American Board of Orthodontics (ABO) Practice Exam

The expected percentage of patients experiencing greater than 3mm of root resorption during orthodontic treatment is indeed around 4%. Clinical studies and reviews have documented various rates of root resorption in orthodontic patients, with results indicating that a subset of patients, typically around this percentage, may face significant root loss.

Root resorption is a complex biological response that can occur due to the application of orthodontic forces. Factors influencing this response include the amount and duration of force applied, individual patient characteristics, and the specific treatment mechanics used. While many patients may demonstrate minimal root change, a small but significant percentage experience more severe resorption, leading to concerns about the health and longevity of the affected teeth.

Understanding the prevalence of this complication helps orthodontists to counsel patients effectively, weigh treatment risks, and monitor for changes throughout the course of treatment. This knowledge is crucial in implementing strategies that minimize the risk of root resorption, such as using lighter forces where appropriate and ensuring thorough patient assessments.