Enhanced Bone-to-Implant Contact by Platelet-Released Growth Factors in Mandibular Cortical Bone: A Histomorphometric Study in Minipigs

Purpose: To determine the effects of platelet-released growth factors (PRGF) on bone-to-implant contact (BIC) in minipig cortical bone. Materials and Methods: In each of 8 adult minipigs, 2 implants were placed in the facial wall of the mandible, one implant with and one without PRGF. PRGF was defined as the supernatant from washed, thrombin-activated, allogenic, platelet-rich plasma cells obtained after centrifugation. Four animals were sacrificed at 4 weeks, and the remaining 4 were sacrificed at 8 weeks. For histomorphometric analyses, undecalcified ground specimens were prepared and stained with the Levai-Laczko stain. Results: For the entire follow-up time, 55.30% BIC was found with PRGF versus 38.91% without PRGF (P = .0198). At 4 weeks, BIC was 44.20% with PRGF versus 29.62% without PRGF (P = .0632), and at 8 weeks there was 70.36% BIC with PRGF versus 48.20% without PRGF (P = .1221). Discussion: Growth factors and other molecules released upon activation of platelet-rich plasma cells can enhance implant anchorage in cortical bone. PRGF obtained from allogenic sources does not impair healing. Conclusion: The results indicated that a single application of PRGF before implant placement can be sufficient to increase the percent BIC in minipig cortical bone.