard J. Simonsen, DDS, MS
Professor, Faculty of Dentistry Health Sciences Center Kuwait University PO Box 24923, Safat 13110, Kuwait [email protected]
Editorial Board
Joel H. Berg, DDS, MS
Markus B. Blatz, DMD, PhD
Jeff Brucia, DDS
John R. Calamia, DMD
Alexander Carroll, DDS, MBA
David Chambers, EdM, MBA, PhD
Gordon J. Christensen, DDS, MSD, PhD
Theodore P. Croll, DDS
Alessandro Devigus, Dr Med Dent
Sillas Duarte Jr, DDS, MS, PhD
Newton Fahl Jr, DDS, MS
Jack L. Ferracane, PhD
Ronald E. Goldstein, DDS
Laura C. Kottemann, DMD
Gerard Kugel, DMD, MS, PhD
Tyler Lasseigne, DDS
Pascal Magne, Dr Med Dent, PhD
Tidu Mankoo, BDS
Assad F. Mora, DDS, MSD
Marc L. Nevins, DMD, MMSc
Vijay Parashar, DDS, MS
André V. Ritter, DDS, MS
Richard D. Roblee, DDS, MS
David D. Rolf II, DMD, MS
Leo E. Rouse, DDS
Frank Spear, DDS, MSD
Douglas A. Terry, DDS
Gwenlynn Werner, DMD
David Winkler, DDS
Publisher H. W. Haase
Executive Vice President William G. Hartman
Director, Journal Publications Lori A. Bateman
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Editorial
5VOLUME 1 • NUMBER 1 • FALL 2011
i am very pleased to welcome you to a new addition
to Quintessence Publishing Company’s stable of fine
journals and books in dentistry. this is the first issue of
The American Journal of Esthetic Dentistry, a journal
dedicated to promoting the highest clinical standards of
esthetic dentistry based on an evidence base and on a
minimally invasive approach. We wish to share with our
readers the research advances and clinical accomplish-
ments of the profession over the past several decades.
With our outstanding editorial board
and many others who will aid in the re-
view of papers and ideas for the journal,
we pledge to provide you with the high-
est standard of peer-reviewed informa-
tion in the form of papers submitted by
you, the reader, and fellow dedicated
members of our profession.
the theme of “esthetic dentistry” is a
broad one. one could argue that almost
all phases of clinical dentistry involve—
directly or indirectly—esthetics, and we
will publish papers in most areas of
clinical interest to the general dentist,
who is faced with the enormous task of
keeping up with new developments in
all fields of the profession. You can ex-
pect many papers of the quality you
see here in this issue from around the
globe, and also you can expect excit-
ing new developments in terms of be-
ing able to review your journal and read
the papers online with your iPad or
similar instrument in months to come.
Future editorials will discuss themes
and trends in our profession that i hope
will be of interest to a wide group of
readers. i may take a certain position
on an issue in order to stimulate con-
versation and responses such that a
broad perspective of opinions can be
aired. it will be my job as your editor to
try to stimulate such debates and com-
mentary, such as, for example, around
the current overtreatment problems
in the cosmetic dentistry arena. i also
welcome guest editorials from those of
you who may wish to tackle a particular
subject of interest to the profession. an
active and robust “letters to the Editor”
section is on my list of goals for devel-
opment as time goes on. i hope that
you will feel free to communicate with
me on any ideas or constructive criti-
cism you may have.
Please enjoy the first issue of The American Journal of Esthetic Dentistry !
richard J. Simonsen, ddS, MS
Editor-in-Chief
Welcome aboard!
DENTISTRY
The American Journal of
Guidelines For Authors
MAnuscript subMission
Submit manuscripts via AJED’s online submission service:www.manuscriptmanager.com/ajedManuscripts should be uploaded as a PC Word (doc) file with tables and figures preferably embedded at the end of the document. No paper version is required.
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numerically, in order of appearance in the text. Limit references to those specifically referred to in the text. Use the following style for the reference list:
Journals:1. Al-Johany, SS, Alqahtani AS, Alqahtani
FY, Alzahrani AH. Evaluation of different esthetic smile criteria. Int J Prosthodont 2011;24:64–70.
Books:1. Gürel G. Porcelain laminate veneers:
Predictable tooth preparation for complex cases. In: Romano R (ed). The Art of Treatment Planning: Dental and Medical Approaches to the Face and Smile. Chicago: Quintessence, 2010:249–263.
review process
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Original articles are considered for publication on the condition that they have not been published or submitted for publication elsewhere.
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Managing EditorAmerican Journal of Esthetic DentistryQuintessence Publishing Co, Inc4350 Chandler DriveHanover Park, IL 60133
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10THE AMERICAN JOURNAL OF ESTHETIC DENTISTRYTHE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Minimally Invasive Restorative
Treatment of Hypoplastic
Enamel in Anterior Teeth
Jussara Karina Bernardon, DDS, MS, PhD
Clinical Professor, Department of Operative Dentistry,
Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
Renata Gondo, DDS, MS, PhD
Clinical Professor, Department of Operative Dentistry,
Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
Luiz Narciso Baratieri, DDS, MS, PhD
Professor, Department of Operative Dentistry,
Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
Hypoplastic enamel can compromise the smile by altering the mor-
phology and natural translucency of the teeth. To avoid performing
iatrogenic procedures, etiologic knowledge of the enamel deficiency
is essential to indicate the most appropriate treatment approach.
In the case of white stains involving the enamel and dentin, a no-
table treatment option is a direct restoration with composite resin,
which has excellent optical properties to reproduce the natural tooth
structure and appropriate mechanical properties to ensure treatment
longevity. In this article, a clinical case of a patient who reported
dissatisfaction with her smile esthetics, prompted by the presence
of hypoplastic enamel staining at the central and lateral incisors, is
presented. Treatment consisted of composite resin
restorations with the natural stratification technique.
The final esthetic result proved the possibility of
obtaining natural-looking restorations, while en-
suring the esthetic and functional satisfaction of
both the patient and clinician. (Am J Esthet Dent 2011;1:10–24.)
Correspondence to: Dr Jussara Bernardon
Armaro Antônio Viera 2489, apto 403, Itacorubi, Florianópolis, Santa Catarina, Brazil.
Fax: 55 048 38799226. Email: [email protected]
VOLUME 1 • NUMBER 1 • FALL 2011VOLUME 1 • NUMBER 1 • FALL 2011
Fig 1 Proximal view of the anterior teeth. Note the change in color and presence of white spots.
11
BERNARDON ET AL
12THE AMERICAN JOURNAL OF ESTHETIC DENTISTRYTHE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Several factors may compro-
mise the esthetics of the
smile, including hypoplastic
enamel, which may affect the
morphology, texture, and color of
the tooth surface, the result of an
incomplete or defective forma-
tion of the enamel organic ma-
trix. The intensity and duration
of stimulation on ameloblasts
reflect the extent and location of
enamel defects.1 Lesions may
be triggered by hereditary or
environmental factors. With he-
reditary factors, generally only
the enamel of primary and per-
manent teeth is affected.2 Hy-
poplastic enamel resulting from
environmental factors, however,
can be caused by a variety of
influences, including nutritional
deficiencies, rashes (eg, mea-
sles, chickenpox, scarlet fe-
ver), syphilis, hypocalcemia,
systemic disorders, ingestion of
chemicals (eg, fluoride), trauma,
infections of the primary denti-
tion, or by idiopathic causes.2,3
Environmental factors usually af-
fect only one arch and can alter
both the enamel and dentin.4
Therefore, depending on the
etiology, stains resulting from
hypoplastic enamel may have
systemic features, affecting a
group of teeth, or be localized,
with asymmetric distribution and
isolated to specific teeth.5
These spots compromise
smile esthetics because they
have an opaque, rough, and ir-
regular appearance, compared
to the natural shine and trans-
lucency of enamel. This opacity
prevents light transmission in
the specific region of the lesion,
providing a distinct difference
between it and the surrounding
enamel. Several types of treat-
ments may be recommended
according to severity, and the
least invasive technique should
always take precedence. There-
fore, the etiologic diagnosis is of
paramount importance and aims
to prevent unnecessary treat-
ment of the hypoplastic teeth.
For mild (smooth, light) and su-
perficial lesions, tooth bleaching
can be performed, with or with-
out abrasion of the enamel. This
is a minimally invasive technique
and is limited to the enamel of
the affected area.6 In the case
of moderate or severe stains
with dentin involvement, the
preferred treatment is a direct or
indirect restorative procedure.
With the ongoing development
of composite resins, which pre-
sent a wide range of available
colors and excellent mechani-
cal properties, it has been pos-
sible to perform more esthetic,
predictable, and conservative
restorations.7 The use of com-
posite resin has the advantage
of minimal reduction of the tooth
structure and the completion of
the procedure in a single ap-
pointment.8
BERNARDON ET AL
CLINICAL CASE
The chief complaint of the patient was
esthetic dissatisfaction from discolora-
tion of the teeth and the presence of
white spots on the incisors (Figs 1 and
2). After taking the case history with a
clinical examination, it was determined
that the teeth were naturally dark and
that the white spots were hypoplastic
enamel areas at the incisal and middle
thirds of the maxillary and mandibular
incisors, without functional involvement
(Figs 3 and 4). The patient underwent
radiographic examination, and no peri-
odontal or periapical changes were
evident. The affected teeth yielded a
positive response to the vitality test.
An additional recommended base-
line examination is transillumination,
13VOLUME 1 • NUMBER 1 • FALL 2011VOLUME 1 • NUMBER 1 • FALL 2011
Fig 2 Initial appearance of the
patient. At conversation distance,
the spots, while clearly visible,
can be left untreated if they do not
bother the patient. However, in this
case, the patient was concerned
about the appearance of her teeth.
BERNARDON ET AL
14THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
which involves the use of a transillumi-
nator positioned along the palatal sur-
face of the tooth being assessed (Figs
5a to 5c). This technique allows analy-
sis of the transmission of light through
the hypoplastic defects, identification of
the thickness of the affected areas, and
verification of the degree of compro-
mised enamel (and dentin, if affected).
Thus, transillumination is effective in de-
termining the treatment approach: the
less the light propagation through the
affected areas, the greater the depth
of the stain. If the dentin is involved, the
most common treatment approach is a
direct restoration with composite resin
and limited preparation of the compro-
mised surface.
Initially, because of tooth discolora-
tion, the patient was asked to perform
Fig 3 Preoperative labial view demonstrating yellow coloration of the teeth
and the presence of white spots at the incisal and middle thirds of the maxillary
central incisors and incisal third of the left lateral incisor.
Fig 4 Occlusal view of the maxillary incisors. Note the change in morphology
and surface texture.
BERNARDON ET AL
15VOLUME 1 • NUMBER 1 • FALL 2011
a supervised home whitening or bleach-
ing regimen with 10% carbamide
peroxide gel for 4 weeks (2 hours/day)
(Fig 6). Home bleaching is a relatively
simple, conservative, and effective
treatment,9,10 with satisfactory results
obtained in a short time period.11
Bleaching, associated with restorative
treatment, is a common approach that
aims to establish a more homogenous
condition in terms of saturation and
brightness of the teeth to be restored.12
The restoration was performed 14 days
after completion of the bleaching pro-
cess to ensure that the adhesive proce-
dure and color selection were carried
out properly.13
A microhybrid composite resin sys-
tem (Opallis, FGM) with the appropri-
ate mechanical properties to ensure
Figs 5a to 5c Using a transilluminator placed on the palatal surface of the involved incisors, it was
possible to visualize the stain depth and relate this to the depth of the hypocalcified area.
Fig 6 Frontal view after home bleaching with 10% carbamide peroxide gel for 4 weeks (2 hours/
day). Note that the stains remained visible, confirming the need for restorative intervention.
a b c
BERNARDON ET AL
16THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
strength and maintenance of polishing
and surface brightness and sufficient
optical properties to mimic the features
found in natural teeth was selected for
the restorative procedure.14 A resin
system with both enamel and dentin
shades is recommended because the
natural tooth overlaps these structures
in different thicknesses, which creates
the polychromatic effect seen on natu-
ral teeth.15 The selected system pre-
sented several hues and saturations
for enamel and dentin beyond the
transparent resins, which reproduce
different degrees of translucency, opal-
escence, and fluorescence.
When selecting the color for the res-
toration, the teeth should be clean and
moist so that the natural translucency
is preserved.15 Color scales are essen-
tial, and it is of paramount importance
that they be of the same manufacturer
as the resin system selected to avoid
potential discrepancies between the
chemistry of the different brands avail-
able. This is because the enamel and
dentin shade guides vary in saturation
and translucency depending on the
system used. The color scale should
be positioned as closely as possible to
the tooth. The color selection for den-
tin should be performed at the cervical
third of the affected tooth, where the
dentin is thicker and more saturated,
and enamel color selection should
occur at the middle third. The system
used had separate scales for enamel
and dentin, which is an advantage be-
cause it allowed for an individual evalu-
ation of the structures. In addition, each
tab had a different thickness, and it was
possible to predict the shade of the final
restoration by altering the thickness of
the tab selected (Fig 7). By placing the
enamel shade tab on top of the dentin
shade tab, it was possible to predict
how the resins would interact in the
future restoration (Fig 8). The operative
Fig 7 (left) Choice of color using the color scale positioned on the facial surface of the affected
tooth. The enamel and dentin colors were selected separately.
Fig 8 (right) By placing the dentin shade guide against the enamel shade guide, the final shade can
be visualized.
BERNARDON ET AL
17VOLUME 1 • NUMBER 1 • FALL 2011
field was isolated to ensure a clean and
suitable environment for the bonding
procedures.
The cavity preparation should be
restricted to removing the hypoplastic
enamel using diamond points com-
patible to the size of the lesion under
constant irrigation to avoid heating of
the structure (Fig 9). The entire depth
of the hypoplastic enamel should be
removed. Otherwise, the resulting dif-
ference in opacity between natural and
affected tooth structure can negatively
affect the outcome of the restoration
(Figs 10 and 11).
