In yesterday’s post I looked at the light and color properties of composite and natural teeth. The combination of layers of composite with varying light and color properties is a key step in obtaining natural looking esthetics. As with a tooth, we want to have enamel layers on the lingual and facial with the layers of dentin in between. This multi-layer approach has many variations, but is the essential ingredient in a great result. The layering process begins on the lingual. Using a silicone matrix we create the lingual wall of enamel composite. This first layer should be between >5 and 1mm in thickness from the junction with the prep to the incisal edge. I prefer to capture the incisal edge int he matrix and build it in this first layer of enamel composite to capture the length and thickness of the tooth. I do not try and close the interproximal contacts at this point, and leave the composite a 1mm or so away from the adjacent tooth.I place the composite into the matrix and smooth with a plastic instrument, even evening out the thickness with a sable brush outside the mouth. I then take the matrix and composite to the mouth, seat and cure.
With the lingual enamel layer cured I can remove the matrix and begin to sculpt in the dentin layers. You can use one color of dentin composite or several. This depends on how far to the cervical the composite is being built, and whether you are trying to incorporate a chroma gradient. For composite veneers i will place a small band of dentin composite, one shade darker than the body of the tooth from the cervical up 1-3mm, thinning as it approaches the incisal edge. I then layer on top of this the body dentin feathering to the incisal edge. Lastly I place a small amount of dentin to sculpt the incisal lobes. If you are adding characterization, it is placed between this final dentin layer and the facial layer of enamel composite.
The final layer is the facial enamel composite and interproximal Contacts. Place your plumbers tape or mylar strips prior to placing this last layer. Remember that the tooth and composite will not be a perfect match at this point due to dehydration of the natural tooth structure.