摘要：

目的： 通过形态学、影像学和组织学方法研究盾构技术（socket-shield technique，SST）对比格犬种植修复后牙槽骨吸收和牙龈退缩的影响。方法： 选择3只成年雄性比格犬，每只比格犬拔除双侧下颌第3或第4前磨牙（P3、P4），并进行即刻种植。根据是否采用盾构技术将手术牙位区域分为实验组和对照组（n=3）。种植术后3个月行修复治疗。修复后3个月观察并记录牙龈退缩量和角化龈宽度。收集双侧下颌骨，通过Micro-CT扫描和组织学形态分析，比较牙槽骨垂直吸收量、牙槽骨宽度及种植体骨结合率。结果： 牙龈形态学定量分析显示，修复后3个月实验组牙龈退缩量小于对照组（P<0.05），实验组角化龈宽度大于对照组（P<0.05）。Micro-CT扫描显示，负重3个月后实验组根片组织缺失，颊侧牙槽骨垂直吸收量与对照组相比无显著差异，实验组牙槽嵴顶下1、2、3 mm处颊侧骨宽度均大于对照组（P<0.05）。组织学分析显示，实验组和对照组种植体骨结合率无显著差异。结论： 在观察期内，盾构技术可以显著减少负重后颊侧牙槽骨水平吸收，减少牙龈退缩量。但负重后可能出现根片的吸收或脱落，且无牙周膜留存。

关键词: 盾构技术, 即刻种植, 比格犬, 组织增量

Abstract:

Objective: To investigate whether the socket-shield technique(SST) in implant loading was related to alveolar bone resorption and gingival recession. Methods: The position of premolar(P3 or P4) in bilateral mandibular bone of three adult male Beagle dogs were selected for immediate implantation(6 implants in total). The experimental group and control group were divided according to whether the immediate implant was combined with the socket-shield technique or not. Implant loading was proceeded 3 months after implantation, and samples were collected 3 months after loading. The condition of gingival recession and keratinized gingival width were observed and recorded, and Micro-CT measurement and histologic analysis were performed to access the microarchitecture of mandibular bones. Results: Compared to the control group, the experimental group exhibited a decreased gingival recession and improved width of attached gingival（P<0.05）. The disappearance of root fragment in the experimental group was observed after 3-month loading. There was no significant difference in buccal alveolar bone resorption and bone-implant contact between two groups. The width of the buccal alveolar bone in the experimental group were significantly larger versus control group among the level of 1, 2, and 3 mm below the crest. Conclusion: The socket-shield technique can increase the fullness of buccal alveolar bone and reduce the recession of attached gingiva after loading. However, the root fragment might be absorbed or detach after loading and meanwhile there is no persistent periodontal ligament.

Key words: socket-shield technique, immediate implants, Beagle dogs, tissue augmentation