Effect different protocols of desensitizer agents on bonding strength with enamel and dentin

Abstract

Background: Dental hypersensitivity is a common problem, especially after the placement of restorations. Several treatment methods exist, one of which involves the application of desensitizing agents such as (Gluma) and (Desensitizer Systemp) .

Objective : This study aimed to evaluate the effect of applying desensitizing agents on the bond strength of resin restorations and the bonding agent to the tooth surface, and to assess the effect of desensitizer residue on the brush used.

Methods: 40 extracted teeth divided into two main groups: 20 teeth with enamel surfaces and 20 with dentin surfaces. The main group was divided into 4 subgroups in which the studied materials were applied to the enamel. In the first subgroup, Gluma was used as a bonding agent containing a desensitizer. In the second subgroup, the Tetric N Bond was used as a control group. In the third and fourth subgroups, the Desensitizer Systemp Evoclar was used as a desensitizer before the bonding agent was applied. A single brush was used to apply both the desensitizer and the bonding agent in the third subgroup, whereas a new brush was used to apply the bonding agent in the fourth subgroup. The same procedures were repeated for the dentin groups (subgroups 5, 6, 7, and 8). Each subgroup consisted of 6 teeth, 5 of which were subjected to a shear test to measure the bond strength, and one sample was cut into a longitudinal section to be studied under a scanning electron microscope to measure the gap formed between the composites and the dental surface and its relationship to the bond strength . Statistical analysis was performed via SPSS 20.

Results: Compared with the use of a new brush as a bonding agent, the use of a desensitizer systemp decreases the bond strength of enamel and dentin but only Gluma increases the bond strength on dentin. Compared with the use of a new brush, the use of the same brush to apply the Desensitizer Systemp and bonding agent has a positive effect on increasing the bond strength. All these results were significant for both dentin and ename, (p>0.05). The SEM results revealed a decrease in the gap when Systemp was used, with no correlation between the gap and bond strength.

Conclusion: Using the same brush for the application of the desensitizer system increased the bond strength. There is no correlation between the gap and bond strength.

Keywords: Bond Strength, Scanning Electron Microscopy, Shear Force.