The clinical features and aetiological basis of primary eruption failure.

Primary failure of eruption (PFE) is a poorly understood condition associated with tooth eruption failure. This investigation systematically reviews the literature, evaluates clinical features and associations with PFE, and describes five further cases. Publications were selected and identified as describing PFE when there was no identifiable aetiological factor contributing to eruption failure and no evidence of successful orthodontic extrusion of the affected tooth or teeth. A data abstraction form recorded the following additional information; subject age, gender, general health status, and teeth present. Eighteen publications were sourced that detailed at least one case of PFE in a manner conforming to the selection criteria; these papers included a total of 35 individual cases, to which five previously unreported subjects were added. Within the whole sample of 40 cases, a total of 24 (60 per cent) were females and 16 (40 per cent) males. First and second molar teeth were most commonly affected; incisors, canines, and premolars were also involved, but with a reduced individual frequency. There was no significant difference in incidence between the maxilla and mandible, or between left and right sides. A family history of eruption failure was found in almost 50 per cent of the sample, with eruption failure or ankylosis affecting at least one primary tooth, also a common finding. Within the 40 cases, hypodontia was present at levels higher than population norms. PFE appears to be a condition that predominantly affects the molar dentition. The increased frequency of hypodontia in affected individuals and common findings of a family history regarding tooth eruption problems suggests a significant genetic component to the aetiology of this rare condition.