ceramic adhesive restorations and biomimetic dentistry: tissue … · 2014. 8. 15. · and...
TRANSCRIPT
CLINICAL RESEARCH
354THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Correspondence to: Gil Tirlet
234 Boulevard Raspail, 75014 Paris, France. Tel : +33 43204130: E-mail: [email protected]
Ceramic adhesive restorations
and biomimetic dentistry:
tissue preservation and adhesion
Gil TirletSenior Lecturer, Department of Prosthetic Dentistry, Faculty of Dental Surgery,
Paris Descartes University, Paris, France
Private Practice Specializing in Esthetic Dentistry, Paris, France
Hélène CrescenzoCeramic Dental Technician, Espace Diamant, Cogolin, France
Dider CrescenzoCeramic Dental Technician, Espace Diamant, Cogolin, France
Panaghiotis Bazos, DDS
Emulation, Athens, Greece
TIRLET ET AL
355THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Abstract
Thanks to sophisticated adhesive tech-
niques in contemporary dentistry, and the
development of composite and ceramic
materials, it is possible to reproduce a
biomimetic match between substitution
materials and natural teeth substrates.
Biomimetics or bio-emulation allows for
the association of two fundamental par-
ameters at the heart of current therapeu-
tic treatments: tissue preservation and
adhesion. This contemporary concept
makes the retention of the integrity of
the maximum amount of dental tissue
possible, while offering exceptional clin-
ical longevity, and maximum esthetic
results. It permits the conservation of
the biological, esthetic, biomechanic-
al and functional properties of enamel
and dentin. Today, it is clearly possible
to develop preparations allowing for the
conservation of the enamel and dentin in
order to bond partial restorations in the
anterior and posterior sectors therefore
limiting, as Professor Urs Belser from
Geneva indicates, “the replacement of
previous deficient crowns and devital-
ized teeth whose conservation are justi-
fied but whose residual structural state
are insufficient for reliable bonding.”1
This article not only addresses ceramic
adhesive restoration in the anterior area,
the ambassadors of biomimetic dentist-
ry, but also highlights the possibility of
occasionally integrating one or two res-
torations at the heart of the smile as a
complement to extensive rehabilitations
that require more invasive treatment.
(Int J Esthet Dent 2014;9:354–369)
355THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
CLINICAL RESEARCH
356THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Introduction
Biomimetics is the reproduction or copy
of a model or a standard.2,3 More pre-
cisely, the notion of biomimetics consists
of reproducing and artificially imitating
natural systems in living organisms.
Biomimetics is an emerging interdisci-
plinary field in materials science, engi-
neering, and biology, in which lessons
learned from a biological standard form
the basis for novel technological ma-
terial innovation. It involves the inves-
tigation of both structures and physi-
cal functions of biological composites
of engineering interest, with the goal of
designing and synthesizing new and
improved materials.
The term bio-emulation was intro-
duced as a new expression for the dis-
cipline of dentistry, corresponding to
the reproduction of the natural model
via spatial, structural and optical histo-
anatomic emulation.4 In contemporary
dentistry, the concept of biomimetics
is a true synonym for natural integra-
tion,3 meaning biological, biomechan-
ical, functional and esthetic integration,
which closely mimicks the physiological
behavior of the natural tooth.3,5
Because of sophisticated adhesive
techniques and the progress that has
been made in ceramic adhesives, today
it is possible to produce a biomimetic
match between esthetic substitution ma-
terials and the anatomical substrates of
the natural tooth.
Biomimetics associates two funda-
mental attributes at the core of modern
care: tissue preservation and adhesion.
It Is undisputable that this concept has
had the most profound effects on the
paradigms of modern restorative den-
tistry. As Pascal Magne points out,3 the
concept of modern biomimetics can
be summarized into three distinct, but
closely linked, categories:
Observation of nature, biology, its
role, its mechanical behavior, and
its optical characteristics
Respect of nature in preparing a
minimal dental tissue
Reproduction of nature using
adhesion and modern biomaterials
(composites and ceramics)
Reference model:
the natural tooth
Natural teeth are the physiological result
of a subtle association between enam-
el, rigid and breakable, and the dentin,
resilient and flexible. From a functional
point of view, dentin cannot exist if an
enamel shell does not cover it.3 These
two tissues are associated and joined
together by an incredibly rich anatom-
ical interface called the dentoenamel
junction (DEJ). It is capable, through
the intermediary of large fasces of col-
lagen fibers to deflect and to impede the
spreading of crevices in the enamel due
to plastic deformation.3
Thus, due to its role as a buffer and
stress absorber, it is a reference model
for adhesive systems and polymer adhe-
sives used for reinforcing the biomech-
anical integrity of dental crowns5 (Fig 1).
