[Reason for failure in the treatment of impacted and retained teeth].

The positioning of an impacted or retained tooth in either children or adults presents a real challenge for the two practitioners involved, the orthodontist and the surgeon in charge of the surgical exposure. The maxillary canine is the tooth most often impacted in the anterior segment, with a prevalence of 2% in the general population. One can understand, therefore, the functional and esthetic challenge for the surgical-orthodontic team whose aim will be to reposition the impacted or retained tooth in the arch. A large number of mistakes must be avoided in order to achieve a satisfactory result for both the patient and the practitioner. Modern imaging techniques should be used to obtain a precise diagnosis of the location of the tooth and to perform surgery which will spare the tooth in question as well as the surrounding anatomic structures. The directions and forces of the traction used will need to be carefully thought out in order to move the tooth into its final position on the arch in optimal conditions. The periodontal setting will be optimized and checked at every step of the treatment. The aim, in fact, is to anticipate the onset of periodontal problems on the grounds that prevention is easier than cure. © EDP Sciences, SFODF, 2016.