Clinical

Porcelain laminate veneers. What, when and how?

Porcelain veneers have been around for many years and have shown high success rates. They can be used to correct discrepancies of size, shape, colour and position of teeth. This article aims to discuss the restoration of aesthetics with porcelain laminate veneers.

he 1998 Adult Dental Health Discoloured teeth often require more Survey highlighted that 27% of aggressive preparations, which allows for dentate adults were dissatisfied a greater thickness of porcelain to mask with the appearance of their the discolouration (Gabra et al, 1988). Tteeth. The most common reason for Physiological ageing can also result in dissatisfaction was the colour of their numerous crack lines appearing in the teeth followed by tooth alignment, enamel which, over time, can pick up spacing and broken teeth (Bradnock et and internalize stains (Table 1). Veneers al, 2001). can be used to mask these visual surface As a result we have seen a change in defects of enamel (Toh et al, 1987). patient attitude towards , with Figure 1. A single porcelain veneer. more patients seeking cosmetic treatment Correction of malaligned to improve their aesthetic appearance. surface. The porcelain veneer itself is a teeth and tooth size/shape It is not uncommon for today’s patients thin shell of porcelain (Figure 1) which discrepancies to present at the surgery requesting has relatively poor strength but once Patients with anterior malaligned teeth cosmetic procedure such as porcelain bonded to enamel with resin its strength should be encouraged to correct the veneers, which they have read about on increases (Walls et al, 2002). They are malocclusion to improve arch form the internet and magazines or seen on the often referred to as porcelain laminate and tooth position with a non-invasive television. veneers as they are placed on the labial approach using as a gold Porcelain veneers were first described surface of teeth, particularly the upper standard. In cases where the malocclusion by Horn in 1983 as a minimally invasive anterior teeth in order to create an is associated with intrinsic discolouration restoration used to improve the overall illusion that improves the aesthetics of and/or discrepancies in tooth size and colour and shape of teeth. Veneers have the original underlying teeth. shape, such as peg-shaped laterals, only recently become more popular due Indications for porcelain orthodontics alone may not improve the to advances in porcelain materials and aesthetics. In these situations, veneers bonding techniques, allowing bonding veneers may be considered as an adjunct to of porcelain to an etched enamel Masking discolouration and orthodontic treatment to improve the visual defects of anterior teeth overall aesthetics (Spear, 2004). The aesthetic appearance of teeth affected While orthodontics remains the Mital Patel and Kathryn Durey are by intrinsic staining can be improved with treatment of choice for correcting Specialist Registrars in Restorative veneers (Toh et al, 1987). The common malocclusions, there are many adult Dentistry, Paul A Brunton is a causes of intrinsic staining are shown in patients who will be reluctant to accept Professor of , Table 1. The level of staining can vary and this option and will want an alternative the ability of veneers to mask heavily- restorative treatment option (Curry, Leeds Dental Institute, Clarendon stained teeth depends on the opacity of 1999). This is often due to the duration Way, Leeds the porcelain used, luting cement shade of orthodontic treatment and the need and opaquers used, and thickness of the to wear a fixed orthodontic appliance Email: [email protected] restoration (RCS(Eng), 1997). (Shannon, 1999). If the occlusal

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create an illusion which restores correct Table 1. Sources of stains affecting the teeth anatomical proportions (Rouse, 1997). Contraindications to Extrinsic stains porcelain veneers and Stains that are outside of the tooth substance, either on the tooth surface or the acquired pellicle. Causes include: cigarettes/cigars; poor /chromogenic alternative options The primary goal of veneers is to bacteria; tea, coffee, red wine and other foods; mouthwashes (for example, chlorhexidine) improve aesthetics and not to restore

