Can Histological and Histomorphometrical Changes Be Induced in Rat Mandibular Condyle following Ovariectomy and Long-term Extremely Low Frequency Magnetic Field Exposure?

The quantity and quality of maxillary and mandibular bone have long been a focus of attention for dental clinicians. The mandibular condyle is a major growth site and plays an important role during mandibular growth. The aim of the present study was to evaluate the effects of long-term extremely low frequency magnetic field (ELF-MF) and hormonal changes produced by bilateral ovariectomy on the histologic and histomorphometric structure of rat mandibular condyle. Forty mature female Sprague-Dawley rats were randomly divided into four different groups (n =10): control (Cnt), ovariectomy (OVX), ELF-MF exposure (ELF-MF), ELF-MF exposure with OVX application (ELF-MF+OVX). All rats were subjected to bilateral ovariectomy except those in Cnt and ELF-MF groups. ELF-MF and ELF-MF+OVX groups were exposed to 1.5 mT ELF-MF during 6 months, 4 h a day. After all applications, left condyle of rats were removed to examine histopathologically. Some histopathologic changes were observed, such as irregular appearance in bone marrow cavities in rat condyles of OVX, ELF-MF and ELF-MF+OVX groups. Some disorders in transition from hypertrophic field to ossification layer and irregular appearance in calcification were determined in OVX group. In OVX+ELF-MF and ELF-MF groups, there was significant disruption and latency in calcification and ossification areas. However, no significant differences were found in the thickness of the condylar cartilage layer between groups (P > 0.05). It was suggested that long-term ELF-MF exposure and ELF-MF exposure with ovariectomy application can affect the histologic structure of rats’ condyle. Consequently, it was concluded that long-term ELF-MF exposure and ovariectomy application can induce histopathological changes in the structure of the condyle and ELF-MF exposure cannot alter ovariectomy-induced changes.