The aesthetics in dentistry play an important role today. Several surveys show that between 75 and 90 per cent of the people surveyed consider well-maintained and beautiful teeth an important feature of an attractive appearance. Aesthetic restorations in the anterior and posterior range should thus not be discernable from the natural tooth substance and the intervention minimally invasive.
Patients are no longer willing to compromise, especially when it comes to restorations in the anterior range. Restorations with discoloured or dark, insufficient margins are tolerated less and less and even perceived as aesthetically detracting. The rule of thumb is that the restoration should be 'invisible' from speaking distance.
The demand for highly aesthetic and durable restorations is met with the employment of modern composite in multiple shade variations, opacities and degrees of translucency used with the corresponding adhesive technique and minimally invasive preparation technique. Even larger defects can be restored with modern composites to achieve outstanding results. With the appropriate indication and analysis (functional analysis) there is no need to fear the comparison of the result to full ceramic restorations.
Case study: Anterior tooth restoration
A 24-year-old patient presented with an insufficient anterior restoration on tooth 21 (figs 1 and 2). After consulting with patient and explaining the different therapy alternatives, such as crowns, indirect veneers or replacing the restoration with a highly aesthetic composite, the patient decided on the latter option due to its gentleness to the tooth substance.
Checklist and planning
It is crucial for aesthetic success that one gathers sufficient information in advance about the tooth to be restored, the neighbouring teeth, and their structure and shape characteristics. Because the tooth dehydrates during the treatment and thus appears lighter and more opaque, the shade determination is carried out on the moist tooth after the elimination of extreme colour contrasts. This should not be changed during the treatment (with and without a rubber dam).
The shade of the upper cuspid is a guide for the correct undertone of the dentine shade. The enamel shade is determined from the incisal edge of the neighbouring teeth, here on tooth 11. In addition to the shade selection, an analysis of the shape is also important. To accomplish this, a sketch should be made with characteristics such as incisal edge contour, dentine zone, transparency zone, margins, bulges and shade anomalies. A photo status is additionally very helpful and especially easy nowadays with digital photography.
A silicone shell was fabricated in this case, which reflects the palatal and incisal contour of the tooth. An initial shape made from composite can be quickly fabricated using this shaping aid. With the assistance of the shell, the tooth can be reconstructed and later grinding of premature contacts in the area of the guide surfaces minimised.
The contact points and the vestibular-oral dimensions can also be restored relatively quickly in the direct multi-layer technique (fig 3). To provide stable placement during its use, the silicone shell should extend to at least the neighbouring teeth.
Preparation
The treatment area has been isolated with a rubber dam from 14-24 (fig 4) and the silicone shell cut in a way so that it easily fits without a gap despite the rubber dam (fig 5). The rubber dam provides an absolutely dry working field and facilitates a better overview of the treatment field. This allows one to calmly concentrate on the layering of the restoration, without worrying about the working field being contaminated with saliva and/or blood, which can lead to impairment of the bonding properties of the adhesive system.
The old restoration is removed, the caries excavated and the bead seal determined. Appropriate SonicFlex instruments are used in the approximal areas to avoid injury to the neighbouring teeth (fig 6).
The margin structure is important for creating an 'invisible' transition later. To conceal the transition, care should be given when preparing the labial, broad chamfer (2-3mm) with a fine-grain diamond bur (fig 7) to ensure that it is rounded and not uniform. An undulated progression is additionally helpful, since this type of chamfering prevents bundled light refraction (fig 8). A narrow chamfer of 0.5-1mm is sufficient palatal, which is prepared with a palatal bud (fig 9).
Adhesive technique
The conditioning of the enamel and dentine was carried out with 35 per cent orthophosphoric acid in the total-etch technique after the preparation. The conditioning should provide a micro-retentive etching pattern in the enamel and, in the dentine, the smear layer should be dissolved, the dentine tubules opened and the collagen fibres exposed.
The neighbouring teeth were isolated with a Teflon band first and thus protected. The mere razor-thin layer of the Teflon band ensures a tight approximal contact. This also permits simple layering and modeling, since matrices are very cumbersome.
The etching procedure was carried out in two steps, in which the etching gel (Vococid, Voco) is applied to the enamel area first for 15 seconds and then the remainder of the cavity or dentine filled in afterwards. The etching gel
should be left there for a maximum of 15 seconds (fig 10). The total etching time is ca.30 seconds for the enamel and 15 seconds for the dentine. These etching times should not be exceeded to avoid over-etching.
Rinsing and cleansing the phosphoric acid and precipitation remains from the enamel with the air-water spray should take place for a minimum of 20 seconds or preferably 30 seconds. The airjet was used to subsequently dry the treated surfaces. It is important to avoid over-drying the dentinal surface to prevent a collapse and/or the collagen fibres from adhering to each other. Otherwise, the adhesive cannot penetrate the fibres and post-operative sensitivities can result. The dentine should exhibit a slightly moist, glistening surface and the enamel should typically have a chalky-white appearance (fig 11). A possible over-drying and/or collapse of the collagen network can partially be reversed by re-wetting the dentine with a moistened micro-brush.
