[Effect of self-etching and single-bottle bonding systems on shear bond strength of fissure sealant to primary and permanent enamel]

Application of self-etching bonding systems to primary and permanent teeth has increased due to the simplicity of work and fewer steps. This experimental study aimed to compare the effect of conventional acid etching and single-bottle and self-etching bonding systems on shear bond strength [SBS] of light-cured fissure sealant to primary and permanent enamel. In this experimental study, the smoothest unprepared proximal enamel surfaces of 30 primary molars [groups 2, 4 and 6] and 30 permanent premolar teeth [groups 1, 3 and 5] were divided into 6 groups of 10. Groups 1 and 2 [control] were acid-etched and received light-cured fissure sealant [Concise 3M-ESPE]. Groups 3 and 4 [SB] were subjected to acid etching + Single Bondadhesive + fissure sealant. Groups 5 and 6 [PLP] received self-etching bonding system [Prompt L-Pop, 3M, ESPE] + fissure sealant. Specimens were then subjected to 500 thermal cycles with the dwell time of 30 seconds. Shear bond strength was determined using Universal Testing Machine [Zwick, Germany]. Mode of fracture was determined under stereomicroscope and data were analyzed using ANOVA, [between-subjects effect] and LSD. SBS was not significantly different between the control and PLP or SB and PLP groups [P>0.05]. However, the difference in SBS between the control and SB groups was statistically significant [P=0.022]. The SBS in primary teeth was less than in permanent teeth in all groups [P<0.05]. Self-etching bonding system [PLP], similar to conventional acid etching technique, provides adequate bond between the light-cured fissure sealant and unprepared enamel. Application of Single Bond Adhesive effectively increased the fissure sealant bond strength

[Evaluation of the effect of fluoride gel and varnish on the demineralization resistance of enamel: an in vitro]

Fluoride has an important role in the prevention of caries. This study assessed the efficacy of three types of topical fluoride: fluoride varnish, APF gel [sultan], APF gel [Kimia] in protecting the enamel from demineralization in an in vitro environment. Sixty human caries-free premolars where randomly assigned into four groups of 15 specimens. The control group was washed with deionized/distilled water. Weekly gel [Kimia] was treated with APF gel [1/23%] for 2 minutes weekly, weekly gel [Sultan] was treated with APF gel [1/23%] for 60 seconds weekly, weekly varnish fluoride was treated with Durashield [2/26%]. Specimens were then placed in a cycle of demineralization [pH= 4.3] for 6 hours and remineralization [pH= 7] for 17 hours. This pH- cycle was repeated for 3 weeks [21 days]. The teeth were sectioned buccolingually and evaluated under polarized light microscope. Then the depth of each lesion was measured from the deepest demineralization point of the lesion. The data were analyzed using Kruskal-Wallis and Dunn test for pairwise comparison. The control group had the deepest lesions [mean depth, 140 +/- 37micrometer]. The varnish group had the shallowest lesions [mean depth, 60 +/- 37 micrometer] with a 75.3% reduction percent. However, there was no significant difference in the depth of demineralization between all fluoride treated groups. The difference between fluoride groups and the control group were significant. Treatment of the enamel of permanent teeth with various topical fluorides significantly inhibited demineralization, but there was no significant difference between varnish or gel application