Despite extensive research, the use of autologous platelet-rich plasma (PRP) to treat major bone abnormalities remains controversial. As a substitution, allogeneic PRP from donors who have been thoroughly vetted not just produces a more accurate and reliable treatment but also does not require drawing significant amounts of blood. Allogeneic PRP is nevertheless usually understudied, especially given its immunogenicity in this use. This study's objective was to assess the effects of using PLGA/HA scaffold together with platelet-rich plasma (PRP) on bone regeneration of critical-size mandibular defects in a rabbit model. Material and methods: - A total of 18 mandibular defects were made, and three groups (each n = 6) were created. The first group received a hydroxyapatite matrix and polylactic-polyglycolic acid HA/PLGA) scaffold in combination with PRP. The second group received only HA/PLGA scaffolds. The third group, which served as the control, had a critical-sized defect left empty. Specimens were collected and evaluated by means of micro-CT scans and histological analysis after 3 months. Results: PRP + PLGA/HA led to more extensive new bone formation (p < 0.05) in contrast to the PLGA/HA scaffold only group and the control group. In conclusion, In a mandibular rabbit model, a mixture of PRP, PLGA, and HA enhances bone repair. This research supports the use of autologous (PRP) as an over-the-counter treatment for bone repair.