Shear strength of sealants placed with non-rinse conditioning compared to a conventional acid etch-rinse technique

The present study compared the shearing strength of a non-rinse conditioning (NRC) compomer sealant to that of a conventional sealant. Thirty molars and premolars were sectioned longitudinally. The resulting halves were divided into 4 groups. Cylinders of sealants were bonded to the sections using a gelatin capsule as a matrix, as follows: Group A (n = 15) NRC + Prime & Bond + Dyract Seal; Group B (n = 15) same as group A but with phosphoric acid and rinse; Group C (n = 15) conventional phosphoric acid + Helioseal; Group D (n = 15) NRC + Helioseal. After immersing the specimens in water for 7 days, the samples were mounted on the Instron testing machine at a 20 mm/min crosshead speed. The results were subjected to ANOVA with Scheffe test, with a significant level of .05. No shearing strength values could be obtained for the specimens of group D. Some cylinders separated from the enamel while still immersed in the water, and in others the adhesion was too low, and no readings could be observed. For all groups, failure occurred at the sealant-enamel interface. The mean value for group A was 5.33 MPa, significantly less than that of groups B 9.12 MPa and C 9.63 MPa (p < 0.006). No significant difference of the mean shear strength was evident between groups B and C. No rinse conditioning with Dyract Seal led to a considerably lower bond strength value than Dyract Seal and Helioseal with phosphoric acid and rinsing.