2001 Volume 19 Issue 1 Pages 16-25
The purpose of this study was to evaluate the influence of non-resin impregnated layer on dentin adhesion both by the nanohardness (NH) measurement of resin-dentin interface as well as micro tensile bond strengths to human dentin surfaces using two new selfetching primer systems. Dentin discs were prepared from freshly extracted human third molars. Specimens were divided into two groups. Group 1; Dentin surfaces were treated using self-etching primer system. Unifil Bond (GC) or Clearfil MEGABOND (Kuraray) were applied per manufactures directions. Group 2; Dentin surfaces were etched with K-etchant (Kuraray) for 60 seconds, to intentionally over-etch the dentin substrate. Then dentin surfaces were treated with self-etching primer systems same as Group 1. NH of the resin-dentin interface was measured using an ENT-1100 Nanoindentation tester (Elionix). Micro tensile bond tests were performed on additional specimens after 24 hours. After both measurements, specimens were observed by SEM. Data were evaluated by one-way ANOVA, Fisher's PLSD test, p<0.01. Results showed that NH of 5, um towards the hybrid layer in Group 2 was significantly lower than Group 1. No significant difference in bond strength were showed between non-etched and etched dentin in each of the material groups. Although areas within 5gm from the border of hybrid layer appear demineralization, bond strength of self-etching primer systems after 24 hours were not affected by dentin etching.
