A Detailed Overview on Veneers –
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Diagnostic and Clinical Considerations
ABSTRACT
Cosmetic dentistry is comprehensive oral care that combines both art and science to optimally
improve dental health, aesthetics and function. Its objective is to provide maximum improvements in
aesthetics with the minimum trauma to the dentition. Veneer is a thin layer of tooth colored material
applied to the tooth to restore localized or generalized defects and intrinsic discoloration. The
evolution of material sciences, ceramics, and adhesive system permits improvements of the aesthetic
smile design of patients. The current manuscript is a review that highlights the diagnostic
considerations; repair and maintenance; and recent advances in veneers.
Keywords: Aesthetic dentistry; smile design; repair of veneers; lumineers.
1. INTRODUCTION
The term “esthetics” is borrowed from the Greek word “aesthesia” meaning sensation or sensibility. It
can be defined as belonging to the appreciation of the beautiful. Pilkingtonin 1936 defined dental
esthetics as the science of copying or harmonizing our work with that of nature, making our art
inconspicuous. The word “cosmetic” means “kosmos” or adornment in Greek.
The success of a restoration depends on sound mechanical, biological and esthetic principles. An
ideal restoration must satisfy these requirements. Irfan Ahmad has suggested the HFA triad,
according to this, dental treatment must be directed to fulfill the Health, Function and Aesthetics for
the patient [1]. Various techniques for esthetic rehabilitation treatment include a combination of:
preoperative and postoperative clinical photographs of patients, diagnostic models with wax ups,
composite resin mock-ups on the patient and computer-imaging simulations.
Veneer is a layer of tooth colored material that is applied to a tooth to restore localized or generalized
defects and intrinsic discoloration. Veneers are made up of chair-side composite, processed
composite, porcelain and compressed ceramic materials. The process of applying a thin veneer of
preformed porcelain, composite resin or plastic material to a tooth is called laminating. Laminates can
successfully transform smiles painlessly, conservatively and quickly with long lasting results.[2]
The objective of Cosmetic Dentistry is to provide maximum improvements in aesthetics with minimum
trauma to the dentition. Rendering or restoration of the smile is one of the most appreciated
treatments provided by the dentist. Correction of discoloured, malformed or crooked teeth can
produce dramatic changes in appearance, which often results in improved confidence, personality and
social life. Veneer is considered one of the most conservative operative treatment procedures
because the tooth preparation involves the removal of less than half the thickness of the enamel,
leaving the remaining portion intact before veneer placement [3]. Many clinical studies have
concluded that bonded laminate veneer restorations delivered good results over a period of 10 years
2. CLASSIFICATION OF VENEERS
I.
Based on method of fabrication:
i.
Direct technique
ii.
Indirect technique
II.
Based on extent of coverage:
i.
Partial veneers- for localized defects or areas of intrinsic discolouration that involve only a
portion of the clinical crown.
ii.
Full veneers – when majority of the facial surface or whole crown of the tooth is discoloured or
restoration of generalized defects.
III.
Based on tooth preparation – full veneer:
i.
Full veneer with incisal lapping.
ii.
Full veneer with window preparation.
IV.
Based upon the materials & techniques used:
i.
Directly fabricated composite resin veneers.
a) Direct partial veneers
b) Direct full veneers
ii.
Indirectly fabricated veneers
a) Etched porcelain veneers
b) Processed composite veneers
c) Castable ceramic veneers
iii.
Veneers for metal restorations.
V.
Based on the preparation designs
i.
Window preparation: the incisal edge of the tooth is preserved.
ii.
Feather preparation: the incisal edge of the tooth is prepared bucco- palatally, but the incisal
length is not reduced.
iii.
Bevel preparation: the incisal edge of the tooth is prepared bucco-palatally and the length of
the incisal edge is reduced slightly by 0.5-1 mm.
iv.
Incisal overlap preparation: the incisal edge of the tooth is prepared bucco-palatally and the
length is reduced (about 2 mm), so the veneer is extended to the palatal aspect of the tooth
[7].
2.1 Indications
1. Teeth with intrinsic / extrinsic discoloration- single/multipleExtrinsic – Plaque, chromogenic bacteria, chlorhexidine mouthrinse, beverages (tea,coffee,
red wine), iron supplements.
Intrinsic – tetracycline stains, fluorosis, haematological diseases, devitalization, smoking,
caries and dental restorative materials.
2. Enamel defects- gross enamel hypoplasia of the anterior teeth, amelogenesis imperfecta.
3. Presence of diastema
4. Teeth with abnormal shape and form.
5. Improper surface texture.
6. Mal-aligned teeth- For developing the esthetic illusion of straight teeth where orthodontic
treatment is not sought or indicated.
7. Malocclusion- The configuration of lingual surface of anterior teeth can be changed to develop
incisal guidance or centric contacts in malocclusion or periodontally compromised teeth.
