Untreated Coronal Caries Co-recorded With a Restoration on the Same Tooth in US Adults: A Nationally Representative Cross-Sectional Study

Background. National studies report untreated caries and restorative experience separately; same-tooth co-recording is uncharacterized nationally. We estimated this pattern and compared information available before and after oral charting. Methods. This cross-sectional study included adults aged 20 years or older from the National Health and Nutrition Examination Survey 2015–2016 (n=5,200) and 2017–March 2020 pre-pandemic (n=8,162). Epidemiologic estimates incorporated the survey design. Exploratory interpretable models compared pre-examination with aggregate completed-chart information. Results. Later-period weighted prevalence was 5.2% (95% CI, 4.1% to 6.7%) overall and 6.6% (5.1% to 8.4%) among adults with a recorded restoration. Participants meeting the definition averaged 1.39 involved teeth; 25.2% had at least 2. Of 633 involved teeth, recorded caries and restoration surfaces overlapped in 1, did not overlap in 612, and were indeterminate in 20. Fair or poor self-rated oral health (adjusted prevalence odds ratio, 7.4; 95% CI, 4.4 to 13) and unmet dental need (2.5; 1.7 to 3.5) were associated with the pattern. Principal findings were consistent across periods. Completed-chart models had higher ROC AUC than pre-examination models (0.862 vs 0.753), but same-examination information precluded independent clinical prediction. Conclusions. Same-tooth co-recording does not establish recurrent caries or restoration failure; the exploratory models were not evaluated as diagnostic or treatment-decision tools. Practical Implications. A recorded restoration does not rule out untreated caries on that tooth. Comprehensive caries assessment and preventive care remain necessary during dental examination.