Effect of matrix system on the quality of proximal contact in posterior bulk-fill resin composite restorations- an in vitro study.

OBJECTIVE

Evaluate the effect of matrix systems on the proximal contact force (N) between molars and premolars in two class-II bulk-fill resin composite restorations.

METHODS

The Typodont model of the first molar, with adjacent molar and premolar simulating the periodontal ligament was used to analyze proximal contact in two class-II restorations (n = 10) made with OPUS Bulk Fill resin composite. Four types of matrices were tested: two sectional (Palodent V3 and Unimatrix R) and two circumferential (SuperMat and universal metal matrix. Intact tooth was used as the control group). The specimens were radiographed and proximal contact force (N) were measured in a microtensile testing machine (Odeme). Data were analyzed using two-way ANOVA followed by the Tukey and Dunnet tests (α = 0.05).

RESULTS

The contact force on the premolar was lower than that on the molar (P < 0.001) irrespective of the matrix system. The sectional matrices produced similar proximal contact forces as the intact tooth (P = 0.109) and higher than the circumferential matrices (P < 0.001), irrespective of the tooth-type contact. The radiographic analysis showed predominantly perfect proximal contact in the sectional matrix specimens.

CONCLUSIONS

The contour and proximal contact forces were influenced by the matrix systems and tooth contact location. The sectional matrices had better proximal contact force than the circumferential matrices.

CLINICAL RELEVANCE

Compared with circumferential matrices, sectional matrices are more flexible and can be moved easily to the direction of the adjacent tooth to produce better proximal contact in class-II bulk-fill resin composite restorations.