8. Multiple carious lesions and decalcifications.
9. Attrition / abrasion / erosion.
10. Stained or defective restorations that appear unesthestic on labial surfaces of teeth.
11. Trauma / fracture of multiple anterior teeth.
12. Aging - For discoloured teeth or attrited teeth due to aging, improvement can be done by
bleaching or bleaching with subsequent veneering.
13. Wear patterns- Porcelain laminates are useful in teeth with slow progressive wear patterns. If
sufficient enamel remains and the desired increased in length is not excessive, porcelain
veneers can be bonded to the remaining tooth structure to change shape, color or function.
14. Agenesis of lateral incisor.
2.2 Contra- Indications
Teeth having insufficient enamel.
Young permanent teeth.
Teeth exhibiting severe occlusal wear patterns, due to para-functional habits.
Severe periodontal involvement with severe crowding.
Poor oral hygiene.
Inability to etch the enamel in excessively fluoridated teeth.
Patients with high caries rate.
2.3 Ideal Requirements of a Veneer
1. Biological compatibility, especially with gingival tissues and periodontium.
2. Chemical durability of both the veneer material and its bond to enamel.
3. To be wear resistant.
4. Good aesthetics, which depends on: color of veneer, Translucency, Color of the luting agent,
Resistance to both staining and discoloration.
5. Replicate tooth contour, with a minimum thickness (not thicker than 0.5mm)
6. Smooth surface and margins, capable of retaining high lustre.
7. To be able to mask all sorts of discoloration without the need of an excessive increase in
thickness.
8. To be able to copy well, natural colours of tooth both at cervical and at its middle portion and
incisal.
9. To be easy to prepare.
10. When in service, to resist fracture and be easily repaired or substituted when fracture occurs.
11. To be of a low cost.
2.4 Diagnostic Considerations
2.4.1 Assessment of the face
It is important to assess the shape of the face, skin color, symmetry, maxillary and mandibular lip
lines. Patients with a narrow face may desire veneers with long and narrow teeth to emphasize the
facial shape or round and short teeth to soften the narrowness of the face. Veneers appear brighter
and high in value – dark skin and appear yellow and low in value as the skin tone becomes lighter.
2.4.2 Assessment of the smile
It is important to assess the shape, form, color of the teeth. The clinician should note the maxillary
incisal edge position in relation to the lower lip, the amount of gingival display during smiling and
speaking and the overall quality of the smile. In an ideal tooth arrangement, the smile line should
coincide or follow the curvature of the lower lip while smiling.
The space that includes the teeth and tissues (inferior border of the upper lip, superior border of the
lower lip) that is revealed when smiling is called the smile zone. Smile zones can be classified into the
following types namely - straight, curved, ellipse, bow, rectangular and inverted. This is helpful is
assessment of the smile. [6]
2.4.3 Photographs
The pre-operative photographs documents the pre-operative condition and aids the technician for the
veneer fabrication. This should include- a full face smile, retracted frontal view with the shade tab held
beneath the incisal edges of the maxillary incisors, a close-up view of the teeth to be veneered and a
post-preparation view with the shade tab.
2.4.4 Computer imaging and diagnostic mock Ups
Computer imaging of the patient’s smile and making the desired changes on the screen – provides
the patient and the dentist a realistic preview of the expected result. Preparation and waxing on the
diagnostic cast is necessary when veneers are required to lengthen teeth, close spaces or correct
mal-aligned teeth.
Technique for tooth preparation for porcelain veneer fabrication:-
Incisal edge preparation-Three preparation designs have been suggested regarding the incisal edge
preparation of ceramic laminate veneers:
the window or inter-enamel preparation,
the incisal bevel 0.5-1 mm
the overlapped incisal edge 2-4 mm preparation.
The window or inter-enamel preparation is used for minimal teeth preparation – removal of stains or
discoloration with no need for crown length correction. In this technique, the main preparation is on
the labial or facial tooth surface and the incisal portion just prepared from facial surface and no
preparation at all done at both incisal edge and palatal surface.The depth is equivalent to half the
thickness of facial enamel (0.5 – 0.75 mm - mid facially; 0.2 – 0.5 mm = gingivally). The
disadvantages manifested are decreased retention and weakened incisal portion of the ceramic
laminate veneers.
For the incisal bevel preparation technique the outline form includes the entire facial surface,
extending 0.5 – 1mm cervical to the mark at the gingival tissue level. The study of Castelnuovo
et.al,[8] revealed that the incisal bevel of 0.5-2 mm will result in nearly a butt joint and the palatal
reduction of the incisal edge will result in a chamfer finishing line. This leads to more strength of
veneer and decreases the risk of broken thin shell of non-supported veneers ledges, the incisal
bevel will strongly achieve that purpose especially in the case of multiple ceramic laminate veneers.
Half of the enamel thickness should be removed: 0.75mm- incisally; 0.5mm - mid facially; 0.3 mm -
gingivally on the facial surface.