There is no need to bevel the cavo-
superficial angle, preserving as much
healthy tooth structure as possible (Fig
12). The absence of preparations en-
sures a reversible treatment without
compromising esthetics or the adhe-
sive bond. After the preparation was
complete, conditioning was performed
with 37% orthophosphoric acid for 15
seconds on the dentin and 30 seconds
on enamel (Fig 13), followed by appli-
cation of the adhesive system, accord-
ing to the manufacturer’s instructions
(Fig 14).
Fig 11 After preparation,
the white spot was still evident,
which called for its removal
with a diamond bur of smaller
diameter.
Fig 12 Final aspect of the
hydrated cavity preparation,
which was restricted to removal
of the white spot.
Fig 9 After rubber dam was
used to isolate the affected
teeth, the white spot was re-
moved using diamond burs.
Fig 10 Occlusal view of the
preparation. Note the remaining
white spot that could compro-
mise the restorative outcome if
not removed.
Fig 13 Etching of the hard
tissue with 37% orthophosphoric
acid (15 seconds for dentin,
30 seconds for enamel).
Fig 14 Application of the ad-
hesive system according to the
manufacturer’s instructions.
BERNARDON ET AL
18THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
The restorative procedure was per-
formed using the stratification tech-
nique, based on the techniques of
building ceramics. This new trend is
also referred to as the anatomical tech-
nique.16,17 In this technique, layers of
selected materials are used to repro-
duce the enamel and dentin structures
while also respecting their thickness
and anatomical contour.
The artificial dentin reconstruction
was performed using the dentin resin
DA1 (Opallis). This resin was applied
covering the deepest portion of the cav-
ity to sculpt the shape of the mamelons
(Figs 15 and 16). Dentin mamelons can
have various shapes and determine
the translucent halo characteristics
of the tooth (Fig 17). Each layer was
photopolymerized for 40 seconds. To
complete the artificial dentin, a resin for
bleached teeth was applied at the tip
of the mamelons (D-Bleach, Opallis).
In a natural tooth, dentin presents as
an intense and very reflective opaque
white color on the tip of the mamelons.
However, when light penetrates the
dentin through the enamel, it results in
Fig 15 Composite resin was
placed in the preparation to
reproduce the dentin layer.
Fig 16 Mamelons must be
defined when applying the
composite resin.
Fig 17 Frontal aspect after
placing the second dentin resin
layer for bleached teeth. Note
the design of the mamelons.
an “orange” appearance. This is the
counter-opalescence feature of dentin.
To reproduce this effect, an opalescent
and highly translucent resin (T-Blue,
Opallis) was placed on the tips of the
mamelons and between the dentin and
incisal edge of the tooth (Fig 18).
Then, artificial enamel was recon-
structed using a single enamel resin
layer (E-Bleach) (Fig 19). In the stratifi-
cation technique, it is important to con-
sider that the artificial enamel thickness
should correspond to one third of that of
natural enamel18 to avoid value reduc-
tion of the restoration. This means that
a thicker layer of artificial enamel results
in a gray and more monochromatic res-
toration.14 This is because the refrac-
tory index of the natural tooth structure
is different from that of the composite
resin.14 The enamel surface was final-
ized at this time, avoiding use of dia-
mond points (Fig 20).
The same procedures were per-
formed for the maxillary right central
(Figs 21 to 24) and left lateral inci-
sors (Figs 25 to 28). After complete
polymerization and at a later session,
BERNARDON ET AL
19VOLUME 1 • NUMBER 1 • FALL 2011
Fig 18 A highly translucent
resin was placed on the opal-
escent areas of the incisal third
region of the tooth.
Fig 19 Positioning of the final
enamel composite resin layer.
Care was taken to cover all
preparation margins.
Fig 20 Proximal view of the
vertical development and lobes
shaped in the definitive restora-
tion.
Fig 24 Final aspect of the
restoration of the maxillary right
central incisor.
Fig 23 Incremental tech-
nique for resin application:
DA1, D-bleach H, T-Blue, and
Bleach (Opallis).
Fig 27 (left) Mamelon design
using dentin resin (DA1 and D-
Bleach, Opallis).
Fig 28 (right) Final aspect of
restoration. Note the contrast
between the restoration and the
natural tooth, which is dehy-
drated as a result of absolute
isolation.
Fig 21 Removal of the white
spots on the right central inci-
sor with a diamond bur.
Fig 25 Removal of the hypo-
plastic enamel on the left lateral
incisor.
Fig 22 After hydration, the
preparation was completed
with removal of the white spot.
Fig 26 Final aspect of the hy-
drated cavity preparation, which
was restricted to removing only
the hypoplastic white spot.
BERNARDON ET AL
20THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
the surface of the restoration was tex-
tured, and finishing and polishing were
completed (Figs 29 to 32). Surface tex-
turing is indispensable in ensuring a
natural-looking restoration because
an irregular surface provides light dis-
persion. Lobules and development
grooves (vertical texture), horizontal
grooves, and perikymata should be
reproduced using extra-fine diamond
Fig 30 Vertical development and
the edges were completed with an
oval format extra-fine diamond bur.
Fig 32 The restoration was pol-
ished to make the surface bright and
smooth.
Fig 29 A surface enhancer was used to identify the differ-
ent reflection areas of the teeth.
Fig 31 Note the similarity in morphology between the cen-
tral incisors after texturing.
BERNARDON ET AL
21VOLUME 1 • NUMBER 1 • FALL 2011
burs. Finishing was completed using
flexible disks and rubber tips. Polish-
ing with felt disks and polishing pastes
ensures surface brightness and de-
creases plaque retention. The final
result showed that composite resin
provides a suitable material to produce
esthetic effects similar to that of the
natural tooth structure (Figs 33 to 39).
Figs 33a to 33c A transilluminator was again used to visualize the similarity in light transmission
between tooth and restoration (compare to Figs 5a to 5c).
Fig 34 Final aspect of restorations, frontal view.
Fig 35 (right) Final aspect of restorations, palatal
view.
a b c
BERNARDON ET AL
22THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Figs 36 to 38 Final smile after bleaching and restora-
tive treatment. Note the correct merging of the dental
substrate with the composite resin and reproduction of
the optical aspects in the incisal third region.
BERNARDON ET AL
23VOLUME 1 • NUMBER 1 • FALL 2011
Fig 39 The patient was satisfied with the end result. Note the naturalness and harmony of the smile
with the facial esthetics.
BERNARDON ET AL
24THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
CONCLUSIONS AND GUIDELINES FOR PRACTITIONERS
In cases of hypoplastic enamel, a correct
diagnosis is indispensable for an appro-
priate treatment prognosis. In lesions
with dentin involvement, direct compos-
ite resin restorations promote satisfacto-
ry results with conservation of a healthy
dental structure, excellent mechanical
properties, and reproduction of the nat-
ural tooth color and characteristics.19
Proper color selection is not enough;
satisfactory resin system selection and
proper realization of the stratification
technique must also be accomplished.
Following this protocol is critical to the
quality of treatment received.
This article is based on a chapter in the book Clinical Vision: Cases and Solutions by Dr Baratieri and was originally written in Portuguese.
REFERENCES
1. Elcock C, Smith RN, Simpson J, Abdellatif A, Bäckman B, Brook AH. Comparison of methods for measurement of hypoplastic lesions. Eur J Oral Sci 2006;114(suppl 1): 365–369.
2. Clarkson J. Review of terminol-ogy, classifications, and indices of developmental defects of enamel. Adv Dent Res 1989;3:104–109.
3. Ribas AO, Czlusniak GD. Anomalias do esmalte dental: Etiologia, diagnostico e tratamento. Biol Health Sci 2004;10:23–26.
4. Bendo CB, Scarpelli AC, Novaes JB Jr, Valle MPP, Paiva SM, Pordeus IA. Enamel hypoplasia in permanent incisors: A six-month follow-up. RGO 2007;55:107–112.
5. Sensi lG, Marson FC, Strassle H, Duarte SJ. Recuperação Cosmética de Deformidades Dentais. Pro-odont Estética, ed 2. Porto Alegre: Artmed, 2008: 156–178.
6. Croll TP. Enamel Microabrasion. Chicago: Quintessence, 1991.
7. Simonsen RJ. Developmental defect restorations. In: Simonsen RJ. Clinical Applica-tions of the Acid Etch Tech-nique. Chicago: Quintessence, 1978:63–70.
8. Machado FC, Ribeiro RA. Defeito de esmalte e cárie dentária em crianças prematu-ras e/ou de baixo peso ao nascimento. Pesq Bras Odontoped Clin Integr 2004; 4:243–247.
9. Haywood VB, Heymann HO. Nightguard vital bleaching. Quintessence Int 1989;20: 173–176.
10. Leonard RH Jr, Bentley C, Eagle JC, Garland GE, Knight MC, Phillips C. Nightguard vital bleaching: A long-term study on efficacy, shade retention, side effects and patients’ perceptions. J Esthet Restor Dent 2001;13:357–369.
11. Joiner A. The bleaching of teeth: A review of the literature. J Dent 2006;34:412–419.
12. Hirata R. Tips: Dicas em Odontologia Estética. São Paulo: Artes Médicas, 2011:576.
13. McGuckin RS, Thurmond BA, Osovitz S. Enamel shear bond strengths after vital bleaching. Am J Dent 1992;5:216–222
14. Baratieri LN, Belli R. Resinas compositas. In: Baratieri LN. Clinical Solutions—Fundamen-tals and Techniques. Flori-anópolis: Editora Ponto, 2008:131–142.
15. Baratieri LN, Belli R. Colo: Fundamentos básicos. In: Baratieri LN. Clinical Solu-tions—Fundamentals and Techniques. Florianópolis: Editora Ponto, 2008:21–55.
16. Ardu S, Krejci I. Biomimetic direct composite stratification technique for the restoration of anterior teeth. Quintessence Int 2006;37:167–174 [erratum 2006;37:408].
17. Vanini L. Light and color in anterior composite restora-tions. Pract Periodontics Aesthet Dent 1996;8:673–682.
18. Vanini L, Mangani F, Klimovs-kaia O. Colour in dentistry. In: Vanini L, Mangani F, Klimovs-kaia O. Conservative Restora-tion for Anterior Teeth. Viterbo, Italy: ACME, 2005:97–200.
19. Bernardon JK, Gondo R. Restorative treatment of hypoplastic stains in anterior teeth. In: Baratieri LN. Clinical Vision: Cases and Solutions. Florianópolis: Editora Ponto, 2010:62–101.
26THE AMERICAN JOURNAL OF ESTHETIC DENTISTRYTHE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
The Gray Zone
Around Dental Implants:
Keys to Esthetic Success
Iñaki Gamborena, DMD, MSD, FID
Private Practice, San Sebastian, Spain; Clinical Assistant Professor,
Department of Preventive and Restorative Sciences, University of Pennsylvania
School of Dental Medicine, Philadelphia, Pennsylvania, USA.
Markus B. Blatz, DMD, PhD
Professor and Chairman, Department of Preventive and Restorative
Sciences, University of Pennsylvania School of Dental Medicine, Philadelphia,
Pennsylvania, USA.
Correspondence to:
Dr Iñaki Gamborena
Resurecccion mª de Azkue, 6 20018
San Sebastian, Spain.
Email: [email protected]
VOLUME 1 • NUMBER 1 • FALL 2011VOLUME 1 • NUMBER 1 • FALL 2011
Single-implant restorations in the anterior maxilla have become a routine treat-
ment option. While customized tooth-colored prosthetic components show great-
ly improved clinical outcomes, esthetic success relies not only on the restorative
result, but also on the condition of the soft tissues. A common esthetic shortcom-
ing is the grayish appearance of the peri-implant soft tissues, which are difficult
to manipulate around dental implants. The parameters and clinical guidelines that
should be used to influence esthetic success and avoid the gray zone around
implant restorations can be categorized into five key factors: (1) optimal three-
dimensional implant placement for functional and esthetic long-term implant
success; (2) maximized soft tissue thickness to conceal the implant-restorative
interface; (3) proper abutment selection to improve biocompatibility, tissue stabil-
ity, color, translucency, and fluorescence; (4) careful crown restoration to imitate
the natural teeth; and (5) awareness of the lip line, which may greatly influence the
final outcome. Mimicking the inherent optical properties, especially fluorescence,
of natural teeth with implant components and crown materials is fundamental for
ideal restorative and soft tissue esthetics. (Am J Esthet Dent 2011;1:26–46.)
27
GAMBORENA ANd BLAtz
28THE AMERICAN JOURNAL OF ESTHETIC DENTISTRYTHE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
The esthetic success of a dental
restoration is judged by its inte-
gration with the surrounding dentition
in respect to position, angulation, di-
mensions, proportions, shape, surface
morphology, and shade.1–3 Other cru-
cial esthetic parameters that are often
overlooked include the morphology,
texture, and ultimately the color of the
surrounding gingiva.3,4 The soft tissue
is the natural frame of the teeth and
any dental restoration and is, therefore,
a fundamental parameter for esthetic
success.1,3,5 This aspect is often ne-
glected because successful soft tissue
outcomes—including handling, manip-
ulation, and healing—are very demand-
ing, time intensive, and unpredictable.5
Magne et al6 described a prevalence
of grayish soft tissue discolorations
around tooth-supported full-coverage
porcelain-fused-to-metal and even all-
ceramic restorations. Interestingly, oth-
er perioral facial parameters such as
position of the upper lip and height of
the smile line7–9 also seem to influence
the degree of gingiva discoloration.
