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

Background: A pits and fissures sealant is an effective method for preventing dental car-ies. Using a bonding agent before applying the sealant may increase its retention. This study aimed to compare the microtensile strength (mTBS) 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 methods: Twenty 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 mTBS 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 sta-tistical analysis tests were used to analyze the mTBS and the enamel-sealant interface, respectively. Results: The mean mTBS for the bonded group was significantly higher (p = 0.001) in the imme-diate group (36.87 +/- 14.95 MPa) and the aged group (31.08 +/- 15.88 MPa) than in the respectivenonbonded groups (19.77 +/- 9.67 MPa and 19.52 +/- 14.14 MPa). The mTBS 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. Conclusion: The 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. (C) 2020 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.