The effect of extraction of infraoccluded deciduous molars: A longitudinal study.

Infraocclusion of deciduous molars is often associated with ankylosis. Such teeth are believed to be potential sites of malocclusion, with a risk of tipping of neighboring teeth and loss of space. Extraction has therefore been the most widely recommended treatment. The aim of this study was to follow longitudinally the effect of extraction versus nonextraction treatment in twenty-three homologous pairs of mandibular deciduous molars with infraocclusion when unilateral extraction was performed. The study comprised fifteen children with a mean age at the start of 10.1 years. Recordings were made at the start of the study and every 6 months thereafter until eruption of permanent successors. Periodic identical periapical radiographs and study models were taken every 6 months. Ten of the twenty-three mandibular deciduous molars on the nonextraction side showed progression of the degree of infraocclusion. All infraoccluded deciduous molars exfoliated within the normal time. There was a normal alveolar bone height on both sides after eruption of the successors. Extraction resulted in a gradually increasing space loss in fourteen of the fifteen children. In two cases a definite space deficiency at the time of eruption of the successors was registered. It has been possible to confirm very few of the previously reported negative effects following nontreatment of infraoccluded deciduous molars on exfoliation, eruption, and occlusal development in this study. The results favor a more conservative approach to extraction therapy of infraoccluded deciduous molars.