Caries and periodontitis are major causes of suffering and healthcare spending. Despite large scale universal prevention programs in Sweden and other counties, some groups of people have persistent high levels of disease, suggesting a more targeted approach to prevention is needed. The aims of the proposed research are to (1) use a data driven approach to identify refined measures of caries and periodontitis, perform hypothesis-free genome-wide association studies and environment-wide association studies using these refined measures, and model how the most important genetic and lifestyle factors interact. This will help identify whether the patterns of disease seen clinically represent diseases with different genetic/molecular or lifestyle bases and identify which interventions might be effective for reducing risk for people with high genetic/molecular susceptibility; (2) identify whether effects of genetic or lifestyle factors on dental diseases are mediated through the oral microbiota. This will help improve understanding of the interplay between host risk factors and microbiota and will drive the development of new resources which will be useful for dental care and other Swedish studies; and (3) use current methods for causal inference from genetic data to test whether associations between dental diseases and systemic diseases are co-morbid or causal. This will help clarify the role of primary care dentists in screening for (or prevention of) important complex diseases.