Fabricating visually imperceptible class III restorations following the principles of tissue conservation is an extremely challenging task. For this reason, whenever possible, the labial surface is not involved in cavity preparation. However, there are situations where this is not possible.

In the case presented in this post, there is a need for replacement of a class III restoration.

✅ After prophylaxis, a careful shade selection is carried out. The final restoration will present composite resin masses for dentin (less translucent) and enamel (more translucent), with success dependent upon a perfect aesthetic balance between them. The overuse of a translucent composite produces a grayish “ half-moon “, while excess composite for dentin generates an opaque “ half-moon “ equally aesthetically unpleasant.

✅ Isolation of the operatory field with a rubber dam is performed giving better visualization of the access and facilitating the operatory steps.
✅ The adjacent tooth is protected during cavity preparation using a wedge and metallic matrix.
✅ The old restoration is removed using a high-speed diamond but under water 💦 cooling. In the presence of caries or areas of staining that interfere with the aesthetics, the use of low speed spherical smooth bur is indicated to conclude the cavity preparation.

Beginning the adhesive procedures :
The adjacent teeth are protected with a Mylar strip, enamel and dentin are conditioned and after rinsing the substrate, excess moisture with gentle air jets and cotton pellets/sponges. Then the adhesive is applied and cured properly.

👉🏻 The most critical aspect to achieve good results in aesthetic class III restorations involving the labial surface is probably the reproduction of translucency observed in natural teeth. However, it is not enough to use composites with different degrees of translucency to reproduce enamel and dentin. It is also necessary to mimic the relationships of thickness that these tissues have in natural teeth.
In the case presented here, since the palatal surface is not involved in the preparation, the first composite increment has the function of reproducing the relationship of the proximal contact between the restoration and the adjacent tooth.

🎁 Two techniques are suggested for the correct application of this increment ;
In the first, the composite resin is placed against a Mylar strip stabilized by a wooden wedge which also promotes a slight dental separation. The increment is cured with the matrix yet in position.

In the second technique, the composite is inserted against a Mylar strip and the palatal matrix is pushed until it is fully removed and then the composite is light-cured.

Both techniques present successful results. Both of them are recommended and then choose the one that best fits.

With the proximal surface now properly restored, we start the reproduction of the dentin portion lost in the cavity preparation. Thus less translucent and more saturated resin is used.
⛔️ Remember that a perfect balance between volume and translucency of dentin and enamel is essential to achieve aesthetics.

👉🏻 Note that at the end of dentin composite insertion, space should still remain that will be eventually filled by a composite for enamel. The last increment of the composite is responsible for mimicking the optical characteristics of enamel and should also exhibit good polishing properties. It is applied and shaped with spatulas and brushes to minimize excesses. The better the sculpture of this increment, the less work on finishing and polishing steps that begin by removal of proximal excesses with a #12 scalpel blade.

Ideally, finishing and polishing procedures should be performed in a subsequent session to allow for a better evaluation of the aesthetic restoration and to take the maximal advantage of the materials used. Exactly, for this reason, it is advantageous to fabricate restorations with minimal excess.

Finishing and polishing of the proximal surface of the restoration were initially performed with abrasive strips in decreasing order of abrasiveness. Then flexible abrasive discs were employed also in decreasing order of abrasiveness to carry out minor shape adjustments and reflective areas of the restoration. Discs of lower granulation are eventually used for obtaining surface smoothness. The step is completed with polishing pastes applied with the aid of felt discs.

All these precautions and procedures help greatly and are indispensable to obtain a restoration that reestablishes function and the aesthetic appearance of the natural tooth.

Notice 👀 in the final photograph that despite the involvement of the labial surface the restoration is virtually invisible due to the correct mimicking of the shape and the shade of the surrounding tooth structure.