OBJECTIVEThis study investigated the shear bond strength and the ability of resin adhesive containing different amounts of bioactive glass (BG) to prevent dentin demineralization.

METHODSBG bonds at 30%, 40%, and 50% concentrations comprised a mixture of coupling agents modifying BG and Single Bond 2. Forty permanent premolars extracted for orthodontic treatment were randomly divided into four groups, namely, control group (BG-free), 30% BG group, 40% BG group, and 50% BG group. Composite resin and dentin were prepared into bonding specimens by using respective adhesives and then immersed in artificial saliva at pH 4 for 1 week. Changes in the pH values of the solution were measured every 24 h. The microtensile bond strength (TBS) of each specimen was examined after immersion in distilled water at 37 °C for 24 h.

RESULTSThe TBS values of the control group, 30% BG group, 40% BG group, and 50% BG group were (27.76±0.29), (27.05±0.58), (26.95±0.69), and (25.12±0.24) MPa, respectively. The TBS of the control group was not significantly different from that of the 30% BG group (P=0.06) but significantly higher than that of the 40% BG and 50% BG groups (P=0.04 and P=0.00, respectively). In addition, TBS was significantly higher in the 30% BG and 40% BG groups than in the 50% BG group (P=
0.00 and P=0.00, respectively). The pH values of the solution increased with increasing BG content.

CONCLUSIONSBG bonds are useful in the prevention of dentin demineralization. However, in this study, the 30% BG group did not affect the short-term bond strength. The 50% BG group displayed the optimum ability to inhibit demineralization but showed the worst bond strength.