Effects Of Permanent Premolar Germ During Primary Molar Orthodontic Movement And Its Mechanisms In Dog

Department of Orthodontics, Stomatological College Fourth Military Medical University Xi'an 710032Corrections of malocclusion in primary dentition are important because they affect the growth and development of the cranio-dento-facial pattern at this time.However, there were few reports about the effects of permanent teeth germs during primary teeth orthodontic movement. On the other hand, their biological mechanisms remain unknown.In order to investigate the effects of permanent teeth germs and the changes of their eruption in primary teeth movement, we examined the movement of permanent teeth germs and the changes of their eruption in this experiment when primary teeth were moved mesially. Histological and biological experiments were used to study the biological mechanisms of these effects and changes. Cytological mechanisms were assessed with Human dental follicle cell cultured in vitro. These experimental aims were to direct the work in clinic.This study mainly contains the following works:Part I Effects of permanent tooth germ and its eruption during primary molar orthodontic movement in dog and research of its mechanisms? Effects of permanent tooth germ and its eruption during primary molar orthodontic movement in dogAIM: To investigate effects of permanent tooth germ and eruption of premolar during primary molar movement in dog. METHODS: 12 Chinese male dogs (15-16 weeks) were selected, and divided into 4 groups: Oday> Tday-. 14day and 21 day. The appliance was used between second primary molar and primary canine. The distances of second primary molar movement and third permanent premolar germ were measured. The number of osteoclast in alveolar bone was counted and compared. Histological changes around tooth germ were observed. Results: Compared with the control side, after 21 days, the distances of second primary molar movement and third permanent premolar germ were increased by 31.5% and 31.9% respectively in experimental side. Third permanent premolar erupted was moved mesially by 30.3%. The number of osteoclast in raesio alveolar bone was increased markedly. Bone remodel was observed around third permanent premolar germ. CONCLUSION: Primary tooth orthodontic movement may result in the movement of permanenttooth germ in alveolar at the same direction.[Key words] Primary tooth orthodontic movement; permanenttooth germ; permanent tooth eruption; osteoclast? Expressions of BMP ^ IL-1 a ^ TNF-a in periodontal tissue ofdog's third premolar germ during second primary molarorthodontic movementAIM: To investigate the expression and localization of BMPJL-1 a ,TNF- a in periodontal tissue of dog's third premolar germ during second primary molar orthodontic movement. METHODS: Immunohistochemical staining technique was used to observe the expressions and localizations of BMP % IL-1 a ?TNF-a in periodontal tissue of dog's third premolar germ during second primary molar orthodontic movement. RESULTS: Compared with the control side, in experimental side, the expression of BMP were stained deeply in the dental follicle and alveolar bone of distal part of third premolar germ, and stained weakly in the dental follicle and alveolar bone of mesial part of third premolar germ; the expression of IL-1 a was different, deeply in the dental follicle and alveolar bone of mesial part of dog's third premolar germ, and stained weakly in the dental follicle and alveolar bone of distal part of third premolar germ; As TNF- a , no stain in the dental follicle of third premolar germ. Conclusion: Bone remodel around the permanent tooth germ resulted from primary tooth orthodontic movement. [Key words] Primary tooth orthodontic movement; permanent10tooth germ; BMP; IL-1 a ; TNF- a ; immunohistochemical technique? Expressions of CSF-1 -. TGF- P 1 in periodontal tissue of dog's third premolar germ during second primary molar orthodontic movementAIM: To investigate the expressions and localizations of CSF-1, TGF- P 1 in periodontal tiss...