Evaluation of the optimal etching times and fissure sealant materials for bonding on primary teeth enamel: An in vitro study

The recommended 15-s acid etching time expands the enamel surface and facilitates the infiltration of restorative materials. Because of this clinical advantage, 15 and 30 s have become the most prevalent acid etching times in recent years. This study aimed to evaluate the effects of conventional and self-adhesive flowable composites (SAFCs) that were etched for different durations on primary molar teeth. Teeth were divided into eight groups (n = 16) and restored either with Vertise™ Flow and orthophosphoric acid or with Conseal F and orthophosphoric acid for 15, 30, 45, or 60 s. Then, the specimens were subjected to shear stress at a cross-head speed of 1 mm/min until the bond failed. After conducting the microshear bond strength (μSBS) test, failure modes were analyzed using scanning electron microscopy at 80 × magnification. Statistical analysis was performed using Independent sample T-tests and other T-tests (p < 0.05). According to the μSBS results, a statistically significant difference was observed among all groups (p < 0.05). Additionally, there were statistically significant differences between both restorative materials after etching for 15 s (p = 0.011; p < 0.05) and 60 s (p < 0.001; p < 0.05). While adhesive-type fractures were mostly observed in the SAFC groups, mixed-type fractures analyzed by scanning electron microscopy were determined to be relatively common in the Conseal F groups. An etching time of 15 s for primary tooth enamel was recommended instead of 60 s for all fissure sealants. In addition, the application of Vertise™ Flow after 15 s of acid etching was preferred over the application of Conseal F.