Article_6_1_6
AESTETHIC DENTISTRY
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS –
Review Article
PART II: ANTERIOR TEETH – LAMINATE VENEERS
Gottfried Schmalz1,2,a* , Marianne Federlin1,b
1
Department of Operative Dentistry and Periodontology, Medicine Faculty, University Hospital Regensburg, D-93052 Regensburg, Germany
2
Department of Periodontology, School of Dental Medicine (ZMK Bern), University of Bern, CH-3010 Bern, Switzerland
DMD, PhD, Professor, Dr hc mult.
a
DMD, PhD, Professor
b
ABSTRACT DOI: https://doi.org/10.25241/stomaeduj.2019.6(1).art.6
Background: For anterior teeth with large defects or for teeth which need major changes in OPEN ACCESS This
color, shape or size, laminate veneers are a highly esthetic and comparatively tissue conservative is an Open Access article
treatment option within a large group of other therapeutic measures. The survival rates of under the CC BY-NC 4.0
license.
laminate veneers are > 90% over 10 years and in the range of full coverage crowns. For patients
Peer-Reviewed
with heavy bruxism and/or small clinical crowns the longevity may be reduced. Article
Objective: to review the main guidelines for dental treatment using laminate veneers.
Citation: Schmalz G, Federlin
Data Sources: dental literature (Web of Science, PubMed, Google Scholar) about laminate M. Partial ceramic crowns:
veneers between 1998 and 2019. Esthetic and tissue conservative
restorations – Part II: anterior
Study Selection: articles, reviews and textbooks about laminate veneers were selected to obtain teeth – Laminate Veneers
the most relevant information. Stoma Edu J. 2019;6(1):43-54
Data Extraction: all data evidence-based about laminate veneers technique were extracted. Received: March 11, 2019
Data Synthesis: all data considered important and relevant for the laminate veneers technique Revised: March 25, 2019
Accepted: March 27, 2019
were presented step by step in a coherent and concise way. Published: March 29, 2019
The conclusions were: *Corresponding author:
• Preparation should be as conservative as possible (0.3 – 0.5 mm cervical-buccal reduction). Professor Dr. Dr. h.c. mult.
• Special methods for impression taking and for temporization should be applied. Gottfried Schmalz, DDS, PhD,
Department of Operative
• The ceramic material needs to have optimal esthetic properties including adequate Dentistry and Periodontology,
translucency. University Hospital Regensburg,
Franz-Josef-Strauss Allee 11,
• The choice of the luting material is based on optimal bonding (etch & rinse, SE). Solely light D-93052 Regensburg, Germany,
curing luting composite materials or flowable composites can be used for optimal and long- Tel: +49-941-944-4980,
Fax: +49-941-944-4981,
lasting esthetics for ceramic thickness of up to 1 mm. e-mail: gottfried.schmalz@
ukr.de
• In order to protect the laminate veneers against parafunctional forces during night sleep a
protective splint (night guard) is recommended. Copyright: © 2019 the
Editorial Council for the
Keywords: Laminate veneers; dental ceramic; esthetics; dental light curing; flowable composite Stomatology Edu Journal.
resins.
1. Introduction Fig. 1 shows a clinical case, where this technique
For anterior teeth with cavities extending into large has been applied. Such restorations are commonly
parts of the buccal surface and potentially needing named laminate veneers. They impress with optimal
replacement of the incisal edge, the classical esthetics and require less removal of sound tooth
treatment method for many years has been a full tissue than full coverage crowns [1]. Part I of this
coverage crown, either made of resin materials, article [2] focused on the restoration of posterior
ceramics, or combination of metals with (mainly) teeth with partial crowns, here our results over the
ceramics. In anterior teeth with smaller defects, recent 20 years and data from the literature with
major esthetic problems related to color, shape and partial crowns in anterior teeth, i.e. laminate veneers
size have also been reasons for full coverage of such are described. The objective of this article is to
teeth, consequently removing quite large amounts discuss whether this is a reliable treatment option,
of sound tooth hard tissue [1]. However, for a and to which critical points attention has to be paid
number of years, adhesive technology has enlarged in order to achieve a successful treatment outcome.
the spectrum of treatment options. Adhesively
bonded resin-based composites can be used very
successfully in many of such cases. 2. Definition
In more complicated cases, partial crown coverage For anterior teeth, partial coverage (here mainly the
of anterior teeth may be a treatment option, which buccal aspect) of the clinical crown by a restoration
has been successfully used in posterior teeth [2]. is also termed “laminate veneer”. Some authors
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PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
Review Article
(a) (b)
(c) (d)
Figure 1. Restoration of severely discolored teeth with extended composite resin restorations (a); during and after internal bleaching (b,c); restored
with two laminate veneers (d).
distinguish between (1) veneers with no or only a fillings [5]. On tetracycline-stained teeth 99% out of
minor inclusion of the incisal edge and (2) anterior 546 ceramic veneers were in situ after up to 2.5 years
partial crowns with an extended inclusion of the [6]. Also, after longer observation periods (7-year
lingual surfaces [3]. However, this subdivision Kaplan-Meier survival rate) in a prospective clinical
appears somewhat academic and the terms partial study a retention rate between 97.6 and 100% was
crown in anterior teeth or laminate veneers are used reported [7].
synonymously in this review. After 5 years, Aristidis et al. recorded the clinical
performance of ceramic veneers (61 patients)
concerning esthetics, marginal integrity, marginal
3. Longevity discoloration, fracture rate, and patient satisfaction.
A number of clinical studies on the longevity of In this study, 98.4% of the veneers were satisfactory
laminate veneers have been published with varying without intervention and the patient satisfaction
observation times ranging from 40 months to more was very high [8]. After up to 20 years, laminate
than 15 years. Similar to partial crowns in posterior veneers made of silicate glass-ceramic had an
teeth, the clinical survival rates of ceramic laminate estimated survival probability of 93.5% over 10 years.
