بررسي تاثير زمان پرداخت بر استحكام برشي اتصال كامپوزيت رزين و كامومر به عاج

THE EFFECT OF POLISHING TIME ON THE SHEAR BONDING STRENGTH OF RESIN COMPOSITE AND COMPOMER TO DENTIN

Introduction: Suitable bond strength between tooth and restorative material is one of the most important factors in durability of restoration. The polishing of a restoration should be performed when the bond strength will not be influenced by the stress that is produced by the mechanical procedure of polishing. The aim of this study was to evaluate the effect of polishing time on the shear bond strength of resin composite and compomer to dentine of tooth. The aim of this study was to evaluate the effect of polishing time on the shear bond strength of resin composite and compomer to dentin of tooth. Methods: Truncated cone cavities were prepared in the horizontal corona! occlusal dentinal sections of 48 human molar teeth. Specimens were randomly divided in 4 experimental groups. The specimen cavities of group l and 2 were filled with resin composite and the specimen cavities of group 3 and 4 were filled with compomer. The specimens of group 1 and 3 were polished immediately after filling the cavities by restorative material and the specimens of group 2 and 4 were polished after 24 hours storage of samples in normal saline at 37°C. All of the specimens were stored in normal saline at 37°C for one week. The push out test was used to evaluate the shear bond strength of resin composite and compomer to dentin and the mean values of shear bond strength of the four groups were determined. The results were analyzed with ANOVA and Duncan tests. Results: The results showed statistically significant differences between the mean shear bond strength values of group 1 and 3, group land 3, and groups 3and 4. Group 4 possessed the highest shear bond strength while group 3 possessed the lowest shear bond strength. Conclusion: It was concluded that hygroscopic expansion of compomer and improvement of bond strength of the compomer during the storage time due to delayed polishing increases the shear bond strength between compomer and dentin. On the other hand, since the type of setting reaction of the resin composite is polymerization, the time of polishing had no significant influence on the shear bond strength between resin composite and dentine.