Methods: Cervical carious dentin of 16 extracted human premolars was removed using a steel-round-bur with Caries Detector(Kuraray Noritake Dental) to obtain caries-affected dentin(CAD). Exposed dentin surface of cervical abrasion-lesion(ALD) of 16 premolars was cleaned with a polishing-brush and water. Standardized cervical V-shaped cavity having gingival sound-dentin-wall(SD) and occulusal wall with beveled-sound-enamel(SE) was prepared in the buccocervical region of 16 premolars. Two recent all-in-one adhesive systems, Clearfil Tri-S Bond Plus(TP, Kuraray Noritake Dental) and Scotchbond Universal Adhesive(SU, 3M ESPE), were used. CAD, ALD, SD and SEwere pretreated with the adhesive systems according to the manufacturer’s instructions. The immediate tensile bond strength(ITBS) of the two systems to four types of tooth substance were measured(n=8). The data of ITBS were examined using ANOVA, Tukey’s q-test and Weibull analysis.
Results: The mean ITBS(s.d.) in MPa to CAD/ALD/SD/SE were TP; 24.4(6.1)/23.7(6.6)/27.2(4.7)/24.7(5.5), SU; 24.0(6.8)/24.4(6.2)/25.9(5.0)/24.0(5.4). There were no significant differences in the ITBS among four tooth substances, regardless of the adhesive system. Weibull modulus values(Wm) of the four substances based on the ITBS of the two systems were 3.5/4.2/5.9/4.9. Wm of CAD and ALD were significantly smaller than the value of SD at p<0.01. Estimated ITBS at 10% probability of failure level of CAD, ALD and SE were statistically smaller than that of SDat p<0.05.
Conclusion: The bonding reliability to CAD and ALD pretreated with two recent adhesive systems was inferior to that to SD and SE. Especially at 10% probability of failure level, the bonding to CAD and ALD might be damaged by a significant smaller stress as compared with SD.