Intrinsic stains A Discolouration that has occurred due to changes to the structural composition of the teeth. These stains are within the structure of teeth and are caused by: Metabolic changes: Alkaptonuria, congenital erythropoietic porphyria, congenital hyperbilirubinaemia Inherited disorders: Amelogenesis imperfecta, dentinogenesis imperfecta Iatrogenic causes: Tetracycline staining, fluorosis Traumatic causes: Enamel hypoplasia, pulpal haemorrhage products Idiopathic causes: Molar incisor hypomineralisation B Ageing: Thinning of enamel and increased dentine deposition Internalised stains Incorporation of stain into the tooth structure post eruption due to development of defects on enamel surface. Usually occurs due to: caries and/or restorations relationship of the anterior teeth is shape can be corrected with veneers, favourable (adequate overbite/overjet and along with establishment of correct no crossbites), veneers can be used to interproximal contacts in an attempt to correct mildly malaligned, crowded and rotated teeth (Spear, 2004). C The veneers can be placed so that it allows correction of the bucco-lingual position of individual teeth and levelling of the incisal edges. Veneers however do not allow the correction of any discrepancies in the gingival zenith levels, which also play an important role in the overall aesthetic appearance. The position of the gingival zeniths can be corrected with -lengthening surgery, soft tissue grafting or by movement of teeth D in the vertical plane using orthodontics prior to placement of veneers (Kokich, 1997; Weihe, 1997). Patients presenting with a median or anterior interproximal spacing often have well-aligned teeth; however, there is a discrepancy between the size of the jaw and the teeth. Often the teeth are too small for the jaw (microdontia), which results in spacing Figures 2a–d. Pictures a and c show preoperative photos of teeth affected by and an unaesthetic appearance. These amelogenesis imperfecta. Aesthetics have been improved using composite resin as discrepancies in the tooth size and shown in pictures b and d.

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Figure 4. Commonly used incisal preparations. A—incisal overlap. B—incisal bevel. C—feathered incisal finish. (Incisal reduction required for a and b.) The teeth can often be restored with case selection and careful preoperative very minimal bevelling or no preparation treatment planning is essential (Walls et using composite resins (Figure 2). The al, 2002). The most important factor in material can be directly bonded to the restoring an aesthetic smile is the need to tooth and, unlike porcelain, it does not maintain symmetry and harmony in both need to be a certain thickness for strength the horizontal and vertical plane across Figure 3. Reduction of incisor in at least and optimal light-reflecting properties. the patient’s facial midline (Tipton, 2001). two planes and the use of silicone index Although composites stain more easily Patient assessment begins from the for tooth preparation. than porcelain, they have the advantage moment the patient walks into the surgery that they can easily be polished, repaired with an assessment of their smile line and function (Toh et al, 1987). It is, therefore, or replaced. Composites are however amount of tooth and gingival display at important that they are placed only in time consuming, technique sensitive and rest and while talking and smiling. This areas of minimal occlusal loading and require more patient compliance than is followed by an intraoral assessment also avoided in patients who are bruxists traditional veneers. of the soft tissues and teeth in terms of (Christensen, 1985). The labial surfaces Recently there has been much hype in size, shape, colour, position and relative of upper anterior teeth are well suited the media about lumineers. A lumineer proportions. to this when they are in a class I incisal is a very thin veneer made from patented The idea of golden proportion has relationship; however, veneers should be cerinate porcelain, which is strong in thin been mentioned in the literature but avoided in patients who have an edge-to- sections. They are approximately one-third is proven to be too rigid for use in edge (class III) incisal relationship or a to a half of the thickness of conventional dentistry, often resulting in narrowing of cross bite as these can result in excessive porcelain veneers and have been referred the maxillary arch (Magne et al, 2003). stresses during function resulting in the to as ‘contact lenses for teeth’. It is, therefore, better to plan treatment veneers failing (Sheets and Taniguchi, Compared to conventional veneers, based on average width-to-length ratios 1990). Veneers, along with other they require minimal or no preparation of teeth. If the length of teeth need to advanced restorative procedures, should of the tooth and can restore an aesthetic be increased, then a decision needs to also be avoided in patients with poor oral appearance in as little as two visits. be made as to whether or not you can hygiene and unstable periodontal disease. Currently there is no data on the long- add length to the incisal portion of the Alternative more conservative term outcome for lumineers and only veneer, i.e. to increase incisal show or treatment of extrinsic stains (Table 1), dentists who are registered with the does the gingival margin need to be and some intrinsic stains, can include a company that manufactures lumineers in moved apically with combination of microabrasion and tooth USA can provide them (Pillai, 2010). surgery or a combination of both. whitening. Advances in / The decision will depend on amount of bleaching techniques have recently seen Clinical technique from gingival display, tooth display, smile line a reduction in the need for veneers to and the incisal plane. The incisal plane of improve the overall aesthetic appearance. start to finish the upper maxillary teeth should be level Where these methods are not effective, Preoperative planning with and follow the lower lip line when or tooth size and shape is to be altered, Long-term follow up studies of the patient is smiling. modern composite resins now provide an veneers have shown high survival rates Once a detailed assessment has been excellent alternative veneering material to (Friedman, 1998; Dumfahrt and Schaffer, made alginate impressions, facebow and porcelain. 2000); however, to achieve these rates, interocclusal record need to be taken for

