Effects of preparation techniques on root canal shaping assessed by micro-computed tomography

Abstract

BackgroundRoot canal shaping without any procedural error is of the utmost preference. Therefore, the purpose of this study was to use micro-computed tomography to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files.Material/MethodsSixty extracted upper second premolars were selected and were divided into 2 groups of 30. Before preparation, all samples were scanned by micro-CT. Then, 30 teeth were prepared with stainless steel files and the remaining 30 with ProTaper rotary files. Canal transportation and centering ability before and after root canal shaping were assessed using micro-CT. The amount and direction of canal transportation and the centering ratio of each instrument were determined in the coronal, middle, and apical parts of the canal. The 2 groups were statistically compared using one-way ANOVA.ResultsProTaper rotary files gave less transportation (p<0.001) and better centering ability (p<0.00001) compared with stainless steel files.ConclusionsThe manual technique for preparation of root canals with stainless steel files produces more canal transportation, whereas rotary files remain more centered in the canal.

Computed tomography evaluation of rotary systems on the root canal transportation and centering ability

“…This result differs from previous studies that indicate that the apical segment usually has more canal transportation toward the outside of the curve. 19,22,25 As in the present study, an average deviation from the direction of the different thirds was used, and hence our results probably reflect the higher incidence of deviation inside of the curve that occurs in the cervical and middle segments, as previously reported by Stavileci et al 9 An important difference between the NiTi systems used in the present study is related to the number of the files used. ProTaper and Twisted File systems use a small number of files in an attempt to simplify the root canal instrumentation, whereas Hero and Liberator systems allow the use of a larger number of instruments.…”

“…9,25 In the present study, we observed a greater incidence of distal deviations (inside of the curve) on all systems used. This result differs from previous studies that indicate that the apical segment usually has more canal transportation toward the outside of the curve.…”

“…17 However, more accurate information can be achieved with micro-computed tomography (micro-CT) 6,13 and computed tomography (CT), 1,7,8,20 which allows for the quantitative and qualitative evaluation of root canals in 3 dimensions. 9 Therefore, in the present study, the root canal transportation and centering ability of four different NiTi rotary systems were evaluated with CT. Table 3. Mean of centering ability (mm) and standard deviation among the groups and root section levels.…”

“…3,4,5 Moreover, NiTi instruments allow for greater conical canal preparation with less work time and more centered shaping of the canal in its original axis, producing rounder preparations and reducing procedural errors. 4,6,7 Several studies have demonstrated successful results with continuous rotation full-sequence NiTi systems such as ProTaper, 8,9 Hero 642, 10 Liberator 5 and Twisted File. 1,11 However, differences between the design and manufacturing procedures associated with these systems may result in variability in the final shape of the instrumented root canal.…”

Analysis of preparation time, wear, transportation and centering ability of Flexofile and Prodesign® M manual instruments in curved root canals preparation

“…Glosson et al [18], Gambill et al [11], Short et al [19], Elliot et al [20], and Schäfer and Florek [21] revealed a better centering ability in the preparation using NiTi instruments than using stainless steel instruments. According to Stavileci et al [22], the centralization capacity of NiTi instruments is in part determined by their characteristic flexibility.…”