Using bonding agent prior to pits and fissure sealant application enhances the microtensile bond strength and the interface morphology

BackgroundA pits and fissures sealant is an effective method for preventing dental caries. Using a bonding agent before applying the sealant may increase its retention. This study aimed to compare the microtensile strength (µTBS) of a fissure sealant with and without a bonding agent and to characterize the enamel-sealant interface using confocal laser scanning microscopy (CLSM). The null hypothesis was that the use of a bonding agent before fissure sealant application would not change the microtensile strength or the enamel-sealant interface.Materials and methodsTwenty caries-free premolars were used. Each tooth was divided into four parts. The first two parts were assigned to the bonded group, where a bonding system was used before sealant application. The remaining two parts were treated only with a fissure sealant (i.e., the nonbonded group). In each group, the µTBS was examined after 24 h (n = 20) and after a 3-month aging period (n = 20). Five other caries-free extracted premolars were used to assess the enamel-sealant interface using CLSM. Two-way analysis of variance (ANOVA) and Pearson chi-square statistical analysis tests were used to analyze the µTBS and the enamel-sealant interface, respectively.ResultsThe mean µTBS for the bonded group was significantly higher (p = 0.001) in the immediate group (36.87 ± 14.95 MPa) and the aged group (31.08 ± 15.88 MPa) than in the respective nonbonded groups (19.77 ± 9.67 MPa and 19.52 ± 14.14 MPa). The µTBS was not significantly different in either group after aging (p = 0.46 [bonded group] and p = 0.98 [nonbonded group]). In addition, using a dental adhesive, before applying a fissure sealant resulted in a significantly higher (53%) resin penetration into the enamel with the continuous integrity of the resin.ConclusionThe use of a bonding agent before the application of fissure sealant resulted in superior microtensile bond strength immediately and after aging. In addition, the enamel-sealant interface characteristics were improved.