Root ZX根尖定位仪准确性的体外实验研究

In vitro study on the accuracy of Root ZX electronic apex locator

目的:分析影响Root ZX根尖定位仪测量牙齿操作长度准确性的因素。方法:选择根尖孔发育完成的单根管离体牙40个,在生理盐水琼脂模型上,分别在根管内灌注25g/L次氯酸钠液、生理盐水、170g/LEDTA、30mL/L过氧化氢液和蒸馏水,在根管干燥条件下,用Root ZX测量牙齿操作长度,分析根管内容物对Root ZX测量值的影响。另外,选择根尖缩窄大小各异的牙齿23个,用Root ZX测量根管长度,计算探测锉尖离根尖孔的距离,分析该距离与根尖缩窄大小的相关关系。结果:以距根尖孔0～1mm为标准,RootZX的准确率为97.5%。同一根管内不同内容物时,Root ZX测量值间的差异无统计学意义(P>0.05),探测锉尖离根尖孔的距离与根尖缩窄的大小呈正相关(r=0.8584)。结论:RootZX测量牙齿操作长度的准确性不受根管内容物的影响;根尖缩窄大小是影响Root ZX准确性的决定因素,电测长与根尖缩窄大小呈负相关。

AIM： To explore the factors which influenced the accuracy of the Root ZX in measuring the root canal length. METHODS： Forty extracted teeth with single straight canals and completed foramina were selected. Electronic measurement with Root ZX was taken on a normal saline agar model when the canals were filled with 2.5% NaOC1, 0.9% NaC1, 17% EDTA, 3% H202, distilled water and in dry condition respectively. The additional experiment was made on twenty -three teeth with different size of apical constrictions. Every tooth was measured with Root ZX under dry and moist canal conditions respectively, so the distance between the tip of probe file and foramen was obtained. RESULTS ： The accuracy of Root ZX in determining the canal length in 0 to 1 mm distance of apical foramen presented 97.5% regardless of canal contents and dry condition. The distance between the tip of file and foramen showed positive correlation to the diameter of apical constriction. （γ = 0. 8584）. CONCLUSION： The accuracy of Root ZX was not influenced by the root canal contents. The diameter of apical constriction was a key factor affecting the performance of Root ZX and showed negative correlation to the electrical measurement.