目的 观察佩戴软弹性咬合板对磨牙症患者牙周组织应力的影响。方法 创建颌骨和牙列的三维有限元模型,对模型右侧上、下颌的每颗牙加载与牙体长轴呈0°、45°、90°的成人最大咬合力,分析使用不同厚度软弹性咬合板(1 mm、2 mm)后,牙槽骨及牙周膜所受应力的大小及分布,设不使用软弹性咬合板组做阴性对照。结果 在各咬合力加载角度下,与对照组相比,1 mm软弹性咬合板对牙周膜应力的缓冲效率平均为16%,对牙槽骨应力的缓冲效率平均为15%。2 mm软弹性咬合板对牙周膜及牙槽骨应力缓冲效率平均为26%及25%。在所有组别中,牙周组织的最大应力均集中于颊、舌侧牙槽嵴顶附近,但使用软弹性咬合板后应力集中范围减少,应力分布更均匀。结论 软弹性咬合板可以作为咬合应力的缓解装置,它有助于消减磨牙症产生的额外应力对牙周组织造成的破坏。

Objective To observe the effect of wearing an elastic soft occlusal splint on the stress of periodontal tissue in patient with bruxism. Methods A three-dimensional finite element model of jaw and dentition was created. Each tooth in the test area was loaded with the maximum adult occlusal force at 0°, 45°, and 90° with respect to the long axis of the tooth. 1 mm and 2 mm elastic soft occlusal splint were used, and the stress of the alveolar bone and periodontal ligament with and without elastic soft occlusal splint were analyzed and compared. Results Compared with the control group, 1 mm splint reduced the periodontal ligament stress of patient by an average of 16% and the alveolar bone stress by an average of 15%. After wearing a 2 mm splint, the patient's periodontal ligament and alveolar bone stress were reduced by 26% and 25% respectively. In all groups, the maximum stress of the periodontal tissue was on the buccal and lingual alveolar ridge crest, but the stress distribution was more uniform after using the soft occlusal splint. Conclusion The soft occlusal splint can be used to relieve occlusal stress and help eliminate the damage to periodontal tissue caused by the extra stress in bruxism.

目的 对下颌角肥大钻凿法截骨整形手术进行生物力学研究,并探索该术式的优化改进。方法 采用有限元方法,建立下颌角钻凿法截骨整形手术及其改良术式的三维有限元模型并进行应力分析、比较。结果 模型-1(钻凿法下颌角截骨整形手术模型)下颌角断裂失效载荷在所有术式中最高,为2426N。其余的改良术式模型(模型-2~7)失效载荷均低于模型-1,分别为2018N、1854N、1447N、1183N、1028N、876N。同时,模型-7与其他模型对比,其应力分布范围最小,关节盘von Mises应力手术侧大于非手术侧,大部分区域为0.52～3.25 MPa之间,最大不超过9.86 MPa。结论 在非均匀钻孔加去下颌角颊侧皮质骨的同时施加最大咬合力和下颌支后缘约束的手术方法最优。

Objective To study the biomechanics of osteotomy surgery for mandibular angle hypertrophy with drilling method and to explore the optimization and improvement of this operation. Methods Using the finite element method, the three-dimensional finite element models of osteotomy surgery for mandibular angle hypertrophy with drilling method as well as its modified operations are established,meanwhile, the stress analysis and comparison are performed. Results Model-1 (mandibular angle osteotomy surgery model by drilling method) had the highest fracture failure load among all surgical methods, which was 2426N. The failure loads of the other modified surgical models (model-2 ~7) were all lower than that of model-1, which were 2018N, 1854N, 1447N, 1183N, 1028N and 876N, respectively. Meanwhile, compared with other models, the stress distribution region of model-7 was the smallest, with the von Mises stress in operating side of the articular disc was greater than that of the non-operating side, and most of the area was between 0.52～3.25MPa and the maximum of 9.86MPa. Conclusion The non-uniform drilling and removal of the buccal cortical bone of the mandibular angle are combined with the maximum occlusal force and the constraint of the posterior margin of the mandibular ramus is the best operation method.

目的 探索不同浓度苯妥英钠(PHT)对大鼠牙周膜干细胞(rat periodontal ligament stem cells, rPDLSCs)粘附于牙根面的影响,为PHT应用于牙周重建提供一定的实验依据,为牙周炎的治疗提供了新思路。方法 提取大鼠rPDLSCs,培养并纯化。通过多项诱导分化、表面标记物鉴定后,使细胞在不同浓度PHT刺激条件下,与牙骨质片共同培养,检测粘附于牙骨质片上的细胞量并作比较。结果 20～80 mg/L 浓度范围内的PHT能够促进rPDLSCs的粘附数量,40 mg/L PHT组促进粘附的效果最强。实验组与对照组有显著统计学差异。结论 适合浓度的PHT可以促进rPDLSCs粘附于牙骨质表面,40 mg/L PHT组促进粘附的效果最强。

Objective To investigate the effects of PHT on attachment of rat periodontal ligament stem cells (rPDLSCs) to cementum chips, in order to provide a certain experimental basis for periodontal regeneration and new ideas for therapy of periodontitis. Methods To isolate rPDLSCs from SD rats, culture and purify them. To identify the cells by their apperance, induced multi-direction differentiation potential and cell surface markers. The rPDLSCs were cultured with cementum chips under the action of different concentrations of PHT. Then testing and comparing the amount of cells attached on the cementum chips in different groups. Results The concentraion among 20～80 mg/L of PHT can increase the number of attached cells. 40 mg/L PHT can promote the cells attachment mostly. Conclusion A proper concentration of PHT may promote rPDLSCs to attach to cementum chips′ surface, 40 mg/L PHT may promote the cell attachment mostly.