The authors note that “this problem is
particularly evident in the presence of
the upper lip, which can generate an
‘umbrella effect’ characterized by gray
marginal gingivae and dark interdental
papillae.”6
This umbrella effect is magnified with
dental implant restorations in the an-
terior maxilla because the supporting
hard and soft tissues are often com-
promised even before restorative treat-
ment and are influenced by the color
and design of the implant, its prosthetic
components, and the definitive resto-
ration.10–17 Therefore, ideal periodontal
and restorative esthetic success with
maxillary anterior implant-supported
restorations presents a great challenge
for the entire dental team and depends
on a variety of parameters.10–14
The parameters and clinical guide-
lines that should be used to influence
esthetic success and avoid the gray
zone around implant restorations can
be categorized into five key factors: (1) optimal three-dimensional (3D) implant
placement for functional and esthetic
long-term implant success; (2) maxi-
mized soft tissue thickness to conceal
the implant-prosthetic component inter-
face; (3) proper abutment selection to
improve biocompatibility, tissue stabil-
ity, and color to provide a perfect blend
with surrounding tissues and teeth; (4) careful crown restoration to imitate the
natural teeth; and (5) awareness of the
lip line, which may greatly influence the
final outcome.
3D IMPLANT PLACEMENT
The fundamental factor for long-term
functional and esthetic success as well
as soft tissue color and stability is opti-
mal 3D implant placement.18 A simple
but essential guideline is to position the
implant as close as possible to where
the natural tooth was or ideally would
be.10 If a line is drawn at the center of
the implant along its long axis and ex-
tending through the tooth restoration,
it should run through the center of the
incisal edge of the prospective tooth
(Fig 1). The greater the 3D mismatch
between the crown and implant body,
the poorer and less stable the final
GAMBORENA ANd BLAtz
29VOLUME 1 • NUMBER 1 • FALL 2011
outcome will be. The incisal edge is
also the target for the angulation of
the implant. An implant that is angu-
lated too far to the buccal aspect will
result in greater tissue recession under
functional load. Conversely, a palatally
placed implant leads to a more ex-
treme emergence profile, resulting in
increased bone resorption and thinning
of the tissues. Both situations will lead
to an intensified grayish appearance of
the soft tissues at the gingival margin.
The third dimension is determined
by the depth of the implant in respect
to the marginal bone and soft tissue.
An implant placed at the proper depth
allows for the development of an ideal
emergence profile and a soft tissue col-
lar void of a gray zone. It is impossible
to create a proper emergence profile
when the implant is placed too shal-
low, while an implant placed too deep
is difficult to manage clinically and in-
creases the possibility of peri-implant
infection, inflammation, and bone loss.
A surgical guide fabricated from the
diagnostic wax-up/setup is an indis-
pensible tool to ensure proper 3D im-
plant placement. The anticipated incisal
edge position of the final tooth restora-
tion determines the position, angulation,
and depth of the implant in all three di-
mensions, which directly influence the
position, height, and thickness of the
surrounding hard and soft tissues.10,12
SOFT TISSUE THICkNESS
Even in cases where ideal implant
placement was achieved, the esthetic
outcome may become compromised
over time due to resorption of the mar-
ginal bone and soft tissues.5,19
Fig 1 (right) Maxillary anterior implants should
be positioned and angulated so that a virtual line
through the center of the implant along its long
axis would run through the center of the incisal
edge of the prospective crown.
GAMBORENA ANd BLAtz
30THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Case 1 (Figs 2 to 6) illustrates a situa-
tion where a single implant was placed
immediately after extraction of the
maxillary right central incisor without
any hard or soft tissue augmentation. A
modified metal abutment was fabricat-
ed, and the definitive restoration was
inserted (Figs 2 and 3). A follow-up
photograph taken several years post-
operatively reveals a grayish appear-
ance of the soft tissue surrounding the
implant restoration (Fig 4). This discol-
oration becomes increasingly evident
11 years after completion as a result of
Figs 2a and 2b A modified metal abutment was used after im-
mediate implant placement at the maxillary right central incisor site
without bone or soft tissue augmentation.
Fig 3 Postoperative situation
showing the implant-supported
crown.
Fig 4 (above left) Follow-up view after several years reveals a
grayish appearance of the soft tissues.
Fig 5 (above right) Follow-up view after 11 years showing soft tis-
sue discoloration due to the metal abutment.
Fig 6 (left) Periapical radiograph after 11 years reveals loss of
buccal bone.
Case 1
GAMBORENA ANd BLAtz
31VOLUME 1 • NUMBER 1 • FALL 2011
the resorption of the buccal bone and
surrounding soft tissues, revealing the
unfavorable gray color of the metal im-
plant abutment (Figs 5 and 6).
To avoid this result, it is advisable
to maximize tissue thickness in every
case and for both delayed and imme-
diate implant placement.19–22 In fact,
the mucosal characteristics of the peri-
implant tissues necessitate connective
tissue grafting for long-term esthetic
success.21 With clear surgical objec-
tives, a modern approach should al-
ways include the most conservative
procedure that satisfies the esthetic
and functional requirements. For ex-
ample, if a bone graft is unnecessary,
stage-one surgery should always be
performed with a minimal flap incision,
such as a split-thickness flap or even
no flap, to avoid unnecessary exposure
of the underlying bone. Several authors
have indicated that flapless surgical
implant placement using computer-
assisted surgical guides minimizes
bone resorption, preserves soft tissue
architecture, and improves the healing
process.23 While some of these results
still need to be verified in long-term clin-
ical trials, the positive effects of flapless
implant placement on patient comfort
due to the minimally invasive nature
of the procedure are clearly evident.23
The key components of this surgical
process are maintenance of the inter-
proximal bone, minimal bone exposure
only on the implant site, precise coro-
nal graft suturing central to the implant
axis, and tension-free flap closure and
adaptation.
The design of the healing abutment,
which can be placed during or after
connective tissue grafting, is another
critical issue. Connective tissue grafts
(CTGs) are placed around implants to
enhance gingival margin stability and
create a more fibrous and less mobile
tissue complex.19–22 In dentistry today,
the clinician’s search for soft tissue
abundance in the early stages of im-
plant treatment means creating a large
amount of soft tissue during or soon af-
ter implant placement and manipulat-
ing these tissues during the prosthetic
phase. This is a shift from traditional ap-
proaches in which multiple subsequent
soft tissue grafts are performed until
the desired thickness was achieved.
Multiple surgical interventions, how-
ever, are less predictable because
the scarring and compromised blood
supply make every subsequent graft-
ing attempt more challenging. For
ideal prosthetic soft tissue manipula-
tion, the healing abutment should be
significantly narrower than the tooth to
be replaced. At first, the tissue will not
have the same scalloped architecture
as found around natural teeth. How-
ever, when the provisional restoration
is placed, its subgingival contour and
shape will determine the position and
scallop of the soft tissue margin.10,13 It
also seems advantageous to connect
the definitive abutment as early as pos-
sible and not to remove it after that time.
Thicker peri-implant soft tissue
masks the implant-abutment-restoration
interface and provides a better color
match between the soft tissues around
the implant and those around the neigh-
boring teeth.15–17 Some basic guide-
lines for tissue thickness and abutment
selection are as follows:
GAMBORENA ANd BLAtz
32THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
• A soft tissue thickness greater than
3 mm allows for the use of titanium or
zirconia abutments without negative
esthetic implications.
• A thin soft tissue of less than 2 to
3 mm requires either a CTG or zirco-
nia abutment.
• A dentin-colored abutment is always
preferred.
In Case 2 (Figs 7 to 13), a colored in-
stead of a white zirconia abutment was
placed due to the presence of less than
1 mm of labial soft tissue. This approach,
along with the adequate soft tissue sup-
port and contour, provided a satisfying
outcome.
ABUtMENt sELEctiON
In an evaluation of the soft tissue around
single-tooth implant crowns, Fürhauser
et al24 showed that the color of the peri-
implant soft tissue matched that of the
reference tooth in no more than one-
third of cases. Another study found that
all-ceramic implant abutment and crown
Case 2
Fig 7 Thin peri-implant soft
tissue of only 1 mm was
evident on the buccal aspect.
Fig 8 A custom-colored
zirconia abutment (Procera, No-
bel Biocare) was fabricated to
optimize the esthetic outcome.
Fig 9 Colored zirconia abut-
ment and alumina crown
(Procera Crown Alumina, Nobel
Biocare).
Fig 10 Intraoral occlusal view
showing the soft tissue support.
Fig 11 Postoperative buc-
cal view. The tooth-colored
abutment and all-ceramic
crown blend favorably with the
adjacent teeth and surrounding
soft tissue despite the compro-
mised soft tissue thickness.
Fig 12 Postoperative peri-
apical radiograph.
Fig 13 (left) Occlusal view of
the definitive implant-supported
restoration.
GAMBORENA ANd BLAtz
33VOLUME 1 • NUMBER 1 • FALL 2011
materials provide a better soft tissue
color match with neighboring teeth than
do conventional metal-alloy compo-
nents.16 zirconia has been shown to be
the preferred implant abutment material
due to its high strength13,25,26 and ex-
cellent biocompatibility.27–29 The short-
comings of zirconia include its higher
cost and unfavorable optical properties
in regard to color and fluorescence.30
Case 3 (Figs 14 to 55) includes all
previously described factors and treat-
ment parameters. The missing maxillary
left central incisor was replaced with a
Case 3
Fig 14 Preoperative periapi-
cal radiograph of the missing
maxillary left central incisor.
Fig 15 Preoperative intraoral situation.
Fig 17 Intraoral view of the edentu-
lous ridge topography.
Fig 18 Virtual
implant placement for
guided surgery.
Fig 16 Lateral
tomogram showing
the extent of the ridge
defect.
dental implant (Figs 14 to 18). Ideal 3D
implant placement was planned on the
computer and transferred via guided
surgery. During stage-one surgery,
the implant (3.5 × 13 mm, NobelAc-
tive, Nobel Biocare) was inserted, and
a CTG harvested from the maxillary
tuberosity was placed to increase tis-
sue thickness (Figs 19 to 23). Figure
24 shows the augmented edentulous
ridge 6 months postoperatively. Next,
a zirconia abutment was connected to
the implant, and a provisional restora-
tion was fabricated, relined in the oral
33VOLUME 1 • NUMBER 1 • FALL 2011
GAMBORENA ANd BLAtz
34THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
cavity, and cemented (Figs 25 to 29).
The different lighting conditions (natu-
ral and ultraviolet [UV] light) shown in
Figs 30 to 33 reveal the optical short-
comings of these materials, especially
the lack of natural fluorescence. Figure
Fig 19 Implant placement (3.5 × 13 mm,
NobelActive, Nobel Biocare).
Fig 20 A subepithelial CTG was harvested
from the maxillary tuberosity to augment the
deficient ridge.
Fig 21 After placement of the CTG, the flaps
were adapted without tension and sutured with thin
suture material to limit trauma.
Fig 22 Labial view of the adapted flap after
suturing.
Fig 23 Intraoral situation 1 week postopera-
tively.
Fig 24 Postoperative situation after 6 months
reveals improved ridge morphology.
Case 3 Continued
GAMBORENA ANd BLAtz
35VOLUME 1 • NUMBER 1 • FALL 2011
34 shows the detailed optical charac-
teristics of natural enamel and dentin
under different light sources.
Fluorescence is a crucial property
for natural esthetics.30–32 Colorants
and fluorescent modifiers that can be
applied to zirconia abutments even af-
ter milling and finishing have recently
been developed.30 The abutment or
framework is dipped into a fluores-
cent coloring liquid before sintering
to infiltrate the zirconia (Colour Liquid
Case 3 Continued
Fig 25 Definitive zirconia abutment and provi-
sional restoration.
Fig 26 (right) Insertion of the colored zirconia
abutment.
Fig 27 (above left) Try-in of the provisional crown.
Fig 28 (above right) Precision of fit was verified extraorally.
Fig 29 (right) Periapical radiograph used to verify fit.
GAMBORENA ANd BLAtz
36THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Fluoreszenz, zirkonzahn). the abut-
ment is blow dried after the dipping
process to remove the excess and then
placed under a drying lamp to prevent
damage to the heating elements of the
sinter furnace.
In addition to the regular zirconia, a
more translucent zirconia (Prettau
zirconia “translucent,” zirkonzahn)
along with 16 coloring liquids (zirkon-
zahn) are available. Figures 35 to 37
illustrate the infiltration process and its
Fig 32 Optical properties of the zirconia abut-
ment under natural light.
Fig 33 Optical properties of the zirconia abut-
ment under UV light reveals a lack of fluores-
cence.
Fig 34 Color charac-
teristics of natural enamel
and dentin: (a) The three
basic color zones; (b)
areas of brightness/value;
(c) enamel characteristics
under a polarizing filter;
(d) color characteristics
of dentin; (e) degrees
of dentin fluorescence
under UV light.
Fig 31 Optical properties of the provisional
crown under UV light. Note the lack of fluores-
cence.
Fig 30 Optical properties of the provisional
crown under natural light.
Case 3 Continued
GAMBORENA ANd BLAtz
37VOLUME 1 • NUMBER 1 • FALL 2011
effect on the optical appearance under
different light sources. Three different
abutments were fabricated: translucent
zirconia with and without fluorescence
and conventional zirconia with fluores-
cence. Figures 38 to 40 show the pa-
tient’s favorable soft tissue thickness
and the clinical try-in of the three differ-
ent abutments under regular and UV
light. Interestingly, the translucent abut-
ment provided the best match in natu-
ral light but the worst under UV light.
Fig 35 Three different abutments were fab-
ricated with conventional zirconia, a more
translucent zirconia (Prettau zirconia “translu-
cent”), and fluorescent colorants (Colour Liquid
Fluoreszenz): colored translucent zirconia with
fluorescence (transl + fluoresc) and without fluo-
rescence (translucent), and conventional zirconia
with fluorescence (zr + fluoresc). Natural light
reveals the chroma characteristics.
Fig 36 Fabrication of a fluorescent abutment:
(a) Provisional composite abutment; (b) duplicat-
ed zirconia abutment before the sinter process;
(c) dipping of the zirconia abutment into fluo-
rescent colorants before sintering; (d) definitive
abutment after sintering.
Fig 37 The three different abutments under UV
light. Conventional colored zirconia and fluoresc-
ing liquid (zr + fluoresc) reveal the most favora-
ble effect.