veneers were rated to be very good and up to 40 Significantly increased failure rates were associated
months more than 93 % of the restorations were with bruxism and non-vital teeth, and marginal
still in situ [4]. As laminate veneers are also used in discoloration was worse in patients who smoked [9].
teeth with existing composite restorations, it was In a prospective study over ten years, ceramic veneers
interesting to analyze if such restorations have a maintained their esthetic appearance. None of the
negative influence on the general outcome for veneers were lost. The percentage of restorations
laminate veneers. Interestingly, no statistically that remained “clinically acceptable” (without need
significant differences had been observed in this for intervention) significantly decreased from an
study [4] between cases with and without composite average of 92% (95 CI: 90% to 94%) at 5 years to 64%
restoration being present. Slight marginal defects (95 CI: 51% to 77%) at 10 years. Most of them could
(16 of 87 veneers) and slight marginal discoloration be repaired, only 4 % needed replacement [5].
at the margins were observed (12 of 87 veneers), but In another long-term study, the clinical performance
no secondary caries or endodontic complications of ceramic laminate veneers bonded to teeth
[4]. However, in another clinical study increased prepared with the use of an additive mock-up and
marginal problems have been reported, when the aesthetic pre-evaluative temporary technique (APT)
ceramic margin was in contact with composite was evaluated over a 12-year period. Briefly, with
44 Stoma Edu J. 2019;6(1): 43-54 http://www.stomaeduj.com
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
sensitivity, and satisfaction with restoration shade at
Review Article
the end of 12 years [10].
In a recent systematic review and meta-analysis,
13 publications have been included. The estimated
overall cumulative survival rate was 89% (95%
CI: 84% to 94%) in a median follow-up period of 9
years. The estimated survival for glass-ceramic was
94% (95% CI: 87% to 100%), and for feldspathic
porcelain veneers, 87% (95% CI: 82% to 93%). It
was not possible to perform a meta-analysis of the
influence of enamel/dentin preparation on failure
rates. Fracture or chipping of the ceramic was the
(a) most frequent complication, providing evidence
that ceramic veneers are a safe treatment option
that preserves tooth structure [11]. Fig. 2 shows an
exemplary case, where laminate veneers had been
controlled after 15 years.
All these results are in the same order of magnitude
as survival data reported for all ceramic full coverage
crowns, e.g. 95.4% - 94.5% after 5 years (reinforced
glass ceramic: Empress) [12] or 94.8% or more in situ
after up to 10 years (Li-disilicate) [13,14].
Problems may occur in teeth with small clinical
crowns, when the size of the teeth shall be enlarged
(b) and the area for bonding becomes comparatively
small. Heavy bruxism is generally considered to be
a contraindication for laminate veneers [9], because
strong horizontal forces (1) endanger the bond of
the veneer to the tooth structure and (2) may lead
to a fracture of thin incisal ceramic. Discoloration of
the margins and wear of the luting material are also
reported in the literature [5], especially for smokers
[9]. The accuracy of fit with the aim of a small primary
marginal gap, which has to be filled with the luting
material, will reduce the wear. Furthermore, the
correct choice and use of the luting material seems
(c) to be an important factor (see below). The above
Figure 2. Restoration of severely discolored and abraded teeth (a) with mentioned meta-analysis showed the following
laminate veneers (b) and control after 15 years (c); slight marginal
discolorations are visible.
rates: debonding: 2% (95% CI: 1% to 4%); fracture/
chipping: 4% (95% CI: 3% to 6%); secondary caries:
the APT technique the dentist creates an immediate 1% (95% CI: 0% to 3%); severe marginal discoloration:
mock up from composite resin in the patient’s 2% (95% CI: 1% to 10%); endodontic problems: 2%
mouth, in order to design the outline of the veneers (95% CI: 1% to 3%); and incisal coverage odds ratio:
together with the patient. Then, this is transferred 1.25 (95% CI: 0.33 to 4.73) [11]. For non-vital teeth
to the technician who produces a silicone index there is a slight chance for further discoloration
for further treatment. The preparation is performed after the application of laminate veneers, which was
in conjunction with this index, allowing for a reported to result in minor esthetic problems [5].
minimally invasive approach. Sixty-six patients were Thus it can be concluded, that ceramic partial
restored with 580 porcelain laminate veneers. The crowns/laminate veneers are a reliable treatment
technique used for diagnosis, esthetic design, tooth method in anterior teeth. They show survival rates,
preparation, and provisional restoration fabrication, which are in the same order of magnitude as for
was based on the APT protocol. Over 80% of tooth full coverage crowns, but more sound tooth tissue
preparations were confined to the dental enamel. is conserved. However, special techniques must be
Over 12 years, 42 laminate veneers failed, but followed in order to keep failures at a minimum.
when the preparations were limited to the enamel,
the failure rate resulting from debonding and
microleakage decreased to 0%. Ceramic laminate 4. Which Ceramic?
veneers presented a successful clinical performance In part I of this review the different ceramics available
in terms of marginal adaptation, discoloration, for ceramic partial crowns have been described
gingival recession, secondary caries, postoperative and the reader is referred to this publication [2].
