Orthodontics
 
 

CONGENITALLY MISSING TEETH

Hypodontia and Oligodontia

Researchers in the D'Souza laboratory at the University of Texas at Houston Dental Branch, in collaboration with researchers at Baylor College of Medicine, have identified a gene responsible for congenitally missing teeth (teeth that never developed) in a Houston family. Congenitally missing teeth can occur in two variations, hypodontia and oligodontia. Hypodontia is characterized by the absence of six or fewer permanent teeth, while oligodontia is characterized by the absence of more than six permanent teeth. The researchers' efforts revealed that a mutation in the PAX9 gene was responsible for a rare form of oligodontia, missing molars, in the Houston family (published in the January 2000 issue of Nature Genetics). Finding more genes responsible for congenitally missing teeth may unravel the genetic code for all teeth, and, it may potentially provide for genetic screening and new forms of treatment for individuals with this condition.

The D'Souza laboratory and the Department of Orthodontics are recruiting families that have a history of congenitally absent permanent teeth. Individuals who believe that they meet the inclusion criteria below should fill out the online questionnaire. Suitable candidates may be asked to donate a small sample of blood for DNA analysis. If you are interested in collaborating in our research efforts please contact Drs. Rena D'Souza and Sylvia Frazier-Bowers at missingteeth@uth.tmc.edu for more information.

Multiple spaces occurring due to missing permanent molars
Panoramic X-ray shows missing permanent molars (indicated by arrows)
     
 
 

Inclusion Criteria:
Persons who qualify for this study must:

  • have missing permanent teeth due to failure to develop and not due to decay or gum disease.

  • know of at least one family member who is also missing permanent teeth due to failure to develop.

  • be otherwise healthy and not previously diagnosed with a genetic syndrome or cleft lip/palate

  
   
Primary Failure of Eruption
  Investigators in the Department of Orthodontics and the D'Souza lab are also interested in a rare condition in which permanent teeth fail to erupt fully or partially, presumably because of a malfunction of the eruption mechanism. These patients have no other recognizable disorder, and no apparent mechanical interference with eruption. If you are interested in collaborating in these studies and can identify individuals with the features listed below please contact missingteeth@uth.tmc.edu.

 
 
 
 
Affected Side
Normal Side
 
 


Persons with 'primary failure of eruption' have some or all of the following features:

  • Back teeth which do not meet (posterior lateral open bite)
  • Teeth which did not erupt are not blocked (non-ankylosed teeth)
  • Back (posterior) teeth are involved more than front (anterior) teeth
  • Teeth may fail to erupt on one side (unilateral) or both sides (bilateral) but is frequently unilateral
  • Involved teeth may be completely 'wedged' (impacted) in bone, or may erupt partially with or without overlying soft tissue, or erupt into occlusion and then cease to erupt
  • Involved teeth do not seem to respond normally to treatment with 'braces' (at most 1-2mm of movement); and usually 'braces' (orthodontic force) cause the tooth to become 'immobilized' in the bone (ankylosis)
  • No apparent medical problems or syndromes involved
  • May or may not affect close relatives
  


DB Web Team
Valerie L. Moncada
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