Oguntimein, Oluwamurewa AyodejiThirty million Americans are living with diabetes; making it the seventh leading cause of death, with 1.3 million Americans dying every year. As such, the total treatment costs of diabetes rose from $245 billion in 2012 to $327 billion in 2017. One factor driving these high costs is diabetes’ comorbidity with other chronic diseases and associated complications – e.g., hypertension, , heart disease, stroke, amputation and blindness. Little attention has focused on periodontal disease- the sixth complication of diabetes awareness, education, and intervention. This research adds to the literature via two studies that assessed diabetics’ knowledge and understanding of the bi-directional relationship between diabetes and periodontal disease. The first study examined gender and self-efficacy differences in knowledge and understanding of the bi-directional relationship between diabetes and periodontal disease among 927 diabetics. Findings suggest diabetics are unaware of their increased risk of periodontal disease based on the low mean 5.79±2.366 scores on the knowledge and understanding scale. After controlling for diabetes duration, smoking status, and other covariates, males had less knowledge and understanding of the bi-directional relationship (p<.0001). Self-efficacy was not significantly associated with participants’ knowledge and understanding of the bi-directional relationship (p= 0.543). The second study assessed health literacy differences in diabetics’ knowledge and understanding of the bidirectional relationship between diabetes and periodontal disease. Education, employment and income were tested as moderators between knowledge and understanding of the bidirectional relationship and dental hygiene practices. After controlling for diabetes duration, dental insurance status, and other covariates, participants with marginal or inadequate health literacy had less knowledge and understanding of the bi-directional relationship compared to participants with adequate health literacy (p<.0001). Education, employment, and income were not moderators. The findings support the need for targeted periodontal disease risk and dental hygiene practice education. These studies are presumably the first to assess diabetics’ knowledge and understanding of the bi-directional relationship between diabetes and periodontal disease. These studies are significant contributions to the limited amount of research and illuminate the need to educate diabetics regarding their increased risk of periodontal disease and the importance of practicing dental hygiene behaviors to prevent diabetes complications.enDiabetes and Periodontal Disease Bi-Directional Relationship: An Examination of Diabetics' Knowledge, Understanding, Social Determinants and Self-Efficacy Impact on Dental Hygiene PracticesDissertationPublic healthBehavioral sciencesDental HygieneDental VisitsDentistsDiabetesHealthcare ProvidersPeriodontal Disease