Radiographic, Histologic, and Biomechanical Evaluation of Combined Application of Platelet-rich Fibrin with Blood Clot in Regenerative Endodontics

Introduction: No in vivo study has been reported on the mechanical reinforcement of a tooth after regenerative endodontic treatment (RET). The present work aimed to evaluate the concurrent use of platelet-rich fibrin (PRF) with a blood clot (BC) in RET concerning periapical healing, root development, and tooth structural reinforcement. Methods: In our study, 24 premolars from 3 beagle dogs were assigned into control, BC, and PRF + BC groups. Periapical healing was monitored with quantitative measurements of root elongation and thickening radiographically. Tooth biomechanical integrity was assessed with the fracture resistance test. Histologic evaluation was conducted. Results: There was a significant difference among the periapical radiolucency decreasing rate of the control (43.75%) and the BC (100%) and PRF + BC (100%) groups (P < .05). The increase of root length and thickness in both the BC and PRF + BC groups was significantly greater than that in the control group (P < .05). No significant difference was detected between the 2 experimental groups regarding periapical healing or root development (P > .05). Teeth in the BC (249.3 +/- 64.1 N) and PRF + BC (281.7 +/- 37.8 N) groups had significantly higher fracture resistance than those in the control group (108.5 +/- 23.3 N) (P < .05). No significant difference was revealed between the BC and PRF + BC groups (P > .05). Histologic evidence of cementumlike tissue deposition along the canal wall with scattered bonelike tissue in the canal was observed. Conclusions: Either a combination of PRF with BC or BC alone could improve periapical healing, induce root development, and reinforce tooth structure. No additional benefit of PRF to BC in RET was found.