Effect of Carbonate Apatite Hydrogel-Advanced Platelet-Rich Fibrin Injection on Osteoblastogenesis during Orthodontic Relapse in Rabbits

Objective This study aimed to determine the effect of carbonate apatite (CHA) hydrogel-aPRF on osteoblastogenesis during relapse in rabbits. Materials and Methods Forty-five rabbits were divided into three groups ( n = 15): the control, CHA, and CHA-autologous platelet-rich fibrin (aPRF) groups. An open-coil spring was compressed between brackets to distalize the lower incisors of the rabbits by delivering a force of 50 cN for 1 week. The new position of the teeth was retained for 14 days, and CHA hydrogel-aPRF was injected every 7 days. The appliances were then debonded to allow relapse. On days 0, 3, 7, 14, and 21 after debonding, transforming growth factor (TGF)-β1 and bone morphogenetic protein (BMP)-2 expression was examined using immunohistochemistry staining and Runx-2 levels were analyzed by enzyme-linked immunosorbent assay. The data collected were analyzed using analysis of variance and a post hoc Tukey’s test ( p < 0.05). Results Histomorphometric analysis revealed that TGF-β1 expression in the CHA-aPRF group is statistically higher than that in other groups on days 0, 3, and 7 after debonding ( p < 0.05). BMP-2 expression in the CHA-aPRF group was also statistically higher than that in the other groups on days 3, 14, and 21 after debonding ( p < 0.05). ELISA showed that Runx-2 levels are slightly higher in the CHA-aPRF group than in the other groups ( p > 0.05). Conclusion Although injection of CHA-aPRF aids in osteoblastogenesis associated with enhancing TGF-β1 and BMP-2 expressions, it does not significantly upregulate Runx-2 levels.