Effect of ovariectomy-induced osteoporosis on the amount of orthodontic tooth movement: a systematic review of animal studies

Abstract

Understanding the impact of osteopenia and osteoporosis on orthodontic tooth movement could be of benefit to the orthodontist, but research in humans presents practical and ethical problems. The ovariectomized animal model could provide useful information on osteoporosis. To compare the amount of tooth movement during or after the application of orthodontic forces between ovariectomized animals and control or sham-operated subjects. Unrestricted searches in seven databases and manual searching of the reference lists in relevant studies were performed up to February 2021 (PubMed, Central, Cochrane Database of Systematic Reviews, Scopus, Web of Science, Arab World Research Source, ProQuest Dissertations, and Theses Global). We searched for studies quantitatively comparing the amount of tooth movement during or after the application of orthodontic forces between ovariectomized animals and control or sham-operated subjects. Following study retrieval and selection, relevant data were extracted, and the risk of bias was assessed using the SYRCLE's Risk of Bias Tool. Exploratory synthesis and meta-regression were carried out using the random effects model. Thirteen studies were finally selected and no specific concerns regarding bias were identified. During the active period, ovariectomy was associated with a statistically significant acceleratory effect on the rate of orthodontic tooth movement compared to non-treated rats (3 weeks; 4 studies, 0.15 mm more movement in the ovariectomized rats; 95 per cent confidence interval: 0.10-0.19; P = 0.000). Exploratory meta-regression showed that this difference could increase over time. Following force discontinuation, no statistically significant differences were observed [3 weeks; 1 study (median ± SE), Ovariectomy group: 0.30 ± 0.04 mm; Sham operation group: 0.18 ± 0.03; P = 0.1558]. Ovariectomy-induced osteoporosis may affect the rate of orthodontic tooth movement. Although animal studies should be approached with caution regarding their translational potential, the safe practice would suggest that one should consider potential implications. PROSPERO (CRD42018118003).