Abstract:

Objective

To evaluate the influence of desensitizers on the bond strength of dentin interface with or without etching removing smear layers.

Methods

Ninety whole molars were selected.The enamel of the crown was removed to explore the dentin. Standardized smear layers were created with 500-grit silicon carbide （SiC） paper under running water. Teeth were stratified sampled randomly and divided into three groups according to the type of desensitizing agent：All-Bond 2 （Group A）， Systemp（Group S） and the control group （Group C）. Each group was divided into three subgroups：pre-etched group， normal-etched group and non-etched group. Provisional restorations and permanent restorations were made for the teeth of each group successively. All the teeth were sectioned to obtain bar-shaped specimens with boned surface area about 1.1 mm × 1.1 mm × 8 mm. The bond strength was tested in a MTS tester with a crosshead speed of 0.5 mm/min.

Results

In the microtensile bond strength （MTBS）test， the bond strength of each group was：A-2 （32.45±12.15） MPa， A-1 （27.36±10.23） MPa， A-0（19.30±11.08） MPa；S-2 （31.03±13.47） MPa， S-1 （31.58±12.84） MPa， S-0 （14.93±10.66） MPa；C-2（25.64±14.81） MPa， C-1 （27.47±14.37） MPa， C-0 （20.33±13.41） MPa. There was no significant difference among the application of All-bond2， Systemp， and control （P＞0.05）. The bond strengths of the non-etched groups were significantly lower than that of the pre-etched or normal-etched groups （P＜0.05）. However， there was no significant difference between the pre-etched or normal-etched groups （P＞0.05）.

Conclusions

The application of desensitizers would not reduce the bond strength between dentin and final restoration. There is no significant difference in bond strength with or without removing the smear layers before the application of desensitizing agent.

Key words: Postoperative sensitivity, Desensitizer, Bond strength, Microtensile, Etching