Influence of bioactive glass air abrasion on the bond strength of adhesive to caries-affected dentin.

The purpose of this study was to investigate the influence of bioactive glass (BAG) air abrasion on the microshear bond strength (μSBS) between caries-affected dentin and universal adhesive used in etch-and-rinse (E&R) or self-etching (SE) mode. A total of 40 extracted, caries-infected human molars were randomly divided into 4 treatment groups based on dentin surface treatment and etching mode: E&R, E&R/BAG air abrasion, SE, and SE/BAG air abrasion. The teeth were flattened to provide a caries-affected, midcoronal dentin surface. After restoration procedures, the caries-affected surfaces were submitted to μSBS testing. Two-way analysis of variance and Student t test were used to analyze the data, with significance set at P < 0.05. The E&R/BAG group had the highest mean (SD) μSBS, 23.66 (6.05) MPa, but the value was not significantly different from that of the E&R group without BAG air abrasion, 22.06 (7.51) MPa. However, air abrasion with BAG adversely influenced the μSBS of the adhesive in SE mode, resulting in values of 10.51 (2.01) MPa in the SE/BAG group compared with 17.45 (3.65) MPa in the SE group (P < 0.0001). In the groups subjected to BAG air abrasion, the etching mode had a significant effect on μSBS (P < 0.0001). Scanning microscopic evaluation revealed little difference between the E&R and E&R/ BAG groups in hybrid layer and resin tag formation, but BAG air abrasion resulted in fewer resin tags and less resin penetration when the adhesive was used in SE mode. Bioactive glass air abrasion did not have any adverse effects on the μSBS of universal adhesive used in E&R mode, while it did reduce the μSBS when the adhesive was used in SE mode.