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articulated study casts. The laboratory technician should be given a detailed prescription for a diagnostic wax up based on your clinical assessment. The laboratory should also be asked to provide a clear suck-down matrix of the wax up, which can be filled with temporary crown and material chair-side and used to create a chair-side aesthetic preview to show the patient what the final results will look like. Once the patient and the clinician have approved the wax up, the teeth can be prepared for the veneers. The aim of tooth preparation is to define the margin of the veneer for the technician and create adequate space so that the veneer can be made without over contouring the restoration, which can lead to poor aesthetics and periodontal inflammation. At the same time the preparation needs to be as conservative as possible.

Tooth preparation Buccal reduction Ideally the preparation should remain within enamel; however, a number of studies have suggested that even with Figures 5a–b. Clinical photographs showing possible complications of porcelain care, the exposure of dentine is likely laminate veneers. (Nattress et al, 1995), which can result in sensitivity and microleakage around made using the diagnostic wax up, can the soft tissue during preparation should the margins if into dentine (Pashley, help the clinician to visualize the shape be considered (Walls et al, 2002). 1990). At the cervical margin where and depth of preparation required in the enamel is thinnest, a reduction of order to achieve the final desired aesthetic Interproximal preparation 0.4 mm is advised, increasing to 0.7 mm result (Brunton et al, 2000). The overall Interproximally, it may also be necessary towards the middle third of the tooth shape of the preparation should mimic to extend the preparation further (Walls et al, 2002). the natural curvature of the tooth and proximally below the contact point to Preparation techniques can include therefore it should be performed in at disguise discolouration, but care should be free-hand preparation using diamond burs least two planes (Figure 3). taken to avoid the creation of undercuts. or the use of depth grooves which are made Ideally the preparation should not extend using standard burs of known diameter Marginal definition through the contact points. In cases or specially designed depth-gauge burs. At the cervical margin, a chamfer finish where veneers are being used to correct While these burs have shown a reduction line of 0.4 mm depth should be produced. malaligned teeth, this may be necessary— in the variation in preparation depth Where possible, subgingival extension of in which case, appropriate temporization in comparison to free-hand preparation the buccal margin should be avoided as is necessary to prevent tooth movement (Cherukara et al, 2002), several authors this increases the risk of gingival trauma between preparation and cementation have reported that preparations made and makes it difficult to control moisture (Rouse, 1997). using depth-gauging burs are often during cementation. However, in cases over prepared in comparison to those with marked discolouration, this may Incisal preparation prepared freehand, which tend to be be necessary to achieve an acceptable Four types of preparation for the incisal underprepared (Linden et al, 1991). The aesthetic result and the use of retraction edge have been described and these were use of a sectioned putty matrix (Figure 3), cord or a flat plastic instrument to protect illustrated clearly by Walls et al (2002).

