Primary failure of eruption (PFE) is when a non-ankylosed tooth fails to erupt. The eruption path has been cleared for the tooth yet it does not erupt. The tooth can erupt partially and remain submerged. PFE affects posterior teeth, it affects all teeth distal to the most mesial affected tooth, it is rarely symmetric and frequently unilateral, it can affect any or all posterior sextants and there is an abnormal response to orthodontic treatments. It results in a posterior open bite and potential ankylosis of the affected teeth over time.
Primary failure of tooth eruption is caused by heterozygous mutation in the PTHR1 gene (168468) on chromosome 3p21.
