The therapeutic role of systemic versus local administration of Propolis in enhancing bone formation after rapid maxillary expansion in albino rats

Abstract Objective The aim of the present study was to compare the effect of systemic versus local administration of propolis on accelerating bone formation after rapid maxillary expansion (RME) in albino rats. Patients and methods Total thirty-two young male albino rats were randomly divided into four equal groups ( n = 8). Group I (expansion group), group II (control group), group III (systemic propolis group), group IV (local propolis group). Rats in group I were subjected to RME for 1 week, then rats were euthanized. Rats in group II were subjected to RME for 1 week, then their expanders were converted into retainers for retention and rats were kept without treatment. Rats in group III were subjected to RME for 1 week, then their expanders were converted into retainers and rats received daily systemic propolis throughout the retention period. Rats in group IV were subjected to RME for 1 week, then their expanders were converted into retainers and rats were injected with single dose local propolis hydrogel into the expanded mid-palatal suture immediately after device deactivation. Then, rats in the last three groups were euthanized after 4 weeks retention period. Premaxilla was dissected and prepared for histological and immunohistochemical analysis. Results Histologically, local propolis enhanced bone formation which appeared as wide bony plate of interdigitated finger-like bony processes on both sides of the suture. These bony plates nearly approximated to each other at the end of our experimental period. Statistical analysis showed that the new bone surface area was significantly higher in local propolis treated group compared to the other groups. Conclusion Both local and systemic propolis enhanced osteogenesis. Notwithstanding, local propolis had more regenerative effects compared to systemic propolis in the reconstruction of the suture architecture after RME.