MTA用于修复不同厚度根分叉穿孔封闭性的体外实验

目的：在研究离体情况下使用染色萃取法研究MTA修复不同厚度根分叉穿孔的封闭效果。方法：将60颗人恒磨牙随机分为3组，每组20颗。每组分别预备其髓底使根分叉剩余厚度分别为3mm，2mm，1mm。3个实验组均人工制备根分叉穿孔，每组中15颗牙使用MTA修复底穿孔，5颗作为阳性对照。另5颗牙未制备根分叉穿孔作为阴性对照。使用HIDEX酶标仪在550nm检测96孔板的吸光度评价其渗漏性。结果：3组间染料吸光度均有统计学差异（p〈0．01）．有较厚根分叉的渗漏低于较薄根分叉。根分叉最薄的～组（1mm）渗漏最明显。结论：剩余牙本质壁厚度对MTA修复根分叉穿孔的封闭性有影响。在直接使用MTA修复较薄根分叉穿孔（〈1mm）时，应充分考虑其预后效果。

Sealing ability evaluation of mineral trioxide aggregate used to repair different-thickness furcation perforations in vitro

Objectives： This in vitro study aimed to investigate the effect of varying thickness of fucal perforations sealed by MTA using the dye extraction method. Methods： Sixty extracted human molars were randomly divided into three groups with 20 teeth each. Perforations were created in the centre of the pulp chamber floors and the thickness remained 3 man, 2 mm and I mm respectively. Three experimental groups of 15 tecth each were repaired with MTA and 5 teeth with unsealed perforations used as positive controls for every experimental group. Another 5 teeth without perforations were used as negative controls. After dye extraction, absorbance was measured on a spectrophotometer at 550 nm. Results： Statistically significant difference in dye absorbance was found among the three groups （ p 〈 0.01 ）. Leakage in perforations with thicker dentine wall was relatively lower than that in thinner ones. The thinnest fureations （ 1 ram） repaired with MTA showed the most leakage. Conclusions： The thickness of remaining dentine walt affected the sealing ability of MTA used to repair the perforations. It seems necessary for clinicians to evaluate the prospects of success in the treatment of a thin perforation （less than or equal to 1 mm in thickness） when repaired with MTA directly.