Root resorption following slow maxillary expansion

In the present investigation the occurrence and nature of root resorption in patients treated with slow maxillary expansion appliances was studied with the aid of radiographs and histological sections from premolars. The radiographs failed to reveal any root resorption, but on the histological sections resorption lacunae were identified. Three types of resorption were distinguished: active, arrested and repaired. The majority of the resorption cavities were located on the bucco-marginal side of the premolars and were of the arrested or repaired type. Examination in polarized light revealed that the reparative cementum was different from normal cementum and that no new attachment had been established between the principal fibres in the periodontal ligament and the reparative cementum.