Gingival Invagination Research Of Orthodontic Tooth Extraction Cases In The Clinical

Objective:The research is to study teeth extraction sites preservation techniques taking effect on the healing of orthodontic tooth socket,tooth movement and gingival invagination, and to evaluate the orthodontic treatment effect of this techniques in the tooth extraction cases which supply reference for the orthodontic clinic.Methods:Selecting three patients coming to the orthodontic department of Stomatology Hospital of Lanzhou University who needed to be extracted the 12 first premolars. Under the condition of local anesthesia, the first premolars were extracted by minimally invasive method. Randomly selecting one side to be the experimental group, and embedding the Bio-Oss bone materials into the tooth socket, then covering the Bio-gide collagen membrane, leaving the other side to be the control group, which was dealt with the conventional process. CBCT were taken on the operation day, sixth weeks later after the operation and the day canine teeth having been removed to the desired position. Orthodontic therapy began sixth weeks later after the operation. At the booked time we measured the movement distance of bilateral canine teeth, and we used CBCT to measure the width and height of bilateral alveolar ridge on the teeth extraction sites, the changes of the roots, the changes by comparing one side of gingival with the other side and the occurrence of gingival invagination.Results:1. After six weeks of the operation, the reduction of the alveolar bone width of both jaws in the control groups were obviously larger than that in the experiment groups, which had significant difference (P<0.05). The reduction of the alveolar bone height of maxillary in the control groups were bigger than that in the experiment groups, which had significant difference (P<0.05), whereas the changes of alveolar bone height of the mandibular in both groups had no significant difference (P>0.05).2.Three months and six months later after dragging the canine teeth towards distal movement, the movement distances of both upper and lower canines in experimental groups were larger than that in control groups, which had significant difference (P>0.05).3.When the canines had been moved to the desired position, it could be analyzed by percentage of roots volume loss that both sides of canines roots had been absorption, while the percentages of canine roots volume loss of both jaws in the experimental groups were smaller than that in control groups, which had significant difference (P>0.05).4.0n the preservation techniques sides, experimental sides, there were no gingival invagination on both jaws after the canines having been removed to the desired position. While on the control sides there was only one patient whose maxillary was found gingival invagination, and two patients whose mandibular were found gingival invagination.Conclusion:Alveolar ridge preservation techniques can effectively maintain the alveolar ridge width and height of the teeth socket, and prevent the atrophy of alveolar bone. Comparing with the conventional orthodontic therapy, it can make teeth move faster, make roots loss smaller and more effectively prevent the occurrence of gingival invagination.