Substitution model: adhe-
sive ceramic restorations
The replacement of the enamel shell with
a soft material, such as composites, only
TIRLET ET AL
357THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
allows for a partial restitution of the rigid-
ity of the dental crown. From this point of
view, the choice of ceramics allows for a
faithful restitution of this rigidity.2,3
Furthermore, aging is synonymous
with the volumetric reduction of the
enamel layer, and thus, an increase in
the flexibility of the tooth due to its de-
creasing rigidity.
The restitution of the original volume
of the enamel thus represents an esthet-
ic as well as a biomechanical approach.
Adhesive bonding technology and ce-
ramics have the ability to reverse and
resist the effects of aging on teeth.3 For
the aforementioned reasons, a rational
selection of restorative materials proves
to be essential.
Another essential point is the mater-
ial to combination ratio. The CER/COMP
ratio should ideally be superior to 3. This
is of great importance, due to the con-
tracting of polymers in the bonding com-
posite, and the differences in thermal
expansion between the two materials.
Thus, for an average bonded joint den-
sity of 100 mm, the ideal density of the
veneer should be a minimum of 300 mm.
A ratio inferior to the critical level of 3 will
have important consequences in terms
of potential failure rates of the restoration
(fissures and cracks in the ceramic ad-
hesive restoration).3
Therefore, the changing of paradigms
must be accompanied by the progres-
sive passage from full coverage ce-
ramic restorations to partial coverage
ceramic restorations.6 The latter may
take the form of inlays, onlays, overlays,
veneerlays in the posterior sector and
in veneers, half veneers or chips in the
anterior sector.6 The scope of this article
aims to address the various partial cov-
erage ceramic adhesive restorations in
the anterior sector.
The recognition of the importance of
the integrity of dental tissue is the focus
of biomimetics. An analysis of these last
points is critical following the removal of
a prior restoration, trauma, or the elimi-
nation of a decayed lesion, in order to
economize hard tissue removal.
This analysis must be conducted in
conjunction with the occlusion scheme
at hand, with emphasis on the presence
or absence of horizontal and/or oblique
stress, the latter being the most detri-
mental for teeth (eg, supraocclusion,
dental wear, parafunctions, poor align-
ment).
Composites – in part due to their in-
herent low elastic modulus – appear to
be challenged by mechanical stresses,
both masticatory and occlusal, when
replacing large anterior coronal defi-
ciencies.7 In conjunction, the thermal
conduction mismatches them, and hy-
groscopic expansion renders them even
Fig 1 View of the natural incisors photographed
in transmission, allowing for the observation of dif-
ference in thickness between the enamel (of the cer-
vical on the edge of the incisor) and the dentin, as
well as the amelodentin junction.
CLINICAL RESEARCH
358THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
more vulnerable over time.7 Additionally,
composites require relatively frequent,
meticulous clinical maintenance in or-
der for them to reach their approximate
10-year life expectancy. Swift, with a pan-
el of experts, concluded that the more
complex the restoration, the shorter the
longevity.8 This statement partially con-
firms the deficiency in stiffness attain-
ment by composite, in order to recover
the original rigidity – that of enamel.
Thus today, in our clinical approach,
the stratification of anterior composites
may increasingly give way to partial cov-
erage ceramic adhesive restorations in
cases of large anterior coronal deficien-
cies, which are most often required in
adults in situations where stable high
esthetic requirements and longevity are
demanded.9-11 These types of restor-
ations embody the conservative doc-
trine, undisputedly placing them as the
therapeutic ambassador for modern
biomimetic dentistry.
This article will illustrate four clinical
cases, three of which deal with vital teeth
and one with a non-vital tooth. The clinic-
al situations have been chosen in order
to demonstrate that beyond the biomi-
metic approach (the chosen path for al-
most 20 years of “French” conservative
and esthetic dentistry, today considered
to be modern), the practitioner must de-
ploy all modern therapeutic possibilities
in order to not only treat the damaged
tooth or teeth but also take into consider-
ation the targeted esthetic requirements
of their patients, particularly in regards
to the therapeutic gradient.12
Case studies
Case 1
A 65-year-old woman, concerned about
her central upper incisors, presented for
an esthetic consultation. Her chief com-
Fig 2 Initial situation. Fig 3 Clinical view of preparation with post and
core (POM, Ivoclar/Vivadent on 12) and Partial
preparations with conservation of maximum enamel
on 11 and 21. The thickness of the preparation was
between 0.4 and 0.6 mm thus creating an optimal
enamel surface for bonding.
