Atypical retention of infraoccluded primary molars with permanent successor teeth

Infraocclusion of primary molar teeth is relatively common. The majority of infraoccluded primary molars with permanent successors exfoliate naturally. There are currently no evidence based guidelines for the treatment of infraoccluded primary molars with permanent successor teeth.

The three cases presented demonstrate atypical retention of infraoccluded primary molars, following a conservative approach. In case 1 taking a conservative approach over 5 years, the infraocclusion became gradually more severe. Tilting of the adjacent teeth and the centre-line shift caused by leaving the affected tooth in place during dental and alveolar development was significant. In Case 2 the severely infraoccluded 55 required surgical removal and exposure of the underlying permanent successor (15). Case 3 showed a maxillary premolar (14) and first permanent molar (16) tilted toward the partially erupted, ectopic, rotated 15. Surgical removal of the impacted maxillary primary molar was required.

Although there is evidence available to support the conservative treatment of such cases, it does not always lead to a favourable outcome. Detrimental effects on the adjacent teeth and occlusion were observed and surgical intervention was required.