Introduction
It has been demonstrated that conservative dentistry techniques rely on bonding and
adhesive lutting.[[1]],[[2]],[[3]] Bonding to enamel has been shown to be more durable than dentin due to intact enamel
provides the most reliable substrate for etched porcelain laminate veneers.[[4]],[[5]] An adequate tooth preparation must provide uniform reduction and sufficient clearance
to allow the ideal thickness of the final restoration without causing any disturbance
of the periodontal tissue, esthetics, and structural durability.[[6]] The clinician should follow a conservative way when restoring teeth that have been
previously restored, especially for young adult patients.[[7]],[[8]] Ceramic veneers have shown to be a long-lasting treatment when compared to composite
veneers and provide higher long-term esthetics.[[9]],[[10]] Veneers have become the most common conservative fixed restoration because they
require only 25% of the amount of tooth reduction when compared to complete coverage
crown restorations.[[11]] The excessive buccal reduction can lead to compromised bond strength due to exposure
of the dentin.[[12]]
Clinical challenges associated with porcelain veneers include its fracture or chipping
and luting composite resin shrinkage.[[13]],[[14]],[[15]] The success of ceramic veneer restorations depends on many factors such as proper
diagnosis, preparation design,[[16]] adhesive bonding techniques,[[17]],[[18]] and patient home care with excellent oral hygiene.[[19]] Using new laboratory techniques and optimal dental materials, it is possible to
produce ultrathin ceramic veneers with a thickness of 0.1–0.5 mm, which can be bonded
to tooth surface with minimal or no tooth preparation in order to modify the position,
color, and shape of the teeth.[[20]],[[21]] Currently, there are several ceramic materials available in the market, such as
lithium disilicate, feldspathic porcelain, feldspathic porcelain reinforced with leucite,
and lithium disilicate reinforced with zirconia.[[22]],[[23]],[[24]],[[25]] High survival rates with low failure numbers have been found for ceramic veneers
bonded to enamel.[[26]],[[27]]
During the diagnosis steps, it is essential the fabrication of an adequate diagnostic
wax-up to evaluate the discrepancies between current and ideal tooth measurements,
restorative space available, occlusal scheme, and any treatment needed in the opposing
arch.[[28]],[[29]],[[30]],[[31]] This information can be transferred to the patient mouth as a diagnostic mock-up
using bis-acryl material. During this step, the patient can physically evaluate the
desired outcome and the clinician can modify specific areas as needed. The final result
of the mock-up can be used as a reference for the fabrication of the final ceramic
restorations.
Another advantage of the mock-up technique is its use as a reduction guide for the
clinician during the teeth preparation. The use of a rubber dam before bonding the
final ceramic restorations aims to prevent any contamination and maximize the bonding
properties between the ceramic and the tooth surface.[[32]],[[33]] This clinical report describes a conservative approach involving patient evaluation
with a diagnostic mock-up, followed by conservative tooth preparations on the diagnostic
mock-up, and complete isolation with rubber dam for the bonding procedure of feldspathic
veneers.
Case Report
A 35-year-old female patient presented to the clinic with the chief goal of improving
her smile [[Figure 1]]. During the clinical examination, it was noticed that central and lateral incisors
(#7, 8, 9, and 10) were previously restored with direct composite veneers, and both
upper canines (#6 and #11) had uneven incisal reduction [[Figure 2]], [[Figure 3]], [[Figure 4]]. The patient has been with these restorations for 5 years, and the composite veneers
present yellow staining on all the buccal surfaces and around the margins. An adequate
diagnostic wax-up (GEO Classic, Renfert, Hilzingen, Germany) was needed to evaluate
the discrepancies between current and ideal tooth dimensions, restorative space available,
and occlusion [[Figure 5]]. After the wax-up was approved by the patient, a diagnostic mock-up with a self-cured
temporary composite material – bis-acryl (Structure Premium, VOCO GmbH, Cuxhaven)
– was made in order to evaluate in placed the future dimensions of the proposed ceramic
restorations [[Figure 6]] and [[Figure 7]]. The patient was pleased with the results of the diagnostic mock-up and requested
to move forward in the treatment. The final treatment plan included porcelain ceramic
veneers on teeth #6, 7, 8, 9, 10, 11, and 12.
