Mestriner Marcelo Antonio, Enoki Carla, Mucha José Nelson
Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
Braz Dent J. 2006;17(2):155-60. doi: 10.1590/s0103-64402006000200014.
This study evaluated the degree of buccolingual inclination of mandibular tooth crowns relative to torque. For such purpose, mandibular and maxillary stone casts from 31 Caucasian Brazilian adults with normal occlusion, pleasant facial aspect and no history of previous orthodontic treatment were examined. A custom device was developed for measuring the degree of inclination (torque) of bracket slots of orthodontic appliances relative to the occlusion plane, at three bonding height: standard (center of clinical crown), occlusal (0.5 mm occlusally from standard) and cervical (0.5 mm cervically from standard). Except for the mandibular incisors, which presented a small difference in torque from one another (lingual root torque for central incisors and buccal root torque for lateral incisors), the remaining average values are close to those found in the literature. Due to the convexity of the buccal surface, the 1-mm vertical shift of the brackets from occlusal to cervical affected the values corresponding to the normal torque, in approximately 2 degrees in central and lateral incisors, 3 degrees in canines and 8 degrees in premolars and molars.
本研究评估了下颌牙冠相对于转矩的颊舌向倾斜程度。为此，对31名咬合正常、面部美观且无正畸治疗史的巴西成年白种人的下颌和上颌石膏模型进行了检查。开发了一种定制装置，用于测量正畸矫治器托槽槽沟相对于咬合平面在三个粘结高度处的倾斜程度（转矩）：标准高度（临床牙冠中心）、咬合高度（比标准高度高0.5mm）和颈部高度（比标准高度低0.5mm）。除下颌切牙彼此之间的转矩存在微小差异（中切牙为舌侧根转矩，侧切牙为颊侧根转矩）外，其余平均值与文献报道的值接近。由于颊面的凸度，托槽从咬合高度到颈部高度1mm的垂直移动对正常转矩值产生了影响，中切牙和侧切牙约为2度，尖牙为3度，前磨牙和磨牙为8度。
