上下颌骨微型支抗种植体-骨整合的变化

Implant-bone changes following maxillary and mandible mini-implant as anchorage

背景:微型种植体作为骨支抗越来越多地应用于正畸治疗中,一些研究表明上下颌脱落率明显不同,但关于上下颌微型支抗种植体-整合差异的相关报道较少。目的:应用不脱钙的硬组织切片法观察载荷对微型种植体上下颌骨整合的影响。设计、时间及地点:对比观察实验,于2007-06/2008-03在河北医科大学第二医院动物室完成。材料:微型钛螺纹种植体(直径1.6mm,长度8mm)及配套设施由西安中邦钛生物材料有限公司提供。方法:将72枚微型种植体植入在家猪的上下颌骨内,按照植入至取材的时间及载荷分为即刻组、3周无载荷组、6周载荷组,9周载荷组、12周载荷组和12周无载荷组。载荷开始时间为种植体植入后4周。制作种植体-骨的硬组织切片,用图文分析系统计算其周围骨的整合情况。主要观察指标:种植体-骨结合率及种植体周围骨钙化面积百分率。结果:①除6周载荷组外,其余各组下颌种植体-骨结合率均高于上颌,无论是种植体表面50m还是500μm范围内,下颌骨面积率也均高于上颌。②在种植体周围50μm范围内,3周无载荷组骨面积率最低,6周载荷组骨面积率最高。在500μm范围内,同一颌内各组骨面积率差异无显著性意义。③12周载荷组上下颌的种植体-骨结合率、骨面积率均高于12周无载荷组。结论:①下颌种植体拥有更大的骨量支持。②种植体周围50μm范围内是骨改建最活跃的地带,而超过500μm以外的区域骨改建活跃程度显著降低。③经过一定愈合期后一定范围的载荷是可以增加种植体-骨结合率和量。

BACKGROUND： Mini-implant has been applied extensively in the therapy of orthodontics as anchorage. Studies have indicated that there is a distinguished difference between the failure rate of the mini-implant in maxillary and mandible. However, relevant reports on the difference of the osseointegration about mini-implant in maxillary and mandible are rare. OBJECTIVE： To investigate the effects of different bone structures between maxillary and mandible on the healing process of mini-implant by sclerous tissues sectioning. DESIGN, TIME AND SETTING： Comparative and observational trial. The study was performed at the Animal Laboratory of Second Hospital Affiliated to Hebei Medical University from June 2007 to March 2008. MATERIALS： Titanium threaded mini-implant （1.6 mm diameter, 8 mm length） and supporting apparatus were provided by Xian Zhongbang. METHODS： According to the time that the mini-implants stay in the bone and loaded or not, all 72 mini-implants were divided into 0-week unloading, 3-week unloading, 6-week loading, 9-week loading, 12-week loading and 12-week unloading in maxillary and mandible, respectively. Each group was loaded at 4 weeks after implantation. After all the animals were sacrificed, their maxillary and mandibles were dissected. The specimens were made into section and stained by toluidine blue. The implant-to-bone surface on histology of the sections was analyzed. MAIN OUTCOME MEASURES： Percentages of bone to implant contact （BIC %）; percentages of peri-implant within calcified area （CA % within 50μ m and CA % within 500μm）. RESULTS： Except 6-week loading group, the BIC % and CA % of each mandible group was greater than maxillary group either within 50 μm or 500 μ m. Within 50μ m the lowest contact rate was found at 3-week unloading group, and the peak was reached at the 6^th week. No significant difference was found within 500μm. The BIC % and CA % of 12-week loading were greater than 12-week unloading group in maxillary and mandible. CONCLUTION： The sediment yield of bone around the mandible implant is higher. The area within 50 μm surrounding the implants is the most active reconstruction area, and the activity is gradually decreases excess 500μ m. Following certain healing period, certain loads could increase implant-bone union rate and mass.