ผลของไดแคลต่อค่ากำลังแรงยึดเฉือนและค่าการรั่วซึมของเรซินซีเมนต์ / ชุติมา โฆษิตพันธวงศ์ = Effects of dycal on shear bond strength and microleakage of resin cements / Chutima Kositpantavong
The purpose of this study was to investigate the effect of Dycal on the shear bond strength and microleakage of three different resin cements. Shear bond strength test method: The occlusal dentin surface of ninety extracted human third molar teeth were exposed and then randomly divided into 3 groups (n=30). The first group was left uncovered. The second and the third group were covered with Dycal for 7 and 28 days. Each group was divided into 3 subgroups for each resin cement. After reaching the cover time Dycal was removed. Each of resin cement systems (self-adhsive;RelyX U100, self-etch;PanaviaF2.0, total etch;Superbond C&B) was applied and placement of resin composite rod. All bonded specimens were stored in distilled water at 37°C for 24 hours. The specimens were then subjected to the shear bond strength test by universal testing machine. The fracture surfaces were examined under stereomicroscope at 50x magnification. Microleakage test method: Ninety Class II cavities were prepared on lingual and buccal surfaces. (1 tooth=2 cavities) All preparations were made under the cementoenamel junction (CEJ) 1 mm. All cavities were randomly divided into 3 groups for each time period of temporary cementation with Dycal (n=30). Two composite inlays were fablicated for one cavity in master die. Composite inlay was fixed into the cavity with Dycal and stored in distrilled water at 37 C for 7 days and 28 days. The third group was left uncovered. After reaching the period of time, inlay and Dycal was removed. Cavities were divided into 3 subgroups according to 3 resin cements. All bonded specimens were stored in distilled water at 37°C for 24 hours. Specimens were coated with nail varnish, except 1 mm away from gingival margin, then immersed in 0.5% basic fuchsin dye solution for 24 h. The teeth were sectioned occlusogingivally through the center of each restoration. An optical microscope at x50 magnification was used to score the dye penetration. Result: The data were statistically analyzed by 2 way ANOVA. For RelyX U100 resin cements, there were significant differences between the control group and the Dycal covering dentin group, the mean shear bond strength of Dycal covering dentin at 28 days and 7 days was lower than control group whereas there was no significantly different between 28 days and 7 days. It was found that no significant differences in PanaviaF2.0 and Superbond C&B groups at any duration of treating dentin with Dycal. The mode of failure was mostly adhesive in nature. There were no significantly different in microleakage among the different time of each resin cement. In every period of time group, microleakage of Superbond C&B was significant lower than RelyX U100. Microleakge of PanaviaF2.0 was significant lower than RelyX U100 in 28 days group. Conclusion: Dycal reduced bond strength of dentin to RelyX U100 but does not affect bond strength of dentin to PanaviaF2.0 and SuperbondC&B. Dycal was not effect microleakage in all 3 resin cements.