Case 3 Continued
GAMBORENA ANd BLAtz
38THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
The most favorable fluorescent effect
was achieved with colored convention-
al zirconia and fluorescing liquid.
In summary, the selection of zirconia
implant abutments should be based on
the following factors:
• 3D implant position: The screw-
access opening in the abutment
should not compromise mechani-
cal strength, and the circumferential
thickness should be at least 0.8 mm.
• Soft tissue thickness: A minimum of
3 mm is ideal.
• Interocclusal space: Sufficient abut-
ment height is required for ideal
strength and resistance.
• Implant abutment color: The order
of priority should be fluorescence/
value, translucency, and shade
(chroma and hue).
• Color of the intended crown restora-
tion (alumina versus zirconia).
For optimal stability and fit of the
coping, the preparation margin of the
implant abutment is generally a circum-
ferential chamfer or rounded shoulder.
On the labial aspect, the margin is typi-
cally placed deeper than on the palatal
aspect, but should not extend more than
1 mm subgingivally to avoid difficulties
during cement removal. The abutment
should support approximately 90% of
the total surrounding soft tissue con-
tour, with the crown supporting no more
than 10%.30
Fig 38 (above left) Intraoral try-in of the three
abutments under natural light.
Fig 39 (above right) Ideal soft tissue thickness
(> 3 mm).
Fig 40 (left) Intraoral try-in of the three abut-
ments under UV light.
Case 3 Continued
GAMBORENA ANd BLAtz
39VOLUME 1 • NUMBER 1 • FALL 2011
The provisional restoration generally
remains in place for 4 to 6 weeks until
the position of the tissue is stable. A
final impression of the abutment should
then be made to transfer this informa-
tion to the laboratory for fabrication of
the definitive restoration.
CROWN RESTORATION
The definitive crown material is se-
lected based on its core structure to
enhance the optical characteristics of
the intended restoration. The coping
is chosen by its ability either to mask
underlying structures or to complement
the underlying abutment color. zirconia
is increasingly used as a coping ma-
terial due to its versatility in respect to
strength, thickness, color, and translu-
cency, but especially due to its inherent
brightness and options for fluorescence
through infiltration.13–17,30 It seems only
logical that when a fluorescent abut-
ment is used, the material selected for
the definitive crown should also offer a
certain degree of fluorescence to match
the adjacent natural dentition.30–32 It is
important to evaluate the optical prop-
erties of the coping in relation to the
remaining natural dentition under differ-
ent light sources. UV light reveals the
dramatic effects of fluorescence, which
provides the vitality and brightness ex-
hibited by natural teeth.
Fluorescence is an inherent property
of natural teeth31,32 but is rarely found
in “esthetic” dental materials.33–40 In
natural teeth, the root and coronal den-
tin show the highest degree of fluores-
cence, especially in the gingival third,
while enamel has low fluorescent prop-
erties.30–32 Ceramic coping materials
such as alumina37 and zirconia39 do
not provide natural fluorescence and,
therefore, are treated with fluorescent
modifiers and/or veneered with fluores-
cent dentin stains, liners, and shoulder
porcelains.30,37,39 As in natural teeth,
the fluorescent effect is most prominent
in the gingival third of the restoration.
Therefore, natural fluorescence does
not only influence the optical effects of
the restoration itself, but also greatly in-
fluences the color and appearance of
the surrounding soft tissues.30
Figures 41 to 55 show the selection
of the definitive coping material and the
final outcome of Case 3. Figures 41 and
42 reveal the influence of fluorescent
stains on the value and chroma of alu-
mina and zirconia copings under natu-
ral and UV light. The impact of using a
fluorescent (Fig 43) versus a nonfluo-
rescent coping (Fig 44) is quite obvious
on the stone cast (Figs 45 and 46) and
even more so in the oral cavity (Figs 47
to 55). The definitive implant-supported
crown shows optical and fluorescent
properties that ideally match the exist-
ing natural dentition under various light
sources.
LIP LINE
A high lip line or “smile line” that reveals
all anterior teeth and large amounts of
gingival tissue7,8 is a great challenge
for the dental team since it is impossible
to hide the implant-restorative interface.
A high smile line may be due to vertical
maxillary excess or a hypermobile lip.
GAMBORENA ANd BLAtz
40THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
It is a common rule that, besides be-
ing symmetric, the most cervical aspect
of the gingival margins of the central in-
cisors should be at the same level as the
canines, while the margins of the lateral
incisors should be approximately 1 mm
below an imaginary line drawn from
the canine-centrals-canine.1 It seems
Fig 43 Definitive fluorescent abutment on the
stone cast demonstrating ideal fluorescence
under UV light.
Fig 44 Nonfluorescent coping on the cast
under UV light.
Fig 45 Fluorescent coping on the cast under
UV light.
Fig 46 Definitive crown showing fluorescent
properties under UV light.
Fig 41 The influence of fluorescent stains on
the value and chroma of alumina and zirconia
copings under natural light: (a and c) without
fluorescence; (b and d) with fluorescence.
Fig 42 Fluorescent properties of alumina and
zirconia copings under UV light: (a and c) without
fluorescence; (b and d) with fluorescence.
Case 3 Continued
GAMBORENA ANd BLAtz
41VOLUME 1 • NUMBER 1 • FALL 2011
advisable for central incisor implant
restorations to initially place the gingi-
val margin slightly more incisally. This
slight “overcompensation” will prove
extremely helpful to counterbalance
tissue recession typically seen over
time. The CTG now becomes an essen-
tial aspect for functional and esthetic
Case 3 Continued
Fig 48 Intraoral try-in under UV light demon-
strates ideal blending of the fluorescent properties
of the definitive crown with the adjacent teeth.
Fig 49 Definitive implant restoration.
Fig 51 (right) The definitive abutment and res-
toration provide the same degree of fluorescence
as a natural tooth.
Fig 47 Intraoral try-in of definitive crown under
natural light shows an excellent blend with the
shade of the adjacent teeth.
Fig 50 Postoperative occlusal view showing
the soft tissue support and contour.
GAMBORENA ANd BLAtz
42THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
integration of the implant-supported
restoration, especially in the presence
of a high lip line.
Occasionally, unfavorable changes
of the gingival margin levels may occur
at the teeth adjacent to the implant res-
toration. These are based on the dis-
tance between the free gingival margin
and the supporting bone and may re-
quire more extensive tissue grafting
to control gingival levels at both the
natural and implant-supported teeth.
The added connective tissue causes
the fibrotic mucosa around the implant
to migrate more coronally. In rare cas-
es, the additional soft tissue becomes
so abundant that a gingivectomy fol-
lowed by a fibrotomy becomes neces-
sary to establish ideal crown lengths
and gingival margin contours.
The unfavorable umbrella effect is
most prevalent in patients with a high
Fig 52 Postoperative view under natural light
showing the color match of the implant-supported
crown with the natural dentition.
Fig 53 Postoperative view under UV light
showing the ideal blend of fluorescent properties
between the restoration and natural dentition.
Fig 54 Postoperative intraoral situation. No gray zone is evident. Fig 55 One-year postopera-
tive peri apical radiograph of
the implant at the left central
incisor site.
Case 3 Continued
GAMBORENA ANd BLAtz
43VOLUME 1 • NUMBER 1 • FALL 2011
smile line.6 The gray zone may become
visible at the implant restoration site
even when all of the key factors are im-
plemented perfectly. Differences in soft
tissue thickness and volume may cause
these color dissimilarities, which are
then amplified by the shear presence of
the upper lip, causing a shadow on the
soft tissue and the light to be reflected
and transferred in a different manner.
Case 4 (Figs 56 to 61) demonstrates
a situation in which the maxillary left cen-
tral incisor was replaced with an implant-
supported crown in a patient with a high
Fig 56 Intraoral view of the definitive zirconia
abutment.
Fig 57 A CTG was placed earlier to ensure
ideal soft tissue thickness.
Case 4
Fig 58 Intraoral situation after 1 year reveals
differences in peri-implant soft tissue color and
morphology.
Fig 59 Preoperative view showing the patient’s
high lip line.
Fig 60 Postoperative situation. An unfavorable
gray zone is visible during an average smile.
Fig 61 A high smile reveals the gray zone
through the umbrella effect.
GAMBORENA ANd BLAtz
44THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
smile line. A CTG was placed to en-
hance the soft tissue contours. While all
of the key aspects were implemented
successfully, the slight differences in
soft tissue volume created an unfavora-
ble grayish effect (Figs 60 and 61).
In contrast to the previous case,
Case 5 (Figs 62 to 67) exemplifies
successful implementation of these
key factors in a patient with a high lip
line for long-term esthetic and func-
tional success.
Fig 62 Intraoral view of the crown prepara-
tion of the right central incisor and the definitive
colored zirconia implant abutment at the left
central incisor.
Fig 63 UV light reveals the natural fluores-
cence of the modified zirconia implant abutment.
Fig 64 Preoperative intraoral view of the failing
central incisor crowns.
Fig 65 Postoperative intraoral situation show-
ing the color and soft tissue match.
Fig 66 Initial situation. Note the high lip line. Fig 67 Successful implementation of the five
key factors prevented the appearance of a gray
zone despite the high smile line.
Case 5
GAMBORENA ANd BLAtz
45VOLUME 1 • NUMBER 1 • FALL 2011
CONCLUSIONS
Five key factors were identified to avoid
the gray zone around maxillary ante-
rior implant restorations: 3D implant
placement, soft tissue thickness, abut-
ment selection, crown restoration, and
lip line. Mimicking the inherent optical
properties, especially fluorescence, of
natural teeth with ideal prosthetic im-
plant components and crown materials
is fundamental for ultimate restorative
and soft tissue esthetics.
ACkNOWLEDGMENTS
The authors would like to thank Iñigo Casares for the beautiful porcelain work featured in this article and Fernando zozaya for the detailed fabrication on the zirconia abutments.
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16. Jung RE, Holderegger C, Sailer I, khraisat A, Suter A, Hämmerle CH. The effect of all-ceramic and porcelain-fused-to-metal restorations on marginal peri-implant soft tissue color: A randomized controlled clinical trial. Int J Periodontics Restorative Dent 2008;28:357–365.
17. van Brakel R, Noordmans HJ, Frenken J, de Roode R, de Wit GC, Cune MS. The effect of zirconia and titanium implant abutments on light reflection of the supporting soft tissues [epub ahead of print 20 Jan 2011]. Clin Oral Implants Res.
18. Garber DA. The esthetic dental implant: Letting restoration be the guide. J Am Dent Assoc 1995;126:319–325.
19. Grunder U. Crestal ridge width changes when placing implants at the time of tooth extraction with and without soft tissue augmentation after a healing period of 6 months: Report of 24 consecutive cases. Int J Periodontics Restorative Dent 2011;31:9–17.
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46THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
20. Linkevicius T, Apse P, Grybauskas S, Puisys A. The influence of soft tissue thickness on crestal bone changes around implants: A 1-year prospective controlled clinical trial. Int J Oral Maxillo-fac Implants 2009;24:712–719.
21. Speroni S, Cicciu M, Maridati P, Grossi GB, Maiorana c. Clinical investigation of mucosal thickness stability after soft tissue grafting around implants: A 3-year retrospec-tive study. Indian J Dent Res 2010;21:474–479.
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23. Esposito M, Grusovin MG, Maghaireh H, Coulthard P, Worthington HV. Interventions for replacing missing teeth: Management of soft tissues for dental implants. Cochrane Database Syst Rev 2007;(3):CD006697.
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25. Att W, kurun S, Gerds T, Strub JR. Fracture resistance of single-tooth implant-supported all-ceramic restorations after exposure to the artificial mouth. J Oral Rehabil 2006; 33:380–386.
26. Nothdurft FP, Merker S, Pospiech PR. Fracture behaviour of implant-implant- and implant-tooth-supported all-ceramic fixed dental prostheses utilising zirconium dioxide implant abutments. Clin Oral Investig 2011;15: 89–97.
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28. Rimondini L, Cerroni L, carrassi A, torricelli P. Bacte-rial colonization of zirconia ceramic surfaces: An in vitro and in vivo study. Int J Oral Maxillofac Implants 2002;17: 793–798.
29. Degidi M, Artese L, Scarano A, Perrotti V, Gehrke P, Piattelli A. Inflammatory infiltrate, microvessel density, nitric oxide synthase expression, vascular endothelial growth factor expression, and proliferative activity in peri-implant soft tissues around titanium and zirconium oxide healing caps. J Periodontol 2006;77:73–80.
30. Gamborena i, Blatz MB. Fluoresence—Mimicking nature for ultimate esthetics in implant dentistry. Quintessence Dent Technol 2011;34:7–23.
31. Benedict Hc. A note on the fluo-rescence of teeth in ultra-violet rays. Science 1928;67:442.
32. Araki T, Miyazaki E, kawata T, Miyata k. Measurements of fluorescence heterogeneity in human teeth using polarization microfluorometry. Appl Spectrosc 1990;44:627–631.
33. Lee Yk, Lu H, Powers JM. Fluorescence of layered resin composites. J Esthet Restor Dent 2005;17:93–100.
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48THE AMERICAN JOURNAL OF ESTHETIC DENTISTRYTHE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Determining the Influence of
Flowable Composite Resin
Application on Cuspal
Deflection Using a
Computerized Modification of
the Strain Gauge Method
Hamdi H. Hamama, BDS, MDS Assistant Lecturer, Conservative Dentistry Department, Faculty of Dentistry,
Mansoura University, Mansoura, Egypt.
Nadia M. Zaghloul, BDS, MDS, PhD Associate Professor, Conservative Dentistry Department, Faculty of Dentistry,
Mansoura University, Mansoura, Egypt.
Ossama B. Abouelatta, BEng, MSc Engg, PhD
Associate Professor, Production Engineering and Mechanical Design
Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt.
Abeer E. El-Embaby, BDS, MDS, PhD Lecturer, Conservative Dentistry Department, Faculty of Dentistry,
Mansoura University, Mansoura, Egypt.