TIRLET ET AL
359THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Fig 4 Preparation
after curing of the ad-
hesive system on 11.
Fig 6 Final result at 1-week follow-up. Note the
biological and morphological appearance. This
view perfectly illustrates the biomimetic concept
using the “enamel substitution,” allowing the total
recovery of the intrinsic strength of the teeth.
Fig 5 View of the
ceramic adhesive
restoration at bond-
ing. The adhesive
used was Optibond
Solo plus (Kerr).
Fig 7 One-month follow-up with contrastor.
plaint was that she disliked the shape
and the position of 21 and 11 (Fig 2).
The following treatment plan was pro-
posed to the patient: the rehabilitation of
her smile by a new crown on 12 (she pre-
sented gingival inflammation induced
by the actual prosthesis’ overcontour),
as well as two resin-bonded partial-cov-
erage ceramic restorations. Tooth 22
dictated the esthetic outcome and guid-
ed this minimally invasive rehabilitation
(Figs 3 to 7). No crown lengthening in or-
der to correct the gingival margin archi-
tecture was performed since the patient
preferred to avoid additional surgery.
Although a lack of symmetry among the
anterior teeth can be observed, the pa-
tient’s smile is still harmonious and natu-
ral (Figs 8 to 11).
CLINICAL RESEARCH
360THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Case 2
A 17-year-old patient consulted in or-
der to re-evaluate previous endodontic
work on tooth 21 that was completed 3
years previously following a trauma – it
was discolored due to a root canal. The
therapeutic choice in this case only took
into consideration the biological, bio-
mechanical and esthetic rehabilitation
of tooth 21 per the patient’s esthetic re-
quest (Fig 12).
The composite restoration was fixed
with a stainless steel post and core,
which characterizes conventional den-
tistry based on mechanical concepts
(Fig 13). An initial radiograph was taken,
which displayed the high quality of the
endodontics (Fig 14). The composite
restoration and the stainless steel post
and core were removed (Fig 15).
A dental dam was applied. The crown
presented very good residual tissue. After
sandblasting, etching and the placing of
Fig 8 One-year follow-up (with two lateral softbox).
At this time, we can notice a little gingival injury (me-
sial side on 12) caused by severe tooth brushing.
Fig 10 One-year follow-up: left lateral view of the
smile. The asymmetry in the shape and the dental
composition remains the principal key to the smile’s
expression.13
Fig 9 One-year follow-up. Image taken with con-
trastor (with two lateral soft boxes).
Fig 11 One-year follow-up: right lateral view of
the smile.
TIRLET ET AL
361THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
the adhesive system, flow micro hybrid
composite was applied at the base of
pulpal chamber preceding the placement
of the restoration composite (UD2, Enamel
HRi, Mycerium). A post was not necessary
in this situation due to the important ferrule
effect – the result of the conservation of
residual tissue (Fig 16).
The ceramic adhesive restoration
(e.max MO1, Ivoclar Vivadent) on the
buccal side was prepared, increasing
the enamel surface. A metallic matrix was
Fig 13 The composite restoration is fixed with a
stainless steel post and core.
Fig 15 Clinical view following the removal of the
composite restoration and prior to the removal of the
stainless steel post and core.
Fig 12 Initial clinical situation.
Fig 14 An initial radio-
graph exhibits the high
quality of the endodontics.
Fig 16 Clinical view of 21 with dental dam.
CLINICAL RESEARCH
362THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Fig 17 Preparation of the ceramic
adhesive restoration on the buccal
side.
Fig 19 Final occlusal view with the palatal exten-
sion going beyond the cingulum.
Fig 21 View of the
ceramic adhesive res-
toration at the moment
of bonding. The adhe-
sive used was Optibo-
nd Solo plus.
Fig 18 Completion of the buccal
preparation with an Acteon/Satelec
insert.
Fig 20 View of the Emax MO1 ce-
ramic adhesive restoration.
Fig 22 Radiograph fol-
lowing bonding that dem-
onstrates the perfect fit
and seal of the restoration.
TIRLET ET AL
363THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
connected to a plastic corner (Fender
wedge, Pred), which protected the ad-
jacent teeth. The buccal preparation
was completed with an Acteon/Satelec
insert for finishing two diamond grits: 76
microns and 46 microns to perfectly fin-
ish the margins (Figs 17 to 19). The ce-
ramic adhesive restoration was bonded
(Figs 20 and 21) and a radiograph at-
tested for a good adaptation (Fig 23).
