AIM: To compare the obturation effect of two tapered gutta - percha master cone using cold later al condensation on different shape canals. METHODS: Forty extracted teeth with a single canal were divided into two groups, round carnal group and oval canal group. The canals were instrumented by M2 and obturated with 0.02 or 0.06 master cone by cold laterally condensed method. X - ray films of each teeth from buccal - lingal and mesio - distal di rection were taken. All the teeth were cut horizontally at the 3 and 5 mm from the apex, and micro - photographs of the cross sections were taken. The percentage of gutta - percha filled area was measured using an image analysis program. Obturation time consumed were recorded. RESULTS: The qualities of X - ray films of mesio - distal direction of oval shape canals were worse than those of buccal - lingal direction. In round canals, there was no difference of PGP( percentage of gutta-percha filled area) between0.06 and 0.02 cones at 3mm level(P>0.05) , while in oval canals, the PGP with 0.02 cones was higher than that of 0.06 cones (P < 0.05). At 5mm level, there was no significant difference between 0.06 and 0.02 cones (P > 0.05 ). Time consumed with 0.06 cones was shorter than that with 0.02 cones. CONCLUSION: In clinic, wed better choose 0.06 tapered master gutta - percha whose taper is close to that of round canals, which will be time - saving and better effects. While in oval canals, with regards to the obturation of bucca - lin gal, 0.02 tapered gutta - percha cones may be the better choice.%目的:比较不同锥度牙胶尖冷侧压法充填不同形态根管的充填效果.方法:选择离体单根管牙齿40个,圆形和扁形根管各20个,M2机用镍钛器械预备根管后,分别使用0.02和0.06锥度主牙胶尖以冷侧压技术进行根管充填.拍摄颊舌向和近中远中向X线片;距根尖3 mm和5mm处切断,对横断面进行显微照相,分析图像,计算牙胶面积与根管横断面积百分比;记录不同锥度牙胶尖根管充填的操作时间.结果:扁根管近中远中向X线片的根充影像的连续性和密度均一性均不及颊舌向的影像.距根尖3 mm处,圆根管0.06锥度的主牙胶尖的PGP与0.02锥度的无显著性差异(P>0.05);而扁根管0.02锥度的主牙胶尖的PGP高于0.06锥度的PGP(P<0.05).距根尖5mm处,各组均无显著差异(P>0.05).使用0.06锥度牙胶尖根充耗时明显短(P<0.05).结论:临床上,圆根管宜采用与根管锥度相近的主牙胶尖根充,扁根管考虑到颊舌向的充填,应酌情采用0.02锥度主牙胶尖.
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