1. External root resorption in orthodontics is the gradual loss of dental root tissue caused by the inflammatory process during orthodontic tooth movement. It commonly affects the maxillary incisors and can reduce root length by up to half.
2. Risk factors include hereditary predisposition, local anatomical factors like short roots, impacted teeth, and parafunctional habits that cause intermittent tooth movement like bruxism.
3. Radiographic examination is important for diagnosis and monitoring the progression of external root resorption during and after orthodontic treatment. Cone beam computed tomography provides more accurate assessment compared to traditional radiographs.