ProTaper机用镍钛锉对弯曲根管成形效果的评价

Assessment of Shaping Ability of ProTaper in Curved Canals

目的评价机用镍钛锉ProTaper预备弯曲根管时的根管成形能力。方法利用一套笔者自主研制的“模拟牙齿根管辅助分析测量系统”软件,定量检测8个树脂模拟根管在用ProTaper以冠下法预备前后的形态变化,并进行统计学分析。结果机用镍钛锉ProTaper预备后会减小根管的原始弯曲度,但主锉选择F2还是F3对弯曲度变化的影响不大。ProTaper对弯曲根管中段的凹侧壁和根管口处的凸侧壁有过度切割的趋势,但根尖点的偏移量很小,仅0.021mm左右。结论机用镍钛锉ProTaper预备高度弯曲的根管时,主锉仍可选择F3。但对于根管内侧壁凹陷的弯曲根管而言,要注意避免因ProTaper过度切割而造成带状侧穿。

Objective To evaluate shaping ability of nickel-titanium rotary instruments （ProTaper） in curved root canals. Methods The computer assistant measure system of simulated root canal was used for quantitative analysis of root shape of eight simulated root canals during ProTaper shaping process. Blue ink was injected into the simulated root canals before instrumentation, when F2 reached work length （WL）（F2） and When F3 reached WL（F3）. Orifices and apexes were sealed with adhesive tapes. Root canal images were gained by Mustek BP4800TA scanner. The images before and after preparation were turned into Di-numerical images and fused. The changes of central line positions and curvatures were measured in quantity through this system. Data of seven preestablished point from orifice to apex were recorded and analysed by SPSS 10.0 soft ware. Results ProTaper system reduced the angles of simulated canals. Selecting F2 or F3 as the master apical file （MAF） had no influence on the changing rate of the root angles. ProTaper had excess cutting on the outer wall of orifice and the inner wall of curve part, but the displacement of apex was minimal （.only 0.021 mm）. Conclusion ProTaper has preferable shaping ability. To prepare very di^cult curved canals, the master apical file （MAF） could be F3. Attention should be taken when preparing some curved canals with hollows in their inner walls, in order to avoid the lateral perforation.