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Of these the three most commonly used Temporization The setting mechanism of the cement are shown in Figure 4. The decision The ideal temporary restoration is one should also be considered. Light-cure relating to type of preparation is mainly that is aesthetic, protects the tooth and and dual-cure cements are available and a an aesthetic one, as there is little evidence maintains the while being easy decision should be made considering the available to support one particular to remove without causing damage to the thickness of the veneer. This is important technique in terms of longevity. If the preparation. Temporization of veneers as polymerization of cements light-cured length of the tooth needs to be increased is best avoided where possible as the through opaque porcelain or porcelain or the tooth is heavily discoloured, the typically unretentive form and minimal of more than 0.7 mm, has been found veneer should be extended over the nature of the preparations makes it to be inadequate (Linden et al, 1991). incisal edge, using either the incisal notoriously difficult. However, if there is a In this situation, dual-cure materials are overlap or bevel preparation. This allows risk of sensitivity, tooth movement or the recommended (Santos, 2004). Where greater control of aesthetics; however, aesthetics of the preparations are poor, porcelain is thinner, light-cured cements sufficient reduction must take place to direct composite veneers or resin-based are advised as dual-cure materials do ensure that porcelain thickness is at least temporary veneers made from temporary not polymerize as effectively and this 0.5 mm in order to resist fracture. crown and bridge material can be placed. may affect their long-term colour stability A preformed clear suck-down matrix (Peutzfeldt, 1995). Impression taking based on a wax up can facilitate this Once the luting cement has been selected A good impression is paramount in (Reshad et al, 2008). Ideally the matrix the veneer should be cleaned with an the successful provision of porcelain should not extend beyond the gingival alcohol-based solvent prior to cementation veneers. Due to the precise nature of the margins of the preparations so that excess to remove contaminants. Similarly, restorations the impression material used material can be removed easily. It is the preparations should be pumiced needs to be accurate and dimensionally important to ensure that the temporaries immediately prior to cementation and stable. Elastomeric materials are fit well and do not compromise oral ideally any existing composite restorations considered to be the materials of choice. hygiene or gingival health as gingival replaced (Dunne and Millar, 1993). In the general practice setting, addition inflammation can make cementation To ensure maximum bond strengths, cured silicones are commonly used for difficult due to compromised moisture strict moisture control should be maintained indirect restorations (Brunton et al, control. To increase strength, the throughout the cementation procedure. 2005) due to their superior dimensional temporaries can be linked together. This can be achieved using rubber dam or stability, which means dies are accurate The temporary restorations can be by more conventional means such as cotton- even if impressions are not poured cemented using a spot-etch technique wool rolls and gingival retraction cord. It straight away. A delay in casting is often in the centre of the labial surface only is important to read the manufacturer’s unavoidable if the impression needs to to ensure easy removal. Often, if a suck- instructions, as there are likely to be subtle be posted or transferred to a laboratory down matrix is used the material can be differences in procedure between luting off site. Usually a light-bodied material left to set in situ. While it sets, there will systems. In general terms, after pumicing, is syringed over the prepared teeth and be some shrinkage of the material around the preparations should be etched, washed, the margins to pick up fine detail and a the preparations which will help retain dried and a dentine/enamel bonding agent heavier material is placed in the stock tray the temporary veneers, thus eliminating applied to the tooth. The veneer can then for the bulk of the impression. the need for a temporary cement. be positioned and excess cement removed For an accurate impression, it is from the margins prior to light curing. If also necessary to ensure good moisture Cementation finishing is required, this should be done control as silicone-based materials The definitive veneers should be tried in the using fine diamond burs and finishing discs. are hydrophobic (repelled by water). mouth prior to their cementation. As the This can often be achieved with the restorations are generally less than 1 mm Prognosis use of salivary ejectors, cotton wool thick, they are fragile and difficult to handle Patient satisfaction rates with porcelain rolls and patient education. Just prior and care is required. The shade of the veneer veneers are generally high (Granell-Ruiz to seating the impression the teeth, should be assessed and if necessary, there is et al, 2010). Nonetheless, porcelain veneers especially around the margins, should some capacity to alter shade by choosing are unlikely to maintain aesthetics for as be dried using the air from the 3 in 1. an appropriate shade of luting cement. The long as the tooth remains in function Once set the impression needs to be effect of the luting cement can be assessed and will over time require replacement carefully assessed under good lighting by using the try-in paste provided in most causing some further damage to the and magnification to check for obvious kits, which is equivalent to the shade of underlying tooth structure. In a study of flaws like air blows or drags. cement lute chosen. 323 veneers followed up for a minimum

