Primary failure of eruption and other eruption disorders—Considerations for management by the orthodontist and oral surgeon

Tooth eruption is a highly variable process, and the disorders that stem from a defective eruption process are often difficult to diagnose. The eruption process can range from normally timed and sequenced events to one characterized by eruption delays or a primary failure of eruption (PFE, OMIM #125350)—with partially or completely unerupted teeth in the absence of a mechanical obstruction. Our understanding of the molecular basis of tooth eruption was drastically strengthened when one gene, parathyroid hormone receptor 1 (PTH1R), was found to be causative for familial cases of PFE. Although PFE is a relatively rare condition, knowledge of a biological mechanism underlying the development of PFE illuminates: (1) the influence of genetics on orthodontic tooth movement in general; (2) the differential diagnosis of clinical eruption disorders; and (3) the correlation of a biologic basis with the clinical management of eruption failure. In this article, we consider the best clinical management of eruption disorders from the standpoint of what is known from a biological perspective about normal tooth eruption and therefore eruption disorders. Specifically, how the diagnosis influences the clinical management of eruption disorders using biologic versus clinical factors is considered. These advances in our understanding of normal and abnormal tooth eruption now allow for a systematic clinical diagnostic regime that may include a surgical approach or simply the elimination of treatment with a continuous archwire.