Does the rate of orthodontic tooth movement change during the estrus cycle? A systematic review based on animal studies

Table 1 Characteristics of the included studies

Study	Animals and tooth movement model	Group Characteristics	Measurement Methodology	Results ^b
Haruyama et al. [27]	Wistar rats; 10 weeks; 136 g NiTi expansion spring between R and L FM [13 g] Force application: at each stage for 5 cycles	Proestrus Group: 8 estrus Group: 8 Metestrus Group: 8 Diestrus Group: 8 Sample size calculation: nm	Tracings of casts: callipers [at appliance removal] Method error assessment: Yes	Estrus	Metestrus	Diestrus	Proestrus
				*
				Estrus > Proestrus
Tan et al. [28]	Wistar rats; 3 months; 300 g NiTi CCS between Mx I and FM [20 g] Force application: at each stage for 5 cycles	Proestrus Group: 10 Estrus Group: 10 Metestrus Group: 10 Diestrus Group: 10 Sample size calculation: nm	Plaster models: callipers [at appliance removal] Method error assessment: nm	Estrus	Metestrus	Diestrus	Proestrus
				*
				Estrus > Proestrus
Celebi et al. [29]	Cats; 2–4 yrs NiTi CCS from mini implants to Mx C [80 g] Force application: 12d	Estrus Group: 6 ^a Anestrus Group: 6 Sample size calculation: nm	Silicone impressions: digital callipers [d 0,6,12] Method error assessment: nm	Estrus < Anestrus^a

d, days; CCS, closed coil spring; FM, first molars; L, left; Mx, maxillary; NS, non-significant; R, Right
^aEstrus was induced by administration of 150 IU equine chorionic gonadotropin. In cats, estrus is characterized by increased estrogen levels. In the anestrus group blood estradiol levels were at basal value
^bThe asterisk denotes a statistically significant difference

ISSN: 1472-6831