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PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
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In anterior teeth, mechanical properties do not thickness in preparations with and without different
Review Article play such a great role as in posterior teeth; instead, methods of incisal coverage. After dynamic loading
esthetic considerations are of major concern. Esthetic simulating 5 years of service, a significantly higher
properties are mainly related to the translucency of number of palatal cracks was found in ceramic with an
ceramics [15], which is defined as the extent to which extended palatinal preparation design (see also Fig.
light is diffused rather than reflected [16]. Extensive 4). Such cracks were found in areas of maximum stress
experiences exist with feldspathic ceramics and concentration in natural teeth [23] and the results are
glass ceramic reinforced with leucite, less with in line with FEA analyses from Magne and Douglas
(monolithic) lithium disilicate reinforced silicate [24] showing highest stress concentrations at the
ceramics, some of which are less transparent than extended palatinal chamfer areas. Therefore, if such
glass ceramics [17]. Recently, translucent lithium- a preparation design is chosen, ceramic thickness
disilicate ceramic with two levels of translucency at the palatinal site should be increased (for leucite-
has been marketed, a high and a low translucency reinforced glass ceramic) to more than 0.5 mm. In vitro
material [16]. For full coverage crowns few clinical studies have also shown that the fracture resistance of
studies with (monolithic) lithium disilicate ceramics laminate veneers with 0.5-mm preparation depth was
are available and they report positive results [14,18]; greater than that of the 0.3-mm and 1-mm preparation
for laminate veneers, clinical data using this ceramic depth [25], which, however, for the 1 mm thickness
are scarce. Zirkonia ceramics are comparatively may have been due to the fact that the preparation
opaque and are presently not used for laminate mainly exposed dentin. It is generally accepted that
veneers [19]. With newer polymer containing/-based the preparation should be kept – as much as clinically
materials, which have to be milled, little clinical possible – to the enamel as bonding substrate and
experience with laminate veneers exists for the time over-contour of the veneer should be avoided. On
being. the other side, an adequate material thickness is
Which ceramic to select? Over the recent 25 years the needed for masking the discolored hard tooth tissues
authors used mainly leucite reinforced glass ceramics, and to give the technician freedom for the esthetic
which were pressed and then individualized. If the design [26,27]. Form those and other studies it can be
restorations are produced in a dental laboratory, an concluded that although a ceramic thickness of 0.3
experienced technician and a close communication – 0.5 mm has generally been recommended [26], it
between dentist and technician are essential. It is has to be adjusted to the individual clinical situation.
advisable that the technician should be present Magne and Belser [20] have therefore recommended
when selecting the tooth color and designing that in the cervical area the ceramic thickness should
the shape of the veneers. Finally, the color of the be 0.3 – 0.5 mm, in the middle third around 0.7 mm
prepared tooth has to be taken into account. and at the incisal coverage at least 1.5 mm.
A completely different approach uses prefabricated
veneers from ceramics (recently also from composite
5. Which Preparation? resins), which are adhesively luted to the unprepared
5.1. Ceramic thickness or only slightly roughened enamel [28]. This is meant
In contrast to posterior teeth, the thickness of the as a one visit, cost-effective alternative [28]. Reports
ceramic is not mainly determined by the masticatory on clinical outcome are scarce.
forces, but by esthetics and the idea of tooth
substance conservation [20]. The determination of the 5.2. Enamel vs. dentin
appropriate ceramic thickness has, nevertheless, to As mentioned above, the bond strength of laminate
take biomechanical aspects into consideration, which, veneers to enamel is generally regarded to be higher
however, are different in the anterior region of the than that to dentin [29], although it depends on
mouth compared to posterior teeth, which have been the adhesive system used. However, it has been
described in part I [2]. Obviously, fracture resistance recommended that the ideal preparation for laminate
of ceramic will depend, beside other factors, upon veneers should remain within enamel [30]. In a clinical
the ceramic thickness [21]. Recently, Costa et al. [1] study longevity of veneers with a preparation solely in
performed in vitro studies using FEA (finite element enamel was better than in dentin, but the difference
analysis) comparing 0.3 and 0.8 mm thick lithium was not statistically significant [26]. A special problem
disilicate ceramic used for veneering human canines. is the extension into the cervical dentin for esthetic
They found that 0.8 mm thickness was associated reasons. In vitro studies have shown that similarly
with better stress distribution and lower tensile favorable marginal adaptations of ceramic veneers
stress concentration than 0.3 mm thickness; thus to dentin and enamel can be achieved using high
the authors concluded that higher ceramic thickness viscosity luting composites with their corresponding
may contribute to higher longevity, although the adhesive systems [31]. Cötert et al. however reported
maximum stress values did not overcome the that a supragingival preparation had a significantly
material’s limit to failure. Furthermore, Stappert et positive effect on the overall survival rate [26].
al. [22] investigated the fracture behavior of veneer Furthermore, iso-or supragingival margins have a
ceramic (leucite-reinforced glass-ceramic) of 0.5 mm positive effect upon gingival health (Fig. 3).
46 Stoma Edu J. 2019;6(1): 43-54 http://www.stomaeduj.com
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
Review Article
(a)
Figure 4. Preparation design (from left to right) without incisal coverage,
with horizontal coverage and with coverage combined with a small or
extended palatinal chamfer/shoulder ; view from (A): buccal, (B): approximal
and (C): palatinal; palatinal chamfer is visualized by a line;
(Courtesy of Dr. F. Cieplik).
for those without incisal coverage [33]. In a more
recent meta-analysis by Hong et al. [34] comprising
10 clinical studies, veneers with incisal coverage had
a worse prognosis as compared to those without.
However, the difference was not statistically
significant. Apparently, horizontal mechanical
forces which are directed to the incisal ceramic part
(b) are responsible for slightly lower survival rates of
laminate veneers with incisal coverage. However, not
only the thickness and the mechanical properties of
the ceramic material play a role, but also the patient.
Here, patients with a tendency to bruxism have
been reported to have a higher failure rate [9]. This
should be taken into account when planning the
preparation. The incisal coverage may have different
designs: a pure overlap by reducing the incisal part
by about 2 mm or a further palatinal chamfer below
the 2 mm reduction (see also Fig. 4).
Concerning marginal integrity and fracture
resistance, no difference between the two designs
(c) has been reported in the literature [22,35], although
one in vitro study indicated that deep palatinal
Figure 3. Restoration of a diastema and increasing tooth size ( a): Iso- or
supragingival preparation leads to optimal healthy gingiva (b): view from
chamfer or butt joint preparation will result in a stress
buccal; (c): view from palatinal). concentration at the palatinal area and an increased
ceramic thickness is recommended [22].
