Veneer

Porcelain Veneers
Comparison between a porcelain-metal dental crown, an all-porcelain dental crown and a porcelain veneer laminate
Specialty	{{#statements:P1995}}
MeSH	D003801

Definition

According to GPT(Glossary of Prosthodontic Terms), a veneer is :

1. a thin sheet of material usually used as a finish;
2. a protective or ornamental facing;
3. a superficial or attractive display in multiple layers, frequently termed a laminate veneer.

Types of Veneers

Comparison between a porcelain-metal dental crown, an all-porcelain dental crown and a porcelain veneer.

1.Laminate Veneers

Laminate veneering is a conservative method of restoring the appearance of discolored, pitted, or fractured anterior teeth. It consists of bonding thin ceramic laminates onto the labial surfaces of affected teeth. The bonding procedure is the same as that for ceramic inlays except that a photopolymerizing luting resin is usually used.

Advantages and Indications

The main advantage of laminate veneers is that they are conservative of tooth structure. Typically, only about 0.5 mm of labial reduction is needed. Because this is confined to the enamel layer, local anesthesia is not usually required. The main disadvantage of the procedure relates to difficulty in obtaining restorations that are not excessively contoured. This is almost inevitable in the gingival area if enamel is left for bonding. Little has been reported about the effect of the restorations on long-term gingival health or how often they need replacement over a patient’s lifetime. Esthetic veneers should always be considered as a conservative alternative to cemented crowns. In many practices, they have largely replaced metal-ceramic crowns in the treatment of multiple discolored but otherwise sound anterior teeth. Extensive existing restorations are a contraindication to porcelain laminate veneers.

2.Partial Veneer Crowns

Several types of partial veneers are available: for posterior teeth, there are three-quarter, modified three-quarter, and seven-eighths crowns; for anterior teeth, three quarter crowns and pin ledges.

Indications

Partial veneer crowns can often be used to restore posterior teeth that have lost moderate amounts of tooth structure, if the buccal wall is intact and well supported by sound tooth structure. They may be used as retainers for an FDP or wherever restoration or alteration of the occlusal surface is needed. Anterior partial veneers are rarely suitable for restoring damaged teeth, but they can be used as retainers, offer a conservative approach to reestablish anterior guidance, and can be used to splint teeth. They are particularly suitable for teeth with sufficient bulk because they can accommodate the necessary retentive features.

Contraindications

Partial veneer restorations are contraindicated on teeth that have a short clinical crown because retention may not be adequate. They are also contraindicated as retainers for long-span FDPs. They are rarely suitable for endodontically treated teeth, especially anterior teeth, because the remaining tooth structure is insufficient for the retentive features. Likewise, they should not be used on endodontically treated posterior teeth if the buccal cusps are weakened by the access cavity or on teeth with extensively damaged crowns. As is true of all cast restorations, partial veneer restorations are contraindicated in the presence of active caries or periodontal disease. The shape and alignment of teeth are important determinants of the feasibility of partial veneer crowns. The alignment of axial surfaces should be evaluated, and partial veneer crowns should not be prepared on teeth that are proximally bulbous. Making the necessary proximal grooves on these teeth will leave unsupported enamel. Similarly, it is often not possible to prepare adequate grooves on thin teeth with restricted faciolingual dimension. Partial veneer crowns are usually prepared parallel to the long axis of the tooth, and poorly aligned abutment teeth are a contraindication. When poorly aligned teeth are prepared for a partial-coverage restoration, problems with unsupported enamel often result.

Advantages

The primary advantage associated with partial veneer crowns is conservation of tooth structure. Another advantage is reduced pulpal and periodontal insult during tooth preparation. Access to supragingival margins is rather easy, and the operator can perform selected finishing procedures that are more difficult or impossible with complete coverage restorations. Access is also better for oral hygiene. Because less of the margin approximates the soft tissues subgingivally, there is less gingival involvement than with complete coverage. During cementation of a partial veneer, the luting agent can escape more easily than during cementation of complete cast crowns, which facilitates seating of the restoration. Because of direct visibility, verification of seating and cement removal are simple. When the restoration is in service, the remaining intact facial or buccal tooth structure enables electric vitality testing.

Disadvantages

Partial veneer restorations have less retention and resistance than do complete cast crowns. Tooth preparation is more challenging because only limited adjustments can be made in the path of placement. The preparation of grooves, boxes, and pinholes requires dexterity of the operator. Some metal is displayed in the completed restoration, which may be unacceptable to patients.

3.Gum Veneers

Initially, hard veneers were made with acrylic but they caused damage to the gingiva as they were hard, and also, veneering beyond the canine was not possible due to undercuts. Now flexible gum veneer made of silicone has replaced acrylic to overcome these problems. Moreover, there is more patient comfort and esthetics. The veneer will have to be redone every 6–12 months depending on habits such as smoking and dietary habits.

Indications

1. Gingival recession and open interdental spaces due to loss of papillae after periodontal disease or therapy
2. Open interdental spaces causing phonetic problems
3. Provisional coverage prior to definitive restorations

Contraindications

1. Poor oral hygiene
2. Untreated or unresponsive periodontal health
3. High caries activity
4. Patients with a known allergy to silicone

See also

• Cosmetic dentistry
• Crown (dentistry)
• Dental restoration
• CAD/CAM Dentistry
• Prosthetic dentistry
• Light activated resin

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