title: Changes in periodontium after extraction of a periodontally-involved tooth in rats.
abstract: OBJECTIVE
  Recent interest has focused on intentional replantation to restore an original tooth. Some studies have shown successful results with intentional replantation for periodontally involved teeth. For long-term success of replantation, a healthy periodontal status of the recipient site is required so that delayed replantation is more suitable for periodontally involved teeth. To reveal the ideal timing for delayed replantation of periodontally involved teeth, the healing process of extraction sockets after extraction of periodontitis-induced teeth in rats was evaluated.
  
  
  METHODS
  Twenty-eight rats were randomly divided into two groups: a control group (n=8) and test group (n=20). In the test group, periodontitis was induced by a ligature around the cervix of the mandibular first molar of all of the rats. Two weeks later, the mandibular first molars were extracted in all of the animals. The animals were sacrificed on days 0, 3, 7, and 10 after extraction and histological and immunohistochemical analysis was performed.
  
  
  RESULTS
  In histological analysis of the test group, inflammatory cell infiltrate was found abundantly in the remaining periodontium 3 days after tooth extraction and decreased gradually at later time points. In immunohistochemical analysis of the test group, both interleukin-6 (IL-6) and, tumor necrosis factor-α (TNF-α) were numerous in the furcation area at each postextraction day. IL-6 was stained more heavily between 3 and 7 days after extraction; at day 10 after extraction, little staining was observed. TNF-α staining was more intense at 3 days after extraction and gradually weakened at later points in time.
  
  
  CONCLUSIONS
  Within the limits of this study, it takes at least 10 days to resolve periodontal inflammation in rat extraction sockets.
authors.affiliation: Department of Periodontology, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Dong-Ju
authors.initials: DJ
authors.lastname: Kim
authors.forename: Jae-Kook
authors.initials: JK
authors.lastname: Cha
authors.forename: Cheryl
authors.initials: C
authors.lastname: Yang
authors.forename: Ahran
authors.initials: A
authors.lastname: Cho
authors.forename: Jung-Seok
authors.initials: JS
authors.lastname: Lee
authors.forename: Ui-Won
authors.initials: UW
authors.lastname: Jung
authors.forename: Chang-Sung
authors.initials: CS
authors.lastname: Kim
authors.forename: Seung-Jong
authors.initials: SJ
authors.lastname: Lee
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Choi