应用微型种植体支抗压低犬切牙过程中牙周组织改建的实验研究

Rebuilding of periodontal tissue in application of mini-implant anchorage for incisor intrusion in dogs

目的:应用微型种植体支抗压低犬切牙,观察此方法压低牙齿时牙周组织的改建情况,为种植体支抗压低牙齿的正畸临床应用提供理论依据和应用指导.方法:实验犬6只,在两侧上颌第二切牙与第三切牙颊侧牙槽中隔各植入一枚微型种植体,上颌6颗切牙通过个别带环焊接托槽与片段弓丝连扎,用镍钛拉簧每侧施加120g力.分别于加力后0,1,3,7,14和30d处死实验犬,取切牙及其牙周组织进行X光片检查,以及标本处理、组织切片、HE染色观察.结果:切牙根尖区与牙槽嵴顶部牙周组织改建最为活跃,主要表现为骨质吸收;此外切牙唇腭侧牙周组织也发生了明显的改建活动.结论:应用种植体支抗压低犬切牙时,切牙除了实现垂直向的压低移动以外,同时还发生了冠唇向根舌向的转动,这对于该方法的正畸临床应用具有一定的指导意义.若压低牙齿力值过大,会导致牙根尖吸收,因此在临床应用中应重点注意力值大小的选择,并应尽可能使用持续性的力量压低牙齿.

AIM： To observe the rebuilding of periodontal tissue in application of mini-implant anchorage for incisor intrusion in dogs. METHODS： Six dogs were used for the experiment. On the buccal site, a mini-implant was placed at interalveolar septum between the maxillary second incisor and the third incisor on each side. The six maxillary incisors were connected together through the individual bands welded brackets and the segmental wires. An intrusive force （ 120 g） was applied by Ni-Ti spring on each side. An animal was sacrificed at the end of 0,1,3,7,14 and 30 days respectively after the activation. Then X-ray examination and HE staining were performed. RESULTS： The periodontal tissues in apical area and crest of ridge rebuilded most actively. In addition, the periodontal tissues on the buccal and the lingual sites also rebuilded. CONCLUSIONS： The crowns of incisors turn to labial side when the incisors are intruded in application of mini-implant anchorage. This has some instructive meaning to clinical application. It would cause apical root resorption, if the force applied is large excessively. Therefore, we should pay more attention to the level of force and use continuous force to intrude incisor in clinical practice.