AbstractBackgroundNon‐insulin‐based insulin resistance indices provide a cost‐effective assessment of insulin resistance. As periodontitis has a bidirectional relationship with diabetes, this study used these indices to analyze the association between insulin resistance and periodontitis and compared their diagnostic accuracy.MethodsThe study used healthcare big data from the Korea National Health and Nutrition Examination Survey (KNHANES, 2013–2018). Periodontitis was determined based on the Community Periodontal Index (CPI). Among the indices, triglyceride to high‐density lipoprotein cholesterol ratio (TG/HDL‐C), metabolic score for insulin resistance (METS‐IR), triglyceride glucose index (TyG), TyG adjusted with body mass index, TyG adjusted with waist circumference (WC), and TyG adjusted with waist‐to‐height ratio (WHtR) were compared. A multivariate logistic regression model was constructed by dividing the data into quartiles, and receiver operating characteristic (ROC) analysis was performed to compare the diagnostic accuracy.ResultsThe prevalence of periodontitis increased with increasing quartile of the insulin resistance index. The multivariate logistic regression analysis showed that insulin resistance and periodontitis were significantly associated in the fourth quartile for all indicators (p < 0.05). In particular, the area under the curve (AUC) value of the TyG adjusted with WHtR was the highest at 0.64, implying that it had the best diagnostic accuracy among the compared indices.ConclusionTyG‐related indices were associated with the prevalence of periodontitis, and the TyG adjusted for WHtR showed the greatest diagnostic accuracy for periodontitis.Plain Language SummaryThis study looked at the association between a measure called the triglyceride glucose index (TyG) and periodontitis using data from 22,994 people in South Korea. The TyG helps to identify insulin resistance, a condition where the body does not respond well to insulin, which is crucial for controlling blood sugar levels. Unlike traditional tests that require blood samples and are time‐consuming, the TyG is simpler and cheaper. Our research found an association between insulin resistance and periodontitis. Among the different versions of the TyG, the one that combined the TyG with the waist‐to‐height ratio (TyG*WHtR) was the most accurate in identifying those who might have periodontitis. This means that using the TyG*WHtR could be a helpful way to find and help people who are at risk for insulin resistance and potentially improve their oral health early on.