关键词: 牙痕, 法医学, 三维测量, 免冲洗酸, 复合体, 磷酸, 微渗漏

Abstract:

Objective To compare the microleakage of compomer sealant with non - rinse conditioner and resin sealant with phosphoric aci（d 35%）by dye test and scanning electron microscop（e SEM）observation. Methods 16 extracted third permanent molars were divided into 4 groups: Group Ⅰ, non- rinse condition（er NRC）+ Prime & Bond NT+ Dyract seal; Group Ⅱ, phosphoric acid（ 35%）+ Concise sealant; Group Ⅲ, phosphoric acid（ 35%）+ Dyract seal; Group Ⅳ, NRC+Prime & Bond NT+Concise sealant. The teeth were then coated with nail polish, placed in a 50% AgNO3 dye for 18 hours, and sectioned with a diamond saw. SEM observation was performed to evaluate microleakage in the teeth. Results Silver nitrate penetration was found in each group. The percentage of microleakage in group Ⅰ was higher than that in group Ⅱ, and group Ⅳ was higher than that in group Ⅱ（ P<0.01）. The percentage of microleakage of resin sealant with phosphoric acid was lower than that in compomer sealant with NRC （ P<0.01）. On SEM observation, resin tags and few gaps were found in groups with phosphoric acid. Some gaps and bubbles were found at the bottom of the fissures, particularly in the narrow fissures because of the failure of sealant penetration. Conclusion Resin sealant used with phosphoric acid was better than compomer sealant with NRC on microleakage.

Key words: toothmark;forensicmedicine;three-dimensionalmeasurement;, non- rinse conditioner, compomer, phosphoric acid, microleakage