The hydrophilic primer of the Solobond Plus (Voco) adhesive system was rubbed uniformly into the dentine with a micro-brush for a minimum of 30 seconds as the second step (fig 12). This ensures adequate penetration into the collagen network and dentine tubules. After the reaction time, the primer was carefully dried with the airjet until a thin, shiny, even film developed on the dentinal surface (fig 13).
The adhesive was subsequently applied to the entire cavity (fig 14). A reaction time of ca.10-20 seconds is required for the adhesive to mix with the primer particularly in the dentine tubules and to form a hybrid layer. After a corresponding examination and drying of the excess bonding with the airjet, the hybrid layer and adhesive are stabilised from the polymerisation and now offer the composite an ideal foundation as the connecting link (fig 15).
Highly aesthetic composite
With anterior restorations, shade, translucency as well as good handling during the layering of enamel and dentine are a priority. The build-up of the anterior restoration is carried out here with Amaris (Voco), a highly aesthetic, light-curing, composite-based restorative. The system features five opaque shades (O1 to O5) and three translucent shades (TL, TN, TD). Amaris (Voco) thus permits a simple and safe layering technique and facilitates individual shaping and colouring. Two flowable materials (highly translucent HT and highly opaque HO) are available for special effects.
The first step was creating the design of the palatal shape with the assistance of the previously fabricated silicone shell. Additionally, the translucent composite (Amaris TN) was thinly applied to the silicone shell (fig 16) and adapted to the palatal surface of the tooth (fig 17). The composite was uniformly shaped from vestibular with a Heideman spatula, while holding the silicone shell. The composite was subsequently polymerised for 20 seconds first from vestibular, then from palatal. The approximal surfaces were directly shaped onto the Teflon band with a spatula (fig 18). The Teflon band is quite thin, but offers adequate isolation to the composite and simply pulled out from between the teeth after the therapy is completed. This is how one achieves an outstanding approximal contact that is more than sufficient (fig 19). After construction of the palatal and approximal walls, the opaque composite (Amaris O3) was modelled for the build-up of the dentinal core (fig 20).
Finger-shaped mamelons were incorporated into the incisal edge area with opaque composite O2. The flowable, highly translucent HT was placed around and between the mamelons. To achieve optimal shade depth and plasticity, a somewhat lighter opaque composite (O2) and the translucent shade TL were applied (fig 21 and 22). To finish the restoration, the dentine core build-up was covered vestibular with a 0.5-1mm thin layer of translucent composite. This layer decreased in thickness from the incisal to cervical region (fig 23). The vestibular top layer was kept rather thin, since too much translucent composite can cause the restoration to appear grey.
It is imperative with the layering that the composite is pressed on the tooth surface with pluggers or a micro-brush to prevent air bubbles and to achieve a good marginal seal. The characteristic shape attributes of the anterior teeth should be kept in mind even during the modeling to limit the finishing to a minimum (fig 24).
After each layer, the tooth should be examined from the front and from the side to avoid losing sight of the correct shape of the restoration in its dimensionality.
Contouring, surface texturing and finishing
The contouring and surface texturing were carried out with a finishing diamond and Soflex discs without pressure on low speed. The longitudinal grooves were ground in first and then the diagonal grooves (figs 25 and 26). The finishing was conducted with special composite polishers and Occlubrushes containing silicon carbide. The tooth was then loaded with fluoride varnish as a final step to protect the enamel.
The shade could not be check immediately after removing the rubber dam, since the natural tooth substance was dehydrated and thus presented as very opaque and whitish. It is therefore wise to wait at least 24 hours after completion of a restoration before carrying out any required shade and/or surface corrections (rehydration completed). The good shade adaptation of the restoration was established in a one-week follow-up appointment (fig 27). The recall after six months showed an intact restoration with a stable shade (fig 28).
Conclusion
Amaris is a composite for highly aesthetic restorations, especially in the sensitive anterior range. It permits excellent handling, since it is non-tacky and stable; yet it also provides outstanding adaptation and shaping to the cavity margins. The shade selection is simple and facilitates naturally aesthetic colouring. The shades remain stable and the composite additionally has a chameleon effect. Results that were previously reserved for indirect restoration are thus now achievable with only eight shades, less trauma to the tooth and at a fraction of the cost. The composite can be polished to a high gloss and it is resistant to abrasion, thanks to its high filler content. The case presented here shows that a predictable, highly aesthetic result can be achieved with only a modest amount of effort for the preliminary planning and the right methods and materials.