Aim or purpose: This study aimed to investigate the potential causal link between oral health and anxiety using data from NHANES and Mendelian Randomization, addressing the gap highlighted in recent literature (Pi Y, Jiao Z, Wang L. J Affect Disord. 2024;351:661–670). Materials and methods: A total of 12,499 participants from the 2007-2012 NHANES dataset were included in this study. Multivariate logistic regression models were used to assess the relationship between oral health and anxiety. MR analyses were conducted using data from the IUE Open GWAS database to explore potential causal relationships between oral health and anxiety. Results: Logistic regression analyses showed that when dental health was Poor as the reference group, the Very good and Fair dental condition groups were significantly associated with all three models and were protective factors for anxiety, and higher levels of oral health were associated with increased risk of anxiety. Stratified analyses showed that very good dental condition was significantly associated with a reduced risk of anxiety, especially among 18-45 age group (OR = 0.7992, P< 0.001). Mendelian Randomization further confirmed a significant positive causal relationship between oral ulcers and anxiety (OR = 1.017, P = 0.002). Conclusions: Our study revealed an association between good oral health and reduced risk of anxiety, which was further confirmed by Mendelian randomization analyses, providing new insights into the link between oral health and anxiety.