Fig.1
This patient presented with defective old amalgam proximal restorations that cause food impaction and difficulty on flossing. So we decided to replace the old restoration with new, more anatomical ones.

Fig.2
The amalgam restorations were removed under rubber dam isolation, starting with pre-wedging to protect the rubber dam (and the papilla), and to increase separation between the teeth to improve visibility and minimize sound tissue removal.

Fig.3
The final cavity design had left a very wide proximal space, so we needed a contoured matrix to achieve a correct positioning and shaping of the contact area.

Fig.4
The transparent biofit HD matrix from Bioclear was used in this case as it has a high contoured profile. Both matrices were placed at the same time to avoid over contouring of one proximal wall in the space of the adjacent tooth.

Fig.5
Lateral view shows the level of the contact point.

Fig.6
After restoring the proximal wall of the molar, the first matrix was removed to avoid creating a loose contact. This type of matrix is 75 microns thick, which is considered very thick, so extra separation, using a large wedge. Moreover, the wedge was wrapped in teflon tape to achieve a tighter seal and to enhance separation ad matrix retention.

Fig.7
The proximal wall of the premolar was restored, then the matrix was removed. As you can see, the increased separation made the contact seem open.

Fig.8
The occlusal anatomy was restored by using FMT (Fast Modeling Technique), the composite was placed as a single mass. Fissures should be deep to reduce the C factor. P shade composite from White Dental Beauty was used in this case, which is a universal composite for the posterior teeth.

Fig.9
After curing the composite, the fissures were sealed with a dental brown tint.

Fig.10
Both fillings were sandblasted by sodium bicarbonate powder using the Aquacare device to enhance the final polish.

Fig.11
After final polishing and removal of the wedge, you can see the proximal space closed.

Fig.12
Lateral view is very useful to evaluate the level of the contact area and the proportions of the occlusal and gingival embrasures.

Fig.13
The final result.

Conclusions

Planning a posterior proximal restoration is a mix of space engineering selecting the right materials and tools. To achieve optimal anatomical features for long-lasting and biocompatible restorations, very step should be well planned and executed.

Bibliography

1. Hardan L, Sidawi L, Akhundov M, Bourgi R, Ghaleb M, Dabbagh S, Sokolowski K, Suarez C, Szymanska M. One-Year Clinical Performance of the Fast-Modelling Bulk Technique and Composite-Up Layering Technique in Class I Cavities. Polymers 2021;13:1873.
2. Manauta J, Salat A. Layers An Atlas of Composite Resin Stratification. 2012. Quintessence Pub.
3. Van Dijken JW, Pallesen U. 2016. Posterior bulk-filled resin composite restorations: a 5-year randomized controlled clinical study. J Dent. 51:29–35.
4. Ferraris F. Adhesion, layering, and finishing of resin composite restorations for class II cavity preparations. Eur J Esthet Dent. 2007 ;2(2):210-21