Purpose: The effects of 2 graft materials, ß-tricalcium phosphate (Cerasorb) alone and a combination of Cerasorb and platelet-rich plasma (PRP), on the bone regeneration process were evaluated in the canine mandible. Materials and Methods: The mandibular premolars of 12 beagle dogs were surgically removed. The extraction sockets were filled with Cerasorb on the control side and a mixture of Cerasorb and PRP on the test side. Bilateral biopsy samples were taken from the graft insertion sites at 6, 12, and 24 weeks after surgery. Sections were prepared from the undecalcified resin-embedded samples. Results: Six weeks after grafting, the proliferation of cellular osteogenic mesenchyma was more abundant in the test group. The histomorphometric data revealed a significantly higher percentage of bone area in the test group (45.9%) than in the control group (30.8%) (P .05). Twelve weeks after grafting, the test group still had some advantage over the control group in terms of bone regeneration (52.5% bone in the test group versus 49.4% in the control group, P .05). Twenty-four weeks after grafting, bone-forming activity was nearly equal in the 2 groups, and the bone area in the 2 groups did not differ significantly (62.9% and 61.9%, respectively) (P .05). Discussion: The histomorphometric results suggested more intensive bone regeneration in the early healing phase following the topical application of PRP. Conclusion: The increase in bone density facilitated by grafting with a combination of Cerasorb and PRP requires thorough study in humans.