Reconstructing Tooth Proximal Surface With Composite Resin Using Contemporary Sectional Matrix Systems

Restoring defective proximal contour, embrasure, and contact to normal tooth anatomy in proximal cavities remains a clinical problem to this day. Multiple sectional matrix systems have been developed over the years to help achieve positive outcomes; however, objective examination of contemporary systems is scarce.

To evaluate proximal contour and composite resin flash, marginal overhang, and ring retention of different sectional matrix systems.

Totally 45 mesio-occlusal cavity-prepped ivory plastic lower right first molars were used. Three different sectional matrix systems were evaluated: STRATA-G, Garrison; Complete Biofit HD, Bioclear; and Palodent Plus, Dentsply Sirona. Fifteen teeth were restored with a composite resin for each matrix system. The teeth were scanned and analyzed using 3D analysis software. Matrix systems' rings retention was analyzed using a pull-out test in a universal testing machine. A one-way analysis of variance (ANOVA) and Tukey's post hoc test (α = 0.05) were used to analyze the data.

Significant differences in average deviation in proximal contour and ring retention were observed among matrix systems (p < 0.05). There was no significant difference in average marginal overhang between matrix systems (p = 0.182). The STRATA-G matrix system had the lowest proximal contour variation (100 μm). Higher variations of 115 μm and 160 μm were seen in the Biofit HD and Palodent Plus matrix systems, respectively. The SRATA-G matrix system produced a minimal marginal overhang of 26.9 μm, while the Biofit HD and Palodent Plus matrix systems showed marginal overhang increases of 34.0 μm and 36.9 μm, respectively. Ring retention of the STRATA-G sectional matrix ring (7.27 N) was significantly higher than Biofit HD (5.47 N) and Palodent Plus (3.35 N) (p < 0.05).

The SRATA-G matrix system showed less deviation in proximal contour and resin marginal overhang than both the Biofit HD and Palodent Plus matrix systems. Also, SRATA-G had the most retentive sectional matrix ring.

Multiple sectional matrix systems are available for clinicians. Objective analysis of these systems' impact on the tooth proximal contour and resin marginal overhang of restored surfaces may provide clinicians with a deeper understanding of their differences. Enhanced ring retention allows the clinician to complete the restoration worry-free of the ring being displaced.