Sunday, 9 May 2010

Primary Failure of Eruption (PFE)

This is a typical clinical picture of PFE, patient, affected unilaterally on the right side.

The teeth with PFE become ankylosed when orthodontic forces are applied.

The PFE was first described by WR Proffit in 1981, however the molecular basis of this was unknown up to today.

Definition: "Primary failure of eruption is characterized by non syndromic eruption failure of permanent teeth in the absence of mechanical obstruction" Proffit WR, Vig KWL. Primary failure of eruption: a possible cause of posterior open-bite. Am J Orthod 1981;80:173–90.

Failure of erruption in multiple teeth is common in syndromic patients, such as kleidocrania dysplasia, ectoderm mal-plasia, Garner, and Apert syndrome.

Non syndromic failure however is rarely seen in more than one tooth. and mainly that is the lower wisdom teeth or the upper canines.

Reasons for this failure can be

  1. Barriers such as odontoma, supernumerary tooth, cyst etch
  2. Abnormal tooth germ position or deformity
  3. Bone deficiency such as cleft patient cases
  4. Lack of space
  5. Ankylosis

Those teeth however are not ankylosed and up to now the molecular basis of this failure to erupt was unknown.

This article in Feb 2010, is giving the solution of this not so common clinical entity.

American Journal of Orthodontics and Dentofacial Orthopedics
Volume 137, Issue 2, February 2010, Pages 160.e1-160.e7

The article is following 4 families and through genome-wide linkage analysis, after direct DNA sequencing, provides the information that PFE is actually a result of three heterogenous mutations of the PTHR1 gene.

The affected were half of the offsprings, giving the characterization of an Autosomal Dominant Inheritance.

Those are some of the common symptoms of PFE:
  • The posterior teeth are more frequently affected, that is,the first and second molars are more frequently affected than premolars and canines
  • If a tooth in a further anterior position presents an eruption disturbance, the posterior teeth are usually affected as well
  • The affected teeth resorb the alveolar bone above the crown, but erupt only partially or fail to erupt
  • Both deciduous and permanent teeth can be affected
  • The condition is usually asymmetrical
  • Primarily non-ankylosed teeth tend to become ankylosed as soon as orthodontic forces are applied

Of course the problems derived clinically can be disastrous with the application of a straight wire on those cases. As you can see from those pictures, of the cant created on the lower jaw by the insertion of a straight wire on a PFE patient that was not diagnosed properly prior  orthodontic treatment start.

Panoramas of the same PFE patient in different ages, notice the vertical bony defect, and the dilaceration of the roots (apical bend).

Take Home Message:
  • Failure of primary eruption of more than one and especially posterior teeth, and even more when it is uni-lateral, and the patient is non-syndromic, should give the clinician the signs to think of PFE
  • Remember that special gene analysis can and should be advised to reach a certain diagnosis
  • Even more important for the orthodontist, those teeth are not to be touched orthodontically as it results to ankylosis, and especially a straight wire approach would be detrimental.


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