Figures 23 to 26 show the final result and
biomimetic integration after bonding.
Figure 27 shows the clinical result at the
3-year follow-up.
Fig 24 Black and white picture to appreciate
brightness of the single restoration.
Fig 26 Smile integration.
Fig 23 Clinical view one week after bonding.
Fig 25 One-week follow-up (with contrastor).
Fig 27 Three-year follow-up.
CLINICAL RESEARCH
364THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Case 3
A 34-year-old man had a large compos-
ite on the left central incisor (21). The
patient refused proposed orthodontic
treatment. He preferred to find another
esthetic solution to restore his tooth. The
suggested treatment consisted of re-
placing the composite restoration with
a ceramic bonded partial restoration
(Fig 28).
Fig 28 Initial situation.
Fig 29 The clinical view of the preparation for the
ceramic half veneer. Excellent tissue preservation
can be observed.
Fig 31 The preparation following placement of
the dam before bonding.
Fig 30 The final step in preparation with diamond
ultrasonic insert.
Fig 32 Ceramic half-veneer
restoration before bonding.
TIRLET ET AL
365THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
When the preparation for the ceramic
half veneer was carried out, excellent
tissue preservation could be observed.
The tooth was then prepared with a di-
amond ultrasonic insert (Fig 29 to 31).
A rubber dam was applied before the
bonding of the ceramic half-veneer
(Figs 31 and 32). Figure 33 and 34
(1 year and 6 months follow-up with two
lateral soft boxes) shows the final biomi-
metic results.
Case 4
A 35-year-old woman came to our prac-
tice because of a bike trauma (Fig 35).
We diagnosed crown fractures from me-
dium to severe on teeth 11, 21 and 22
and also had to plan endodontic treat-
ment. A temporary composite build
up was performed on the three teeth.
Preparations were guided by mock-ups
(Figs 36 to 38). Figures 39 to 43 show
the biomimetic results. Figure 44 shows
a radiograph to control apical healing
Fig 33 Final biomimetic result.
Fig 35 Initial situation: emergency.
Fig 34 Final situation (with two lateral soft box).
Fig 36 Preparation driven by mock-up.3,14 The
wax-up permitted the creation of a mock-up with
a silicone index use during the preparation stage.
CLINICAL RESEARCH
366THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Fig 39 Final view: one-week follow-up after
bonding.
Fig 41 Polarized view with Polar_eyes (Emulation).
Fig 38 View of four preparation for ceramic ad-
hesive restorations. No post or crown in this case
even on non-vital teeth and preservation of maximal
enamel.
Fig 37 Mock-up just after preparation. (Luxatemp
Star, DMG)
Fig 40 Black and white picture to appreciate
brightness of the four restorations.
Fig 42 Lateral view of smile: right side.
TIRLET ET AL
367THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
Fig 45 Buccal view at one-year follow-up. Note
the biomimetic integration and especially the bio-
logical integration with the gum.
Fig 44 Radiograph with complete apical healing
on four anterior teeth.
Fig 43 Intra buccal view: right side.
Fig 46 Buccal view at two-year follow-up (with
two lateral soft boxes).
and demonstrates a lack of Post and
core (Endodontic treatment: Dr Anne
Laure Simon, Paris). Figures 45 and 46
show the results at a two-year follow up
with two lateral soft boxes).
Conclusion
In choosing partial coverage ceramic
adhesive restorations, biomimetics per-
mits the imitation of the biological, es-
thetic, biomechanical and functional
properties of enamel and dentin.
Provided there is diligent implemen-
tation and management of modern
dental technology, dental adhesive sys-
tems have proven to be reliable over
time, thus imparting a secure bond
between the tooth and the restoration.
Nonetheless, deep knowledge of bio-
mechanical principles and techniques
of conservative tooth preparation are
essential to create optimal conditions
CLINICAL RESEARCH
368THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
for the implementation of a favorable
oral restitution.
The timelessness, the ideal surface
characteristics and biomechanical inter-
action that are ensured by a high per-
formance dynamic bond to the tooth as
a whole, classify ceramics as the ideal
restorative materials and the best choice
in terms of esthetic satisfaction. Optimal
rigidity in delicate areas, excellent chew-
ing capacity, biocompatibility with peri-
odontal tissues, combined with excel-
lent continuity between the material and
enamel after bonding, bestows them
with the ability to act as a true enamel
replacement. It is important, however,
to be attentive in order to conserve the
maximum amount of enamel by imple-
menting contemporary protocols, such
as preliminary wax-ups, mock-ups and
volumetric driven matrix guided reduc-
tions.