5.3. Incisal coverage 5.4. Preparation Margins
Both incisal coverage and non-coverage have been Proximal preparation design can be classified into
described in the literature (Fig. 4a-c) and the defect “proximal chamfer” and “proximal slice” or “shoulder/
size primarily decides which preparation to choose. butt joint” type preparation. Chamfer type approximal
However, even if from this point of view an incisal preparations proved in one study to reveal higher
overlapping is not necessary, an incisal overlapping clinical success rates [26]. The interproximal extension
has some clinical advantages. First of all, it may of the preparation shall comprise the anatomical
improve the mechanical properties of the laminate equator so that the cavity margins are beyond the
veneer [32] and it may result in better esthetics [27]. visible area. It is a matter of discussion, if the contact
Finally it facilitates proper seating of veneers during points shall be resolved or if the veneer margin can
luting. Cötert et al. reported that the overlapped be located in the contact point area. According to
incisal edge had a significantly positive effect on classical concepts, contact point areas are difficult
the overall clinical survival rate [26]. However, as to clean and thus prone for secondary caries. On
a result of a meta-analysis of existing literature the the other side, appropriate oral hygiene; e.g. using
estimated survival rate for laminate veneers with flosses, can prevent secondary caries at contact point
incisal coverage was reported to be 88% and 91% areas (Fig. 5). Resolving the contact point offers more
Stomatology Edu Journal 47
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
Review Article
(a) (b)
Figure 5. Different preparations of the proximal area: (a) between 1.1 and 2.1 contact point was not resolved in order to save tooth structure; between
1.2 and 1.1 and between 2.1 and 2.2 the contact point was opened as a result of the tooth position of the lateral incisors; (b) final laminate veneer
restorations.
(a) (b)
(c) (d)
(e) (f )
Figure 6. Different preparations:(a): shoulder preparation with a palatinal chamfer before preparation; (b,c): preparations; (c,d): inserted veneers; (e):
another case of a palatinal chamfer preparation;( f): or incisal reduction without a chamfer.
48 Stoma Edu J. 2019;6(1): 43-54 http://www.stomaeduj.com
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
Review Article
(a)
(a)
(b)
(b)
(c)
Figure 7. Selected preparation instruments: (a): instrument kit; (b):
Instrument for determination the preparation depth;( c): finishing the
preparation to improve adhesion.
options for the esthetic design of the interproximal
area and the closure of “black triangles [27]. Buccal (c)
preparation can be performed as a chamfer or as Figure 8. Preparation for a laminate veneer on tooth 1.2 (a); silicone
index to control the preparation (b); final restoration (c).
a shoulder/butt joint (Fig. 6). What is important is
that the margin of the preparation is clearly visible/ quality and should be roughened. Some authors
detectable. Incisal overlapping of 2 mm with a recommend acid etching to improve the cleaning
palatinal chamfer preparation instead of a feathered effect and to roughen the exposed fillers [37].
incisal edge preparation are recommended by some
authors [26,36]. According to a meta-analysis, a butt 5.6. Preparation instruments/guides
joint type preparation least affects the strength of Special sets of preparation instruments are offered by
the tooth and the chamfer preparation type is more industry (Fig. 7); A very helpful instrument is the one
susceptible to ceramic fractures [36]. by which the maximum preparation depth can be
defined. One way to control the preparation is to use a
5.5. Existing composite restorations guide either made from orthodontic wire [38] or by an
As has been lined out above, clinical studies indicated impression before the preparation (or from the mock
that the presence of composite resin restorations up), which is reduced with a knife to the upper third
at the margins may influence the marginal quality of the tooth, which is being prepared (Fig. 8). Prepared
[4]. However, data are inconclusive [4,5]. In an in- tooth hard substance should be finished using a fine
vitro study, the margins of luted veneers had the grid diamond (Fig. 7 c). From all information presented
same morphological quality towards a composite above on the preparation for laminate veneers it can
resin restoration as compared to prepared enamel be concluded that a preparation depth of 0.3 – 0.5
[37]. In any case, such fillings should be of optimal mm iso- or slightly subgingival in the cervical area
Stomatology Edu Journal 49
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
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Review Article
(a)
Figure 9. One-step impression for veneers on teeth 1.2 and 2.2 with foils
separating contact points (arrows).
can be regarded as a general rule and thickness
can vary from 0.3 mm in the cervical area to 1.5 or
more in the incisal area; deviations are, however,
possible and necessary in each individual case, e.g.
due to tooth decay, extensive tooth discoloration or
adjustment of alignment of teeth. Incisal coverage
has a tendency to reduce longevity and here the
patient situation (e.g. bruxism) should be taken (b)
into consideration and special measure like the
application of a resin splint to be used as a night
guard (see below) is highly recommended.
6. Impression
Basically, all routine impression techniques can be
applied. However, especially if the contact points
are not resolved, a one-step impression technique is
advisable. It is helpful for the technician, if a small foil (c)
is placed in the contact point area during impression.
Fig. 9 shows such an impression using a polyether
impression material.
7. Temporaries
While temporaries for partial ceramic crowns for
posterior teeth follow widely accepted techniques,
temporaries for veneers in anterior teeth are
challenging because generally little tooth substance
has been removed. A classical method is that the
teeth are prepared for veneers on a gypsum model
and the dental technician produces such veneers (d)
according to the planned design/mock up. If more
than one tooth has been prepared the temporaries
are produced in one piece. They are then adjusted
to the patient by relining with a flowable composite
(Fig. 10). If more than one veneer is prepared, this
relining will lead to a reasonable bond. If there are
doubts, an adhesive can be used on a limited tooth
area (spot etching). The use of a thermoforming
sheet, which has been prepared on the mock up
model and which is filled with a composite has
also been recommended. However, meticulous (e)
occlusal adjustment in cases of incisal overlapping is
necessary due to the thickness of the sheet material. Figure 10. Temporaries: preparation on model (a); fabrication of
temporaries on the model (b); temporaries polished (c); relining with a
Temporaries can be luted with non-eugenol
flowable composite (d); in situ (e).