Regarding the third preparation technique, the edge lapped or the overlapped incisal edge 2-4 mm
preparation, a study by Akogoluet.al, [9] assessed the failure mode and the load of fracture of ceramic
laminate veneers where the preparation are done and finished at either enamel or dentin. It revealed
that the lower fracture load was achieved when 4mm incisal reduction entirely done on dentin surface
than those of only 2 mm dentin reduction. It also concluded that the fracture resistance was nearly
similar with no statistical significant difference for both veneers of less than 2 mm preparation at the
incisal edge area and for intact teeth with no incisal edge preparation (the window type). Dentist
should be able to choose the proper preparation technique either incisal edge bevelling (0.5-1 mm) or
complete over-lapped technique (2-4 mm) according situation of the case to achieve long lasting
2.5 Preparation of Labial Surface
Since this surface resembles the most esthetic portion of ceramic laminate veneers, obtaining
the accurate preparation depth can be achieved via several methods. Depth cutter burs are very
useful to make grooves or cuts that control preparation depth. The depth for minimal invasive
approach is 0.5 mm.The standard reduction is 0.3 mm on the gingival third, 0.5mm on the middle
third, 0.7 mm on the incisal third of the labial surface and 1.5 - 2 mm on the incisal edge.The silicon
putty index after wax up is also helpful. Free-hand technique is not recommended for beginners
to avoid the risk of overcutting or unequal reduction levels of labial tooth surface.
2.6 Preparation of Interproximal Surface
There is no restriction regarding the interproximal tooth preparation for ceramic veneers. Few authors
recommended no-preparation especially with window type when a minor tooth discoloration confined
to facial surface with no interproximal extensions. Others advised a conservative interproximal
preparation with no contact area opening, if discoloration extended at proximal area. In diastema
closure, slight opening of the interproximal contacts is recommended. In some situation when
preparing multiple teeth with tight contact a slice preparation or breakage of contact will be advisable
in order to free way the contacts and enhance contour adjustments.
2.7 Palatal Extensions
Short wrapping – The veneer extends only to the facial margin of the tooth
Medium wrapping – The veneer extends into the bulk of the mesial or distal marginal ridge
by penetrating 50% of the interdental area
Long wrapping – The veneer encircles the entire interdental area
The margins should not be placed on the concavity but rather should be placed above the concavity
or below on the smooth convex area of the cingulum.
2.8 Cervical Margin Preparation
In porcelain laminate veneers cervical margin is one of the critical areas from esthetic and biological
point of view. Finish line may be at one of these three locations; supra-gingival, equi-gingival and
sub-gingival. The Supra-gingival finish line is more hygienic and biological for gingival tissues but less
esthetic. Chamfer finish line is more accepted and will be more beneficial for technician to determine
where to build and construct the porcelain laminate veneers. The sub-gingival finish line is more
esthetic but less biocompatible for the gingival tissues. This type can be used efficiently in case of
severely discoloured teeth like tetracycline stains to mask the undesirable discoloration at the cervical
margins. Cervical margins are a challenge for luting cement as fluids secreted from gingival crevice
impair a good seal between the fitting surface of laminate veneer and the tooth structure. Many
studies have concluded that if the tooth preparation was more conservative and confined to enamel,
the bond strength between recent resin cements and enamel will be better than with dentin [7].
Window preparation is
Preferred in Direct Composite Veneers.
Preserves lingual and incisal surfaces
Preservation of functional surfaces
Reduces wear of opposing tooth
Incisal lapping design is preferred for
Lengthening of tooth
Incisal defect
Facilitates seating of veneer
3. TECHNIQUE FOR DIRECT PARTIAL VENEER
Outline the extent of defect.
The Existing composite resin or decay is removed.
A Coarse elliptical/round diamond bur used to remove 0.5-0.75mm of the defective enamel.
Chamfer finish line for definite cavity margin.
Sub-gingival extension- if the defect is subgingival
Tooth is then etched with 37% phosphoric acid and dentin bonding agent is applied.
Microfilled or more opaque composite is placed depending on the extent of the defect.
4. TECHNIQUE FOR DIRECT FULL VENEER
Anesthetization and tooth isolation.
Shades of composite are tried on.
Half the depth of enamel-0.5-0.75mm mid facially and 0.2-0.5mm along gingival margin is
reduced.
Tooth is roughened and a definite chamfer finish line from papilla tip towards the incisal edge
on both the mesial and distal proximal surfaces.
Incisal edge included, reduce atleast 1mm.
Margins should be at the crest of the gingiva.
Shade selection and isolation.
Contoured anatomical matrix is placed and wedged loosely.
Tooth is then etched with 37% phosphoric acid and the dentin bonding agent is applied.
Composite is placed and cured and shaped with a composite roller in case of discoloured
teeth, opaquers are used to mask the defects