cosmetic dentistry - beauty & science

industry report _ composite restorations I ontherecreationofdentaltissuesofnaturalthick- ness, layer by layer. We believe that special atten- tion has to be paid to restoring the enamel layer. The image below, with a cross-section of a natural incisor, demonstrates why it is so important to concentrate on recreation of this outermost layer (Figs. 1 & 2). Ifyoupreparethetoothwithwidebevelsonthe labial and palatal surfaces (black imaginary prepa- ration line) around two thirds of the restoration volume would be constituted of enamel. Enamel determines the value of the dental shade, being lighter (higher value) or darker (lower value), while the dentine determines the hue and chroma of the dental shade. Enamel becomes darker as individu- als age, so it is necessary to have several translu- cent composite shades that can mimic the ageing enamel. For a natural-looking anterior restoration, the mostimportantstepistherecreationoftheenamel and therefore we recommend that you start by determiningthevalue.Theentireclinicalprocedure for this restorative technique is described step by step in the following example. Suppose the tooth #21 exhibits an inaesthetic restoration of the inci- sal edge, which would be replaced as follows: _Step 1 When determining the value, decreas- ing the ambient lighting in the operatory room is advised in order to concentrate on the incisal edge and middle part of the neighbouring tooth, where the enamel is thick, allowing you to determine its colour (Fig. 3). _Step 2 The hue and the chroma are determined from the cervical area of the crown, where the enamel is thin and the colour of the dentine shines through (Fig. 4). _Step 3 The old restoration is removed and a wide bevel preparationhasbeenmadeonthelabialandpalatal surfaces (flame shaped burs) (Figs. 5 & 6). _Step 4 A rubber dam and transparent matrix strips are placed (Fig. 7). _Step 5 Firstly, the palatal layer of a translucent com- posite material, G-ænial IE (GC), can be positioned by means of a silicon index or by bending the trans- parent matrix band strips and sculpting the palatal I 27cosmeticdentistry 3_2012 Fig. 5 Fig. 6 Fig. 9 Fig. 7 Fig. 8