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PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
cements, whereas the postulated influence of resin for luting, a 90 % retention rate was observed
Review Article
eugenol upon the bond strength of adhesives is (patient as statistical unit) or 97.5% (veneer as
a matter of discussion [39]. Alternatively, water statistical unit) [43].
diluted polycarboxylate cement (Durelon) has been Again, the irradiation time was doubled. Therefore,
recommended. indeed this method can be recommended for
luting veneers; the time of light application should,
however, be doubled (see below).
8. Which adhesive/ luting material?
8.1. Adhesive technique 8.3. Universal adhesives
Generally, laminate veneers must be luted using Generally, it should be taken into account that the
an adhesive technique and basically, the same chemical activators of dual curing luting materials are
materials and procedures can be used as for partial acid-sensitive and that these luting materials should
ceramic crowns in posterior teeth. However, there basically not be used together with self-etching
are some special points which have to be taken adhesives. However, recently, new dental adhesives
care of; optimal adhesion is of utmost importance were marketed containing MDP as adhesive agent.
as well as optimal and long-lasting esthetics. If the These adhesives can be used together with an etch-
preparation is solely in the enamel, etch and rinse and-rinse, a self-etch and a selective etch approach.
adhesives should be used, in other cases selective Details have been described in part I of this article
enamel etching using a universal dental adhesive [2]. They can also be used together with dual-curing
(see below) is recommended. luting materials. However, this is manufacturer-
specific and the instructions for use must be
8.2. Dual curing or light curing only? carefully followed [2] and special dual cure activators
For ceramic partial crowns in posterior teeth, may be required. For this group of newly introduced
generally dual curing luting composites are adhesives (Universal adhesives) positive results have
recommended [2]. been found in a clinical study for partial crowns in
However, especially for veneers, the use of purely posterior teeth [44], but little data are reported so far
light curing flowable composites was described, for laminate veneers.
because a chemical initiating system used in the dual
curing products was claimed to have a tendency for 8.4. Modification of color by luting material
discoloration over time. Basically, it is possible to use luting materials with
However, recently no difference was found in a different color and thus influence the color of the
clinical study related to color stability between restoration (fine tuning). However, the potential of
a light cured resin composite and a dual curing such a fine tuning is limited. If the color of the veneer
luting material [40]. If veneers are luted with light does not match, the veneer should be corrected.
curing only materials, the optimal quality of cure Generally, a rather translucent luting material is
(polymerization) has to be guaranteed. In own in vitro recommended in order to optically link the veneer to
studies on the curing of luting composites with and the tooth structure. If it is attempted to fine-tune the
without chemical activation we could show that with color by the luting material, this must be checked
highly transparent ceramics like leucite reinforced before the actual luting step by using a try-in paste.
glass ceramics up to 2mm ceramic thickness,
composite luting materials can be sufficiently cured 8.5. Light curing
without additional chemical curing [17]. Appropriate light curing is essential for the successful
The time of light application should be at least two- outcome of the treatment. General problems of light
fold compared to the situation with an additional curing have been delineated in part I [2]. General
chemical activation. In a more recent in vitro study recommendations for the delivered energy to the
1 mm thick specimens of a leucite reinforced glass composite luting material vary between 16 and 25
ceramic and a lithium disilicate ceramic (slightly J/cm².
less translucent) were luted using composite resins As the translucency of the veneer/luting composite
with different shades with 1200 mW/cm² and an system is dependent on a large variety of factors
irradiation time of 20 seconds. The least opaque [41], recommendations for a prolongation factor are
cements revealed the best mechanical data and associated with a certain degree of uncertainty.
there was no difference between the two ceramic However, in the literature prolongation factors of
materials [41]. two to -three-fold are described, which would mean
In a clinical study, the delivery of laminate veneers for a standard light curing unit with an irradiance
using a direct restorative composite rather than a of around 1000 mW/cm² an irradiation time of
resin cement resulted in significantly less chipping at least (!) 40 seconds. The light source must be
and fractures, higher fracture strength in both placed directly on the ceramic. Recently, a number
accelerated fatigue and load-to-failure [42]. In a of dental material experts met in Oslo and worked
further clinical study with feldspathic laminate on a consensus statement on ‘Light Transmission
veneers over 7 years using a light cured composite Through Indirect Restorative Materials’ and ‘Bioactive
Stomatology Edu Journal 51
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
Restorative Materials’ [45]. place thin foils at the contact point before (one
Review Article Here are the most important facts: phase) impression taking (Fig. 9).
There is an exponential decline in the amount of ►► Final determination of the color and the
light that reaches the bottom of the restoration as shape of the veneers taking the color of the
its thickness increases; prepared tooth into consideration; this should
to use the recommended adhesive - cement preferably be done together with the technician
combinations, particularly when using self-etching in the dental practice.
universal adhesives together with dual-cure resin ►► Temporaries: use individually prefabricated
cements; temporaries and fix them with a flowable
to recognize that resins that are solely light-cured composite resin (Fig. 10); alternatively,
must receive sufficient light, to check the thickness temporaries can be produced by filling a
of the restoration, and to stay within the cement flowable composite into a splint, which has
manufacturer’s instructions for use; been produced on the mock-up model; or one
to recognize that most “dual curing” resin materials can use an impression made from a mock-up
benefit from receiving additional light exposure; model and fill it with an auto-polymerizing
to recognize that doubling the exposure time will composite resin.
not compensate for the reduction in transmitted ►► Try-in of the restoration: remove all (!)
light if the thickness of the restorative material has remaining temporary cementation material
doubled (e.g., from 1.0 to 2.0 mm) [45]. from the tooth; cautiously adjust proximal
contact points and occlusal surfaces avoiding
any high pressure, because ceramic veneers
9. Step by Step laminate veneers checklist are in this state highly prone to fractures.
►► Case selection/Prevention program: as has Use try-in pastes or petrolatum/glycerine
been lined out in part I for posterior teeth, also in order to have optic connection between
patients scheduled for laminate veneers must veneer and tooth, simulating the luting
exercise an excellent oral hygiene because procedure and then control the color. Perfect
luting resins may enhance bacterial growth [46, color match must result from the veneer itself.