Correspondence to: Dr Hamdi H. Hamama
Conservative Dentistry Department, Faculty of Dentistry,
Mansoura University, PO Box 35516, Mansoura, Egypt.
Email: [email protected]
VOLUME 1 • NUMBER 1 • FALL 2011VOLUME 1 • NUMBER 1 • FALL 2011
49
This study evaluated the influence of the application of flowable composite resin
on cuspal deflection using a computerized modification of the strain gauge
method. Forty sound extracted mandibular molars, which received a mesio-
occlusodistal slot preparation, were divided into two groups of 20 molars each
based on the type of restorative materials used. Each group was further divided
into two subgroups of 10 molars each relative to the application of flowable
composite resin at cavity internal line angles. Cuspal deflection was measured
using a new computerized modification of the strain gauge method. The mean
cuspal deflection values (µm/m) and standard deviations were calculated and
subjected to normality and homogeneity of variances tests. If they passed the
tests, they were subjected to parametric statistical analysis (independent sample
t test). The results showed that groups containing flowable composite resin
exhibited higher cuspal deflection values than groups without flowable composite
resin. The application of flowable composite resin at the internal cavity line angles
increased cuspal deflection, possibly due to the material’s high volumetric
shrinkage levels, which exerted more stress at the tooth-restoration interface.
Further, the validity of the new computerized modification of the strain gauge
method was proven by the agreement found between the output results and those
of previous studies of cuspal deflection. (Am J Esthet Dent 2011;1:48–59.)
HAMAMA ET AL
50THE AMERICAN JOURNAL OF ESTHETIC DENTISTRYTHE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Rapid development of resin-based
dental composites is one of the
main characteristics of modern esthetic
dentistry. Resin-based composite is now
widely used as an alternative to amal-
gam in stress-bearing areas.1 Consider-
ing the polymeric nature of composite
resin, it has an inherited volumetric po-
lymerization shrinkage property that
leads to contraction stresses at the
restoration-cavity interface.2 This poly-
merization shrinkage has been reported
to be one of the factors directly respon-
sible for marginal leakage at the com-
posite restoration–cavity wall interface.3
The interaction of the polymerization
shrinkage stresses and the adhesive
bond plays a large role in the long-term
function of a composite resin restora-
tion. At sites where these stresses are
higher than the bond strength between
the restoration and dental substrate, a
microgap will form, increasing the prob-
ability of postoperative sensitivity and
recurrent caries.4,5 On the other hand,
if the bond strength is higher than the
polymerization contraction stresses,
the stresses will transfer to the cusps,
resulting in cuspal deflection.2,6–8
A class of low-viscosity composite
resins, commonly called “flowable”
composite resins, has been commer-
cially introduced for restorative dentist-
ry. Flowability is regarded as a desirable
handling property because it allows the
material to be injected through small-
gauge dispensers, thus simplifying the
placement procedure and amplifying
the range of applications suggested
by the manufacturers.9,10 The effective-
ness of flowable composite resin as an
intermediate layer at the internal cavity
line angles is one of the most contro-
versial topics in dentistry. Some stud-
ies support its use due to its stretching
capability (ie, its low Young modulus
of elasticity), which provides sufficient
elasticity to relieve polymerization con-
traction stresses.5,10–14 In contrast,
some studies suggest that the appli-
cation of flowable composite resin in-
creases contraction stresses due to the
material’s high resin content.15–17
Cuspal deflection is a common bio-
mechanical phenomenon observed in
teeth restored with composite resin. It
results from the interactions between
the polymerization shrinkage stresses
of the composite resin and the com-
pliance of the cavity wall.18 There are
many methods to measure cuspal de-
flection, including noncontact methods
(photography,19 microscopy,20,21 laser
scanning,22 and three-dimensional
microcomputed tomography23) and
contact methods (strain gauge,6,24
interferometers,25 and linear vari-
able differential transformers26–29).
Because these methods depend pri-
marily on measuring the difference
between precuring and postcuring val-
ues, they have not provided detailed
data regarding how cuspal deflection
happens in relation to time. However,
the present authors introduce a modi-
fication of the strain gauge method,
which was developed in cooperation
between the engineering and dental
teams of this study.
This study was designed to evaluate
the effect of the application of flowable
composite resin on cuspal deflection of
mesio-occlusodistal (MOD) composite
restorations. Cuspal deflection was
HAMAMA ET AL
51VOLUME 1 • NUMBER 1 • FALL 2011
measured using the new modification
of the strain gauge method. The null
hypothesis was that application of flow-
able composite resin does not increase
the cuspal deflection of MOD compos-
ite resin restorations.
MATERIALS AND METHODS
The materials used in this study are
listed in Table 1.
Tooth selection and preparation
A total of 40 sound extracted mandibu-
lar molars were collected from the Oral
Surgery Department, Faculty of Den-
tistry, Mansoura University, Mansoura,
Egypt. The patients were informed that
the voluntarily donated extracted teeth
would be used for research purposes.
To be included in the study, the mo-
lars were required to have the following
crown dimensions: 9-mm buccolingual
distance and 10- to 11-mm mesiodistal
distance. The collected molars were
observed under magnification (×10) in
a binocular stereomicroscope (LOMO
SF-100 Binocular Stereo Microscope,
MBC-10). Teeth with preexisting cracks,
caries, or attrition were discarded. The
selected molars were carefully cleaned
using an ultrasonic scaler (UDS-J
Ultrasonic Scaler, Ningbo Sunglow Imp
& Exp) and then debrided with pumice
(Americos Industries) using a rotary
brush (Merssage Brush, Shofu). The
molars were disinfected with 0.2% so-
dium azide solution for 48 hours.30 To
prevent dehydration, they were stored
in physiologic saline for a period of no
more than 1 month at 37°C until the
time of the test.
The molars were randomly divid-
ed into two groups (20 molars each)
based on the restorative material used
(Tetric EvoCeram or Grandio). Next,
each group was randomly subdivided
into two subgroups (n =10) relative to
the application of flowable composite
resin at the internal cavity line angles.
Table 1 Composite resin systems used in this study
Material Scientific classification Trade name Batch no. Manufacturer
Composite resin
Restoration NanohybridTetric EvoCeram HB
Grandio
J13387 J14049
Ivoclar Vivadent VOCO
Restoration liner NanohybridTetric EvoFlow
Grandio Flow
K15010 Ivoclar Vivadent
VOCO
Bonding system
Filled, light-curing single component bonding agent for enamel and dentin in conjunction with the
acid etch technique
Etching gel containing 37% phosphoric acid
Excite
Total Etch
J25791 J25793
J25470 K20207
Ivoclar Vivadent
Ivoclar Vivadent
HAMAMA ET AL
52THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Each specimen received a nonreten-
tive MOD slot preparation with the fol-
lowing criteria: occlusogingival depth
of 4 ± 0.3 mm without an axial wall and
a buccolingual diameter of 3 ± 0.3 mm.
The remaining buccal and lingual cav-
ity walls were measured using an elec-
tronic digital caliper (MAX-CAL) after
preparation for verification of the buc-
colingual diameter. The preparation
was carried out using a no. 59 carbide
bur (Komet Dental).
Cuspal deflection test
A 3-cm polyvinyl chloride tube was filled
with acrylic resin (Rapid Repair, Dent-
sply) in the dough stage. The molar’s
roots were positioned at the tube center
and parallel to its long axis, leaving the
crown and 2 mm of the root below the
cementoenamel junction uncovered to
accommodate the leads of the strain
gauge. A dental surveyor was used to
verify that the tooth was parallel to the
tube. After setting of the acrylic resin,
the parallelism of the cavity buccal
and lingual walls was confirmed by the
same surveyor.
All prepared cavities were etched
using Total Etch for 15 seconds accord-
ing to the manufacturer’s instructions.
Two precision strain gauges (KFG-2N-
120-C1-11L1M2R, Kyowa Electronic
Instruments) were attached to the buc-
cal and lingual surfaces of each unre-
stored specimen and bonded with
epoxy adhesive resin (Strain Gauge
Cement, Kyowa Electronic Instruments)
to the middle third of the cavity’s exter-
nal buccal and lingual walls (Fig 1). The
leads of the strain gauge indicator were
connected to the gauge so that the
gauge constituted one-half of a Wheat-
stone bridge, with the other half internal
to the strain gauge indicator. One layer
of the Excite universal bonding system
was applied and cured using a light-
curing unit (Bluephase C8, Ivoclar
Vivadent) at 800 mW/cm2 for 20 sec-
onds. The light intensity was checked
by radiometer (Bluephase Meter,
Ivoclar Vivadent) prior to performing
the test to confirm that the light inten-
sity was not less than 700 mW/cm2.
The teeth were restored with resin-
based composite materials in shade
A2 according to the following groups:
• Group A: Flowable composite resin
(Tetric EvoFlow) was applied at the
internal cavity line angles with a
small-gauge needle and cured for
20 seconds. Tetric EvoCeram was
inserted horizontally in increments.
Each increment was approximately
2-mm thick and cured for 60 sec-
onds: 20 seconds from the occlusal
aspect, 20 seconds from the mesial
aspect, and 20 seconds from the
distal aspect.
• Group B: This group was similar to
group A, except it did not receive
flowable composite resin prior to in-
sertion of Tetric EvoCeram.
• Group C: Flowable composite resin
(Grandio Flow) was applied at the
internal cavity line angles with a
small-gauge needle and cured for
20 seconds. Grandio was inserted
horizontally in increments. Each in-
crement was approximately 2-mm
thick and cured for 60 seconds: 20
seconds from the occlusal aspect,
HAMAMA ET AL
53VOLUME 1 • NUMBER 1 • FALL 2011
20 seconds from the mesial aspect,
and 20 seconds from the distal as-
pect.
• Group D: This group was similar to
group C, except it did not receive
flowable composite resin prior to in-
sertion of Grandio.
During polymerization, the strain
gauge recorded the changes in volt-
age signals, which were then amplified
by the recording system. The ampli-
fied signals were transferred using an
analog-to–digital converter (AD) card
to a specially designed computer pro-
gram (SIProg) for analysis. The results
appeared as a curve between the time
(seconds) and strain values. These
readings for the Wheatstone bridge
are directly proportional to the internal
cuspal deflection of the buccal and
lingual cusps of tested specimens.31
The present study is based on the data
range, ie, the difference between the
maximum and minimum strain values.
However, the data curves will be ana-
lyzed in detail in future studies.
Strain measurement system
The strain measurement system con-
sisted of a three-channel amplifier
circuit (Metrology Lab, Faculty of En-
gineering, University of Mansoura), an
AD card, and a personal computer with
the Strain Indicator Program (SIProg),
which was designed for this study by
Dr Abouelatta (Fig 2).
SIProg was fully written in house us-
ing Matlab packages. The main inter-
face is shown in Fig 3. It consists of
a title bar, menu bar, measuring infor-
mation panel, processing panel, option
panel, and display area. To calibrate
Fig 1 (above) Buccal view
of the strain gauges bonded to
the middle third of the external
cavity wall.
Fig 2a to 2c (right) The
strain measurement system.
Personal computerStrain indicator program
AD cardTooth fixation
3-channel amplifierCuring unit
a
b c
HAMAMA ET AL
54THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
the strain measuring system, specific
microstrain (με) values were applied
on a sample tooth. The strain meas-
urements were recorded using P-3500
Strain Indicators and SB-10 Switch and
Balance Units (Vishay Measurements
Group). The same values were record-
ed by the system in millivolts. A graph
representing the relation between the
strain measurement and correspond-
ing voltage was plotted using an Excel
spreadsheet (Microsoft).
Data analysis
Ten specimens were tested for each
group. SAS version 6.12 for Windows
(SAS Institute) was used for all statis-
tical analyses. The mean cuspal de-
flection values (µm/m) and standard
deviations were calculated and sub-
jected to normality and homogeneity of
variance tests. If they passed the tests,
they were subjected to parametric sta-
tistical analysis (independent sample
t test). All tests were two-sided analy-
ses, and differences were considered
statistically significant when P < .05
with a confidence level of 95%.
RESULTS AND DISCUSSION
The independent sample t test showed
a statistically significant difference (P <
.001) between flowable and nonflow-
able groups in both the buccal and lin-
gual cusps. This finding led to a rejection
of the null hypothesis. Specimens with
flowable composite resin had higher
cuspal deflection values than speci-
mens without flowable composite resin.
The results of the statistical analyses
are shown in Tables 2 and 3. Figure 4
shows an example of the output curves.
The mean cuspal deflection values
obtained from the buccal cusp for
flowable composite resin groups were
41.91 μm/m for Tetric EvoCeram and
44.59 μm/m for Grandio. The mean
cuspal deflection values of the non-
flowable groups were 32.64 μm/m and
39.40 μm/m for Tetric EvoCeram and
Grandio, respectively. This showed
Fig 3 Graphical user interface of the Strain Indicator
Program (SIProg).
Title bar
Menu bar
Display area
HAMAMA ET AL
55VOLUME 1 • NUMBER 1 • FALL 2011
that groups without flowable composite
resin exhibited less cuspal deflection
than groups with flowable composite
resin (Table 2).
The mean cuspal deflection val-
ues obtained from the lingual cusp for
flowable composite resin groups were
22.24 μm/m for Tetric EvoCeram and
21.73 μm/m for Grandio. The mean cus-
pal deflection values of the nonflowable
groups were 16.02 μm/m and 16.51 μm/m
for Tetric EvoCeram and Grandio, re-
spectively. This showed that groups
without flowable composite resin exhib-
ited less cuspal deflection than groups
with flowable composite resin (Table 3).
