Effect of isotretinoin on tooth movement, root resorption and alveolar remodelling

The aim of this study is to evaluate the effects of isotretinoin on tooth movement and evaluate the tendency to root resorption during isotretinoin treatment with or without the orthodontic treatment. For this study, 90 male Wistar Albino rats are selected and divided into 4 groups. SF, SOYA and ISO groups which experimental tooth movement is applied were treated with 0,2 ml/100 gr saline, 0,2 ml/100 gr soybean oil and 7,5 mg/kg isotretinoin diluted in 0.2 ml/100 gr soybean oil for 30 days respectively. At 30th day, 6 rats were sacrificed in each SF and SOYA groups. Then 50 grams of orthodontic force is applied to the first maxillary molars of the remaining rats. After the force is applied, 6 more rats in each SF, SOYA, ISO groups were sacrificed at 7th, 14th and 21st days. ISOK group which was never a subject to the orthodontic tooth movement was treated with 7.5 mg/kg isotretinoin diluted in 0.2 ml/100 gr soybean oil and 6 rats were sacrificed at each 30th, 37th, 44th and 51st days. After 30 days, 6 rats were kept alive at ISO group and 6 rats that were sacrificed for ISOK group were also used for ISO group. The amount of tooth movement at SF, SOYA and ISO groups and the volume of the resorption lacunes at all groups were measured from micro-CT images. Blood – calcium levels were measured at all groups for biochemical means and number of osteoclasts at the mesial (pressure site) and distal (tension site) surfaces of the maxillary first molars were measured histologically. The amount of tooth movement at ISO group were found statistically significant at day 7 but it began to decrease and at 21st day it was lowest among other groups. Between the groups which experimental tooth movement is applied, root resorption was found highest at ISO group and resorption volume increased from coronal to apical. Blood – calcium levels were found lower at ISO group and the number of osteoclasts were also found lower among all other groups at the pressure and tension sites. Isotretinoin accelerates the first phase of tooth movement, then slows it down, increases the root resorption induced by orthodontic treatment and independent from orthodontic force. Keywords: Alveolar remodelling, Tooth movement, Isotretinoin, Root resorption, micro computerized tomography.