Herrera Manuela, Abalos Camilo, Planas Amparo Jimenez, Llamas Rafael
Department of Dental Pathology and Therapeutics, School of Dentistry, University of Sevilla, Sevilla, Spain.
J Endod. 2007 Aug;33(8):995-8. doi: 10.1016/j.joen.2007.05.009.
Small-diameter hand files are systematically used to determine the initial working length and to establish patency of the root canal. In wide canals, electronic apex locator accuracy might be influenced by file size. This article reports on a study to assess the influence of apical constriction diameter on the precision of the Root ZX apex locator by using files of varying diameter on teeth with 3 different degrees of apical widening: 0.37, 0.62, and 1.02 mm. Ten extracted single-root teeth, stored in saline solution at 37 degrees C, were sectioned at the enamel-cement junction and embedded in an alginate mold. Initial working length (L0) was determined with a #10 Kerr file, and canals were irrigated with either 50% citric acid or 5.25% sodium hypochlorite. To assess the ability of the locator to identify the narrowest area of the root canal as constriction diameter increased, the canal was progressively widened by insertion of files of increasing diameter (10-100) at a point L0+1 mm. After each enlargement, the working length (L) was redetermined, with files from #10 (L10) up to the file used for widening. Comparison of statistical results was based on the difference between final working length and initial length (L10) for each apical width. Statistical analysis was carried out with analysis of variance test for comparison of means. Results showed that at apical constriction widths of 0.37 and 0.62 mm, there was no significant difference between initial working lengths as determined by a Kerr #10 file and final working lengths after widening with files of up to #60. In those teeth whose apical width had been increased to 1.02 mm, there was no statistically significant difference between initial and final working lengths as measured by files from #10-#25; however, significant differences were apparent between #10 and #30, #35, or #40 (P<.05), and the degree of significance increased considerably (P<.001) for files #45 or greater. These results suggest that Root ZX apex locator precision varies as a function of apical constriction diameter.
小直径手动锉用于系统地确定初始工作长度并建立根管通畅。在宽大的根管中，电子根尖定位仪的准确性可能会受到锉的尺寸影响。本文报道了一项研究，通过在具有三种不同根尖扩大程度（0.37、0.62和1.02毫米）的牙齿上使用不同直径的锉，来评估根尖缩窄直径对Root ZX根尖定位仪精度的影响。将十颗拔除的单根牙保存在37摄氏度的盐溶液中，在釉牙骨质界处进行切片并嵌入藻酸盐模具中。用#10 Kerr锉确定初始工作长度（L0），并用50%柠檬酸或5.25%次氯酸钠冲洗根管。为了评估随着缩窄直径增加定位仪识别根管最窄区域的能力，在L0 + 1毫米处通过插入直径逐渐增大的锉（10 - 100号）逐步扩大根管。每次扩大后，重新确定工作长度（L），使用从#10（L10）到用于扩大的锉。统计结果的比较基于每种根尖宽度下最终工作长度与初始长度（L10）之间的差异。采用方差分析进行统计分析以比较均值。结果表明，在根尖缩窄宽度为0.37和0.62毫米时，用Kerr #10锉确定的初始工作长度与用#60及以下的锉扩大后的最终工作长度之间无显著差异。在根尖宽度增加到1.02毫米的那些牙齿中，用#10 - #25号锉测量的初始和最终工作长度之间无统计学显著差异；然而，#10与#30、#35或#40之间存在显著差异（P <.05），对于#45及更大号的锉，显著程度大幅增加（P <.001）。这些结果表明，Root ZX根尖定位仪的精度随根尖缩窄直径而变化。