This study used two commercial
nanohybrid composite resin systems,
each with its own flowable composite
resin. This was done to exclude the
manufacturing factor and to avoid bias
toward one brand. The width of the buc-
colingual cavity was slightly larger than
that of an ideal clinical situation. This
was selected to decrease the remaining
buccal and lingual walls and increase
the sensitivity of the strain gauge. The
selection of a nanofilled universal two-
step etch-and-rinse adhesive system
was based on previous studies showing
that this system is the gold standard for
bonding with dentin. The advantage of
the new computerized measuring sys-
tem used in this study was that it provid-
ed accurate details about the process
of deflection in a curve format consist-
ing of peaks and valleys, which will be
further explained in future studies. The
Table 2 Comparison (t test) of cuspal deflection in specimens with and without flowable composite resin (buccal cusp)
P SE SDMean
(μm/m) NFlowable
compositeComposite
system
< .001*1.71 4.52 41.91 10 Yes
Tetric EvoCeram0.51 1.35 32.64 10 No
< .001*0.57 1.79 44.59 10 Yes
Grandio0.34 1.09 39.40 10 No
SE = standard error; SD = standard deviation. *Significantly different at P < .05.
Table 3 Comparison (t test) of cuspal deflection in specimens with and without flowable composite resin (lingual cusp)
P SE SDMean
(μm/m) NFlowable
compositeComposite
system
< .001*0.55 1.46 22.24 10 Yes
Tetric EvoCeram1.18 3.12 16.02 10 No
< .001*0.41 1.29 21.73 10 Yes
Grandio0.36 1.13 16.51 10 No
SE = standard error; SD = standard deviation. *Significantly different at P < .05.
HAMAMA ET AL
56THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
accuracy of measurements even when
based only on deflection range values
(difference between the postcuring and
precuring values) is more reliable than
with conventional measuring systems
because the data are automatically cal-
culated by SIProg. This new measuring
system also provides a large amount of
data storage and easy recall.
The results showed that the highest
levels of strain were produced during
exposure of the restoration to the light
source for polymerization. The high
stresses associated with the applica-
tion of flowable composite resin may
be explained by the material’s low fill-
er content and high resinous content,
which increases the polymerization
shrinkage.9,32–35 The strain levels did
not decrease during placement of the
restoration, and any stress relaxation
resulting from the flow of the material
was not sufficient to overcome the poly-
merization shrinkage.
The results support the findings of
previous studies. One study suggested
that flowable composite resins shrink
more than conventional composite res-
ins, creating more stress on the bond-
ing agent during curing and possibly
allowing for premature deflection of
the overlaying conventional composite
resin. The authors attributed this to the
difference in flexural modulus caused
by the changes in filler content.33 An-
other study disagreed with the concept
that shrinkage stress generated by a
subsequent layer of higher modulus
composite resin could be absorbed
by an elastic intermediary layer.17 A
review article on polymerization shrink-
age noted that flowable composite
resins produced stress levels similar
to those of nonflowable materials.36 In
addition, an in vitro study concluded
that the use of flowable materials does
not lead to marked stress reduction
and increases the risk of debonding
at the adhesive interface as a result of
polymerization shrinkage.37 Oliveira et
al38 strongly confirmed that using flow-
able composite resin as a liner or base
Fig 4 Sample of an output
curve drawn using SIProg.3630
3620
3610
3600
359010 20 30 40 50 60
Time (s)
Stra
in (µ
m/m
)
HAMAMA ET AL
57VOLUME 1 • NUMBER 1 • FALL 2011
material under a composite resin resto-
ration increases polymerization shrink-
age stresses at the adhesive interface,
potentially leading to adhesive failure.
Chuang et al39 concluded that the use
of flowable composite resin lining may
aggravate cusp flexure.
On the other hand, some studies did
not support the current results. One
study showed that the use of composite
resin liners with a low elastic modulus
was a satisfactory technique for partial
absorption of the stress generated by
polymerization shrinkage; however, this
study was performed using composite
resin blocks, which were not inserted
in prepared cavities.40 Another study
supported the inverse relationship be-
tween filler percentage and shrinkage
strain, which was explained by the cor-
responding decrease in the volume
fraction of monomers present to un-
dergo polymerization. The conclusion
of this study should not be generalized,
however, because it showed bias to-
ward two types of flowable composite
resins and ultimately stated that these
types still suffered from polymerization
shrinkage.41 Finally, a study introduc-
ing a new method of measuring cuspal
deflection reported that polymerization
shrinkage tended to decrease as filler
content increased. This study used a
noncontact cuspal deflection measur-
ing method based on a laser displace-
ment sensor; unfortunately, the validity
of noncontact measurements is still un-
der investigation.22
Based on the results of this study,
the null hypothesis that application of
flowable composite resin does not in-
crease cuspal deflection of MOD com-
posite resin restorations was rejected.
Further, the validity of the new comput-
erized modification of the strain gauge
method was proven by the agreement
of the results with those of other cuspal
deflection studies.
CONCLUSIONS
Under the conditions of this study, it
was concluded that the application of
flowable composite resin at the inter-
nal cavity line angles increased cus-
pal deflection, possibly due to the
material’s high volumetric shrinkage,
which exerts more stress at the tooth-
restoration interface. The limitation of
the new measuring system used was
the need to obtain two symmetric buc-
cal and lingual channels to be able to
judge whether the deflection occurs
simultaneously in both cusps or in one
cusp more than the other. This limita-
tion can now be addressed by the en-
gineering team of this study.
The use of flowable composite resin
is not preferred in MOD cavities be-
cause it increases internal polymeri-
zation stress, which leads to greater
cuspal deflection. Further investigation
is needed to carefully study the SIProg
output curves.
ACKNOWLEDGMENTS
The authors express their deepest gratitude and appre-ciation to Dr Geoff Smith, Center for Applied English Studies, The University of Hong Kong, for his work in revising the article’s language. They also thank VOCO for supplying the Grandio and Grandio Flow materials.
HAMAMA ET AL
58THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
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2. Marchesi G, Breschi L, Antoniolli F, Di Lenarda R, Ferracane J, Cadenaro M. Contraction stress of low-shrinkage composite materials assessed with different testing systems. Dent Mater 2010;26: 947–953.
3. Ozgünaltay G, Görücü J. Fracture resistance of class II packable composite restora-tions with and without flowable liners. J Oral Rehabil 2005;32: 111–115.
4. Eick JD, Welch FH. Polymeri-zation shrinkage of posterior composite resins and its possible influence on postop-erative sensitivity. Quintes-sence Int 1986;17:103–111.
5. Li QS, Jepsen S, Albers HK, Eberhard J. Flowable materials as an intermediate layer could improve the marginal and internal adaptation of composite restorations in Class-V-cavities. Dent Mater 2006;22:250–257.
6 McCullock AJ, Smith BG. In vitro studies of cusp reinforce-ment with adhesive restorative material. Br Dent J 1986;161: 450–452.
7. Suliman AH, Boyer DB, Lakes RS. Polymerization shrinkage of composite resins: Compari-son with tooth deformation. J Prosthet Dent 1994;71:7–12.
8. Van Ende A, De Munck J, Mine A, Lambrechts P, Van Meer-beek B. Does a low-shrinking composite induce less stress at the adhesive interface? Dent Mater 2010;26:215–222.
9. Labella R, Lambrechts P, Van Meerbeek B, Vanherle G. Polymerization shrinkage and elasticity of flowable compos-ites and filled adhesives. Dent Mater 1999;15:128–137.
10. Lee IB, Min SH, Kim SY, Ferracane J. Slumping tendency and rheological prop-erties of flowable composites. Dent Mater 2010;26:443–448.
11. Beun S, Bailly C, Dabin A, Vreven J, Devaux J, Leloup G. Rheological properties of experimental Bis-GMA/TEGDMA flowable resin composites with various macrofiller/microfiller ratio. Dent Mater 2009;25:198–205.
12. Lindberg A, van Dijken JMV, Hörstedt P. In vivo interfacial adaptation of class II resin composite restorations with and without a flowable resin composite liner. Clin Oral Investig 2005;9:77–83.
13. Roberson TM, Heymann H, Swift EJ, Sturdevant CM. Sturdevant’s Art and Science of Operative Dentistry, ed 5. St Louis: Elsevier Mosby, 2006.
14. Summitt JB. Fundamentals of Operative Dentistry: A Contem-porary Approach, ed 3. Chicago: Quintessence, 2006.
15. Stefanski S, van Dijken JW. Clinical performance of a nanofilled resin composite with and without an intermediary layer of flowable composite: A 2-year evaluation [epub ahead of print 23 Nov 2010]. Clin Oral Investig.
16. Gallo JR, Burgess JO, Ripps AH, et al. Three-year clinical evaluation of two flowable composites. Quintessence Int 2010;41:497–503.
17. Unterbrink GL, Liebenberg WH. Flowable resin composites as “filled adhesives”: Literature review and clinical recommen-dations. Quintessence Int 1999;30:249–257.
18. Lee MR, Cho BH, Son HH, Um CM, Lee IB. Influence of cavity dimension and restoration methods on the cusp deflec-tion of premolars in composite restoration. Dent Mater 2007; 23:288–295.
19. Segura A, Donly KJ. In vitro posterior composite polymeri-zation recovery following hygroscopic expansion. J Oral Rehabil 1993;20:495–499.
20. Alomari QD, Reinhardt JW, Boyer DB. Effect of liners on cusp deflection and gap formation in composite restorations. Oper Dent 2001; 26:406–411.
21. Suliman AA, Boyer DB, Lakes RS. Cusp movement in premolars resulting from composite polymerization shrinkage. Dent Mater 1993; 9:6–10.
22. Miyasaka T, Okamura H. Dimensional change measure-ments of conventional and flowable composite resins using a laser displacement sensor. Dent Mater J 2009; 28:544–551.
23. Sun J, Lin-Gibson S. X-ray microcomputed tomography for measuring polymerization shrinkage of polymeric dental composites. Dent Mater 2008; 24:228–234.
24. Meredith N, Setchell DJ. In vitro measurement of cuspal strain and displacement in composite restored teeth. J Dent 1997;25:331–337.
25. Suliman AA, Boyer DB, Lakes RS. Interferometric measure-ments of cusp deformation of teeth restored with compos-ites. J Dent Res 1993;72: 1532–1536.
26. Jantarat J, Panitvisai P, Palamara JE, Messer HH. Comparison of methods for measuring cuspal deformation in teeth. J Dent 2001;29:75–82.
27. Li JY, Fok ASL, Satterthwaite J, Watts DC. Measurement of the full-field polymerization shrinkage and depth of cure of dental composites using digital image correlation. Dent Mater 2009;25:582–588.
28. Pearson GJ, Hegarty SM. Cusp movement of molar teeth with composite filling materials in conventional and modified MOD cavities. Br Dent J 1989; 166:162–165.
29. Pearson GJ, Hegarty SM. Cusp movement in molar teeth using dentine adhesives and composite filling materials. Biomaterials 1987;8:473–476.
30. Dietschi D, Olsburgh S, Krejci I, Davidson C. In vitro evalua-tion of marginal and internal adaptation after occlusal stressing of indirect class II composite restorations with different resinous bases. Eur J Oral Sci 2003;111:73–80.
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31. Donly KJ, Wild TW, Bowen RL, Jensen ME. An in vitro investigation of the effects of glass inserts on the effective composite resin polymerization shrinkage. J Dent Res 1989;68:1234–1237.
32. Alvarez-Gayosso C, Barceló-Santana F, Guerrero-Ibarra J, Sáez-Espínola G, Canseco-Martínez MA. Calculation of contraction rates due to shrinkage in light-cured composites. Dent Mater 2004;20:228–235.
33. Bayne SC, Thompson JY, Swift EJ Jr, Stamatiades P, Wilkerson M. A characterization of first-generation flowable composites. J Am Dent Assoc 1998;129:567–577.
34. Kleverlaan CJ, Feilzer AJ. Polymerization shrinkage and contraction stress of dental resin composites. Dent Mater 2005;21:1150–1157.
35. Stansbury JW, Trujillo-Lemon M, Lu H, Ding X, Lin Y, Ge J. Conversion-dependent shrinkage stress and strain in dental resins and composites. Dent Mater 2005;21:56–67.
36. Braga RR, Ferracane JL. Alternatives in polymerization contraction stress manage-ment. Crit Rev Oral Biol Med 2004;15:176–184.
37. Cadenaro M, Marchesi G, Antoniolli F, Davidson C, Dorigo ED, Breschi L. Flowabil-ity of composites is no guarantee for contraction stress reduction. Dent Mater 2009;25:649–654.
38. Oliveira LCA, Duarte S Jr, Araujo CA, Abrahão A. Effect of low-elastic modulus liner and base as stress-absorbing layer in composite resin restorations. Dent Mater 2010;26: e159–e169.
39. Chuang SF, Chang CH, Chen TY. Spatially resolved assess-ments of composite shrinkage in MOD restorations using a digital-image-correlation technique. Dent Mater 2011; 27:134–143.
40. Cunha LG, Alonso RC, Sobrinho LC, Sinhoreti MA. Effect of resin liners and photoactivation methods on the shrinkage stress of a resin composite. J Esthet Restor Dent 2006;18:29–36.
41. Baroudi K, Saleh AM, Silikas N, Watts DC. Shrinkage behaviour of flowable resin-composites related to conversion and filler-fraction. J Dent 2007;35: 651-655.
60THE AMERICAN JOURNAL OF ESTHETIC DENTISTRYTHE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
All-Ceramic Crowns and
Extended Veneers in Anterior
Dentition: A Case Report with
Critical Discussion
Júnio S. Almeida e Silva, DDS, MSc
PhD Student, Operative Dentistry Division, Federal University of Santa Catarina,
Florianópolis, Brazil; Visiting Researcher, Department of Prosthodontics,
Ludwig-Maximilians University, Munich, Germany.
Juliana Nunes Rolla, DDS, MSc, PhD
Professor, Department of Conservative Dentistry,
Federal University of Rio Grande do Sol, Porto Alegre, Brazil.
Daniel Edelhoff, DDS, MSc, PhD
Associate Professor, Department of Prosthodontics,
Ludwig-Maximilians University, Munich, Germany.
Élito Araujo, DDS, MSc, PhD
Professor, Integrated Clinic, Federal University of Santa Catarina,
Florianópolis, Brazil.