47]; smoking is discouraged as this increases Corrections of the color with the luting cement
marginal staining [9]. are generally not very efficient.
►► Indication: e.g. cavities extending into large ►► Pretreatment of ceramic/tooth: Etching
parts of the buccal surface and potentially of ceramic, silanization and enamel/dentin
needing replacement of the incisal edge, major pretreatment see part I [2].
esthetic problems related to color, shape, large ►► Luting composite: clean teeth thoroughly
size diastema or small corrections of dental again, Ivoclean is a very useful substance;
malocclusions in the anterior part. either dual curing cement or flowable
►► Pretreatment: If teeth are heavily discolored; composite can be used; in the latter case
e.g. after endodontic treatment, bleaching prolong the irradiation time as indicated by
of teeth (intracoronally or externally) is the manufacturer, as a rule of thumb two to
recommended well before the preparation for three-fold compared to the situation without
veneers (Fig. 1). As oxygen peroxide products the ceramic veneer interposed. For the
are used for bleaching, clinicians should wait combination of self-etch/Universal adhesives
for at least 2 weeks after bleaching and before and dual curing luting materials check with
veneer treatment; during this time, residual the manufacturer’s instructions for use.
oxygen, which may interfere with the resin If multiple veneers are to be luted (e.g. upper
setting reaction, can diffuse out of the tooth front), always lute two at a time, beginning with
substances. 1.1 and 2.1, then 1.2 and 2.2, etc. Coverage of
►► Diagnostic wax up/mock-up: using composite the margins with glycerin gel before irradiation
resin, the effect of a veneer treatment can be prevents the formation of a layer of low/non
simulated and the new size of the front teeth polymerized resins (oxygen inhibition layer).
can be controlled together with the patient, ►► Resin splint: in order to protect laminate
e.g. concerning aesthetics and phonetics. An veneers – especially those with incisal
impression can be made and the technician can coverage – against strong horizontal forces
finalize the mock up and prepare a preparation during bruxism during the night a resin splint
guide. (normally for the upper jaw) is recommended
►► Check for existing restorations and replace if (Fig. 11).
not optimal.
►► Preparation: determine the preparation
depths (e.g. 0.3 – 0.5 mm at the cervical buccal Authors contribution
area) potentially using special preparation GS: Planning and writing the text. MF: Writing and
instruments (Fig. 7) and prepare the tooth proof reading the text.
preferably with a chamfer or a shoulder /butt
joint. Use indexes made from mock-up models
to control preparation (Fig. 8); use fine grid
diamonds for finishing; for gingival retraction, Acknowledgments
use aluminum chloride chords. No conflict of interest exists for any of the authors
►► Impression: If contact points are not resolved, of the paper.
52 Stoma Edu J. 2019;6(1): 43-54 http://www.stomaeduj.com
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
The Journal of prosthetic dentistry. 2014;111(5):380-387.
Review Article
[CrossRef] [PubMed] Google Scholar Scopus
References 22. Stappert CF, Ozden U, Gerds T, Strub JR. Longevity and failure
1. Costa VLS, Tribst JPM, Uemura ES, et al. Influence of load of ceramic veneers with different preparation designs
thickness and incisal extension of indirect veneers on the after exposure to masticatory simulation. The Journal of
biomechanical behavior of maxillary canine teeth. Restor prosthetic dentistry. 2005;94(2):132-139.
Dent Endod. 2018;43(4):e48. [CrossRef] [PubMed] Google Scholar Scopus
[Free PMC Article][CrossRef] [PubMed] Google Scholar 23. Magne P, Versluis A, Douglas WH. Rationalization of incisor
2. Schmalz G, Federlin M. Partial Ceramic Crowns: Esthetic and shape: experimental-numerical analysis. J Prosthet Dent.
Tissue Conservative Restorations - Part I: Posterior Teeth. 1999;81(3):345-355.
Stoma Edu J. 2017;4(4):270-281. [Full text links] [PubMed] Google Scholar Scopus
3. Touati B, Miara P, Nathanson D. [Aesthetic Dentistry and 24. Magne P, Douglas WH. Design optimization and evolution of
Ceramic Restoration]. German edition: Schmalz G, Federlin M. bonded ceramics for the anterior dentition: a finite-element
München, Germany: Urban & Fischer Verlag; 2001. analysis. Quintessence Int. 1999;30(10):661-672.
4. Gresnigt MM, Kalk W, Ozcan M. Clinical longevity of ceramic [PubMed] Google Scholar Scopus
laminate veneers bonded to teeth with and without existing 25. Tugcu E, Vanlioglu B, Ozkan YK, Aslan YU. Marginal
composite restorations up to 40 months. Clin Oral Investig. Adaptation and Fracture Resistance of Lithium
2013;17(3):823-832. Disilicate Laminate Veneers on Teeth with Different
[CrossRef][PubMed] Google Scholar Scopus Preparation Depths. Int J Periodontics Restorative Dent.
5. Peumans M, De Munck J, Fieuws S, et al. A prospective 2018;38(Suppl):s87-s95.
ten-year clinical trial of porcelain veneers. J Adhes Dent. [Crossref] [PubMed] Google Scholar Scopus
2004;6(1):65-76. 26. Cotert HS, Dundar M, Ozturk B. The effect of various
[PubMed] Google Scholar Scopus preparation designs on the survival of porcelain laminate
6. Chen JH, Shi CX, Wang M, Zhao SJ, Wang H. Clinical veneers. J Adhes Dent. 2009;11(5):405-411.
evaluation of 546 tetracycline-stained teeth treated with [PubMed] Google Scholar Scopus
porcelain laminate veneers. J Dent. 2005;33(1):3-8. 27. Edelhoff D, Prandtner O, Saeidi Pour R et al. Anterior
[CrossRef] [PubMed] Google Scholar Scopus restorations: The performance of ceramic veneers.
