Veneers

Veneers are wafer-thin, usually laboratory-produced veneers made of ceramic, which are made especially for the anterior region. In esthetic dentistry, the veneer technique makes a significant contribution to helping patients achieve a more attractive and thus more confidently beautiful smile. Nevertheless, the planning of veneers should be preceded by such basic treatment measures as intensification of individual oral hygiene technique, regular dental examinations and professional dental cleaning (PZR).

Indications (areas of application)

  • Minor anterior incisal edge fractures.
  • Anatomical shape anomalies, e.g., peg tooth or mesialized (orthodontically moved forward) canines in position of a second incisor when it is not present
  • Cosmetic or functional incisal edge lengthening.
  • Tooth discoloration
  • Replacement of aesthetically unsatisfactory anterior fillings, especially enamel-margined cervical fillings.
  • Low-grade enamel hypoplasia (enamel formation disorder), which does not expect a sufficient supply of healthy enamel.
  • Low-grade dental malocclusions
  • Conclusion of a tremolo (diastema mediale) or other diastemas (gaps) in the anterior region.
  • As a compromise in adolescent patients with extensive pulp (tooth pulp), by which a crowning indicated in itself is still prohibited, to gain time.

Contraindications

  • Extensively exposed dentin (tooth bone).
  • Carious lesions or composite fillings in the anterior region extending far towards the approximal region
  • Proximal carious lesions or composite fillings extending to the oral tooth surface (toward the oral cavity)
  • Higher degree enamel hypoplasia with insufficient supply of healthy enamel.
  • Large crown fractures (fracture in the enamel and far in the dentin area).
  • Conditions in the occlusion (final bite relationship of the upper and lower jaw) that make a longer retention time of the veneer questionable, e.g. bruxism (grinding), head bite relationship of the incisors or positive anterior step (upper incisors bite behind the lower ones)
  • Extraordinary stress on the veneer restoration, e.g. chewing on pens or similar, opening bottles, etc.
  • Extreme tooth discoloration may not be satisfactorily covered by the thin veneer layer even by conventional veneers; here, if necessary, bleaching in advance.
  • Tooth neck fillings or carious tooth neck lesions that are not enamel-limited after apical (towards the root).
  • Extreme tooth misalignments can not be corrected by veneers without exposing large areas of dentin during preparation
  • Allergy to luting composite

Before treatment

First, there is a discussion of the expected treatment result with the patient. For this purpose, situational impressions of the patient can be taken, which the dental laboratory uses to create situational models made of plaster and, in turn, a so-called wax-up: a wax application simulates the future shape of the tooth. Even more vivid is the simulation of the result with the help of digital imaging, a process in which patient photos are digitally processed.Heavily discolored teeth should be whitened (bleaching) before veneers are made.

The procedures

A. Conventional veneers

A.1. preparation (grinding).

  • Before the actual preparation, impressions are taken, which are then used to provide the teeth with copings made of temporary acrylic material.
  • If necessary, local anesthesia (local anesthesia), waiver of anesthesia possible.
  • Reduction of enamel on the labial side (side facing the lip) of the tooth occurs between about 0.5 mm and 1.5 mm, with the greatest removal in the incisal edge area in the form of an incisal plateau, if this is to be replaced or lengthened. For depth marking, diamond set groove grinders are used, for example.
  • Rounding of the transition between the labial surface and the incisal plateau.
  • The natural proximal contacts (lateral contact with the adjacent tooth) should be preserved, unless veneers are used to close the gap.
  • Preparation impression, on the basis of which the laboratory creates an overall model and so-called die models of the ground teeth, on which the veneers are made.
  • Bite taking to enable the laboratory to bring the upper and lower jaw models into the correct positional relationship with each other
  • Shade selection by means of a color ring corresponding to the veneer material used.
  • Fabrication of the supply copings to protect against enamel edge breakage.
  • Restoration with copings by cementing with eugenol-free (clove oil-free) temporary cement.
  • Alternative: isolation of teeth with glycerine gel, then fabrication of a temporary made of light-curing composite and cementation using enamel-adhesive technique on the smallest area.