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three years, marginal discolouration was veneers have been proven to give a good 15(3): e531–7 described as the most frequently occurring aesthetic result; however, it is an invasive and Horn HR (1983) Porcelain laminate veneers bonded to etched enamel. Dent Clin North Am 27(4): complication (39.2 per cent of veneers). irreversible treatment option which subjects 671–84 This, however, may not necessitate the patient to life-long commitment to Kokich VG (1997) Esthetics and vertical tooth replacement of the veneer. Reasons for restorative dentistry. Successful provision of position: orthodontic possibilities. Compend Contin Educ Dent 18(12): 1225–31 replacement may include decementation porcelain laminate veneers requires careful Linden JJ, Swift EJ Jr, Boyer DB, Davis BK (1991) of the veneer, fracture of the porcelain, preoperative planning and a high level of Photo-activation of resin cements through porcelain veneers. J Dent Res 70(2): 154–7 gingival recession causing exposure of operator skill from tooth preparation to Magne P, Gallucci GO, Belser UC (2003) Anatomic the veneer margin, secondary caries, and cementation. DN crown width/length ratios of unworn and worn sensitivity (Peumans et al, 2004). maxillary teeth in white subjects. J Prosthet Dent Bradnock G, White DA, Nuttall NM, Morris AJ, 89(5): 453–61 Figure 5 shows clinical photographs of Treasure ET, Pine CM (2001) Dental attitudes Nattress BR, Youngson CC, Patterson CJ, Martin replacement veneers in the upper arch to and behaviours in 1998 and implications for the DM, Ralph JP (1995) An in vitro assessment restore aesthetics in teeth heavily stained future. Br Dent J 190(5): 228–32 of tooth preparation for porcelain veneer Brunton PA, Aminian A, Wilson NH (2000) Tooth restorations. J Dent 23(3): 165–70 by tetracycline staining. While aesthetic preparation techniques for porcelain laminate Pashley DH (1990) Clinical considerations of have been improved there is still some veneers. Br Dent J 189(5): 260–2 microleakage. J Endod 16(2): 70–7 Brunton PA, Christensen GJ, Cheung SW, Burke Peumans M, De Munck J, Fieuws S, Lambrechts P, show through of the heavily discoloured FJ, Wilson NH (2005) Contemporary dental Vanherle G, Van Meerbeek B (2004) A prospective teeth. Also note the lower veneers which practice in the UK: indirect restorations and fixed ten-year clinical trial of porcelain veneers. J Adhes were placed several years ago but now . Br Dent J 198(2): 99–103 Dent 6(1): 65–76 Cherukara GP, Seymour KG, Samarawickrama DY, Peutzfeldt A (1995) Dual-cure resin cements: in show exposed veneer margins due to Zou L (2002) A study into the variations in the vitro wear and effect of quantity of remaining recession and fractures of the veneers. labial reduction of teeth prepared to receive double bonds, filler volume, and light curing. porcelain veneers--a comparison of three clinical Acta Odontol Scand 53(1): 29–34 Fortunately these complications occur techniques. Br Dent J 192(7): 401–4 Pillai S (2010) Lumineers: minimal preparation relatively infrequently (Granell-Ruiz et al, Christensen GJ (1985) Veneering of teeth. State of veneers. http://tinyurl.com/32b2c44 (accessed 2010) and, in general, given appropriate the art. Dent Clin North Am 29(2): 373–91 20 July 2010) Curry FT (1999) Restorative alternative to Royal Collage of Surgeons (Eng) (1997) Faculty case selection, survival rates are good. orthodontic treatment: A clinical report. of