ABSTRACT
The purpose of this study was to evaluate the shear bond strength of three kinds of different ceramic brackets with three different bonding adhesives. 5 specimens for each combination were tested for shear bond strength using Instron and for fracture site using SENL And 3 specimens were cross-sectioned for SEM examination of bonding pattern between bracket, resin and enamel surface. The results were as follows 1. The shear bond strength of chemical curing adhesives were higher than that of light curing adhesives. 2. The shear bond strength of Starfire bracket, chemical-bonded type, was lower than that of Transcend bracket, mechanical-bonded type, and Fascination bracket, combined type. 3. Fracture site of each bracket and tooth surface was examined under a light optical stereoscopic microscope, Transcend groups were mainly at the E/R intderface. Fascination groups were mainly at the COMB interface and Starfire groups were mainly at the R/B interface.
Subject(s)
Animals , Adhesives , Ceramics , Comb and Wattles , Dental Enamel , ToothABSTRACT
The purpose of this study was to investigate the cytotoxicity of orthodontic bands in vitro and in vivo.4 types of orthodontic bands were applied to cultured fibroblast and the supermatants were injected into dorsal subcutaneous tissue of mice. In vitro, the cytotoxixity was evaluated by an MTT assay after 2 and 6days.In vivo, the histopathologic observation was performed 2 days after injection. The results were: 1. The cell viability was significantly decreased in the group added phosphoric acid in comparison to control group, but there was not any significance among the experimental group after 2 days. 2. Cell viability decreased in the high Ni containing group after 6 days. 3. The histopathological finding was that the Cr-containing group showed severe infiltration of inflammatory cells and muscular destruction.