Osseointegration of Osseotite s and machined-surfaced titanium implants in membrane-covered critical-sized defects: a histologic and histometric study in dogs Alexander A. Veis Serafim Papadimitriou Paolo Trisi Anastasios T. Tsirlis Nikolaos A. Parissis James N. Kenealy Authors’ affiliations: Alexander A. Veis, Anastasios T. Tsirlis, Nikolaos A. Parissis, Department of Surgery, Implantology and Radiology, Dental School, Aristotle’s University of Thessaloniki, Thessaloniki, Greece Serafim Papadimitriou, Surgery Clinic, Faculty of Veterinary Medicine, University of Thessaly, Karditsa, Greece Paolo Trisi, Biomaterials Clinical Research Association, Pescara, Italy James N. Kenealy, Clinical Research Department, Implant Innovations Inc., Palm Beach Gardens, FL, USA Correspondence to: Alexander A. Veis Theohari 5 Thessaloniki 546 21 Greece Tel.: þ 30 2310 269079 Fax: þ 30 2310 269079 e-mail: veis@otenet.gr Key words: bone regeneration, machined surface, membrane alone, Osseotite s surface Abstract: The texture of an implant’s surface can influence the rate and extent of bone fixation as expressed by the amount of linear bone-to-implant contact (BIC). The purpose of this study was to compare the bone density and linear BIC between Osseotite s and machined-surface implants placed in bony defects without graft material and covered by a membrane. Thirty 2 mm diameter, 10mm length custom implants were prepared for this study having a ‘split surface,’ with one side having the acid-etched surface and the opposite side having a machined surface. Defects were created in the iliac wing of three adult mongrel dogs where a 6-mm-diameter drill was used to generate a 5-mm-deep defect. The implants were inserted into the center of the defect with 5 mm secured into the bone leaving 5 mm free in the defect with a 2 mm gap between the implant and surrounding bone. Expanded polytetrafluroethelyene membranes were placed over the defect sites stabilized with Biotack s pins. The healing times were 2, 3, and 5 months. Histologic and histometric analysis showed significantly lower BIC in the defect region as compared with the portion of implant placed into native bone for both implant surfaces in all groups. There was no difference in BIC values at 2- and 5-month periods between the two surfaces in the regenerated area, while BIC values for Osseotite s surfaces were significantly higher than the machined surfaces at 3 months’ healing time. Changes in bone density, observed between the three groups, affected correspondingly the BIC values in both implant surfaces, the effect being more pronounced in the Osseotite s surface. Coverage of a bony defect by a reinforced space-making barrier alone creates a suita- ble environment for bone regeneration (Schenk et al. 1994). The addition of bone graft to similar defects promoted even more bone development (Slotte et al. 2003). The contributions of bone grafting material to the development of implant adherent bone are not clear – does the amount and quality of regenerated bone around an implant affect the development of bone-to-implant contact (BIC)? Placing hydroxyapatite (HA)-coated implants within a defect re- gion, Stentz et al. (1997) reported a 63.7  4% BIC when demineralized freeze-dried bone allograft (DFDBA) and expanded polytetrafluroethelyene (ePTFE) membranes were used and 42  5.5% BIC with the membranes used without grafting. In contrary, Hockers et al. (1999) found that the development of vital bone was improved by the addition of bone grafting material, but no significant differences were recorded with respect to the develop- ment of implant BIC. A critical factor influencing the develop- ment of BIC is the material and topography of the implant surface (Wennerberg et al. 1995, 1996; Schwartz et al. 1997; Cochran et al. 1998). Stentz et al.’s (1997) study Copyright r Blackwell Munksgaard 2006 Date: Accepted 20 April 2006 To cite this article: Veis AA, Papadimitriou S, Trisi P, Tsirlis AT, Parissis NA, Kenealy JN. Osseointegration of Osseotite s and machined-surfaced titanium implants in membrane- covered critical-sized defects: a histologic and histometric study in dogs. Clin. Oral Impl. Res. 18, 2007; 153–160 doi: 10.1111/j.1600-0501.2006.01316.x 153