The Effect Of Surface Roughness On The Enamel Microtensile Bond Strength Of Four One-bottle Self-etching Adhesives

OBJECTIVE:The aim of the study was to investigate the effect of the surface roughness on the microtensile bond strength(μTBS)of four one-bottle self-etching adhesives.METHODS:Twenty extracted non-carious bovine incisors were randomly assigned into 4 groups according to four one-bottle self-etching adhesives.Each group had 5 subgroups with five enamel surface treatments.The labial enamel surfaces of the teeth were wet grounded flat with 180-,600-,1200-,2400-or 4000-grit SiC paper.After four one-bottle self-etching adhesives(Clearfil S3 Bond,Kuraray Co.,Japan;G-Bond,GC, Japan;Xeno V,Dentsply,Germany;iBond,Heraeus Kulzer,Germany)were applied to the enamel surfaces,the respective composite resins from the same manufacturer (Clearfil AP-X,Kuraray Co.;Gradia Direct;GC;Ceram X,Dentsply;Venus,Heraeus Kulzer)were placed on the adhesive-pretreated enamel surface with two 2-mm increments.After 24-h water storage,the specimens were prepared into 1mm~*1mm~*8mm sticks using the slow-speed diamond saw,and the microtensile bond strength tests were performed with a micro tester(Bisco,USA).Failure analysis was determined using a stereomicroscope.Data was analyzed by the factorial analysis(two main factors:adhesive,surface roughness)and one-way analysis of variance(ANOVA) at significance level of 0.05. RESULTS:The two main factors(enamel surface roughness,the adhesives)had the interaction effects on the enamel micro-tensile bond strengths(p＜0.05).There was not significantμTBS among Xeno V,G-Bond and iBond,irrespective of the grit size used. However,theμTBS of Clearfil S3 Bond significantly increased with the decrease of the SiC grit size(up to 1200-grit).When the enamel surface was polished with 2400-grit SiC paper,a reliable bond strength was obtained.Most failures were adhesive failure in the study.CONCLUSION:Four one-bottle self-etching adhesives in the present study obtained clinical acceptable bond strengths.The effect of surface roughness on the microtensile bond strength depended on the individual self-etching adhesives used.In clinic, super-fine diamond burs were recommended to prepare the enamel in order to obtain a reliable bond strength.