RESUMO
Background: Female patients have the possibility tobecome pregnant during orthodontic treatment. VitaminD usually consumed by pregnant women. Estrogen andVitamin D could affect bone metabolism. Aim andObjectives: The aim of this study was to analyze theeffect of vitamin D during orthodontic movement inpregnant rats by Receptor Activator of Nuclear FactorKappa-Β Ligand (RANKL) expression and osteoclastnumber. Material and Methods: The experimentalobservational analytic study with post-test only controlgroup design and simple random sampling method wasconducted. 24-healthy-female Wistar rats were dividedinto 4 groups; K1: pregnant rats with orthodontic toothmovement and vitamin D on Day 7; K2: pregnant ratswith orthodontic tooth movement and vitamin D on Day14; K3: pregnant rats with orthodontic tooth movementwithout vitamin D on Day 7 and; K4: pregnant rats withorthodontic tooth movement without vitamin D on Day214. Nickle-Titanium coil spring with 10 g/mm forcewas placed between the incisors and the maxillarymolars. The RANKL expression and osteoclastsnumber were analyzed using Analysis of Variance(ANOVA) (p<0.05). Results: The highest osteoclastsnumber (8.494 ± 1.194), and RANKLexpression (7.967± 2.185) found in K1 group with significant betweengroups (p<0.05).Conclusions: Vitamin D increaseosteoclast number and RANKL expression duringorthodontic tooth movement in pregnant rats.