7. Guess PC, Selz CF, Voulgarakis A, et al. Prospective clinical Quintessence Int. 2018;49(2):89-101.
study of press-ceramic overlap and full veneer restorations: [Full text links] [PubMed] Google Scholar Scopus
7-year results. Int J Prosthodont. 2014;27(4):355-358. 28. Dietschi D. Prefabricated Veneers - An established technique
[CrossRef] [PubMed] Google Scholar Scopus is revisited with new technologies. Inside Dentistry.
8. Aristidis GA, Dimitra B. Five-year clinical performance of 2012;8(9):https://www.aegisdentalnetwork.com/id/2012/09/
porcelain laminate veneers. Quintessence Int. 2002;33(3):185- prefabricated-veneers.
189. 29. Ozturk E, Bolay S, Hickel R, Ilie N. Shear bond strength of
[PubMed] Google Scholar Scopus porcelain laminate veneers to enamel, dentine and enamel-
9. Beier US, Kapferer I, Burtscher D, Dumfahrt H. Clinical dentine complex bonded with different adhesive luting
performance of porcelain laminate veneers for up to 20 systems. J Dent. 2013;41(2):97-105.
years. Int J Prosthodont. 2012;25(1):79-85. [CrossRef] [PubMed] Google Scholar Scopus
[PubMed] Google Scholar Scopus 30. Burke FJ. Survival rates for porcelain laminate veneers with
10. Gurel G, Morimoto S, Calamita MA, et al. Clinical performance special reference to the effect of preparation in dentin: a
of porcelain laminate veneers: outcomes of the aesthetic literature review. J Esthet Restor Dent. 2012;24(4):257-265.
pre-evaluative temporary (APT) technique. Int J Periodontics [CrossRef] [PubMed] Google Scholar Scopus
Restorative Dent. 2012;32(6):625-635. 31. Christgau M, Friedl KH, Schmalz G, Resch U. Marginal
[PubMed] Google Scholar adaptation of heat-pressed glass-ceramic veneers to dentin
11. Morimoto S, Albanesi RB, Sesma N, et al. Main Clinical in vitro. Oper Dent. 1999;24(3):137-146.
Outcomes of Feldspathic Porcelain and Glass-Ceramic [PubMed] Google Scholar Scopus
Laminate Veneers: A Systematic Review and Meta-Analysis 32. Chaiyabutr Y, Phillips KM, Ma PS, Chitswe K. Comparison of
of Survival and Complication Rates. Int J Prosthodont. load-fatigue testing of ceramic veneers with two different
2016;29(1):38-49. preparation designs. Int J Prosthodont. 2009;22(6):573-575.
[CrossRef] [PubMed] Google Scholar Scopus [PubMed] Google Scholar Scopus
12. Pjetursson BE, Sailer I, Zwahlen M, Hammerle CH. A 33. Albanesi RB, Pigozzo MN, Sesma N, et al. Incisal coverage or
systematic review of the survival and complication rates not in ceramic laminate veneers: A systematic review and
of all-ceramic and metal-ceramic reconstructions after an meta-analysis. J Dent. 2016;52:1-7.
observation period of at least 3 years. Part I: Single crowns. [CrossRef] [PubMed] Google Scholar Scopus
Clin Oral Implants Res. 2007;18 Suppl 3:73-85. 34. Hong N, Yang H, Li J, et al. Effect of Preparation Designs on
[CrossRef] [PubMed] Google Scholar Scopus the Prognosis of Porcelain Laminate Veneers: A Systematic
13. Valenti M, Valenti A. Retrospective survival analysis of Review and Meta-Analysis. Oper Dent. 2017;42(6):E197-E213.
261 lithium disilicate crowns in a private general practice. [CrossRef] [PubMed] Google Scholar Scopus
Quintessence Int. 2009;40(7):573-579. 35. Stappert CF, Ozden U, Att W, et al. Marginal accuracy of
[Full text links] [PubMed] Google Scholar Scopus press-ceramic veneers influenced by preparation design and
14. Gehrt M, Wolfart S, Rafai N, et al. Clinical results of lithium- fatigue. Am J Dent. 2007;20(6):380-384.
disilicate crowns after up to 9 years of service. Clin Oral [PubMed] Google Scholar Scopus
Investig. 2013;17(1):275-284. 36. da Costa DC, Coutinho M, de Sousa AS, Ennes JP. A meta-
[CrossRef] [PubMed] Google Scholar Scopus analysis of the most indicated preparation design for porcelain
15. Lawson NC, Burgess JO. Dental ceramics: a current review. laminate veneers. J Adhes Dent. 2013;15(3):215-220.
Compend Contin Educ Dent. 2014;35(3):161-166; quiz 8. [Full text links] [PubMed] Google Scholar Scopus
[PubMed] Google Scholar Scopus 37. Christgau M, Friedl KH, Schmalz G, Edelmann K. Marginal
16. Al Ben Ali A, Kang K, Finkelman MD, et al. The effect of adaptation of heat-pressed glass-ceramic veneers to Class 3
variations in translucency and background on color composite restorations in vitro. Oper Dent. 1999;24(4):233-244.
differences in CAD/CAM lithium disilicate glass ceramics. J [PubMed] Google Scholar Scopus
Prosthodont. 2014;23(3):213-220. 38. Cho SH, Nagy WW. Labial reduction guide for laminate
[CrossRef] [PubMed] Google Scholar Scopus veneer preparation. The Journal of prosthetic dentistry.
