The effect of osteopenia on tooth movement in ovariectomized rats. An experimental study.

ABSTRACT

OBJECTIVE: The purpose of this experimental study was to investigate in depth the effects of osteopenia related to the rate, as well as to the quality of orthodontic tooth movement, by combining experimental ovariectomy and molar movement in rats. METHODS: Twenty-four six-month-old female Wistar rats were used in this study. The animals were divided into two groups consisting of twelve animals each Group A (control group) was subjected to orthodontic movement of the upper right first molars. Group B was subjected to orthodontic movement of the upper right first molar following bilateral ovariectomy. Ovariectomy was performed on the first experimental day and the upper right first molars were subjected to orthodontic forces 60 days post-ovariectomy, lasting for 14 days. RESULTS AND CONCLUSION: Direct inspections of the upper jaws, measurements of orthodontic movement of the upper right first molars of Group A and B, as well as histologic examinations of the alveolar bone in the upper right and left first molar regions, showed that osteopenia affects the rate of orthodontic tooth movement, as well as the quality of alveolar bone remodeling, in ovariectomized rats. Specifically, in the ovariectomized animals the alveolar bone of the non-loaded side showed extensive internal resorption, with large marrow cavities, whereas the alveolar bone of the loaded side was dense with almost no marrow cavity and frontal resorption on the surface. It appears that alveolar remodeling after the exertion of orthodontic forces follows the general paradigm of osteoporotic bone remodeling after loading.