Complex restoration VENEERS Group members • Fortunata Cornel 2014-04-07155 • Robinson Imani 2014-04-07638 • Godlisten Swai 2014-04• Sakina Essajee 2014-04-07660 • Happiness Alphonce 2014-04-07217 overview Introduction to veneers Indications of veneers Contraindications of veneers Types of veneers Basic preparation designs direct veneers Indirect veneer techniques conclusion references introduction • A Veneer is a thin layer of tooth colored material applied on the tooth surface to restore localized or generalized defects and intrinsic discolorations. • The materials used are chairside composite, porcelain, processed composite and pressed ceramic material. Indication • Teeth with malformed facial surface • Severe discolored teeth such as fluorosis, tetracycline staining, devitalized teeth and teeth darkened with age which are not conducive for bleaching. • Eroded, abraded or having faulty restorations. • Enamel defects- i.e. small cracks, hypomineralisation • Diastema, single or multiple spaces between 1 or more teeth • Malpositioned teeth, i.e. peg laterals or rotated teeth • Repair of functionally sound metal-ceramic or all metallic restoration with unfavourable color. • Restoring anterior guidance in worn anterior teeth. Contraindications • Insufficient coronal tooth structure e.g. in 1/3rd loss of tooth structure due to fracture and grossly carious or extensively restored teeth. • Actively erupting teeth. • Parafunctional habits such as bruxism. • Severe periodontal involvement and crowding. • Endodontically treated tooth. • Class iii malocclusion or end to end bite. • Poor oral hygiene and high caries status. Types of veneers 1. Classified according to design •Partial or full. 2. According to method •Direct or indirect restorations Partial veneers • These are indicated for localized defects or areas of intrinsic discoloration. • When a small number of teeth are involved or when the entire facial surface is not faulty (i.e., partial veneers), directly applied composite veneers can be completed for the patient in one appointment with chairside composite Full veneers • Indicated for restoration of generalized defects or areas of intrinsic staining involving the whole surface of the tooth. • Full veneers can be accomplished by a direct or an indirect technique • Placing direct-composite full veneers is very time consuming and labor intensive. Direct veneers For cases involving a single discolored tooth, or when economics or patient time is limited, precluding a laboratory fabricated veneer, the direct technique is a viable option. Advantages • Only one appointment is required • The dentist can directly control form and color • Cost for the patient is reduced • Composite veneers are repairable. Indirect veneersare ones made outside of the mouth on a cast in the lab. • Indirect veneers require two appointments but typically offer three advantages over directly placed full veneers: 1. indirectly fabricated veneers are much less sensitive to operator technique. Considerable artistic expertise and attention to detail are required to achieve esthetic and physiologically sound direct veneers consistently. Indirect veneers are made by a laboratory technician and are typically more esthetic. 2. If multiple teeth are to be veneered, indirect veneers usually can be placed much more speed and efficiency. 3. Indirect veneers typically will last much longer than direct veneers, especially if they are made of porcelain or pressed ceramic Tooth preparation • To achieve esthetic and physiologically sound results consistently, an intraenamel preparation is usually indicated. Reasons for intraenamel preparation To provide space for opaque, bonding, or veneering materials for maximal esthetics without overcontouring. To remove the outer, fluoride-rich layer of enamel that may be more resistant to acid-etching. To create a rough surface for improved bonding. To establish a definite finish line. PREPARATION DESIGN FOR FULL VENEER Two basic preparation designs exist; (I) a "window" preparation, and (2) An incisal :lapping preparation Window preparation • Recommended for most direct and indirect composite veneers. This intraenamel preparation design preserves the functional lingual and incisal surfaces of the maxillary anterior teeth, protecting the veneers from significant occlusal stress. • A "window" preparation design also is recommended for indirectly fabricated porcelain veneers if the patient exhibits significant occlusal function as evidenced by wear facets on the lingual and incisal surfaces • By using a "window" preparation, the functional surfaces are better preserved in enamel. This design reduces the potential for accelerated wear of the opposing tooth that could result if the functional path involved porcelain on the lingual and incisal Incisal lapping preparation • Incisal lapping preparation is indicated when the tooth being veneered needs lengthening or when an incisal defect warrant restoration. Additionally, the incisal lapping design is frequently used with porcelain veneers, because it not only facilitates accurate searing of the veneer upon cementation, but also allows for improved esthetics along the incisal edge. • The preparation and restoration of a tooth with a veneer should be carried out in a manner that will provide optimal function, esthetics, retention, physiological contours, and longevity. All of these objectives should be accomplished without compromising the strength of the remaining tooth Direct veneer technique • Teeth are cleaned and isolated • The "window' preparation is typically made to a depth roughly equivalent to half the thickness of the facial enamel ranging from approximately 0.5 to .75 mm midfacially and tapering down to a depth of about 0.2 to 0.5 mm along the gingival margin, depending on the thickness of enamel. • A heavy chamfer at the level of the gingival