Tooth Root-Derived Graft Promotes Complete Bone Replacement in Alveolar Ridge Preservation: Comparative Study with a Collagenic Xenograft in Dogs

Background: Autogenous tooth-derived grafts have been proposed as an alternative to xenografts for alveolar ridge preservation, offering biological similarity to bone and potentially more favorable remodeling. This study compared the healing outcomes of a collagenated xenograft, and a tooth-derived graft prepared with an automated processing device. Methods: Six Beagle dogs underwent bilateral extraction of the third and fourth mandibular premolars. Each animal contributed two sockets grafted with root-derived particulate prepared using an automated device for tooth cleaning, grinding, and demineralization, and two sockets grafted with a collagenated xenograft, all covered by a collagen membrane. After 3 months, histological sections were analyzed to assess crestal dimensions and the relative proportions of mature (lamellar) and immature bone (woven/parallel fibered), residual graft material, and soft tissues. Results: Lingual crest height did not differ between groups, whereas the buccal crest was slightly higher at xenograft sites compared with the tooth-graft sites. The tooth-graft group exhibited significantly fewer residual particles (0.5 ± 1.1%) and a higher proportion of total bone (65.6 ± 9.1%) compared with the xenograft group, which showed 19.7 ± 16.0% graft remnants (p = 0.032). Corticalization at the socket entrance was observed predominantly in the tooth-graft sites. No inflammatory infiltrates were detected in the examined section. Conclusions: Tooth-derived grafts promoted an almost complete replacement by vital bone with minimal residual material, whereas xenografts provided slightly better buccal contour preservation but resulted in regenerated tissues containing persistent graft particles. The biological differences observed may have implications for subsequent implant placement.