Figure 1: Initial face smile
Figure 2: Initial intraoral frontal view
Figure 3: Initial intraoral right-side view
Figure 4: Initial intraoral left-side view
Figure 5: Diagnostic wax-up
Figure 6: Diagnostic mock-up smile
Figure 7: Diagnostic mock-up intraoral
At the following clinical appointment, the same previously approved mock-up with a
self-cured material was created and placed intraorally. Horizontal and incisal vertical
depth grooves were cut into the teeth with a round diamond bur (801 Spherical, JOTA
AG, Rüthi, Switzerland) and marked with a red pencil (Colored Pencils, Prismacolor
Verithin, Oak Brook, IL, USA) in order to have a controlled tooth reduction [[Figure 8]], [[Figure 9]], [[Figure 10]]. Conservative tooth reduction was performed on the diagnostic mock-up and with
the aid of a reduction guide using the fine diamond bur with the conical end (850,
JOTA AG) in high speed.
Figure 8: Reduction grooves on diagnostic mock-up
Figure 9: Marking reduction grooves
Figure 10: Reduction grooves
A putty reduction guide matrix (Hydrorise Putty, Zhermack SpA, Badia Polesine, Italy)
was previously fabricated in order to evaluate incisal and facial reduction, and a
periodontal probe was used to measure the amount of tooth reduction. After conservative
tooth preparations were completed, the teeth were polished and smoothed, and corners
were rounded using coarse, medium, and fine discs (Sof-Lex discs, 3M Oral Care, St.
Paul, MN, USA) [[Figure 11]], [[Figure 12]], [[Figure 13]]. After final tooth preparations were refined and polished [[Figure 14]], [[Figure 15]], [[Figure 16]], a double cord impression technique was used, first packing cord #00 and then #0
(Ultrapak, Ultradent Products Inc., South Jordan, UT, USA) [[Figure 17]] and [[Figure 18]], and the final impression was made using light body and heavy body consistency
polyvinylsiloxane (Virtual 380, Ivoclar Vivadent, Amherst, NY, USA) [[Figure 19]] and [[Figure 20]].
Figure 11: Polishing tooth preparations with coarse polishing disc
Figure 12: Polishing tooth preparations with medium polishing disc
Figure 13: Polishing tooth preparations with superfine polishing disc
Figure 14: Polished final preparation frontal view
Figure 15: Polished final preparation left-side view
Figure 16: Polished final preparation right-side view
Figure 17: Packing cord before final impression
Figure 18: Double cord impression technique for final impression
Figure 19: Final impression intraorally
Figure 20: Final impression made
Final impressions were poured out with type IV stone to obtain the master casts and
individual alveolar dies (Fujirock, GC America Inc., Alsip, IL, USA) [[Figure 21]]. Feldspathic porcelain material was used to fabricate the veneers in order to fulfill
the patient’s high esthetic demands (Noritake Super Porcelain EX-3, Kuraray Noritake
Dental Inc., New York, NY, USA) [[Figure 22]], [[Figure 23]], [[Figure 24]], [[Figure 25]], [[Figure 26]], [[Figure 27]]. At the final cementation appointment, isolation was provided with rubber dam from
#4 to #13, placing holder clamps on #4 and #13 (Rubber Dam Clamps #2, Hu-Friedy, Chicago,
IL, USA). Moreover, clamps (Hygenic Brinker Clamp B4, Coltene/Whaledent Inc., Cuyahoga
Falls, OH, USA) were placed on the specific tooth to which restoration would be bonded
[[Figure 28]]. The placement sequence of the ceramic restorations was first #8 and #9, then #7
and #10, and finally, #6 and #11. The try-in of the final restorations was performed
with the try-in paste according to the manufacture recommendations. After the try-in
and approval of the patient, the ceramic restorations received hydrofluoric acid surface
treatment (IPS Ceramic Etching Gel, Ivoclar Vivadent) for 60 s, followed by rinsing
and drying. Restorations were submerged in water and alcohol in an ultrasonic bath
(5300 Sweep Ultrasonic Cleaner, Quala Dental Products, Nashville, TN, USA) for 5 min
in order to remove any remaining acid. Next, silane (Monobond-S, Ivoclar Vivadent)
was applied for 60 s, and then, the restoration was oil-free air-dried. The tooth
surface was first treated with 32% phosphoric acid gel (Uni-Etch w/Benzalkonium Chloride,
Bisco Dental, Schaumburg, IL, USA) for 30 s and then rinsed and gently dried. Then,
primer and adhesive were applied, air thinned (OptiBond FL, Kerr Dental, Orange, CA,
USA) following the manufacturer’s instructions, and light cured (VALO LED curing Light,
Ultradent Products Inc.) for 20 s. Before the cementation of the veneers on the teeth
#8 and #9, adjacent teeth were cover with Teflon tape to protect and avoid bonding
agent and cement on the margins. A light-cure resin cement (Variolink Esthetic LC,
Ivoclar Vivadent) was applied to both veneers for #8 and #9, and both the veneers
were simultaneously seated on the teeth # 8–9 [[Figure 29]]. The excess of cement was removed with a microbrush and floss in the interproximal
surfaces before light curing for 20 s on the facial, 20 s on mesial, 20 s on distal,
and 20 s on the incisal surface. The same sequence was followed for the teeth and
veneers on #7 and #10 and finally #6 and #11 [[Figure 30]] and [[Figure 31]]. Glycerin gel was then applied to the ceramic surfaces in order to prevent an oxygen
inhibition layer (Liquid Strip, Ivoclar Vivadent), and the surfaces were again light
cured for 20 s each.
