摘要
目的 研究上颌骨牵引延长时上颌骨的应力分布状况,探讨上颌骨牵引器的安放位置与方向的最佳选择。方法 在发育性上颌后缩畸形和腭裂继发上颌后缩畸形的上颌模型上分别加载不同方向及大小的牵引力。分别计算上颌骨最大主应力、最小主应力及颌骨内部的位移情况,并比较两种加载方式对上颌骨内部应力分布的影响。结果 在非腭裂上颌骨,当牵引力方向与正中矢状面平行时,双侧上颌骨前壁应力主要为压应力,但应力较小,当牵引方向与正中矢状而成30°角时,对上颌骨前壁的压应力显著增大;在腭裂继发上颌后缩畸形牵引时,裂隙双侧上颌前壁的压应力显著增大,健侧颌骨的位移显著大于患侧。和牵引方向与矢状面平行时相比较,当腭裂上颌骨斜向牵引时,上颌骨前壁及硬腭的位移均较平行牵引时显著增大;腭裂上颌骨在两种牵引力牵引时均出现上颌前部压应力集中,颌骨内部位移增大,牙槽突裂隙两侧位移增大明显。结论 上颌骨牵引时,应尽量使牵引方向与矢状面平行;在上颌骨牵引时应注意防止上颌牙弓缩窄,牵引阻力增大时应戴(牙合)板至稳定期。
Objective To study the stress distribution of maixillary distraction osteogenesis so as to provide the suitable direc-
tion and place for the distracer. Methods With three-dimensional finite element analysis, the stress distribution and the change
of internal displacement of the maxillia was observed during distraction after Le fort Ⅰ osteotomy in the normal maxilla and the
maxilla with cleft palate. Results When distraction direction paralleled with the median sagittal plane, stress on the anterior walls
of the maxilla was compressive stress. When there was a 30 degree angle between them, the compressive stress increased signifi-
cantly; For patients with cleft palate, the compressive stress increased significantly on the bilateral anterior walls of the maxilla be-
side the gap. When the maxilla with cleft palate was distracted obliquely, the displacement of the anterior walls and the hard palate
increased signicantly, compared with sagittal distraction. Conclution The relapse of patients with cleft palate was significantly
higher even if rigid fixation technique was used, unless occlusal splint had been applied until the osteogenesis was stabilized.
出处
《广东牙病防治》
2003年第4期246-248,共3页
Journal of Dental Prevention and Treatment
