Regenerative potential of platelet-rich plasma added to xenogenic bone grafts in peri-implant defects:: A histomorphometric analysis in dogs

Background: The purpose of this investigation was to evaluate the regenerative influence of platelet-rich plasma (PRP) added to xenogenic bone grafts on bone histomorphometric parameters in a dog model. Methods: Ninety endosseous dental implants were inserted in the mandibles of nine hound dogs. Mesial and distal 3-wall peri-implant defects were surgically created adjacent to the implants. Defects were randomly assigned to three groups: demineralized freeze dried bone with platelet-rich plasma (DFDB + PRP), DFDB alone, and no treatment (NT). Animals were sacrificed at 1, 2, and 3 months according to a previously established randomization schedule, and specimens were subjected to histomorphometric analysis. Percentages of bone area inside the implant threads (BiIT), bone-to-implant contact (BIC), and bone area outside implant threads (BoIT) were recorded. Treatment effects were evaluated using analysis of variance models. Results: The effect of the three treatments on the outcome measures did not differ significantly by healing time (P>0.05 for the healing time by treatment interaction). However, the average (standard deviation) percentage of BIC and BoIT was significantly different between the treatment groups. In particular, the average percentage of BIC differed between peri-implant defects treated with DFDB + PRP (33.8% [11.0]) and those treated with DFDB alone (28.5% [10.8]; P=0.042), as well as those in the NT group (27.9% [11.0]; P=0.024). Furthermore, the average percentage of BoIT differed significantly between defects treated with DFDB + PRP compared to defects in the NT group (51.6% [12.2] versus 43.3% [10.3]; P=0.005). There was borderline evidence to suggest that the average percentage of BilT and BIC was significantly different depending on the length of the healing time(P=0.054 and P=0.085, respectively). Conclusion: This study found that the addition of PRP to xenogenic bone grafts demonstrated a low regenerative potential in this animal model.