Does Longstanding Nicotine Exposure Impair Bone Healing and Osseointegration? An Experimental Study in Rabbits

Objectives: The aim of this study was to analyze the effect of longstanding nicotine exposure on bone healing and osseointegration of titanium implants. Materials and Methods: 20 female rabbits received either nicotine (n = 10) or saline (n = 10) administered subcutaneously via mini-osmotic pumps for 32 weeks. The pump delivered 6 mu g/kg/min of nicotine for the animals in the test group. Blood samples were collected and plasma cotinine levels were measured monthly. Six months after the commencement of nicotine or saline administration three osteotomy preparations, one in right, femoral condyle and two in the right tibia were made. One experimental implant was placed in the femur site and one in the most distal preparation of the tibia. The remaining site in the tibia was left empty. The osteotomy preparation and implant installation procedure was repeated in the left leg of the rabbits after 2 weeks. The implants in the tibial site were subjected to removal torque test (RMT) 2 weeks later. Block biopsies of the two other osteotomy sites were prepared for histological analysis. Results: Although no differences in RMT values were found between test and control groups, there was a significant increase in RMT between 2 and 4 weeks within each group. The histomorphometric analysis of bone-to-implant contact and bone density in the bone defects revealed no differences between the test and the control group after 2 or 4 weeks of healing. Conclusion: Longstanding (6 months) nicotine exposure did not impair bone healing and osseointegration of titanium implants. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 91B: 918-923, 200