Genetics and Oral Health
Many common diseases are not inherited as a single genetics defect but instead result from gene-environment interactions. No gene to date has been identified that has as large an impact on periodontal disease as do environmental influences, such as smoking or diabetes.
Genetic Control of Periodontal Disease
Periodontal disease, like caries, is complex and multifactorial, but shares more of a direct link with overall health, so that risk factors such as smoking and diabetes can significantly contribute to its etiology. Genetics plays a role in the etiology of periodontal disease by controlling periodontal structural integrity as well as affecting the host response to subgingival microbiota. It has been suggested that periodontal disease is a two-step process, requiring both genetics susceptibility followed by a “bacterial challenge.” A study indicated that a number of genes, including several interleukins, played in combination with specific microbiota to produce periodontal disease in mice, while variants of certain genes involved in structural integrity did not require the pathogens to initiate periodontal disease.
Using Genetic Information in Clinical Decision Making in Dentistry
Identifying a basis for severe disease in young individuals or as a means to better understand drivers of inflammation in excess of local factors; as well as monitoring treatment responses are among applications of host testing. Microbial identification may have value when coupled with antibiotic sensitivity testing for selecting antibiotics. Patients who have periodontitis that is refractory to treatment also may benefit from microbial assessments and monitoring. In addition, identification of patient genes that confer risk for microbial imbalance may be an important part of the puzzle, since gene-environment interactions are key when considering the interaction of the microbiome and the host at mucosal surfaces. Clinical measurements (i.e., probing measurements and radiographic evaluations) for assessing the presence or absence of disease remain the single best method for assessing disease.