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):93-9. doi: 10.1046/j.1365-2591.2003.00628.x.
To investigate physical parameters for ProTaper nickel-titanium (NiTi) rotary instruments whilst preparing curved canals in maxillary molars in vitro.
A novel torque-testing platform was used to prepare root canals in 15 extracted human maxillary molars with ProTaper rotary instruments. Peak torque and force was registered along with numbers of rotations required to shape the canals. Canals were divided into 'wide' and 'constricted' groups depending on canal volumes assessed by micro computed tomography. Mean scores for each instrument type were calculated and statistically compared using anova and Scheffé posthoc tests.
Mean torque varied between 0.8 +/- 0.5 and 2.2 +/- 1.4 N cm whilst mean force ranged from 4.6 +/- 2.6 to 6.2 +/- 2.7 N. Mean numbers of rotations totalled up to 21. All three variables registered were significantly correlated to preoperative canal volumes (P < 0.001) and differed significantly between 'wide' and 'constricted' canals (P < 0.001).
Whilst high forces were used in some cases, no ProTaper instrument fractured when a patent glide path was present. There were significant positive correlations between canal geometry and physical parameters during shaping.
在体外对上颌磨牙弯曲根管进行预备时，研究ProTaper镍钛（NiTi）旋转器械的物理参数。
使用一种新型扭矩测试平台，用ProTaper旋转器械对15颗拔除的人上颌磨牙进行根管预备。记录峰值扭矩和力以及根管塑形所需的旋转次数。根据微计算机断层扫描评估的根管容积，将根管分为“宽”组和“窄”组。计算每种器械类型的平均分数，并使用方差分析和谢费尔事后检验进行统计学比较。
平均扭矩在0.8±0.5至2.2±1.4 N·cm之间变化，而平均力在4.6±2.6至6.2±2.7 N之间。平均旋转次数总计达21次。记录的所有三个变量均与术前根管容积显著相关（P<0.001），并且在“宽”根管和“窄”根管之间存在显著差异（P<0.001）。
虽然在某些情况下使用了较大的力，但当存在通畅的引导通路时，没有ProTaper器械发生折断。在根管塑形过程中，根管形态与物理参数之间存在显著的正相关。
