The effect of different lower third molar conditions on the re-crowding of lower anterior teeth in the absence of tight interproximal contacts one-year post orthodontic treatment: a pilot study.

The role of lower third molars in lower incisor crowding is a debatable topic. Some believe the presence or eruption of lower third molars is associated with the crowding of mandibular incisors, others negate such association. Thirty-two newly debonded orthodontic patients, with ages ranging from 14-19 years, were randomly selected. No retainers were used for the lower dental arch. Removal of tight interproximal contacts of the lower anterior teeth was created and maintained by periodic abrasive stripping every 2-3 months, if needed. The cases were followed up for one year. Orthopantomographs (OPGs) and study casts were taken at debonding (post-treatment) and at the end of the one year follow up (post retention). Statistical analysis of the lower third molar conditions--erupted, unerupted, or missing with or without sufficient space for their eruption--versus re-crowding of lower incisors was evaluated using Fisher's Exact Test. The results of this pilot study revealed there was no significant correlation between the different conditions of the lower third molars versus lower anterior re-crowding in the absence of tight interproximal incisal contacts; however, a larger sample size is needed to verify such findings.