People With Tooth Agenesis Needed for Study

Richard Gawel


The Center for Craniofacial Research at the University of Texas Health Science Center at Houston School of Dentistry needs people who are missing teeth that never formed for a research study. Associate professor Ariadne Letra, DDS, PhD, is studying the genetics of tooth agenesis, where one or more permanent teeth fail to develop.

A common craniofacial disorder, tooth agenesis affects about 10% of the general population. It can be mild, with up to 5 permanent teeth missing, or severe, with 6 or more teeth missing. If third molars are included, prevalence may be as high as 25%. Lower premolars and upper lateral incisors are the most frequently affected teeth. 

“Individuals with tooth agenesis face both aesthetic and functional consequences, which increase in severity depending on the number of missing teeth,” said Letra. “In addition to affecting a person’s smile, tooth agenesis affects masticatory function, occlusion, and even maxilla and/or mandible development.”

There are financial consequences for affected individuals as well, and dental rehabilitation costs are high. While a few genes have been identified as defective in some cases, the cause of the condition is still unclear. There is no current treatment for avoiding tooth agenesis either. Palliative treatment involves replacing the missing teeth with a bridge or implants.  

The study is looking to recruit 900 individuals or families missing one or more permanent teeth since birth. The large number is needed to achieve enough power to identify genetic variations that can contribute to the condition. Volunteers are required to come to one appointment lasting about 30 minutes.

“First, I explain the objectives and terms of our study,” Letra said. “Upon patient written consent, we collect some basic medical and dental information, perform a clinical and radiographic examination, and collect a saliva and/or blood sample as a source or DNA. Our study is completely voluntary and free of cost.”

Once the subjects have been examined, the researchers will conduct sophisticated genetic analyses of the DNA from subjects who have tooth agenesis and compare them to individuals or family members who do not have it. 

“Along with numerous genes already identified, our research hopes to identify additional causative genes that can be targeted for use in future treatment and prevention strategies,” Letra said.

For more information, call Letra at (713) 486-4228 or email

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