OBJECTIVE: To investigate the bidirectional association between oral diseases and cognitive function comprehensively. SUBJECTS AND METHODS: This cross sectional study utilized data from the National Health and Nutrition Examination Survey. Oral diseases include periodontitis, dental caries, and tooth loss (end point of oral disease resulting in tooth extraction). Cognitive function included three domains: memory, processing speed, and executive function. A global cognitive score was then derived from sum of the three cognitive domains. Oral cognition associations were examined using various statistical models: (1) Regress oral disease on cognitive function; (2) Regress cognitive function on oral disease; and (3) Structural equation modelling treating cognition and oral disease as latent variables. RESULTS: There were 2508 participants aged 60+ who had both oral and cognitive information. Associations between various oral disease and global cognitive score were observed (Odds ratio OR 0.95, 95% Confidence Interval [0.92, 0.99]; β -0.13, [-0.23, -0.04]; β -0.03 [-0.04, -0.01]; β -0.04 [-0.06, -0.02]; β -0.03 [-0.06, -0.01]; β -0.39 [-0.69, -0.10]). Significant correlation was also found between these oral disease and cognitive function using structural equation model (r -0.22, [-0.34, -0.10]). CONCLUSIONS: This study found robust bidirectional associations between oral disease and cognitive function using various modelling approaches among the aging population.