National Clinical Guidelines. A small proportion of veneered teeth J Prosthet Dent 82(2): 127–9 Restorative indications for porcelain veneer may lose vitality and as a result will require Dumfahrt H, Schäffer H (2000) Porcelain laminate restorations. Faculty of Dental Surgeons of Royal veneers. A retrospective evaluation after 1 to 10 College of Surgeons of England, London endodontic treatment. This is most likely years of service: Part II – Clinical results. Int J Reshad M, Cascione D, Magne P (2008) Diagnostic to occur in young teeth with large pulp Prosthodont 13(1): 9–18 mock-ups as an objective tool for predictable Dunne SM, Millar BJ (1993) A longitudinal study of outcomes with porcelain laminate veneers in chambers and those where discolouration the clinical performance of porcelain veneers. Br esthetically demanding patients: a clinical report. necessitates a more extensive preparation. If Dent J 175(9): 317–21 J Prosthet Dent 99(5): 333–9 the veneer is clinically sound, this scenario Friedman MJ (1998) A 15-year review of porcelain Rouse JS (1997) Full veneer versus traditional veneer failure--a clinician’s observations. veneer preparation: a discussion of interproximal is unlikely to require its replacement. Compend Contin Educ Dent 19(6): 625–8, 630, extension. J Prosthet Dent 78(6): 545–9 632 Santos GC Jr, El-Mowafy O, Rubo JH, Santos MJ Conclusions Gabra DA, Goldstein RE, Feinman RA (eds) (1988) (2004) Hardening of dual-cure resin cements and Porcelain Laminate Veneers. Quintessence, a resin composite restorative cured with QTH It is important to remember the ultimate Chicago and LED curing units. J Can Dent Assoc 70(5): objective of any dental treatment is to Granell-Ruiz M, Fons-Font A, Labaig-Rueda C, 323–8 Martínez-González A, Román-Rodríguez JL, Shannon A (1999) Reconstruction of the maxillary restore health and function as well as Solá-Ruiz MF (2010) A clinical longitudinal study dentition utilizing a non-orthodontic technique. aesthetics using the most conservative 323 porcelain laminate veneers. Period of study Pract Periodontics Aesthet Dent 11(8): 973–6, 978 from 3 to 11 years. Med Oral Patol Oral Cir Bucal Sheets CG, Taniguchi T (1990) Advantages and method of treatment. Porcelain laminate limitations in the use of porcelain veneer restorations. J Prosthet Dent 64(4): 406–11 Spear FM (2004) The esthetic correction of anterior dental mal-alignment conventional vs. instant Key points (restorative) orthodontics. J Calif Dent Assoc n Porcelain veneers are a minimally invasive method of improving the 32(2): 133–41 Tipton PA (2001) Aesthetic tooth alignment using aesthetics of anterior teeth. etched porcelain restorations. Pract Proced Aesthet Dent 13(7): 551–5 n Success depends on appropriate case selection and thorough planning. Toh CG, Setcos JC, Weinstein AR (1987) Indirect dental laminate veneers--an overview. J Dent n Tooth reduction should ideally remain within enamel and mimic the 15(3): 117–24 natural curve of the tooth. Walls AW, Steele JG, Wassell RW (2002) Crowns and other extra-coronal restorations: porcelain n Complications such as discolouration, fracture and sensitivity may laminate veneers. Br Dent J 193(2): 73–6, 79–82 Weihe RG (1997) Postorthodontic restoration with occur. However, generally these are relatively infrequent and patient a combination of gingivoplasty and porcelain satisfaction is high. veneers. Compend Contin Educ Dent 18(8): 744– 8, 750

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