Remodeling Of Periodontal Tissue In Application Of Mini- Implant Anchorage For Teeth Intrusion In Dogs

Implant as a new anchorage method has been applied in clinic since 1990, which is convenient for dentists and patients enormously. In orthodontic clinic, implant can be used to adduct anterior teeth maximatily, as absolute anchorage. As well as, in case of severe disharmony of alveolar height, severe open bite, and imperfect dislocation of anti-maxillary teeth because of long-term agomphiasis, it can be used to realize teeth intrusion.Dogs were used for this research. The remodeling of periodontal tissues and the variation of RANKL in periodontal tissues were observed in application of mini-implant anchorage for teeth intrusion in dogs. And according to that, we analyzed the teeth movement mode.The research contents is as follow:1 Remodeling of periodontal tissue in application of mini-implan anchorage for incisor intrusion in dogsAIM: To observe the remodeling of periodontal tissues 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 (120g) 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, HE staining and RANKL immunohistochemistry 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 continous force to intrude incisor in clinical practice.2 Remodeling of periodontal tissue in application of mini-implant anchorage for posterior teeth intrusion in dogsAIM: To observe the remodeling of periodontal tissues in application of mini-implant anchorage for the maxillary third premolar intrusion in dogs,in order to provide the theory foundation for clinical application. METHODS: Six dogs were used for the experiment. On the buccal and palatal sites of the maxillary third premolar, a mini-implant was placed at the interradicular septa respectively, both on the left and right sites. An intrusive force (100g) was applied by elastic chain crossing occlusal surface of the the maxillary third premolar. An animal was sacrificed at the end of 0,1,3,7,14 and 30 days respectively after the activation. Then X-ray examination, HE staining and RANKL immunohistochemistry staining were performed. RESULTS: The periodontal tissues in apical area, interradicular furcation and crest of ridge rebuilded most actively, which displayed alveolar bone resorption primarily. However, the periodontal tissues on the buccal and lingual sites, as well as the mesial and distal sides did not remodeled markedly. CONCLUSIONS: The maxillary third premolar in dogs is only intruded vertically in application of mini-implant anchorage. 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 continous force to intrude teeth in clinical practice.