Adhesive bond strength of a composite resin to calcium silicate using different adhesion protocols

Abstract

Objective: To evaluate the adhesive bond strength of a composite resin to a calcium silicate cement using different adhesion protocols.

Methods: Sixteen cylindrical acrylic resin blocks containing cavities filled with calcium silicate cement (Biodentine, Septodont) were prepared. After one week of storage at 37 °C and 100% relative humidity, the specimens were divided into four groups (n = 4): A1, universal adhesive; A2, phosphoric acid etching followed by universal adhesive; A3, airborne-particle abrasion with Al₂O₃ followed by universal adhesive; and A4, self-adhesive luting composite (SoloCem, Coltene). After 24 h, bond strength was evaluated using a universal testing machine (INSTRON). Data were analyzed by ANOVA (α = 0.05).

Results: Mean bond strength values (SD), expressed in MPa, were: A1: 4.34 (1.14); A2: 4.29 (1.08); A3: 2.56 (1.22); and A4: 6.05 (3.87). No statistically significant differences were found among the groups (p = 0.1958). Although A4 showed the highest mean bond strength, it also exhibited considerable data dispersion. Cohesive failures within Biodentine were observed in A3.

Conclusions: The evaluated adhesion protocols showed similar bonding performance. Although A4 presented the highest mean bond strength values, the high variability observed prevented the detection of significant differences. The cohesive failures suggest adequate bonding and highlight the influence of substrate mechanical properties on the behavior of the restorative complex.