Composite resins are extremely versatile restorative materials increasingly used in a huge amount of indications. However, the technique of implementation of adhesive restorations with composites - critical aspect to the success of the procedure- is quite sensitive. Certainly, successful restorations are directly linked to a good indication of the case. Thus, in situations where there is a great loss of tooth structure the indirect restoration should be chosen.
The knowledge and the correct implementation of the restorative protocol in suitably indicated cases are conditions to obtain the so desired restorative success.

Some class III lesions are very small and their strictly proximal location can hinder the assessment of the extent and the presence of cavitation. Using small burs is important not to inevitably lead to unnecessary wear of sound structure.

In such cases, an interesting solution is tooth separation through the use of rubber rings or strips, positioned between the teeth, 24 to 48 hours prior to the restorative session. During this time the teeth are slowly separated providing a space that besides allowing for the direct observation of the lesion, will simplify the preparation and execution of the restoration. However, to maintain the space, immediately after carrying out a prophylactic paste and a rubber cup, it is important to stabilize the matrix with suitably sized wooden wedges.

Notice the small lesion extension and the possibility of carrying out a highly conservative cavity preparation, restricted to caries removal.

✅ With cleaned dental surfaces and space already stabilized by the wooden wedges, the shade selection is performed. Because the lesion is small and barely visible, it is rarely necessary to use more than one composite shade. The selection of the most suitable mass can be accomplished by comparing the tooth to be restored with a shade guide or by applying small pellets of composite in an area of the tooth that present coloration similar to that which is planned for the restoration.
In this case, it is essential that the curing is performed by the time recommended by the manufacturer since the color of the resin depends on its degree of polymerization.

✅ After shade selection, the operatory field is isolated and cavity preparation is started.
✅ A metal matrix is recommended for the protection of the adjacent tooth since its proximal surface is right next to the region to be prepared, inserted between the adjacent tooth surface and the wedge.

The association of tooth separation, protector the adjacent tooth with metal matrix, and the use of small diameter spherical burs allow for the preparation of very conservative cavities.

✅ Before starting the adhesive procedures, the cavity surface should be cleaned thoroughly by a stream of sodium bicarbonate or a prophylactic paste.
✅ After cleaning the adjacent tooth is protected with a Mylar strip or polytetrafluoroethylene tape, commonly known as “ thread-sealing “ tape. Phosphoric acid is applied to the entire cavity and approximately 2 mm beyond the margins for 15 seconds.
After copious washing and careful removal of excess moisture, the adhesive system of choice is applied. In this case, an adhesive system that combines the functions of primer and adhesive in a single bottle is being used. This adhesive requires that the application and volatilization solvents be repeated at least two times prior to light curing. Further, an increase of composite resin is carried to the cavity with the appropriate spatulas.

Brushes are useful to manipulate composite and for the removal of excesses to improve the contour of the restoration and to reduce the time required for finishing procedures. After finishing the cavity, light curing is carried out.

The finishing and polishing procedures are performed with the aid of the space obtained earlier. Finishing flexible discs are very suitable to smooth the restored surface when the place of restoration allows for its use.

With the restoration completed, the wedge is removed and then the rubber dam isolation is removed. In a short period of time, the teeth return to their original position restoring proximal contacts, esthetics, and function.

This protocol is the most conservative possible and although requiring prior separation procedure which requires an additional appointment of the patient before the clinical restorative session, it should be indicated whenever possible.