Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Objectives: This study aimed to investigate the effect of Recombinant Human Parathyroid Hormone (PTH 1-34) on attenuating the influence of cigarette smoke on bone around titanium implants. Material and methods: Forty-eight female Wistar rats were used. At the begging of the study, 15 animals were randomly assigned to Group 1 (control) and received subcutaneous injections of saline solution, three-times/week, after implant placement. The other animals received intermittent cigarette smoke inhalation (CSI), 60 days prior and 60 days after implant placement (Al2O3-blasted titanium implants - 4.0 x 2.2 mm). After surgery, these animals were randomly assigned to: Group 2 - subcutaneous injections of saline solution, three-times/week (n = 16) and Group 3 - intermittent doses of PTH (1-34) (40 mu g/Kg), three-times/week (n = 17). Animals were sacrificed 60 days after surgery, and degree of bone-to-implant contact (BIC), bone area (BA) within the limits of the threads and proportion of mineralized tissue (PMT) adjacent to the implants (500 mu m wide zone) were separately obtained in cortical and cancellous bone. Results: Data analysis confirmed that CSI negatively affects bone around implants, as observed for BIC in cortical zone (Cohen's d (d) = -1.26) and for PMT in both zones (d = -6.09 and d = -4.46 for cortical and cancellous zones, respectively). In addition, in the presence of CSI, PTH (1-34) promoted the highest BIC in both regions and BA and PMT in cancellous bone (P < 0.05). The histometric parameter that was not influenced by both PTH and CSI (1-34) was BA in cortical bone (P > 0.05). Conclusion: In the presence of cigarette smoke, a factor related to poor bone healing and low bone density, PTH (1-34) increased bone volume around implants.24910551059Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [471577/2007-3]