Department of Orthodontics, Faculty of Dentistry, Chulalongkorn University, 34 Henri-Dunant Rd, Patumwan, Bangkok, Thailand, 10330.
Angle Orthod. 2012 Sep;82(5):812-9. doi: 10.2319/100611-627.1. Epub 2012 Feb 23.
To determine the effect of labiolingual inclination of a maxillary central incisor on the magnitude and distribution of stresses within the periodontal space.
Five three-dimensional finite element models of a right maxillary central incisor were created with 0°, 10°, 20°, 30°, and 40° inclination. Each incisor model was subjected to a 1 N lingual-directed force and 6-12 N·mm countertipping moment on the labial surface. The stress level within the periodontal ligament was calculated in terms of maximum principal stresses.
With increased inclination, compressive stresses tended to increase whereas tensile stresses tended to decrease. The location where compressive stress was prevalent changed from the midroot area to the apical area on the lingual side, while the area where tensile stresses were predominant changed from the midroot area to the cervical area on the labial side.
There are more compressive stresses concentrated at the apex of incisors with a high degree of inclination than in incisors that are more upright. This may be associated with the higher clinical incidence of apical root resorption found in inclined maxillary central incisors.
确定上颌中切牙的颊舌倾斜度对上颌中切牙牙周间隙内应力大小和分布的影响。
制作了 5 个上颌右中切牙的三维有限元模型，倾斜度分别为 0°、10°、20°、30°和 40°。每个中切牙模型均在唇面受到 1N 的舌向力和 6-12N·mm 的反向扭转力矩。牙周膜内的应力水平用最大主应力来计算。
随着倾斜度的增加，压缩应力趋于增加，而拉伸应力趋于减少。在舌侧，受压应力的主要区域从根中部向根尖部转移，而在唇侧，受拉应力的主要区域从根中部向颈部转移。
与更垂直的中切牙相比，高倾斜度中切牙的根尖处有更多的压缩应力集中。这可能与上颌中切牙倾斜时临床发现的根尖吸收发生率较高有关。
