| External apical root resorption (EARR) is a common deleterious consequence of orthodontic tooth movement with an un-established etiology. Most theories of causation have focused on clinical factors. The purpose of this research is to determine if dentin from different regions of the root is more susceptible to resorption. Our hypothesis is that regional variation of dentin between the coronal, middle and apical regions contributes to osteoclastic attachment and activity. Freshly extracted human premolars from individuals up to the age of 18 years were cleared of cementum and sectioned for resorption assays. Osteoclast attachment was not significantly different between the regions, however the total resorbed area was significantly greater at the apical region compared to the middle and coronal regions. These results suggest that the etiology of EARR may be related to dentin composition. |
