Mutaf, Hasan IlhanBicakci, Ali AltugGumus, CesurInan, Vissun Sevinc2026-02-252026-02-2520262321-46002321-1407https://doi.org/10.25259/APOS_320_2024https://hdl.handle.net/20.500.14365/8705Objectives: Our study aims to examine, histologically and radiologically, the effects of platelet-rich plasma (PRP) applied locally into the midpalatal suture on bone formation during and after rapid maxillary expansion (RME) in rabbits. Material and Methods: A total of 24 healthy male New Zealand rabbits were randomly divided into three groups. All animals were subjected to 7-day maxillary expansion and 14-day retention. In the control group, physiological saline was injected into the midpalatal suture on the 1stday of the retention. Group I received a PRP injection only 1 time just before retention. In group II, the PRP injection was given twice, once 24 h after the start of the expansion and once on the 1stday of the retention. Radiographs were taken before and after the expansion and retention to assess the suture's new bone density. All subjects in three groups were evaluated and compared histologically at the end of retention. Results: A decrease in bone density after expansion and an increase in bone density after retention were seen in all groups. The decrease in bone density after expansion was the least in Group II, and the highest increase in bone density after retention was again in Group II. Inflammation, capillary dilatation, cell infiltration, osteoblastic activity, osteoclastic activity, bone morphogenetic protein-4, and transforming growth factor-beta scores of Group II were significantly higher than the control group. Conclusion: Locally applied PRP during and after RME may contribute to bone formation in the midpalataleninfo:eu-repo/semantics/openAccessBone DensityBone Morphogenetic Protein-4Platelet-Rich PlasmaRapid Maxillary ExpansionTransforming Growth Factor-BetaArticle10.25259/APOS_320_20242-s2.0-105029544109