Partial coverage ceramic adhesive
restorations can be utilized as the re-
storative treatment modality in a variety
of clinical cases, vital and/or non-vital
teeth provided that fundamental bond-
ing requirements can be met.
The goal of this article is not only to
showcase the said restorative modality
in the anterior dentition, as a strong pro-
ponent of biomimetic dentistry, but also
to highlight the possibility of achieving
a seamless integration of restorations at
the heart of the smile as a contrast to ex-
tensive and invasive rehabilitations that
would require more invasive treatment.
Today the possibility exists to estheti-
cally reconstruct teeth while preserving
tissue. It is important to take this major
evolution of biomimetics into considera-
tion in our respective practices.
In conclusion, Pascal Magne at the
Brussels Conference, December 2011,
perfectly illustrated this concept: “Get
bonded, stay bonded.”15
Acknowledgments
I would like express my most sincere
gratitude to my advisor Professor Michel
Degrange for all that he has taught me,
both clinically and scientifically, and
to express my utmost admiration for
all that he has contributed to adhesive
dentistry throughout his career and life. I
would also like to warmly thank my other
mentor Dr Pascal Magne for all that he
has brought me over the past 20 years
through his clinical and scientific work.
His place at the summit of contemporary
dentistry remains for me an absolute ex-
ample and reference.
I would also like thank to my “brother”,
Dr JP Attal for sharing in this exceptional
human and professional adventure at
the university and the hospital, as well
as through GRF’s biomimetic workshops
over the past seven years.
I also extend my warmest thanks to
my new professional “family,” the Bio-
Emulation Group, through whose daily,
challenging exchanges I continue to
progress ever more.
I finally thank Maris Harrington for her
invaluable help in the writing and editing
of this article.
TIRLET ET AL
369THE INTERNATIONAL JOURNAL OF ESTHETIC DENTISTRY
References
1. Belser U. Changement de
paradigmes en prothèse
conjointe. Réalités Cliniques,
2010 ; vol 21 : 79-85.
2. Magne P, Douglas WH.
Rationalization of esthetic
restorative dentistry based
on biomimetics. J Esthet
Dent 1999;11:5–15.
3. Magne P, Belser U. Restau-
rations Adhesives en Céram-
ique: Approche Biomimé-
tique. Paris: Quintessence
International, 2003.
4. Sarikaya M. An introduction
to biomimetics: a structural
viewpoint. Microsc Res Tech
1994;27:360–375.
5 Bazos P, Magne P. Bio-emu-
lation: biomimetically emulat-
ing nature utilizing a histo
anatomic approach; struc-
tural analysis. Eur J Esthet
Dent 2011;6:8–19.
6. Lafargue H. Onlays sans
préparation et minifacettes.
Place de la dentisterie adhé-
sive dans les thérapeutiques
esthétiques et fonctionnelles.
Réal Clin 2010;21:299–309.
7. Macedo G, Raj V, Ritter AV.
Longevity of anterior com-
posite restorations. J Esthet
Restor Dent 2006;18:310–
311.
8. Swift EJ. Ask the experts. J
Compil 2006;18:310–311.
9. Lasserre JF, Laborde G,
Koubi S, Lafafargue H,
Couderc G, Botti S. Restau-
rations céramiques anté-
rieures (2): préparations
partielles et adhésion. Real
Clin 2010;21:183-196.
10. Friedman MJ. A 15-year
review of porcelain veneer
failure. A clinician’s observa-
tions. Compend Contin Educ
Dent 1998;19:625–630.
11. Fradeani M, Redemagni M,
Corrado M. Porcelain laminate
veneers: 6- to 12-year clinic-
al evaluation. A retrospective
study. Int J Periodont Restorat
Dent 2005;25:9–17.
12. Tirlet G, Attal JP. Le gradient
thérapeutique: un concept
médical pour les traite-
ments esthétiques. Inf Dent
2009;41-42:2561–2568.
13. Ifrate R, Dalloca L. Esthé-
tique: art ou technique ? La
perception, un outil essentiel
pour la connaissance. Real
Clin 2010;21:263–271.
14. Gürel G. Les Facettes en
Céramique: De la Théorie à
la Pratique. Paris: Quintes-
sence International, 2005.
15. Pascal Magne: ‘It should
not be about aesthetics but
tooth-conserving dentistry’.
British Dental Journal volume
213 no. 4 aug 25. 2012.