crest provides a definite cavity margin for subsequent finishing procedures: The margins are not extended subgingivally. • The preparation for a direct veneer normally is terminated just facial to the proximal contact except in the area of a diastema. To correct the diastema, the preparations are extended from the facial onto the mesial surfaces, terminating at the mesio-lingual line angles. The incisal edges are not included in the preparations • The teeth should be restored one at a time. • After etching, rinsing, and drying procedures apply and polymerize the resin bonding agent. • Place the composite on the tooth in increments, especially along the gingival margin, to reduce the effects of polymerization shrinkage. • Place the composite in slight excess to allow some freedom in contouring. • It is helpful to inspect the facial surface from an incisal view with a mirror to evaluate the contour before polymerization. Indirect full veneers (1) Processed composite, (2) Etched porcelain. 1) Processed composite Prepared in laboratory to achieve superior properties. Using intense light, heat, vacuum, pressure, or a combination of these, cured composites can be produced that possess improved physical and mechanical properties compared with traditional chairside composites. Have two appointments First appointment Window preparation Incisal lapping Intraenamel preparation Elastomeric impression Second appointment Evaluate fit of veneer Tooth side of veneer is primed Tooth etched, rinsed and dried Adhesive cement applied Veneer placed and excess cement removed Light cured for 40-60 seconds facial and lingual 2)Etched porcelain • The most frequently used indirect veneer type is the etched porcelain. • Porcelain veneers etched with hydrofluoric acid are capable of achieving high-bond strengths to the etched enamel via a resinbonding mediums • In addition to the high-bond strengths, etched porcelain veneers are highly esthetic, stain resistant, periodontally compatible, and appear to significantly outlast composite veneers First Appointment • Tooth preparation We have four aspects of tooth preparation 1-Labial reduction 2-Interproximal reduction 3-Incisal modification 4-Cervical definition • Place a horizontal facial depth cut, it is usually 0.3 mm from proximal line angle to proximal line angle. Make this depth cut at the junction of the cervical and middle one-third of the facial surface of the tooth • Paralleling the entire gingival margin, prepare a definitive chamfer finish line. -Continue the definitive chamfer finish line with diamond bur from the papilla tip toward the incisal edge on both the mesial and distal proximal surfaces. • The facial depth cuts are removed with the diamond bur, and the long axis of the diamond bur is “rolled” into the proximal chamfer area to eliminate any sharp line angles. • Impression taking • Shade selection • Clean teeth with pumice and water to remove any extrinsic stains which exist • Apply temporary/provisional restoration Between appointments there are laboratory procedures Second appointment • Second Appointment (VENEER CEMENTATION PROCEDURE) Remove temporary veneer • Clinical try-in. Evaluate fit and esthetics All veneers should be placed without bonding medium on teeth to assess the fit. • preparing the restoration for cementation. Clean the restorations with acetone or Cavilax if you have tried it in with resin based systems. If you have used only water soluble medium (glycerin, K-Y jelly, Try-in pastes) you need only to rinse. • It is a good idea to clean with enamel etchant (35% phosphoric acid) to help clean any salivary contaminants that may have come in contact with the bonding surface. • Etch with porcelain etchant (porcelain conditioners- 10% HF acid). The time of etch depends on the ceramic materials used • Apply Porcelain Primer or Silane Coupling Agent. It is applied with a brush. The coupling agent acts to wet the surface of the porcelain. The silane coupling agent is allowed to set on the surface (usually for at least 60 sec but some are shorter periods). It can be dried with a gentle stream of air. Do Not Rinse. Set prepared veneer in a lightproof box until ready for cementation • Prepare tooth for bonding. • Isolation. Rubber damn isolation is usually not practical for multiple anterior cementation techniques. Cotton roll isolation and an assistant are usually sufficient for cementation. • Clean all tooth surfaces with rubber cup and pumice/water mixture or chlorohexidine soap/pumice mixture and rinse thoroughly. Place clear Mylar strip between involved adjacent teeth to minimize etching and placement of adhesive and cement on the adjacent unbonded teeth. • Do two veneers at a time. The sequence I usually use is: both centrals first, then lateral and cuspid on one side and finally the lateral and cuspid on the opposite side. • Apply the cement and light cure the porcelain veneer for at least 60 seconds. • Finishing and polishing procedures. conclusion • New emerging concepts in esthetic dentistry with regards to materials, technology and public awareness has made veneers on demand. • We should always keep in mind that we are dealing with organs which can change an individuals entire visual personality. A captivating smile showing an even row of natural gleaming white teeth is a major factor in achieving that elusive dominant characteristic called personality. The objective of cosmetic dentistry must be to provide the maximum improvement in esthetic with the minimum trauma to the dentition. references • Theodore M,Harald O, Edward J.(2002). Art and science of operative dentistry, Mosby health sciences company • Edwina A, Bernard G, Timothy F . (2003) . Pickards manual of operative dentistry, Oxford university press. • Qualtrough A, Satterthwaite J, Morrow L,Brunton P. (2005) . Principles of operative dentistry , Black well publishing company.
