Animal experiment of periodontal tissue remodeling in application of mini-implant anchorage for incisor intrusion
The aim of the present study is to observe the remodeling of periodontal tissue in application of miniimplant anchorage for incisor intrusion in dogs. Six adult male beagle dogs were used for the experiment. On the buccal site, a mini-implant was placed at the interalveolar septum between the maxillary second incisor and the third incisor on each side. The six maxillary incisors were connected together through the segmental wires and the individual bands were welded by brackets. An intrusive force (120 g) was applied by Ni-Ti coil spring on each side. An animal was sacrificed at the end of 0, 1, 3, 7, 14 and 30 days, respectively, after the activation. X-ray examination, HE staining and receptor activator of nuclear factor-kappa B ligand (RANKL) immunohistochemistry staining were performed afterwards. Then, we found that the periodontal tissue in apical area and crest of ridge remodeled most actively. In addition, the periodontal tissue on the buccal and the lingual sides also remodeled. In conclusion, the incisor teeth were not only intruded vertically but also showed rotation of the crown towards the labial side and the root towards the palatal side, by using mini-implants as anchorage. Besides, if the force applied was excessively large, it would cause apical root resorption.
Key words: Anchorage, mini-implant, incisor intrusion, and receptor activator of nuclear factor-kappa B ligand (RANKL).