两种配比纳米羟基磷灰石复合胶原材料对犬拔牙窝骨缺损修复效果的比较

Study on bone regeneration with two different ratios of nano-hydroxyapatite and collagen grafts after tooth extraction in dogs

目的比较两种配比的纳米羟基磷灰石复合胶原材料（nano—hydroxyapatite／collagen，nHAC）在犬拔牙窝硬组织修复中的作用，以期为nHAC的临床应用提供参考。方法按纳米羟基磷灰石和Ⅰ型胶原构成比分别为3：7（A组）和5：5（B组）制备人工骨支架材料，取18只健康成年雄性杂种犬，拔除下颌双侧第二前磨牙，植入A组或B组材料（每组12侧），以不进行处理的自然愈合侧为阴性对照组（C组，12侧）。分别于术后1、3和6个月（每组每个时间点4侧）行螺旋CT扫描测量颌骨高度及CT值，取材行大体观察、组织学观察及X射线显微镜观察并比较拔牙窝骨小梁体积分数及孔隙率。结果nHAC植入牙槽骨后，材料降解吸收，新骨不断生成。术后3个月A组颌骨高度[（15．76±0．28）mm]、CT值[（879±31）HU]、骨小梁体积分数[（22．2±0.4）％]均显著高于B组盼别为（14．88±0．36）mm、（718±29）HU和（20．3±0．4）％]，而孔隙率[（23．6±0．8）％]则显著低于B组[（27．6±0．6）％]（P〈0．05）；C组颌骨高度[（13．77±0．34）mm]、CT值[（588±35）HU]及骨小梁体积分数[（17．4±0．6）％]均显著低于A、B组，且孔隙率[（39．4±0．7）％]显著高于A、B组（P〈0．05）。结论纳米羟基磷灰石和Ⅰ型胶原构成比为3：7的nHAC更利于促进成骨，促进拔牙窝骨组织修复。

Objective To compare the effect of bone regeneration with two different ratios of nano- hydroxyapatite（nHA）/collagen（Col） （nHAC） after tooth extraction in canine. Methods Two kinds of nHAC grafts were prepared with different nHA/collagen ratio of 3 ： 7 and 5 ： 5. Eighteen male healthy adult dogs had been randomly divided into three groups. Immediately after extraction of the mandibular second premolars, each kind of nHAC was implanted into extraction sockets as follow： Group A, nHA/Col=3 ： 7（12 sites）; Group B, nHA/Col=5 ： 5（12 sites）; Group C, blank control group（12 sites）. The bone repairing abilities of the two grafts such as vertical distance of alveolar, CT values, general observation, histological observation, trabecular volume fraction and porosity were separately analyzed at 1st, 3rd and 6th month, respectively （each group had 4 sites in different time periods）. Results nHAC were absorbed gradually after they were implanted into alveolar bone defect and were replaced by new bone. The vertical distance of alveolar bone in Group A（[15.76±0.28] mm） was significant higher than that in Group B（[14.88±0.36] mm）, and CT values of Group A（[879 ± 31] H.U） were higher than those in Group B（[718 ± 29] HU）（P〈0.05）. The trabecular bone volume percentage of Group A（[22.2±0.41%） was higher than that in Group B（[20.3±0.41%）, and the bone porosity of Group A（[23.6±0.91%） was lower than that in Group B（[27.6±0.61%）（P〈0.05）. In addition, the vertical distance, CT values and the trabecular bone volume percentage of Group C was lower than those in Group A and B, but the bone porosity of Group C was higher. Conclusions The nHAC with nHA/ collagen ratio of 3 ： 7 could better promote bone regeneration than nHAC with the nHA/collagen ratio of 5 ： 5 did.