研究牙槽窝内保留颊侧部分牙根，对牙槽窝颊侧骨板高度及牙槽窝骨愈合速度的影响。

选择4只成年Beagle犬双侧下颌及第二、三、四前磨牙的远中根作为实验位点。采用平行对照随机分为以下3组：（1）血液充盈组：拔除前磨牙远中根，血液充盈后关闭创口；（2）Bio-Oss Collagen组：拔除前磨牙远中根，牙槽窝内植入Bio-Oss Collagen，牙槽窝表面覆盖Bio-Gide，严密关闭创口；（3）部分牙根+血液充盈组：去除前磨牙远中根牙冠及牙根的舌侧部分，保留颊侧部分牙根，血液充盈牙槽窝后关闭创口。术后12周拍摄Beagle犬下颌锥形束CT（CBCT），比较颊侧骨板高度变化以及牙槽窝内的成骨情况。采用SPSS 21.0统计软件对颊侧骨板高度吸收量进行秩和检验，检验水准α = 0.05。

术后12周，血液充盈组颊侧骨板高度降低（1.63 ± 0.67）mm，Bio-Oss Collagen组颊侧骨板高度降低（0.77 ± 0.58）mm，部分牙根+血液充盈组颊侧骨板高度降低（0.06 ± 0.10）mm。Bio-Oss Collagen组牙槽窝颊侧骨板吸收量小于血液充盈组，差异具有统计学意义（Z=-2.205，P = 0.027），部分牙根+血液充盈组颊侧骨板吸收量小于血液充盈组，差异具有统计学意义（Z=-3.361，P= 0.001），部分牙根+血液充盈组颊侧骨板吸收量小于Bio-Oss Collagen组，差异具有统计学意义（Z=-2.260，P= 0.024）。术后12周血液充盈组牙槽窝中间区域显示低密影，Bio-Oss Collagen组牙槽窝高密影，形态与牙根轮廓相似，部分牙根+血液充盈组可见较多地松质骨影像。

牙槽窝内保留颊侧部分牙根，相比牙槽窝内植入Bio-Oss Collagen，能更好地保存颊侧骨板高度。保留颊侧部分牙根具有促进牙槽窝内骨生成，加快牙槽窝骨愈合速度的作用。

To observe the buccal bone plate height and socket alteration with a buccal partial root in a tooth socket.

Four adult male Beagle dogs were used. Bilateral mandible the 2ⁿd to 4^th premolar distal roots were randomly divided into three groups, i.e., the group of blood filling (the root was extracted and the wound was sutured after blood filling) , the group of Bio-Oss Collagen (the root was extracted and the wound was filled with Bio-Oss Collagen and covered with Bio-Gide before suturing) and the group of buccal partial root combined with blood filling (the lingual partial root was removed while the buccal partial root was kept; the wound was sutured after blood filling) . CBCT analysis was carried out on the first day and 12^th week post operation. Vertical buccal bone plate alteration and osteogenesis effect in sockets were observed with the 12^th week CBCT images. Statistical analysis was carried out with SPSS 21.0 and the significance level was 0.05.

The buccal bone plate height in the group of blood filling reduced (1.63 ± 0.67) mm, while that of the group of Bio-Oss Collagen and the group of buccal partial root combined with blood filling was (0.77 ± 0.58) mm and (0.06 ± 0.10) mm, respectively. The vertical height alteration of buccal bone plate was much less in the group of Bio-Oss Collagen than the group of blood filling (Z=-2.205, P= 0.027) . So was the group of buccal partial root combined with blood filling compared with the group of blood filling (Z=-3.361, P= 0.001) and the group of buccal partial root combined with blood filling compared with the group of Bio-Oss Collagen (Z=-2.260, P= 0.024) . The sockets were comparatively empty in the group of blood filling. High density bone graft substitute was observed in the group of Bio-Oss Collagen. Cancellous bone was observed in the group of buccal partial root combined with blood filling.

A buccal partial root resided in the tooth socket seems have a better ability to maintain the height of the buccal bone plate than Bio-Oss Collagen. A buccal partial root may accelerate new bone formation and be in favor of tooth socket healing.