A.2. fabrication of the veneer in the laboratory.

The veneer is usually made of pressed ceramic. The resulting monochromatic core serves as the basis for individual painting with fine ceramic mass, which is fired at high temperatures. An alternative and more time-consuming procedure is direct layering of the veneer from ceramic material with final firing at high temperatures, whereby the individualization takes place during the layering process. A.3. insertion using the adhesive technique

If several teeth are to be restored with veneers, adhesive cementation must be performed individually for each tooth after the rubber dam has been placed. The teeth must be separated from each other with transparent matrix pieces.

  • Removal of the temporary restoration, tooth cleaning with paste and brush or rubber cup.
  • Veneer try-in with fit and color control.
  • Shade optimization by selecting the color of the luting composite.
  • Pre-treatment of the veneer inner surface: etching with hydrofluoric acid, thorough rinsing, drying, silanizing (chemical bonding of a silane compound to a surface).
  • Applying a cofferdam (tension rubber) to protect against saliva access in the attachment phase.
  • Protection of the adjacent teeth by matrices
  • Pre-treatment of the tooth: etch enamel with 35% phosphoric acid for 30 sec, spray off for at least 20 sec, dry.
  • Brushing of the bonding on veneer inner side and enamel, drying time and light curing according to manufacturer’s instructions.
  • Application of pure light-curing luting composite on veneer and/or enamel.
  • Careful pressing of the veneer onto the prepared surface until in final position.
  • Optional: fixation of the veneer by light curing only incisal (from the incisal edge) for a few seconds.
  • Removal of excess composite
  • Application of glycerine gel on the adhesive joint: under contact with air, an oxygen inhibition layer is formed on the composite surface; this washes out after completion of the treatment, as a result, the now excess adhesive joint can deposit dyes. Glycerine gel prevents oxygen contact and ensures complete curing of the joint.
  • Further light curing from all sides for 60 sec each.
  • Fine corrections with polishers, finest-grained diamonds, etc.
  • Cofferdam removal
  • Now only control and fine-tune the occlusion (final bite relationship of the upper and lower jaw) and articulation (chewing movements).
  • Final fluoridation to improve the surface structure of the conditioned (etched) enamel.

B. Non-prep veneers (non-invasive veneers)

Unlike conventional veneers, which involve a small amount of removal of tooth structure, the non-prep procedure manufactured veneers ideally completely eliminates the need for preparation. This results in the following differences and advantages or disadvantages to the former procedure:

Advantages:

  • No loss of tooth structure, thus later removal of the veneers without compulsion to re-provide possible.
  • Complete absence of pain without preparation, thereby no local anesthesia required.
  • No temporary care necessary
  • Time saving
  • Suitability for anxiety patients
  • Good suitability for gap closure and extension
  • Therapy for teeth whitening when the success of bleaching is insufficient.

Disadvantages:

  • Only about 0.3 mm thin, so much thinner than conventional veneers.
  • Too thin to cover dark tooth shades or discoloration.
  • To create a harmonious image of the dental arch, several teeth must be treated with non-prep veneers
  • Tooth misalignments not correctable to the same extent as with conventional veneers
  • Dental laboratory must have special ceramics on hand

Possible complications

The following complications may arise from the many intermediate steps of the procedures:

  • Providing veneers despite bruxism or other extraordinary stress on the veneers.
  • Demolition of enamel edges on the prepared tooth before insertion of the veneer.
  • Fracture of the veneer before adhesive cementation.
  • Fracture of the veneer due to insufficient rounding of the transition between the labial (side facing the lip) and incisal (from the incisal edge) preparation surfaces.
  • Lack of biological compatibility of the luting composite/allergy: the decisive role here is played by the unavoidable residual content of monomer (individual components from which the larger and thus hardened polymers are formed by chemical combination) in the finished polymerized material
  • Discoloration or marginal caries due to insufficient application of luting composite in the adhesive joint between tooth and veneer or due to washing out of the oxygen inhibition layer