Orthodontics and External Apical Root Resorption

External apical root resorption (EARR) is a common complication of orthodontic treatment. Many factors have been investigated to explain differences seen among individuals in their susceptibility to EARR. Our central hypothesis is that in addition to the environmental component (increased stress and strain on the teeth, surrounding periodontal ligament, and alveolar bone secondary to occlusal and orthodontic forces), genetic factors that encode proteins and pathways involved in alveolar bone and cementum maintenance underlies EARR susceptibility or resistance. It is estimated that genetic factors can explain approximately 64% of the EARR variation in humans. Current data suggest that more than one gene is involved in the disease process. The identification of genes that modulate susceptibility to EARR will allow for better understanding of the disease processes as well as the screening of individuals before treatment.