不同处理方法对未脱钙异种牙本质颗粒成骨性能的影响

Effect of different techniques on the osteogenic property of undecalcified heterogeneous dentin particles

背景:研究证实,自体牙本质颗粒具有良好的生物相容性和骨传导性,可以作为骨移植材料修复颌骨缺损,但异种牙本质颗粒作为骨移植替代材料的安全性和成骨活性目前还不明确。目的:观察不同方法处理未脱钙人牙本质颗粒在大鼠颅顶骨缺损区骨移植后的组织反应和成骨效果。方法:收集临床拔除的智齿及正畸减数拔除的牙齿(供者对实验知情同意),分别经清洗、粉碎、煮沸、脱脂、消毒处理后,制成0.25-0.5 mm的牙本质颗粒。取40只成年雄性SD大鼠(大连医科大学实验动物中心提供),在颅顶骨上打孔去除骨皮质后制成骨缺损动物模型,随机分4组干预,每组10只:A组植入未经任何处理的牙本质颗粒,B组植入经煮沸处理的牙本质颗粒,C组植入经脱脂处理的牙本质颗粒,D组植入经煮沸和脱脂处理的牙本质颗粒。植入后4,12周,取骨缺损处标本,进行组织学观察。动物实验获得大连医科大学实验动物中心伦理委员会批准。结果与结论:(1)大体观察:植入后4周时,4组标本中的牙本质颗粒均被纤维组织包绕,移植物触诊坚实、稳固,植入后12周时移植物较4周时体积略缩小;(2)组织学观察:植入后4周,各组牙本质颗粒周围均包绕着纤维结缔组织,纤维结缔组织中可见炎性细胞浸润和大量新生血管,牙本质颗粒周围可见多核巨噬细胞,颗粒边缘存在虫噬状吸收区;与植入4周相比,植入12周的牙本质颗粒周围新生毛细血管增多,炎性细胞数量减小,牙本质颗粒周围可见新骨生成,并与颅骨相连接,骨细胞增殖活跃。4组间炎性细胞数、新生血管数及巨噬细胞数和新骨生成量4方面无明显差异(P> 0.05)。(3)结果表明:经过不同方法处理未脱钙人牙本质颗粒在骨移植中引起的炎性反应相似,在大鼠颅骨缺损修复中显示了良好的生物相容性和骨传导性。

BACKGROUND: Autologous dentin particles have been shown to possess good biocompatibility and osteoconductivity, which can be used as bone grafting materials, but the biosafety and osteogenic capacity of heterogeneous dentin particles are still unclear. OBJECTIVE: To observe tissue reaction and osteogenic effects of undecalcified heterogeneous human dentin particles processed with different treatment methods and implanted into skull defect of rat model. METHODS: Extracted human teeth were prepared into 0.25-0.5 mm sized dentin particles after washing, pulverizing, boiling, degreasing and sterilization(donors consent to the experiment). Forty healthy adult male Sprague-Dawley rats were selected to create an animal model of skull defect(provided by Laboratory Animal Center of Dalian Medical University), and the cortical skull bone was removed by round bur perforation. The animals were randomly divided into four groups: untreated, boiled treatment, degreased treatment, and boiled plus degreased groups. Specimens were harvested at 4 and 12 weeks after bone grafting, and the degree of inflammatory reaction and bone regeneration effects were evaluated by gross observation, histological examination and histomophometric analysis. This study was approved by the Experimental Animal Ethics Committee of Dalian Medical University, China. RESULTS AND CONCLUSIONS:(1) Gross observation showed that the dentin particles in the four groups were surrounded by fibrous tissue, and the graft was firm and stable. At 12 weeks, the graft was slightly smaller than that at 4 weeks.(2) Histological observation showed that in each group, the fibrous connective tissue was surrounded by dentin particles and inflammatory cell infiltration and a large number of new blood vessels were observed in fibrous connective tissue. Polynuclear macrophages were visible around the dentin particles, and there were worm-like absorption regions at the edge of the particles. Compared with the 4 th week, the number of new capillaries around the dentin particles increased at 12 weeks, the number of inflammatory cells decreased, new bone formation was observed around the dentin particles, and it was connected with the skull, and the osteocyte proliferated actively. Histological analysis showed that there were no significant differences in the number of inflammatory cells, neovascularization, macrophage count and new bone formation between the four groups(P > 0.05).(3) These results showed that human dentin granule treated by different methods showed similar inflammatory responses in bone grafting, and good biocompatibility and osteoconductivity in rat skull defect repair.