Root ZX根尖电测仪测定根管长度的准确性评价

目的：评价Root ZX根尖电测仪测定根管长度的准确性。方法：49颗(70个根管)根尖发育完全、因正畸需拔除的牙齿在局麻下，开髓、拔髓。Root ZX根尖电测仪测定根管长度，拔除后测定根管实长，比较二者的差异。分别以0．5mm、1．0mm、1．5mm误差评定测量结果的准确性。结果：体内测量平均根管长度为20．81mm，体外测量根管实际长度为21．21mm。84．29％(59／70)测量值位于根管内，8．57％(6／70)恰好位于根尖孔，7．14％(5／70)超出根尖孔。以0．5mm为标准，准确率为64．29％，以1．0mm为标准，准确率为81．43％。若以1．5mm以内为可接受范围，则准确率为90％。结论：Root ZX根尖电测仪能较准确测定根管工作长度，提高根管治疗的质量和工作效率。但仍需和X线照片结合指导临床工作。

An in Vivo Evaluation of Root ZX Electronic Apex Locator

Objective: To evaluate the accuracy of determining root canal length by Root ZX electronic apex locator in vivo. Methods: 49 teeth (70 canals) were obtained from patients waiting to have teeth extracted for orthodontic reason. The teeth were anesthetized, isolated and accessed. Root canal lengths were determined by Root ZX apex locator. After extracted the teeth, accurate canal length of teeth was accessed. The accuracy was compared. Results: By Root ZX apex locator, 84.29%(59/70)were short of apical foramen, 8.57%(6/70)were at the apical foramen, 7.14%(5/70)protruded beyond foramen. With a tolerance level of 0.5mm, an accuracy rate of 64.29% was recorded. With a 1.0mm tolerance level, an accuracy rate of 81.43% was found. With a 1.5mm tolerance level, accuracy was increased to 90%. Conclusion: Root ZX electronic apex locator is an useful and accurate device for the determination of canal length. But it also should be conbined with the exposure of radiograph.