根管交叉角度对琼脂桩核印模制取完整性的影响

目的:以硅橡胶取桩法为对照,考察琼脂/藻酸盐联合法制取桩核印模的效果。方法:制作后牙双根管模具5个,设定不同根管交叉角度,分别为0°、10°、20°、30°、40°。以硅橡胶取模法为对照,应用琼脂/藻酸盐联合法制取桩核印模,在相同角度下分别用2种材料取模20次。对取出的印模进行评价,分析根管交叉角度对2种材料取模的影响。采用SPSS16.0软件包对数据进行统计学分析。结果:硅橡胶组各角度间取桩印模完整率无显著差异(P>0.05);琼脂组中,当根管间交叉角度为40°时,印模完整率(60%)较0°组完整率(95%)及总完整率(83%)低,差异显著(P<0.05);当根管间交叉角度为40°时,琼脂法取桩完整率(60%)低于硅橡胶法(90%)(P<0.05)。琼脂法取桩总完整率(83%)显著低于硅橡胶法(96%)(P<0.05);琼脂/藻酸盐法取桩的完整性与根管角度呈显著负相关(r=-0.901, P=0.037)。结论:当磨牙根管之间角度较小时,使用琼脂/藻酸盐联合法制取桩核印模可满足临床需求,当角度大于30°时,建议使用硅橡胶类材料。硅橡胶类材料取磨牙桩核印模完整率整体上优于琼脂。

Effect of molar root canal angles on the integrity of impression made by agar

PURPOSE: To evaluate the effect of impressions made by agar/alginate compared with silicon rubber material. METHODS: Five moulds of bi-root canal molar, with different root canal angles of 0°, 10°, 20°, 30° and 40° were made. Twenty impressions were made for each mould with either silicon rubber or agar/alginate. The effects of two methods were evaluated and the influence of angles between root canals on the impression methods was analyzed. The data was analyzed with SPSS16.0 software package. RESULTS: Significant difference of integrality rate (IR) of impression was not found in silicon rubber group among different angle groups (P>0.05). IR of 40° group(60%) was significantly lower than that of 0°(95%) and general IR(83%) when using agar(P<0.05). IR of agar(60%) was statistically lower than silicon rubber(90%) in 40° group (P<0.05).The success rate of agar method was significantly lower than silicon rubber method in 40° group. The general IR of agar (83%) was significantly lower than that of silicon rubber (95%)(P<0.05). A significant negative correlation was observed between root canal angles and IR(r=-0.901,P=0.037). CONCLUSIONS: Silicon rubber impression materials are suggested for impression taking when root canal angles are over 30° in molars, while agar/alginate impression method is qualified for smaller angles. The general IR of silicon rubber material is better than that of agar when taking the impression of post and core in molar.