All patients have to undergo a consultation, to detect any potential dental cavities. Any cavity lesions must be removed and obturated, and any nerve infection must be treated. A nerve infection may cause root resorption (shortening of the root) as a response to the orthodontic forces. Teeth with root canal treatments must be radiologically investigated prior to the application of the orthodontic treatment, to assess the quality of the treatment and exclude any bone infections.

The effects of the orthodontic forces on teeth affected by periodontal disease are disastrous. A significant resorption of the bone occurs, the periodontal pockets increase in depth and an increased mobility of the tooth appears. This is why, before commencing any orthodontic treatment, we must make sure that there is no active periodontal disease. Patients with periodontal disease may only benefit from orthodontic treatment after a correct treatment of the disease.

The temporomandibular joint has to be clinically investigated, to detect any signs of dysfunction and, if necessary, the examination is supplemented by imaging methods (radiography, MRI, CT).