Luiz Narciso Baratieri, DDS, MSc, PhD
Professor and Chair, Operative Dentistry Division,
Federal University of Santa Catarina, Florianópolis, Brazil.
Correspondence to: Dr Júnio S. Almeida e Silva
Goethestrasse 70 apt. 314, LMU Dental School, Munich, Germany 80336.
Email: [email protected]
VOLUME 1 • NUMBER 1 • FALL 2011VOLUME 1 • NUMBER 1 • FALL 2011
All-ceramic crowns and veneers have been used extensively in prosthodontics
with proven clinical success. The development of new reinforced ceramics has
led to a broader range of indications. Traditional veneer preparations are now
often replaced with extended defect-oriented preparation designs, ie, extended
veneers. However, although extended veneers can serve as an alternative to full-
crown preparations, they are not the best choice for all clinical situations. Choos-
ing correctly between all-ceramic crowns and extended veneers when restoring
the anterior dentition is crucial to achieving a conservative and long-lasting treat-
ment. This article addresses key evidence-based considerations regarding the
rehabilitation of the anterior dentition using all-ceramic crowns and veneers. Fur-
ther, a case report involving both types of restorations is presented. (Am J Esthet Dent 2011;1:60–81.)
61
Ceramic is known as the most
natural-looking synthetic re-
placement for missing teeth and is
available in a range of shades and
translucencies.1,2 In the past, due to
its relatively low tensile strength and
brittleness, ceramic was generally
fused to a metal substrate to increase
fracture resistance, and its indication
was limited to full-coverage crowns for
ALMEIDA E SILVA ET AL
62THE AMERICAN JOURNAL OF ESTHETIC DENTISTRYTHE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
both anterior and posterior dentition.3
However, the metal base compromises
esthetics by decreasing light trans-
mission through the porcelain and by
creating metal ion discolorations that
can cause significant darkening of the
surrounding gingiva. This is known as
the umbrella effect.4 To overcome such
problems, new ceramic systems and
innovative restorative techniques that
wed esthetics with function have been
introduced, along with scientific evi-
dence endorsing their clinical applica-
tion. As a result, all-ceramic systems
now represent an excellent restorative
alternative for fixed dental prostheses,
single crowns, and veneers in the an-
terior dentition.5,6
The successful clinical performance
of all-ceramic crowns and veneers has
been well established.6–12 However, the
combination of media-driven treatment
plans, rushed-to-the-market products,
and dentists eager to satisfy their pa-
tients’ esthetic demands have formed
a dangerous triad with little concern
for the risk/benefit calculus of den-
tal treatment.13 The resulting overuse
of ceramic veneers is likely a result of
these new reinforced ceramics, which
have a broader range of indications
and which have led to the replacement
of traditional veneer preparations with
extended defect-oriented preparation
designs. These extended veneers of-
fer an alternative to full crowns in the
anterior dentition.10,14–17
The remarkable clinical success of
all-ceramic veneers and crowns not-
withstanding,5,6 the restoration enters
into a restorative cycle as soon as it is
placed following tooth preparation.18,19
All-ceramic crowns have been used
extensively in prosthodontics over the
past few years because their clinical
success has been similar to that of
metal-ceramic crowns, with excellent
survival rates of 98.9% in the ante-
rior region after 11 years.5,6,13,20 The
main causes of failure include cata-
strophic fracture, chipping of the ve-
neer ceramic, and secondary caries.5
Although ceramic veneers are a mini-
mally invasive approach compared to
crowns, less tooth reduction does not
always result in increased longevity. It
has been shown that after 10 years of
clinical service, reintervention without
restoration replacement occurs in 36%
of teeth restored with ceramic veneers,
whereas 7% of teeth restored with ce-
ramic veneers might receive a more
invasive treatment approach.21,22 The
main reported causes of ceramic ve-
neer failure include fracture, microleak-
age, and debonding. That is to say,
ceramic veneers are more suscepti-
ble to future interventions; therefore,
it is crucial that the clinician be aware
of the correct indications for ceramic
veneers to provide the ideal result in
terms of longevity.19 Nevertheless, nei-
ther all-ceramic crowns nor traditional
ceramic veneers should always be the
first choice in the anterior dentition be-
cause several factors must be taken
into consideration before elaborating a
treatment plan.
This article addresses key evidence-
based considerations regarding the
rehabilitation of the anterior dentition
using all-ceramic crowns and veneers.
Further, a case report involving both
types of restorations is presented.
ALMEIDA E SILVA ET AL
63VOLUME 1 • NUMBER 1 • FALL 2011
63VOLUME 1 • NUMBER 1 • FALL 2011VOLUME 1 • NUMBER 1 • FALL 2011
CASE REPORT
The following case report describes the
rehabilitation of the anterior dentition
with all-ceramic crowns and extended
veneers as well as two ceramic partial-
coverage restorations on the maxillary
left and right first premolars using leucite
glass-ceramic (IPS Empress, Ivoclar
Vivadent). The 29-year-old male patient
presented for esthetic rehabilitation of
the anterior teeth. Clinical and radio-
graphic examination revealed the pres-
ence of unsatisfactory Class III and IV
composite resin fillings, some of which
were associated with secondary car-
ies, discolored teeth due to root canal
treatment, and slight tooth misalignment
with length discrepancies in the ante-
rior dentition (Figs 1 and 2). Periodontal
evaluation found no pathologic probing
depths. Occlusal examination revealed
Fig 1 Preoperative labial view. Note the unesthetic appearance of the anterior dentition.
Fig 2 Preoperative palatal view showing proximal excess of the former composite resin fillings, es-
pecially on the mesial surface of the maxillary left central incisor.
ALMEIDA E SILVA ET AL
64THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
normal Class 1 occlusion with function-
al canine and incisal guidance and the
presence of a slight anterior overjet. No
signs of parafunction were observed.
Both lateral incisors and the left cen-
tral incisor had been endodontically
treated, and their clinical crowns were
deeply compromised. For these nonvi-
tal teeth, fiber posts were cemented, the
pulp chambers were restored, and the
pre-existing Class III and IV compos-
ite resin fillings were replaced. The old
composite resin fillings of the remaining
vital teeth were replaced as well. Three
all-ceramic crowns were planned to re-
store the nonvital teeth. Extended ce-
ramic veneers were planned to restore
the anterior vital teeth, and each pre-
molar would receive a partial-coverage
ceramic restoration.
The decision to prepare the vital an-
terior teeth for extended veneers was
based on the extension of the pre-
existing composite resin fillings, which
further oriented the preparations pala-
tally.10 Moreover, since these ceramic
veneers would be placed adjacent to
ceramic crowns, an extended prepara-
tion allowed the crowns and veneers to
be made with the same ceramic. There
is usually an interproximal cosmetic mis-
match due to the differing thicknesses
of the adjacent restorations, which can
be corrected by the ceramist if extend-
ed veneer preparations are made.23
The maxillary premolars were included
in the rehabilitation because both had
unsatisfactory mesio-occlusodistal
composite resin restorations, which
were not only associated with second-
ary caries, but also showed enamel
cracks at the mesial and facial surfaces.
Although some of the composite resin
fillings were associated with secondary
caries, the patient did not present high
caries activity. Caries lesions were more
likely to be developed due to proximal
composite resin excess and poor bond-
ing of the former restorations; therefore,
removal of the pre-existing restorations
eliminated the source of microleakage
and secondary caries incidence.
Leucite glass-ceramic was the ma-
terial of choice because it allows for
adhesive cementation. All vital teeth
displayed plenty of enamel, and
even the nonvital teeth had prepara-
tion margins completely bounded by
enamel. Further, the longevity of this
ceramic system for both crowns and
extended veneers has been well estab-
lished.5,6,10,20 Finally, this esthetic ma-
terial was a feasible choice because
the patient did not present any para
functional habits.
Crown preparation
The first phase of the crown preparation
involved the use of a spherical diamond
bur, which was positioned 45 degrees
perpendicular to the tooth long axis on
the facial cervical area so that the reduc-
tion would end at half of the bur’s diameter
(Fig 3). A cylindric, tapered, round-end
diamond bur was used in the second
phase to create three facial reduction
grooves respecting the axial inclinations
of the tooth. The grooves were subse-
quently evened (Figs 4 to 6). The depth of
each reduction was constantly controlled
using the silicone guide. The final crown
preparations would be approximately
2.0 mm deep.
ALMEIDA E SILVA ET AL
65VOLUME 1 • NUMBER 1 • FALL 2011
Fig 3 (right) First phase of crown preparation of the maxillary
left central incisor. The spherical diamond bur was positioned
45 degrees perpendicular to the tooth long axis.
Figs 4 to 6 (below) Second phase of crown preparation.
Facial reduction grooves were created respecting the tooth
axial inclinations.
ALMEIDA E SILVA ET AL
66THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
The incisal reduction was carried out
in the third phase of the preparation.
Because the silicone guide registered
a pre-existing incisal space of approxi-
mately 1.5 mm according to the wax-
up, an additional 1.5-mm reduction was
performed with the cylindric, tapered,
round-end diamond bur to achieve a
3-mm incisal reduction (Fig 7).
The fourth phase consisted of the
interproximal and palatal wraparound.
A very thin and tapered diamond bur
was used to create a slit from the fa-
cial to palatal surfaces (Figs 8 and 9).
This maneuver created space for the
application of a larger bur for the wrap-
around (Figs 10 and 11). The palatal
surface was then reduced with the aid
of a spherical diamond bur positioned
parallel to the tooth long axis to create a
supragingival cervical groove (Fig 12).
Next, a cylindric, tapered, round-end
diamond bur and a rounded bur were
applied parallel to the tooth long axis
on the palatal surface and palatal con-
cavity, respectively, to create functional
room for the ceramic (Figs 13 and 14).
Following these reductions, the gross
preparation was completed.
Fig 7 Third phase of crown preparation. A 1.5-mm reduction
was still necessary to achieve the desired 3 mm. Incisal reduction
was performed using the same diamond bur used for the second
phase.
ALMEIDA E SILVA ET AL
67VOLUME 1 • NUMBER 1 • FALL 2011
Special extra-fine finishing diamonds
with decreasing coarseness were used
along with rubber points to obtain a well-
refined preparation and working cast
(Figs 15 and 16). Finishing is essential
to eliminate sharp angles and undercut
and provide smooth contours.24 Well-
finished preparations reduce the risk of
postbonding cracks and facilitate the
technician’s work.25,26
Figs 8 to 14 Fourth phase of crown preparation, which consisted of the interproximal and palatal
wraparound.
Figs 15 and 16 Finishing
was carried out using extra-fine
diamond finishing burs with
decreasing coarseness.
ALMEIDA E SILVA ET AL
68THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Extended veneer preparation
The preparation sequence for the ex-
tended veneers was similar to that
described for the crown reductions.
However, veneer preparations are by
nature less invasive and do not involve
the entire palatal surface. The first
phase consisted of the use of a spheri-
cal diamond bur with a 1-mm-diameter
head. The diamond was positioned 45
degrees perpendicular to the tooth long
axis on the facial cervical area so that
the reduction would end at half of the
bur’s diameter, thus generating an ap-
proximate 0.5-mm depth reduction. A
cylindric, tapered, round-end diamond
bur was used in the second phase.
Three facial reduction grooves were
created respecting the axial inclinations
of the tooth, and the grooves were sub-
sequently evened. The interproximal
finish lines were extended to the linguo-
proximal line angle. If pre-existing resin
restorations are located at the prepara-
tion margins, the linguoproximal exten-
sion is extended deeper into the palatal
surfaces until the margins are on sound
enamel. The extended veneer prepara-
tions were then finished and polished
similarly to as described for the crown
preparations.
The completed preparations are
shown in Figs 17 to 19. The extended
Figs 17 to 19 Completed tooth preparations.
ALMEIDA E SILVA ET AL
69VOLUME 1 • NUMBER 1 • FALL 2011
veneer preparations were kept slightly
supragingival because no discoloration
was shown for the vital teeth, whereas
the crown preparation margins were
kept in the intrasulcular space for es-
thetic reasons.
Provisionalization
Provisionalization was carried out with
acrylic resin–based restorations, which
were fabricated at the laboratory. The
provisional restorations (Fig 20) were
contoured so that a smooth emergence
profile could be achieved. The patient
was then able to floss under the connec-
tors of the provisionals. After 1 week,
the patient assessed the function and
esthetics of the restorations. Following
clinical evaluation of the function, pho-
netics, and esthetics, along with the
patient’s feedback, it was decided that
the definitive restorations should be at
least 1 mm shorter in length. A trans-
fer impression with the provisionals in
place was made and sent to the labo-
ratory along with instructions regarding
the definitive restorations.
Impression taking
Appropriate reproduction of the prepa-
rations, adjacent teeth, and surround-
ing soft tissues is mandatory. To obtain
Fig 20 Acrylic resin–based provisional restorations.
ALMEIDA E SILVA ET AL
70THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
a high-quality impression, addition
silicone materials (polyvinyl siloxane)
are recommended due to their elastic-
ity and resistance to tearing. They also
allow multiple pours, which is an es-
sential requirement for fabrication of
adequate master casts.27
A double-cord technique was used
for gingival deflection. The cords were
soaked in astringent solution (25%
aluminum sulfate; Gel Cord, Pascal
International). Compression cord with
a small diameter (no. 00, Ultrapak, Ul-
tradent) was placed at the bottom of
the sulcus. Next, a more superficial and
thicker deflection cord (no. 0, Ultrapak)
was inserted in the entrance of the sul-
cus. Deflection of the gingival sulcus
was carried out for 4 minutes while the
deflection cord expanded due to wa-
ter sorption. With this technique, the
first compression cord must remain in
place during impression taking to seal
the sulcus and limit the flow of the crev-
icular fluid, whereas the deflection cord
is removed after deflection.
