Objective To investigate dental caries prevalence amongst adults in Central Norway and assess changes over the last 45 years. Materials and methods The cross-sectional HUNT4 Oral Health Study was conducted in 2017-2019. A random sample of 4913 participants aged >= 19 years answered questionnaires and underwent clinical and radiographic examinations. Data were compared to findings from previous studies in the same region conducted from 1973 to 2006. Results Mean number of decayed, missing and filled teeth (D3-5MFT) was 14.9 (95% CI 14.7, 15.1), 56% of adults had one or more carious teeth (D3-5T) and 11.8% had >= 4 D3-5T, with the mean number of 1.4 (95% CI 1.32, 1.42). For initial caries, mean D1-2S was 3.8 (95% CI 3.7, 3.9), being the highest for 19-24-year-olds at 8.6 (95% CI 7.9, 9.3). Comparisons with earlier studies showed a decline in mean D3-5MFT for 35-45-year-olds from 26.5 in 1973 to 10.8 in 2019. In 1973, 4.8% of 35-45-year-olds were edentulous, while in present study edentulousness was found only in individuals >65 years. Conclusions Despite a substantial reduction in caries experience over the last 45 years, untreated dentine caries was common, evenly distributed across all age groups. Initial caries particularly affected younger individuals, indicating a need to evaluate prevention strategies and access to dental services.