双相磷酸钙作用下牙周组织缺损再生的Beagle犬正畸牙移动的骨改建功能

Bone remodeling function of orthodontic tooth movement in Beagle dogs with periodontal defect regeneration under action of biphasic calcium phosphate

目的:观察应用双相磷酸钙(BCP)对Beagle犬牙周组织缺损进行再生后正畸牙移动的过程,阐明BCP作为牙周再生支架材料的改建机制。方法:选择6只成年雄性Beagle犬作为研究对象,以每只犬口内右上象限(B区)、左下象限(C区)为对照组,左上象限(A区)和右下象限(D区)建立犬上下颌双侧侧切牙牙周组织缺损模型,于缺损处植入BCP进行缺损组织再生12周后,建立正畸牙移动模型(实验组),分别对实验组和对照组施加应力刺激,并于加力后1、2和4周随机处死2只Beagle犬,标本处理染色后观察应力作用下再生牙周组织的组织学变化及调控成骨活动核心结合因子α1(Cbfα1)的表达情况,观察受应力作用的正常牙周组织内的情况。结果:Masson染色检测,施加正畸压应力刺激后1周,实验组和对照组犬牙周膜均明显变窄,纤维致密,实验组犬牙槽骨以蓝染为主,对照组犬牙槽骨除牙周膜的受压区域外大体呈红色。在施加正畸压应力刺激后4周,实验组犬牙槽骨红-蓝相间,对照组犬牙槽骨红染;2组犬牙周膜内血管管腔变圆。施加正畸压应力刺激后1周,实验组和对照组犬牙槽骨表面布满骨吸收陷窝,内含多核的破骨细胞,其胞浆Cbfα1染色呈阳性;受压变形的牙周膜内细胞排列无序。施加正畸压应力刺激后4周,实验组犬牙槽骨破骨细胞消失,吸收陷窝被成骨细胞充填,骨小梁另一侧的成骨细胞也处于活跃状态,牙槽骨的骨髓腔内间充质细胞和边缘的成骨细胞仍可见Cbfα1阳性表达;对照组犬牙槽骨中的成骨细胞为Cbfα1弱阳性表达。结论:应用BCP再生的牙周组织已接近正常牙周组织,其在正畸力作用下具备正常的成骨功能,可以完成正畸牙移动的骨改建过程。

Objective : To observe the orthodontic tooth movement after regeneration of Beagl dog’ s periodontal tissue defect with biphasic calcium phosphate(BCP), and to elucidate the mechanism of BCP as a scaffold material for periodontal regeneration. Methods : Six adult male Beagle dogs were selected;the right upper quardrant(B) and the left lower quardrant(D) regions of each dog were used as blank control group, and the left upper quardrant(A) and the right lower quardrant(D) regions were used to establish the dog models of periodontal tissue defect of bilateral incisors. BCP was implanted into the defect to regenerate the defect. After 12 weeks of BCP implantation into the defect for defect tissue regeneration, the orthodontic tooth movement models were established (experimental group). Stress stimulation was applied in experimental group and control group, respectively. Two Beagle dogs were randomly executed at 1, 2 and 4 weeks after loading. The specimens were stained, the histological changes of regenerated periodontal tissue and the expression of core binding factor α1(Cbfα1) regulating osteogenesis under stress were observed;the changes in normal periodontal tissue under the same stress were observed. Results : The Masson staining results showed that the periodontal ligament of the dogs in experimental group and control group became narrower and denser at 1 week after stress stimulation;the alveolar bone of the dogs in dogs in experimental group was mainly blue;the alveolar bone of the dogs in control group was generally red except for the compression area of the periodontal ligament. At 4 weeks after stress stimulation, the alveolar bone of the dogs in experimental group was red-blue, while the alveolar bone of the dogs in control group was red;the blood vessels in periodontal ligament of the dogs in two groups were rounded. One week after stress stimulation, the alveolar bone surface of the dogs in experimental group and control group was covered with bone resorption lacunae containing the multinucleated osteoclasts, the cytoplasmic Cbfα1 staining was positive, and the compressed and deformed periodontal ligament cells were arranged disorderly. Four weeks after stress stimulation, the osteoclasts disappeared in experimental group, and the bone resorption lacunae was filled by osteoblasts, and the osteoblasts on the other side of the trabecula were also active;the expression of Cbfα1 was still found in the bone marrow mesenchymal cells and the marginal osteoblasts of alveolar bone. The expression of Cbfα1 was weak in control group. Conclusion : The periodontal tissue regenerated by BCP has reached the normal periodontal tissue. Under the action of orthodontic force, it has normal osteogenesis function and can complete the bone remodeling process of orthodontic tooth movement.