Permanent First Molar Eruption Failure in Children: clinical management of three clinical scenarios

Eruption failure in the mixed dentition presents many challenges, but eruption disorders in a child patient offer solutions that are not possible in adult patients. The opportunity to remedy the occlusal outcomes for eruption problems in the mixed dentition depends on the type of problem; we consider three major categories of eruption problems and corresponding management strategies. The distinction between a mechanical failure of eruption (MFE), ankylosis of a single tooth, or Primary Failure of Eruption (PFE) due to a genetic defect that alters dental eruption is key to the potential intervention. The therapeutic solutions proposed in the literature differ greatly for the three clinical scenarios. In MFE, orthodontic therapy can be successful if the obstacle to eruption is identified early. For cases of ankylosis, the affected tooth can be extracted, and the space closed orthodontically if timed appropriately. A diagnosis of PFE, however, carries a certain poor prognosis with a continuous arch wire; orthodontic forces will result in the intrusion of adjacent teeth.

We evaluated the clinical outcomes of three patients presenting with eruption failure of the permanent first molar(s) due to: 1) ankylosis; 2) MFE; and 3) PFE. Taken together, these cases provide indications for treatment possibilities supporting the growing patient.

Early treatment of ankylosis can yield positive results, but the possibility of failure must be considered and, therefore, monitored carefully. For MFE, the timing of intervention should align with patients in the late mixed dentition. Finally, a diagnosis of PFE carries the certainty that affected teeth cannot be moved orthodontically; the resultant dentoskeletal development may however benefit from a functional orthopaedic appliance to prevent asymmetric growth.