Effect of ovariectomy on maxilla and mandible dimensions of female rats.

OBJECTIVE: The role of estrogen in craniofacial growth still remains unclear. Therefore, the present study aimed to assess the effect of estrogen deficiency on maxilla and mandible dimensions. SETTING AND SAMPLE POPULATION: The study was conducted at the Department of Pediatric Dentistry at the School of Dentistry of Ribeirao Preto, University of Sao Paulo, and used forty female Wistar rats. MATERIAL AND METHODS: Ovariectomy (OVX) and placebo surgery (Sham) were performed when animals were twenty-one-day-old (prepubertal stage). Dimensions of the maxilla and mandible were assessed by craniometric analysis using radiographs, during and after puberty of the animals (45- and 63-day-old, respectively). Quantitative real-time PCR and immunohistochemical analyses were performed to determine the expression and localization, respectively, of estrogen receptor-alpha (ERalpha) and -beta (ERbeta) in different growth sites of the evaluated structures at puberty. The differences between the groups for each outcome were evaluated using the t test with an established alpha error of 5%. RESULTS: There were significant differences between the OVX and Sham groups for horizontal and vertical linear measurements in the maxilla and the mandible at both pubertal and post-pubertal stages (p 0.05). Immunohistochemical analyses revealed the presence of both estrogen receptors in osteoblasts and chondrocytes in the midpalatal suture and mandibular condyle, respectively, in the OVX and Sham groups. CONCLUSION: Our results suggest that estrogen deficiency from the prepubertal stage might increase the growth of the maxilla and mandible in female rats.