Griffen, Ann

Ann Griffen, PhD
Professor and Director of Research in the Section of Pediatric Dentistry.

Research Projects
In order to study the molecular and population genetics of periodontitis-associated bacteria, we use an integrated approach that relies on molecular biology, microbiology, and epidemiology.

Molecular and Population Genetics of Periodontal Pathogens
Chronic periodontitis affects a large fraction of the population.  Although microbes are clearly the etiologic agents, no organism or group of organisms has been unequivocally identified as the primary cause of disease. We have been working on a project to clone and sequence bacterial 16S ribosomal genes isolated from plaque samples. This open-ended approach has allowed us to detect and identify all bacterial species present, including novel, uncultivated and unexpected species. We have also used PCR to study the relationship of a large number of bacterial species, many of them uncultivated, with periodontitis. We are also studying the stability of the subgingival bacterial ecosystem, and the transmission of periodontal pathogens among family members and their acquisition in children.  Discovering pathogenic species and elucidating the natural history of the succession and establishment of oral anaerobes could profoundly affect the direction of future studies and lead to strategies for the prevention and treatment of periodontitis.

Molecular Analysis of the Biofilm in Caries and Health
We are working on a project to identify the bacteria involved in childhood dental caries using molecular methods. Research has primarily focused on Streptococcus mutans as the etiologic agent in caries, but additional bacterial species appear to be important.  Our approach is to clone and sequence bacterial 16S ribosomal genes isolated from plaque samples. This open-ended approach allows us to detect and identify all bacterial species present, including novel, uncultivated and unexpected species. We are identifying the pathogens associated with severe caries of the primary and young permanent dentition, and the bacteria associated with a healthy dentition.  This project will also provide a comprehensive catalog of the supragingival flora in children based on molecular technology. Identification of additional caries pathogens may provide alternative targets for biological interventions, and identification of beneficial health-associated species could provide the basis for therapeutic interventions to establish caries-resistant microbial communities. We are also exploring advanced caries detection systems and visualization of cariogenic bacteria by red fluorescence.

Links
Laboratory of Drs. Griffen and Leys