17. Koch A, Kroeger M, Hartung M, et al. Influence of ceramic 2015;114(4):490-492.
translucency on curing efficacy of different light-curing units. [CrossRef] [PubMed] Google Scholar Scopus
J Adhes Dent. 2007;9(5):449-462. 39. Abo-Hamar SE, Federlin M, Hiller KA, et al. Effect of temporary
[PubMed] Google Scholar Scopus cements on the bond strength of ceramic luted to dentin.
18. Kassardjian V, Varma S, Andiappan M, et al. A systematic Dent Mater. 2005;21(9):794-803.
review and meta analysis of the longevity of anterior and [CrossRef] [PubMed] Google Scholar Scopus
posterior all-ceramic crowns. J Dent. 2016;55:1-6. 40. Marchionatti AME, Wandscher VF, May MM et al. Color
[CrossRef] [PubMed] Google Scholar Scopus stability of ceramic laminate veneers cemented with
19. Manicone PF, Rossi Iommetti P, Raffaelli L. An overview of light-polymerizing and dual-polymerizing luting agent:
zirconia ceramics: basic properties and clinical applications. J A split-mouth randomized clinical trial. J Prosthet Dent.
Dent. 2007;35(11):819-826. 2017;118(5):604-610.
[CrossRef] [PubMed] Google Scholar Scopus [CrossRef] [PubMed] Google Scholar Scopus
20. Magne P, Belser UC. Novel porcelain laminate preparation 41. Ozturk E, Chiang YC, Cosgun E et al. Effect of resin shades on
approach driven by a diagnostic mock-up. J Esthet Restor opacity of ceramic veneers and polymerization efficiency
Dent. 2004;16(1):7-16; discussion 7-8. through ceramics. J Dent. 2013;41 Suppl 5:e8-14.
[Full text links] [PubMed] Google Scholar Scopus [CrossRef] [PubMed] Google Scholar Scopus
21. Ge C, Green CC, Sederstrom D, et al. Effect of porcelain and 42. Gresnigt MMM, Ozcan M, Carvalho M et al. Effect of luting
enamel thickness on porcelain veneer failure loads in vitro. agent on the load to failure and accelerated-fatigue
Stomatology Edu Journal 53
PARTIAL CERAMIC CROWNS. ESTHETIC AND TISSUE CONSERVATIVE RESTORATIONS – PART II:
ANTERIOR TEETH – LAMINATE VENEERS
resistance of lithium disilicate laminate veneers. Dent Mater. 46. Auschill TM, Arweiler NB, Brecx M, et al. The effect of dental
Review Article 2017;33(12):1392-1401. restorative materials on dental biofilm. Eur J Oral Sci.
[CrossRef] [PubMed] Google Scholar Scopus 2002;110(1):48-53.
43. D’Arcangelo C, De Angelis F, Vadini M, D’Amario M. Clinical [Full text links] [PubMed] Google Scholar Scopus
evaluation on porcelain laminate veneers bonded with 47. Hansel C, Leyhausen G, Mai UE, Geurtsen W. Effects of
light-cured composite: results up to 7 years. Clin Oral Investig. various resin composite (co)monomers and extracts on
2012;16(4):1071-1079. two caries-associated micro-organisms in vitro. J Dent Res.
[CrossRef] [PubMed] Google Scholar Scopus 1998;77(1):60-67.
44. Vogl V, Hiller KA, Buchalla W, et al. Controlled, prospective, [CrossRef] [PubMed] Google Scholar Scopus
randomized, clinical split-mouth evaluation of partial
ceramic crowns luted with a new, universal adhesive system/
resin cement: results after 18 months. Clin Oral Investig.
2016;20(9):2481-2492.
[CrossRef] [PubMed] Google Scholar Scopus
45. Price RB, Roulet JF. The value of consensus conferences: peer
review by 50 key opinion leaders! Stoma Edu J. 2018;5(4):202-
204.
Gottfried SCHMALZ
DMD, PhD, Professor Dr, Dr hc
Department of Operative Dentistry and Periodontology
Medicine Faculty, University Hospital Regensburg
Regensburg, Germany
CV
Gottfried Schmalz, DDS, Dr med dent, PhD, is the former chair and current professor at the Department of Operative Dentistry
and Periodontology, University of Regensburg, Germany. He is a member of many scientific organizations and has won
numerous awards, e.g. the Distinguished Scientist Award of the IADR and the Award of Excellence of the European Federation
for Conservative Dentistry. He is the editor of the book ‘Biocompatibility of Dental Materials’; he has authored 5 books and
more than 260 publications listed in PubMed.
He has been Editor-in-Chief of “Clinical Oral Investigations”, since 1996 and Honorary Editor since 2016. Since 2016 he is
chairman of ISO (International Organization of Standardization) Technical Committee 106: Dentistry.
His main scientific interests are material/tissue interactions, oral tissue regeneration and ceramic restorations.
Questions
1. Which is the most important factor for reduced longevity of laminate veneers?
qa. Extensive bruxism;
qb. Patients older than 60 years;
qc. Teeth with endodontic pretreatment;
qd. Smoking.
2. When is an incisal coverage for a veneer preparation recommended?
qa. For patients with insufficient oral hygiene;
qb. For smokers;
qc. For aesthetic reasons;
qd. In young patients (younger than 20 years).
3. Preparation depth for laminate veneers is determined by
qa. Patients ‘demands;
qb. Presence of composite restorations;
qc. Size of defect, tooth discoloration and adjustment of teeth alignment;
qd. Size of the tooth.
4. Luting of ceramic veneers can be done using
qa. Always light curing only composite resins;
qb. Light curing only composite resins together with a transparent ceramics up to 1 mm thickness;
qc. Generally self etch adhesives with dual curing composite luting materials;
qd. Light curing only composite resins together with transparent ceramics of up to 0.3 mm thickness.
54 Stoma Edu J. 2019;6(1): 43-54 http://www.stomaeduj.com