The influence of matrix type on the proximal contact in Class II resin composite restorations.

PURPOSE

This in vitro study evaluated the efficiency of various types of matrices in reconstructing the proximal contact area in Class II resin composite restorations.

MATERIALS AND METHODS

Standardized MO cavities were prepared on artificial molars of a manikin model. Resin composite (Spectrum TPH-3) restorations were placed using the following matrices (n=10): a) circumferential straight metal matrix with Tofflemire retainer-A, b) circumferential pre-contoured metal matrix system-B (Adapt SuperCap), c) circumferential pre-contoured transparent matrix system-C (Adapt SuperCap) and d) sectional pre-contoured metal matrix system-D (Palodent). After completion of each restoration, the manikin model was fixed on a tension-meter apparatus and an orthodontic wire was used to assess the contact tightness (CT), length of contact arc (LCA) and position of contact point relative to LCA% (PCP). The same measurements were performed on a group of intact molars (REF). The results were statistically analyzed with one-way ANOVA and the Tukey test, as well as the unpaired t-test (alpha=0.05).

RESULTS

Matrix D provided the highest CT with the highest LCA, which presented a statistical difference relative to the intact tooth. Restorations with matrix B provided higher LCA than those with matrices A and C, which were found to be comparable to that of an intact tooth. The contact points (PCP) of the filled teeth were located more cervically in matrix D relative to the intact tooth (lower PCP), whereas matrices A, B and C showed more occlusal location (higher PCP).

CONCLUSIONS

Differences were noted among all the matrices evaluated and none was proven sufficient to reconstruct the proximal contact characteristics of an intact tooth.