A one-step, double-mix impression
technique was carried out. The deflec-
tion cord was removed, and the gingi-
val sulcus remained deflected due to
its viscoelastic behavior. It is important
to emphasize that the deflection cord
must be wet during removal so that it
does not attach to the inner walls of the
gingival sulcus and cause bleeding. Af-
ter removal of the deflection cord, the
gingival sulcus was air dried, and the
light-body impression material was in-
serted throughout the gingival sulcus
to penetrate into the sulcus and slight-
ly beyond the preparation margins of
each tooth. Gentle air was blown on the
light-body material to ensure penetra-
tion into the sulcus. A full-mouth metallic
tray was loaded with the heavy-body
impression material, inserted into the
patient’s mouth for 5 minutes, and then
removed.
Definitive restorations
After 2 weeks, the patient returned for
placement of the definitive ceramic res-
torations (Figs 21 and 22). Try-in of the
definitive restorations must be carried out
before initiating the luting procedures. Af-
ter removal of the provisional restorations,
the preparations were cleaned with
pumice and dried. The transparent
try-in paste (Variolink II Try In, Ivoclar
Vivadent) was placed, and any excess
was removed with a spatula. The adap-
tation of the restorations was checked
with a probe, and the patient assessed
the esthetics of the final restorations with
the aid of a mirror.
Adequate surface treatment for both
the hard tissues and ceramic is crucial
to achieve successful bonding.5 The ce-
ramic restorations were placed on the
original stone die, and addition silicone
was manipulated and placed over them.
After setting, the addition silicone was
removed with the restorations attached
(Fig 23). This provided protection of the
glazed external ceramic surfaces and
facilitated the handling of the ceramic
during surface treatment. A hydro-
fluoric acid was applied at the inner
walls of the restorations for 60 seconds
(Fig 24). After rinsing, the ceramic resi-
dues and remineralized salts were elimi-
nated by applying phosphoric acid for
20 seconds, followed by rinsing and air
ALMEIDA E SILVA ET AL
71VOLUME 1 • NUMBER 1 • FALL 2011
Figs 21 and 22 Leucite glass-ceramic restorations.
ALMEIDA E SILVA ET AL
72THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
drying (Figs 25 to 27). Silane, a chemical
coupling agent, was applied with a mi-
crobrush to the inner surfaces of the res-
torations and left for 1 minute (Fig 28).
No rubber dam was used for adhe-
sive placement. Although total isolation
could be achieved for some teeth, other
abutments, especially those with crown
preparations and subgingival mar-
gins, did not allow proper isolation. The
cementation sequence depends on the
arrangement of proximal contact points,
which can be better controlled when all
teeth are isolated at the same time. A
relative isolation with retraction cords is
feasible and allows good isolation, es-
pecially for the maxillary anterior denti-
tion. Thus, relative isolation was used.
Compression cord was inserted at the
bottom of each tooth’s gingival sulcus
Figs 26 (above) and 27 (top right) The phosphoric acid was
rinsed off, and the restoration was air dried.
Fig 28 (bottom right) Silanization.
Fig 23 Removal of the addi-
tion silicone with the restorations
attached for surface treatment.
Fig 24 Etching of the inner
walls of the restorations with
hydrofluoric acid for 60 seconds.
Fig 25 Application of 35%
phosphoric acid to the inner
walls for 20 seconds.
ALMEIDA E SILVA ET AL
73VOLUME 1 • NUMBER 1 • FALL 2011
(Fig 29), and surface conditioning of the
preparations was carried out following
the two-step etch-and-rinse strategy.
First, 35% phosphoric acid was applied
on the preparations and approximately
2 mm beyond the preparation margins
for 30 seconds on enamel and 15 sec-
onds on dentin, when such tissue was
present (Figs 30 and 31). After rinsing
and air drying (Fig 32), a dual-curing
adhesive (Excite DSC, Ivoclar Vivadent)
was rubbed against the preparation sur-
faces and a little beyond the surrounding
preparation margins, followed by gentle
air thinning, and was left unpolymerized
(Figs 33 and 34). A coat of the adhe-
sive was applied to the inner walls of the
restorations, which were then loaded
using the transparent paste of the light-
curing resin cement system (Variolink II,
Figs 29 to 32 Insertion of compression cord
and application of 35% phosphoric acid onto
each abutment tooth. Note that the entire ex-
tended veneer preparation is located within the
enamel shell.
ALMEIDA E SILVA ET AL
74THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Ivoclar Vivadent). Both restorations were
slowly seated by gentle finger pressure
along the insertion axis (Figs 35 to 37).
Gross excess of the resin cement was
eliminated with a spatula. The instru-
ment was guided using a cutting motion
parallel to the margin to avoid extraction
of resin cement from the marginal joint
(Fig 38). Flossing should be avoided
before light curing because it can dis-
locate or detach the ceramic from the
teeth. Light curing was performed at the
Fig 37 (left) Placement of the restoration with
gentle finger pressure.
Figs 33 and 34 Hybridization of the dental hard tissues and application of a dual-curing adhesive
system onto the maxillary right central incisor.
Figs 35 and 36 Application of a coat of adhesive onto the previously silanized ceramic restoration
and subsequent loading with the transparent paste of the light-curing resin cement.
ALMEIDA E SILVA ET AL
75VOLUME 1 • NUMBER 1 • FALL 2011
facial, incisal, and palatal surfaces for
90 seconds at each surface (Fig 39).
Next, the gingival cord was removed
using dental pincers, and excess resin
cement was removed and chipped off
with a no. 12 surgical blade (Figs 40
and 41). Refined finishing and polish-
ing were performed at a subsequent
session. The cementation sequence is
shown in Figs 42 and 43. The final result
is shown in Figs 44 to 50.
Figs 42 and 43 Placement sequence.
Figs 40 and 41 Removal of the compression cord and scraping of the polymerized resin cement
with a surgical blade.
Figs 38 and 39 Removal of excess resin cement with a spatula, followed by light curing.
ALMEIDA E SILVA ET AL
76THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
Figs 44 to 50 Final result.
ALMEIDA E SILVA ET AL
77VOLUME 1 • NUMBER 1 • FALL 2011
DISCUSSION
To optimize the longevity of all-ceramic
crowns and veneers on anterior denti-
tion, the clinician must have a thorough
understanding of all patient-related fac-
tors, the quality of the remaining tooth
tissue, and the proper ceramic system
for the individual situation.5,16,17
Patient-related factors
Several patient-related factors can in-
fluence the survival of crowns and ve-
neers. As with any restorative approach,
patients with high caries activity do not
respond well to treatment because of
the high incidence of secondary caries,
especially if the preparation margins
are localized on dentin.28,29 For these
patients, any attempt to restore the an-
terior dentition with all-ceramic crowns
and veneers should only be made if
preventive and monitoring measures
have been carried out.30
Age matters. The longevity of all-
ceramic restorations can be compro-
mised in individuals over the age of
60.18 There may be an increased load
due to the lack of posterior dentition,
reduced salivary flow resulting from
the use of medication, and periodontal
problems that can weaken the stability of
the tooth. Because enamel thickness di-
minishes over time, ceramic restorations
in elderly patients also do not perform
as well because the cervical area of the
tooth may have little or no enamel.18,31
Root dentin exposure is common,32 and
thus the preparation margins are usually
localized on dentin, which is related to
microleakage incidence.33 Due to these
factors, extra attention and strong moni-
toring must be conducted for elderly
patients with all-ceramic restorations.
Patient compliance with the clinician’s
recommendations is also particularly
important in such cases.
Remaining tooth tissue
The amount and quality of remaining
tooth tissue is an essential factor when
choosing between all-ceramic crowns
and veneers in the anterior dentition.
During elaboration of the treatment
plan, the clinician must verify whether
the tooth is endodontically treated or
vital. If the tooth is nonvital, the need for
placement of intraradicular posts must
be evaluated, and the clinician should
bear in mind that a minimum of 1 mm
of sound dentin must be maintained
circumferentially as ferrule design af-
ter post placement.34 The presence
of darkened substrate is common for
nonvital teeth, and an extra reduction
of approximately 2 mm may be re-
quired to provide room for an esthetic
restoration.35,36 All-ceramic crowns
are superior to veneers for nonvital
teeth because they provide increased
strength, retention, esthetics, and lon-
gevity.35–37 However, stability of the
endodontically treated abutment tooth
can be diminished by the large amount
of tooth structure removed.5,6,37
Ceramic veneers should only be
chosen when bonding is a completely
feasible option, which means the more
enamel the better. The tooth prepara-
tion should be confined primarily with-
in the enamel shell or should display
a substantial (50% to 70%) enamel
ALMEIDA E SILVA ET AL
78THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
area, especially at the preparation
margins.33,38 Debonding of ceramic
veneers has been reported to occur
when dentin comprises 80% or more
of the tooth substrate. In contrast,
debonding is highly unlikely when a
minimum of 0.5 mm of enamel remains
peripherally.13,33,38 Therefore, to avoid
microleakage and secondary caries, it
is crucial that the preparation margins
are bound by enamel and do not end in
composite resin fillings.18,39 Moreover,
partial adhesion to dentin or to exten-
sive composite resin restorations and
high load during static and/or dynamic
occlusion increase susceptibility to ce-
ramic fracture.18 If dentin is the main
bondable substrate or if there are ex-
tensive Class III and IV composite resin
restorations whose dimensions extend
beyond the crown, all-ceramic crowns
should be the first restorative choice.
Ceramic system
In a recent review conducted by Della
Bona and Kelly,6 it was concluded that
for veneers and crowns for single-rooted
anterior teeth, clinicians may choose
from any of the all-ceramic systems
available. However, the choice of ce-
ramic system is highly dependent on
the type of restoration (crown or ve-
neer), type of cementation (adhesive or
traditional), and esthetic and functional
demands.
Ceramic is particularly well suited for
veneer restorations and should be pri-
marily used with an additive approach
to restore missing enamel. Therefore, it
is paramount that the ceramic system
allows for surface treatment by etching
with hydrofluoric acid followed by silani-
zation prior to bonding to the tooth sub-
strate.13,36 Further, since esthetics is of
primary concern for the anterior denti-
tion, an adequate ceramic system for
veneers should have a relatively trans-
lucent core for the ceramist to build in
color intrinsically. Leucite glass-ceramic
and traditional feldspathic ceramic are
the two systems that best meet such
requirements.5,6,10,36
For all-ceramic crowns, a broader
range of systems can be used. Leu-
cite glass-ceramic and lithium-disilicate
glass-ceramic (IPS e.max, Ivoclar Vi-
vadent) are suitable for cases in which
adhesive bonding is possible. Leucite
glass-ceramics especially rely on the
bond strength between tooth and ce-
ramic and provide good esthetics with
proven longevity.5,6,12,20 Ceramics that
cannot be etched and bonded, such as
alumina- and zirconia-based ceramics,
are known as high-strength all-ceramic
materials due to their improved physi-
cal properties. These are best used in
patients with high functional or parafunc-
tional loads. On the other hand, such ce-
ramics present inferior esthetic features
compared to glass-ceramics. Alumina
and zirconia systems are recommended
for cases in which adhesive cementation
is not feasible.5,6 These systems, along
with monolithic lithium-disilicate crowns
for the posterior dentition, can be con-
ventionally luted with glass-ionomer or
zinc-phosphate cements, which are
less technique-sensitive than adhesive
cementation.32,40,41 Table 1 summarizes
the advantages and disadvantages of
all-ceramic crowns and extended ve-
neers in the anterior dentition.
ALMEIDA E SILVA ET AL
79VOLUME 1 • NUMBER 1 • FALL 2011
Critical discussion of case report
Some specific aspects of the illustrated
case report should be discussed. Leu-
cite glass-ceramic was the material of
choice due to the possibility of adhe-
sive cementation since all vital teeth
displayed a sufficient amount of enam-
el. Even the preparation margins of the
nonvital teeth were totally bounded by
enamel. Finally, leucite glass-ceramic
has proven long-term results for both
crowns and extended veneers.5,6,10,20
Although the restorations can be con-
sidered esthetically successful overall,
a subtle value mismatch is evident be-
tween the maxillary right lateral incisor
and the remaining restorations. This
value discrepancy was not noticed dur-
ing try-in, most likely because the final
chromatic result of the cured resin ce-
ment can be different from that achieved
with the homologous glycerin-based
try-in paste.42 The value mismatch
might have been caused by a lack of
ceramic thickness due to insufficient
facial reduction during preparation.
Since extra reduction of endodontically
treated teeth is not recommended,43
the use of a lithium-disilicate glass-
ceramic system with adequate mask-
ing power (IPS e.max Press LT or MO)
could be an alternative to overcome the
insufficient masking ability of the leu-
cite glass-ceramic. Lithium-disilicate
glass-ceramic provides better strength
and responds better chromatically to
small thicknesses than does leucite
glass-ceramic in cases with discolor-
ed abutment teeth.5,44,45 If lithium-
disilicate glass-ceramic is selected to
mask the discolored abutment tooth,
the authors recommend restoring all
other teeth with the same system to
achieve a harmonic esthetic outcome.
Table 2 summarizes the indications for
all-ceramic crowns and extended ve-
neers in the anterior dentition.
Table 1 Advantages and disadvantages of all-ceramic crowns and extended veneers in anterior dentition
All-ceramic crowns Extended veneers
Tooth structure removal – +
Restoration stability + −
Abutment stability − +
Risk of discoloration due to abutment tooth + − / +*+ = recommended; – = not recommended*If translucent glass-ceramic is employed.
ALMEIDA E SILVA ET AL
80THE AMERICAN JOURNAL OF ESTHETIC DENTISTRY
CONCLUSIONS
Restoring the anterior dentition with ce-
ramic is an excellent approach if the
correct treatment plan is developed.
Several patient-related and material
factors can determine the success or
failure of all-ceramic crowns and ve-
neers. Neglecting even a single step
of the restorative process can severely
compromise the treatment outcome.
ACKNOWLEDGMENTS
Special thanks to Wilmar Porfírio for manufacturing the ceramic restorations. The first author was supported by the Brazilian Federal Agency for Support and Evalu-ation of Graduate Education (CAPES) (grant no. BEX 2354101).
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