Roots shortening known as root resorption (RR) is a common “side effect” of orthodontic treatment with fixed appliances. It appears to more than 65% of all cases and its severity can vary from clinically insignificant to severe in 1% to 5% of the cases. When RR is severe can lead to tooth mobility and threaten tooth longevity. This is one of the main reasons why patients should be very careful when choosing who will carry out their orthodontic treatment. The more experienced the orthodontist, the less likely complications will arise. The orthodontist can discuss with the patient their main objectives and treatment plan and formulate an individualized plan suitable for this patient based on their needs following risk assessment. Multiple orthodontic treatments can have deteriorating effects on the roots of the teeth as RR is irreversible.

The etiology of orthodontically induced RR appears to be complex with many potential patient and treatment contributing risk factors. Among the most important risk factors appear to be the duration of force application, the applied force magnitude, the treatment duration, tooth type and history of previous tooth trauma or resorption.

So continuous, heavy orthodontic forces, long treatment duration with fixed appliances and pre-existent dental trauma/ root resorption are factors positively associated with increasing risk for RR. Upper incisors seem to be more prone to RR, followed by lower incisors and upper canines.

It is necessary to inform patients of the risk of RR prior to orthodontic treatment. In the majority of the cases the degree of RR is minor but in cases of serious RR the orthodontic treatment plan should be re-evaluated.

The orthodontist’s knowledge and expertise are important to identify treatment progress and alterations in planning when deemed necessary.