Peters O A, Peters C I, Schönenberger K, Barbakow F
Endodontic Division, Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, 94134, USA.
Int Endod J. 2003 Feb;36(2):86-92. doi: 10.1046/j.1365-2591.2003.00626.x.
To evaluate the relative performance of ProTaper nickel-titanium (Ni-Ti) instruments shaping root canals of varying preoperative canal geometry.
Extracted human maxillary molars were scanned, before and after shaping with ProTaper, employing micro computed tomography (muCT) at a resolution of 36 mum. Canals were three-dimensionally reconstructed and evaluated for volume, surface area, 'thickness' (diameter), canal transportation and prepared surface. Based on median canal volume, canals were divided into 'wide' and 'constricted' groups. Comparisons were made between mesiobuccal (mb), distobuccal (db) and palatal (p), as well as 'wide' and 'constricted' canals, using repeated-measures anova and Scheffé posthoc tests.
Volume and surface area increased significantly and similarly in mb, db and p canals, and gross preparation errors were found infrequently. Root canal diameters, 5-mm coronal to the apex, increased from 0.38 to 0.65 mm, 0.42 to 0.66 mm and 0.57 to 0.79 mm for mb, db and p canals, respectively. Apical canal transportation ranged from 0.02 to 0.40 mm and was independent of canal type; 'wide' canals had a significantly higher (P < 0.05) proportion of unprepared surfaces than 'constricted' canals.
Canals in maxillary molars were prepared in vitro using ProTaper instruments without major procedural errors. These instruments may be more effective in shaping narrow canals than wider, immature ones.
评估ProTaper镍钛器械对术前根管形态各异的根管进行预备时的相对性能。
使用分辨率为36μm的微型计算机断层扫描（μCT）对拔除的人类上颌磨牙在使用ProTaper预备前后进行扫描。对根管进行三维重建，并评估其体积、表面积、“厚度”（直径）、根管偏移和预备表面。根据根管体积中位数，将根管分为“宽大”组和“狭窄”组。使用重复测量方差分析和谢费事后检验对近中颊侧（mb）、远中颊侧（db）和腭侧（p）根管，以及“宽大”和“狭窄”根管进行比较。
mb、db和p根管的体积和表面积均显著且相似地增加，且很少发现严重的预备错误。根尖上方5mm处的根管直径，mb、db和p根管分别从0.38mm增加到0.65mm、从0.42mm增加到0.66mm和从0.57mm增加到0.79mm。根尖根管偏移范围为0.02至0.40mm，且与根管类型无关；“宽大”根管未预备表面的比例显著高于“狭窄”根管（P<0.05）。
使用ProTaper器械在体外对上颌磨牙根管进行预备时未出现重大操作失误。这些器械在预备狭窄根管方面可能比宽大、未成熟的根管更有效。