Figure 21: Master cast and alveolar dies fabricated
Figure 22: Dentin characterization in the feldspathic veneer fabrication
Figure 23: Enamel characterization in the feldspathic veneer fabrication
Figure 24: Incisal edge characterization in the feldspathic veneer fabrication
Figure 25: Line angles definition in the feldspathic veneer fabrication
Figure 27: Ultra-thin feldspathic veneers fabricated
Figure 26: Feldspathic veneers fabricated
Figure 28: Rubber dam isolation for bonding ceramic veneers
Figure 29: Clamps of lateral incisors prior bonding ceramic restorations
Figure 30: Acid etching on lateral incisors prior bonding ceramic restorations
Figure 31: Ceramic veneers bonded under rubber dam isolation
The excess of cement on the cervical area was removed with a #12 blade (Surgical Blade
number 12, Salvin Dental Specialties, Charlotte, NC, USA), and the rubber dam was
removed occlusion; excursive movements and protrusion were checked. The patient was
pleased with the final outcome [[Figure 32]]. An occlusal guard was provided to wear at night in order to prevent any damage
to the restorations. A 2-year follow-up was performed, and the patient was still pleased
with the clinical result [[Figure 33]] and [[Figure 34]].
Figure 32: Final bonded restorations
Figure 33: Two-year follow-up smile
Figure 34: Two-year follow-up intraoral
Discussion
This clinical report describes how a well-planned diagnostic evaluation helps us to
obtain desirable results at the end of the treatment and fulfill a patient’s high
esthetic demands. The wax-up information is transferred to the patient’s mouth in
order to provide a physical evaluation of the tentative design of the final restoration.
At this stage, the patient has the opportunity to request modifications as needed
and have a better idea of the dimensions of the final restorations according to the
lips, smile, and facial symmetry. From the clinician perspective, the mock-up technique
provides the opportunity to evaluate the esthetic results and at the same time provides
a guide for a conservative reduction of the teeth. Reduction grooves in the diagnostic
mock-up help the clinician to have a well-controlled tooth preparation. Experienced
restorative clinicians may not need any reduction groove in order to achieve ideal
tooth reduction, but the authors highly recommend them in order to gain experience
with these conservative preparations.
Complete isolation of the teeth during the final cementation with rubber dam is used
in order to achieve ideal results with the adhesive materials. This clinical report
demonstrated a technique in which a rubber dam was placed from the second premolar
right to the second premolar left in order to secure with clamp retainers, and individual
clamps were placed on each pair of teeth during the cementation of the ceramic veneers.
This type isolation provides several advantages such as preventing contamination of
the working field by saliva, blood, and sulcular fluids. Moreover, it improved the
direct visibility because the rubber dam retracts the cheeks, lips, and tongue while
working intraorally. It also prevents aspiration and laceration from instruments and
speeds up the treatment procedure because the restorative dentist can focus on the
clinical steps without worrying about the patient closing mouth. Obviously, clinicians
can bond final restorations without providing total isolation with a rubber dam; however,
minimal contamination may compromise the effectiveness of the bonding agent. Furthermore,
the restorative dentist will need meticulous help from dental assistants and patient’s
cooperation in order to keep the working field without contamination.
Conclusion
The use of the intraoral diagnostic mock-up technique during the tooth preparation
provides the opportunity to have a controlled reduction needed for conservative veneer
preparations. The goal for any bonding restoration is to maintain the tooth preparation
in enamel in order to achieve an optimal bonded restoration. The application of complete
isolation with rubber dam is needed in order to prevent contamination of the working
field by saliva, blood, and sulcular fluids around the neck of the tooth. A well-planned
diagnostic evaluation and execution of it with a conservative approach should improve
the longevity of the restorations.
