下颌平面角影响种植体应力分布的正交实验

Orthogonal experimental research on the impacts of mandibular plane angle to the stress distribution of dental implants

背景:在临床实践中发现,根据患者下颌平面角选择不同规格的种植体,其长期成功率有所不同,因此有理由设想下颌平面角角度会影响下颌种植体的应力分布,进而影响种植成功率。目的:从下颌平面角角度、下颌骨骨密度以及种植体规格3方面因素对下颌第一磨牙种植体应力分布的力学特性进行正交实验与分析,重点考察下颌平面角对下颌种植体的应力影响规律。方法:针对种植体力学特性问题,此次正交实验涉及3个因素,在影响因素方面确定下颌平面角、种植钉直径、骨密度类型这3个因素,每个因素分别对应3个水平,其中下颌平面角角度分别为14°、22°、34°,种植体直径分别为6.6,8.2,9.6 mm,骨密度类型分别为Ⅱ、Ⅲ、Ⅳ类。根据正交表L9(33)方案将种植体模型植入牙槽骨模型。将不同种植复合体置于力学压力实验机上,压力大小为500 N,其受力结果由应变(应力)数据采集仪进行实时采集。结果与结论:最优参数组合为:下颌平面角为低角,种植体直径为4.8 mm,下颌骨骨密度为Ⅱ型骨。各个因素的主次关系:种植体直径>下颌平面角角度>骨密度。结果表明,下颌平面角角度对种植体的稳固有一定的影响,在同样咬合力的情况下,高角种植体所受应力最大,其次是均角,低角最小。

BACKGROUND： In clinical practice, the selection of dental implants with different specifications is based on the patient＇ s mandibular plane angle, and the long-term success rate is different in dental implants with different specifications. Therefore, it is reasonable to assume that the mandibular plane angle could affect the mandibular stress distribution of dental implants, thus affecting the success rate of dental implantation.OBJECTIVE： To perform an orthogonal experimental study on the mechanical effects of different implant specifications, mandibular plane angles and mandibular bone densities on stress distribution of the first mandibular molar implants. METHODS： A L9（33） orthogonal experiment was designed with 3 three-level factors, including mandibular plane angle （14°, 22°, 34°）, implant diameter （6.6, 8.2, 9.6 mm）, and mandibular bone density （types II, III, IV）. Different dental implants with different combinations were implanted into an alveolar bone model, and placed onto a pressure testing machine under 500 N load. Then, strain （stress） data were collected in real-time and analyzed. RESULTS AND CONCLUSION： The optimal combination was as follows： low angle; 4.8 mm in diameter; mandibular bone with type II bone density. The relations of all the three factors were the diameter of dental implant 〉 the mandibular plane angle 〉 mandibular bone density. To conclude, the mandibular plane angle has some certain influences on the stability of dental implants. If the biting force is the same, dental implant bears the largest stress under the high angle, subsequently followed by the average angle and the low angle.