Immediate loading after implant placement following tooth extraction up-regulates cellular activity in the dog mandible.

Objectives: The aim of this study was to investigate cellular activity of the cervical portion of peri-implant tissue due to immediate loading after implant placement following tooth extraction from the dog mandible, in terms of morphological, immunohistochemical and molecular characteristics. Material and methods: A sand-blasted implant was inserted into the root septum bone of each extraction socket and was connected to a superstructure made from resin and then covered with an expanded polytetrafluoroethylene membrane. Implants without the superstructure were used as the non-loading control group. Animals were sacrificed 1-3 weeks later and specimens were observed using light microscopy and mRNA levels were analyzed by real-time polymerase chain reaction. Results: The new bone formation ratio in the loading group at 3 weeks was significantly higher than in the non-loading group. Alkaline phosphatase (ALP)-positive cells were observed in tissues around the implant surface in both groups at each of the time periods. More osteocalcin (OCN)-positive cells were observed in the non-loading group than in the loading group at 2 weeks. The expression of ALP mRNA in the loading group was significantly up-regulated compared with the non-loading group ( P<0.05). The expression of OCN mRNA in the loading group was significantly up-regulated compared with the non-loading group at 2 weeks ( P<0.05). Conclusion: These results suggest that immediate loading after implant placement following tooth extraction osteogenic affects cellular activity of cervical portion of peri-implant tissue. To cite this article: Sato R, Matsuzaka K, Kokubu E, Inoue T. Immediate loading after implant placement following tooth extraction up-regulates cellular activity in the dog mandible. Clin. Oral Impl. Res. xx, 2011; 000-000. doi: 10.1111/j.1600-0501.2010.02118.x [ABSTRACT FROM AUTHOR]