Journal of implantology and applied sciences ISSN:2765-7833(Print) 2765-7841(Online) 대한구강악안면임플란트학회지

The purpose of this study was to evaluate the usefulness of HA-coated cylinder implant in immediate placement of implants into extraction sockets. The capacity of bone regeneration were compared between using demineralized freeze-dried bone and bovine-derived hydroxyapatite. After extraction of the 4th premolar of maxilla and mandible in adult dogs, Integral^® implants were placed in maxilla with 3.25mm in diameter, 8mm in length and in mandible with 3.25mm in diameter, 10mm in length. The experimental group filled with demineralized freeze-dried bone into the bony defect around the implant was designated as DFDB group, and the other group filled with bovine-derived hydroxyapatite was BDHA group. In the control group, bony defect around the implant was sutured without any graft materials. The experimental animals were killed on the 1st, 2nd, 4th and 8th week after implantation for macroscopic and light microscopic evaluation, and the fluorescent dyes were injected on the 2nd, 4th and 8th week for fluorescent microscopic examination. Results obtained were as follows : 1. Macroscopically, neither infection of graft site nor exposure of implant was noted in any animals used. 2. Osseointegration was observed in all groups without epithelial migration of fibrous tissue around the implant, and osseointegration began from the 2nd week in both experimental groups and from the 4th week in the control. After the 8th week, osseointegration was observed in all groups 3. Experimental groups showed more rapid bone formation than the control and DFDB group showed more rapid formation than BDHA group. DFDB group showed osteoinductive bone formation and BDHA group showed osteoconductive bone formation. 4. The maxillary group showed more rapid bone regeneration than the mandibular group, which the mandibular group showed more dense and lamellated bone pattern than the maxillary group. 5. By fluorescent microscopy, bone remodelling was observed in regenerated bone tissue of all groups. Active bone formation was noted form the 2nd week in both experimental groups and from the 4th week in the control. These results suggest that the demineralized freeze-dried bone can be used as an alternative to auto-genous bone and the bovine-derived hydroxyapatite as an alternative to homogenous bone. It is suggested that the HA-coated cylider implant can be used in immediate placement of implants into extraction sockets instead of screw-shaped titanium implant.