Prognostic factors for alveolar regeneration: Bone formation at teeth and titanium implants

Objectives: There is a limited understanding of the effect of defect characteristics on alveolar bone healing. The objectives of this study were to assess the effect of alveolar bone width and space provision on bone regeneration at teeth and titanium implants, and to test the hypothesis that the regenerative potentials at teeth and implants are not significantly different. Methods: Critical size, 5-6-mm, supra-alveolar, periodontal defects were surgically created in 10 young adult dogs. Similarly, critical size, 5-mm, supra-alveolar, peri-implant defects were created in four dogs. A space-providing expanded polytetrafluoroethylene device was implanted for guided tissue regeneration/guided bone regeneration. The animals were euthanized at 8 weeks postsurgery. Histometric analysis assessed alveolar bone regeneration (height) relative to space provision by the device and the width of the alveolar crest at the base of the defect. Statistical analysis used the linear mixed models. Results: A significant correlation was found between bone width and wound area (r = 0.55892, p < 0.0001). Generally, bone width and wound area had statistically significant effects on the extent of bone regeneration (p < 0.0005 and p < 0.0001, respectively). Bone regeneration was linearly correlated with the bone width at periodontal (p < 0.001) and implant (p = 0.04) sites, and with the wound area at periodontal (p < 0.0001) and implant (p = 0.03) sites. The relationships of bone regeneration with these two variables were not significantly different between teeth and implants (bone width: p = 0.83; wound area: p = 0.09). When adjusted for wound area, bone regeneration was significantly greater at periodontal than at implant sites (p = 0.047). Conclusions: The horizontal dimension of the alveolar bone influences space provision. Space provision and horizontal dimension of the alveolar bone appear to be important determinants of bone regeneration at teeth and implants. The extent of alveolar bone formation at implant sites is limited compared with that at periodontal sites.