根尖定位仪在不同指示点测量特点的体外研究

目的研究2种多频根尖定位仪在不同指示点的测量特点。方法截除75颗单根管前磨牙牙冠，GG钻扩大根管冠、中1／3。计算ProPexⅡ和JustyII在显示0和0．5指示点时，定位锉尖与解剖根尖孔间的距离。结果采用Mann-WhitneyU检验分析。结果指示点为0时，ProPexⅡ和JustyⅡ测量值间差异无统计学意义（P〉0．05），中间值分别为0．39mm和0．37mm。指示点为0．5时，ProPexⅡ和JustyⅡ测量差异有统计学意义（P〈0．05），测量中间值分别为0．56mm和0．69mm。同一定位仪在不同参考点下测量值间差异有统计学意义（P〈0．01）。结论本研究条件下，指示点由0变化到0．5时，2种根尖定位仪定位锉尖均逐渐远离解剖根尖孔。指示点0时2种根尖定位仪定位效果相似。指示点0．5时，ProPexⅡ比JustyII定位更接近解剖根尖孔。

Evaluation of two multi-frequency based apex locators with different scales in vitro

Objective To evaluate two multi-frequency based apex locators with different scales. Methods Seventy-five extracted mandibular premolar were decoronated at cemento-enamel junction. The coronal and middle part of root canal was flared by GG drills. The distance between the file tips and anatomic foramen was calculated and recorded in 0 and 0. 5 scales displayed by ProPex 11 and Justy II. The results were subjected into Mann-Whitney U analysis. Results The difference between ProPex H and Justy 11 was not significant when the scale point was 0 （ P 〉 0. 05 ）, and the average value was 0. 39mm and 0. 37mm. The difference between two locators was significant when the scale point was 0. 5 （ P 〈 0. 05）, and the average value was 0. 56mm and 0. 69mm. The measurements obtained under different scales were significantly different by the same apex locator （ P 〈 0. 01 ）. Conclusion Under the limit of current study, the file tips determined by two apex locators were located gradually away from the anatomic foramen when the scale point was changed from 0 to 0. 5. The measurements of two locators were not significantly different when the scale point was 0, but file tips determined by ProPex H were located much closer to anatomic foramen compared with that of Justy H when the scale point was 0. 5.