Effect of estrus cycle on the rate of orthodontic tooth movement: A systematic review of animal studies

Abstract

Background: As estrogen levels affect bone metabolism, the hormonal changes encountered during the estrus cycle may exert an influence on the rate of orthodontic tooth movement.

Aim: To systematically investigate the available evidence from animal studies regarding the effect of estrus cycle on the rate of orthodontic tooth movement.

Materials and Methods: Search without restriction for published and unpublished literature and hand searching took place. Controlled studies investigating the effect of estrus cycle on the rate of orthodontic tooth movement were reviewed. Following study retrieval and selection, relevant data was extracted and the risk of bias was assessed using the SYRCLE’s Risk of Bias Tool.

Results: From the final records, 3 studies met the inclusion criteria. The rate of orthodontic tooth movement was increased during the stages of the estrus cycle when estrogen and/or progesterone levels were lower. The risk of bias in the retrieved studies was assessed to be unclear.

Conclusion: Hormonal changes during the estrus cycle may affect the rate of orthodontic tooth movement. Although these animal experiment results should be approached cautiously, it could be safe practice to consider the possible impact of these physiological changes in the clinical setting until more information becomes available.