Chen Zhengxi, Pan Xiaogang, Zhao Ning, Chen Zhenqi, Shen Gang
From the Department of Orthodontics, Ninth People's Hospital, School of Stomatology, Shanghai key Laboratory of Stomatology, Shanghai Jiao Tong University, Shanghai, China.
J Craniofac Surg. 2015 Mar;26(2):388-92. doi: 10.1097/SCS.0000000000001337.
Unilateral cleft lip and palate (UCLP) patients frequently present with an asymmetry in the nasomaxillary complex and a maxillary hypoplasia. The aim of this study was to investigate biomechanic effects of asymmetric maxillary protraction in UCLP patients using finite element method.
A finite element model of a UCLP patient's skull was generated using data from spiral computed tomographic scans. On the basis of this finite element model, three groups of orthopedic forces were loaded. All forces were applied in a direction that was 30 degrees downward and forward to the occlusal plane on the region of the alveolar of the maxillary canine. The value of orthopedic force was 5 N in cleft side and 5 N in noncleft side (group A), 6 N in cleft side and 5 N in noncleft side (group B), and 7 N in cleft side and 5 N in noncleft side (group C), respectively.
All 3 groups were effective in promoting maxilla forward. In group B, the displacement difference between the cleft side and the noncleft side was the smallest. The largest value difference between the cleft side and the noncleft side was found in group C.
Maxillary protraction with a loading of 6 N in the cleft side and 5 N in the noncleft side produced the most favorable outcome. It can be suggested that it might be advantageous to perform asymmetric maxillary protraction on UCLP patients.
单侧唇腭裂（UCLP）患者常表现出鼻上颌复合体不对称和上颌骨发育不全。本研究旨在使用有限元方法研究UCLP患者不对称上颌前牵引的生物力学效应。
利用螺旋计算机断层扫描数据建立UCLP患者颅骨的有限元模型。基于该有限元模型，加载三组矫形力。所有力均在向下30度且向前至上颌尖牙牙槽区域的咬合平面的方向上施加。裂隙侧的矫形力值为5N，非裂隙侧为5N（A组），裂隙侧为6N，非裂隙侧为5N（B组），裂隙侧为7N，非裂隙侧为5N（C组）。
所有3组均有效地促进了上颌骨向前移动。B组中，裂隙侧与非裂隙侧之间的位移差异最小。C组中，裂隙侧与非裂隙侧之间的最大差值最大。
裂隙侧加载6N、非裂隙侧加载5N的上颌前牵引产生了最有利的结果。可以认为，对UCLP患者进行不对称上颌前牵引可能是有益的。
