External apical root resorption following orthodontic treatment

This study investigated the association of appliance type and tooth extract ion with the incidence of external apical root resorption (EARR) of posteri or teeth following orthodontic treatment. Pre and posttreatment orthopantom ograms were compared for 97 patients and a 4-grade ordinal scale used to me asure EARR. The incidence of EARR was positively associated with tooth posi tion (P < .001), appliance type (P = .038), and extractions (P = .001), Thi s was observed in an overall analysis mutually adjusted for the effects of age at start of treatment, pretreatment overbite and overjet, use of headge ar, tooth extraction, and type of appliance, The incidence of EARR was 2.30 times higher for Begg appliances compared with edgewise, and it was 3.72 t imes higher where extractions were performed.