Objective: The aim of this study was to evaluate three adhesive methods on the superficial intact dentine.The microtensile bonding strength was also evaluated.
Materials and method: One central incisor tooth fresh extracted was selected for the flat on the buccal surface. The superficial enamel was distributed into four parts. Parts were treated with self-etch, total-etch, total and self etch respectively by waxed the rest parts. The tooth was stored in distilled water for 24 hrs and observed under SEM.
For the microtensile bond strength, Superficial occlusal flat dentin surfaces of 12 intact human premolars were exposed. A block of composite resin was bonded according to the manufacturer instructions. After 24 hrs in water the specimens were sectioned into 1mm² thick slices and subjected to a tensile force at crosshead speed of 1mm/ min. One-way ANOVA was performed for analysis.
Results: SEM revealed the presence of a smear layer which covered the whole dentinal surface and dentinal tubules on the control part. On the P2 all the smear layer was removed and the dentinal tubules were observed to be clear.
P3 was observed to have a thin hybrid layer on the surface, some remained debris, and some of the dentin tubules were blocked, in contrast to P4 which had a thick hybrid layer on the surface, and clearly opened dentinal tubules.
The bond strength of the XenoIII was 15.26MPa, SB 21.78MPa and combination 23.80MPa, respectively. For both XenoIII and SB, SB and combination revealed no significant differences (p>0.05). For combination method revealed significantly higher bond strength than XenoIII method (p<0.05).
Conclusions: It could be concluded that the use of total etch SB totally dissolved smear layer, and the use of combination method significantly influence the formation of hybrid layer, as well as opening of dentinal tubules.