Effects of strontium ranelate on sutural bone formation: a histological and immunohistochemical study.

Aim: Rapid maxillary expansion is performed to correct a skeletal transverse deficiency of the maxilla, which is a frequently- encountered orthodontic anomaly. Strontium ranelate (SrR) is a novel agent that has a dual action, involving anti-resorptive and bone-forming effects. The aim of this study was to evaluate the effects of systemically applied SrR on osteoblastic bone formation after maxillary expansion on the mid-palatal suture of rats using histological and immunohistochemical tests.

Materials and methods: A total of 24 Wistar rats were randomly divided into two equal groups. In all animals, five-day inter-premaxillary expansion was applied and maintained for a seven-day retention period, during which 625mg/kg/day SrR diluted with saline solution was administered orally to the experimental group. The rats were sacrificed and the tissues prepared for histological and immunohistochemical examinations after the retention period.

Results: Osteoblastic activity and the width of the blood vessels in the suture area were significantly increased in the SrR group compared with the control group (p < 0.051. Ossification was also observed to be active under light microscopy by staining with hematoxylin and eosin in the experimental group. Immunohistochemical labelling performed using osteonectin, osteocalcin, TGF-P and VEGF antibodies revealed significant immunoreactivity in the experimental group (p < 0.05).

Conclusion: It may be concluded that SrR contributed to stimulatory osteogenesis in the expansion region. Therefore, a retention period may be shortened and relapse possibly reduced, following the application of SrR after the expansion.