目的　研究矿化胶原复合镁钙合金用于犬拔牙位点保存的可行性。   方法　拔除8只杂种犬下颌双侧第4前磨牙，共32个拔牙窝（近中和远中牙槽窝各16个），随机分为A、B两组。A组植入矿化胶原复合镁钙合金材料，B组仅植入矿化胶原材料，于术后12，24周处死实验犬，制备组织标本，通过大体观察、CBCT、肝肾组织学切片观察以及X射线显微镜检测评价拔牙窝愈合情况及肝肾组织的损伤情况。   结果　两组材料在拔牙窝愈合过程中，逐渐被降解吸收，新生骨组织不断形成。术后12周，实验A组的相对骨密度值以及新生骨组织数量均多于B组，差异有统计学意义（P＜0.05）。术后24周，A、B两组的新生骨组织数量逐渐增多，两组相对骨密度值差异不显著（P＞0.05）。   结论　矿化胶原与镁钙合金的复合材料可用于犬拔牙位点的保存，可促进新骨再生，减缓牙槽嵴的吸收。

Objective　To study the feasibility of mineralized collagen composite calcium magnesium alloy used in the preservation of dog tooth extraction site.　Methods　Forth premolars of eight mongrel dogs from the left and right sides of the mandible were extracted, which then resulted in a total of 32 extraction sockets that were then randomly divided into two groups, A and B, with 16 extraction sockets in each group. Group A was implanted with the composite material of mineralized collagen and calcium magnesium alloy, group B was only implanted with mineralized collagen material, the dog was sacrificed 12, 24 weeks later to prepare tissue specimens. The healing of sockets was evaluated by gross observation,CBCT and X-ray microscopes. The damage of liver and kidney tissues was observed by histological sections of liver and kidney.　Results　After implantation of the two groups of materials in the extraction nest, with the healing of the tooth socket, the material gradually degraded and absorbed, the new bone tissue continued to form. At 12 weeks postoperatively, the relative bone mineral density and the number of new bone tissues in experimental group A were significantly higher than those in control group B (P<0.05). At 24 weeks after operation, the number of new bone tissue in group A and B increased gradually, and the difference of bone mineral density between the two groups was not significant (P>0.05).　Conclusion　The composite material of mineralized collagen and calcium magnesium alloy can be used for preservation of dog 's tooth extraction site, which promotes the regeneration of new bone and reduces the absorption of alveolar ridge.