The Study Of The Interface Between Ti-implant And Different Soft Tissues

Objective Studying the interface between non-gingival mucosa soft tissue (including skin and alveolar mucosa) in oral cavity and meanwhile ,studying the volume of "GCF"(gingival crevicular fluid) of peri-implant and measuring AST and ALP levels of it, with the aim of finding association between implants and them.Methods Making a pediculated skin graft on dog's upper lip ,and then got it into oral cavity via the "skin tunnel", laying it on the maxillary bone(the premolar region) surface (the same size of the alveolar mucosa has been removed),and suturing the graft edges with its surrouding alveolar mucosa. Four weeks later , the graft was alive .After transecting the pedicle, implants were placed with standard method on the alveolar through the skin graft. We made a loose incision on the mucosa of the mandibular sulcus vestibularis(postmolor region), planting implants with the same method mentioned above. We used four dogs , fourteen implants in all. After 1,2,4,and 6 weeks, the dogs were sacrificed, each implant site including the implant and the soft and hard peri-implant tissue, was dissected. These specimens were prepared for scanning microscope and light microscope respectively. During the experimental occasion ,GCF was collect with fiter paper(Whatman 1) every two weeks, which was kept in ependoff in –70oc refrigerator after been weighted. ALP and AST in GCF specimens were measured with auto biochemical analysis machine.Results During the study period ,all grafts were alive and implants were all stability.Peri-implant soft tissue showed inflammation to different extent. Histologically, at four or six weeks, Under light microscope, we found that soft tissue contact with implants. We also found fiber connective tissue attaching on implant tightly using scanning eletron microscope . The trend of volume of GCF and ALP and AST levels got higher as the study time last, which correlated with the clinical evaluation. The volume of GCF of implant was much great higher than it of nature teeth.Conclusion Skin graft and alveolar mucosa both formed fiber connective tissue attachment on the surface of implant, which seal the environment between the oral and bone-interface. Compared to ideal "epithelial cuff" ,the epithelial tissue was absent in our study, which may suggest that strict definite "epithelial cuff" was hard to form in such oral environment. Alveolar mucosa exist some factors that may inhibit forming epithelial attachment on implant in oral cavity. So, there is keratine mucosa exist or not in implant region should be considered. The volume of GCF and AST and ALP levels of it can reflect peri-implantitis, which can be one of the basis of diagnosis and treatment implantitis. We also found it is important to nurse and to keep oral hygiene after operation.