根尖预备尺寸对玷污层清除效果的比较研究

目的:比较5种不同根尖预备方案对根管玷污层的清除效果。方法:将50颗单根管上颌离体前牙随机分为5组,A组:采用机动ProTaper系统将根尖预备至25^#(F2),配合次氯酸钠+EDTA冲洗;B组:根尖预备至30^#(F3),预备及冲洗方法同A组;C组:采用机动ProTaper系统将根尖预备至F3,后用不锈钢K锉预备根尖至35^#,冲洗同A组;D组:采用机动ProTaper系统将根尖预备至F3,后用不锈钢K锉预备根尖至40^#,冲洗同A组;E组:根管预备同D组,冲洗用蒸馏水。利用热场发射扫描电子显微镜,评估玷污层清除情况。结果:B组、C组和D组均明显优于A组 (P<0.05);A组、B组、C组和D组明显优于对照E组(P<0.05)。结论:机动ProTaper将根管预备至30^#,可使足量的冲洗液渗入根尖1/3区,有效去除玷污层及碎屑。

Effectiveness of Apical Preparation Size on the Removal of Smear Layer.

Objective: To compare the effect of five different apical preparation protocols in smear layer removal. Methods: Fifty extracted single-rooted maxillary anterior teeth were randomly divided into five groups,group A: root canals were prepared to 25^#(F2) by ProTaper system,and irrigated by NaOCl and EDTA; group B: root canals were prepared to 30^#(F3),and the preparation and irrigation protocols were same as group A; group C: root canals were prepared to 30^# (F3) by ProTaper system,and then the apical size enlarged to 35^# by stainless steel K-file.The irrigation protocol was same as group A; group D: root canals were prepared to 30^# (F3) by ProTaper system,and then the apical size enlarged to 40^# by stainless steel K-file.The irrigation protocol was same as group A; group E: root canal preparation was same as group D,and irrigated by distilled water.The samples were examined under a thermal field emission scanning electron microscope. Results: Group B,group C and group D showed lower scores than group A (P<0.05); group A,group B,group C and group D showed lower scores than group E (P<0.05). Conclusion: In smear layer removal,the minimum instrumentation for proper penetration of irrigants to the apical third of the canal is a 30^# file by ProTaper system.