Connective Tissue Orientation around Dental Implants in a Canine Model

Objectives: to evaluate the effects of porous surface of dental implants on the orientation of collagen in the canine gingival connective tissue. Methods: Pores with three kinds of diameters on the supracrestal region of dental implants were obtained using Nd: YAG Laser. The diameter of the pores was 10+/-5 um, 40+/-5 um and 70+/-5 um respectively. The implants with porous surface and smooth surface (control group) were inserted in the mandibular bone of beagle dogs. Histomorphometric evaluations of gingival connective tissue were performed after 3 months. Results: The inflammatory reaction of the connective tissue in all the groups showed no significant difference. The length of bone loss and concomitant gingival recession around the implants with smooth surface and 10+/-5 um diameter pores is more than that around the implants with 40+/-5 um and 70+/-5 um diameter pores. The majority of collagen fibers were found to be parallel to smooth implant surface and the surface with 10+/-5 um diameter pores. However, the fibers of oblique or perpendicular orientation to the implant surface were found around the implants with 40+/-5 um and 70+/-5 um diameter pores. Especially the fibers around the implants with 70+/-5 um diameter pores were seen to insert into the pores with oblique orientation. Conclusion: These results concluded that porous surface at the cervical level around the implant can influence the arranged orientation of fibers and induce the fibers insertion into the pores, thus may enhance the combined intensity between implant and gingival connective tissue.