Development of a nomogram for prediction of occlusal dentin caries in Norwegian children at risk: a 36-month follow-up study

The aim of this study was to develop and internally validate a nomogram predictive model for occlusal dentin caries development on first permanent molars (FPMs) over 36 months in children at risk in Norway. For a practice-based split-mouth randomized trial (ClinicalTrials.gov ID: NCT03315312, retrospectively registered in October 2017) comparing effectiveness of caries control methods (fissure sealants versus fluoride varnish), children aged 6 to 10 years considered at high caries risk (D 3 MFT/d 3 mft > 0) were recruited by calibrated dentists and dental hygienists during routine examination in the public dental service and monitored for 36 months. Outcome was development of occlusal dentin caries lesion on FPMs. Data on biological predictors were collected at baseline by clinicians. Data on behavioral predictors were collected using a questionnaire for parents. Clinical predictors included clinic’s county, whether the participant was followed up by the same clinician and caries control method. The least absolute shrinkage and selection operator (Lasso) logistic regression model was used to select relevant predictors and develop a nomogram for predicting dentin caries development. Of 330 participants, 174 (51.7) were boys. The Lasso logistic regression selected four predictors, d 3 mft at age 5 years, occlusal surface baseline status, caries control method, and use of fluoride toothpaste, which were used to construct a nomogram. The Area Under the Receiver Operating Characteristic Curve was 0.69 (95% CI 0.62–0.77), and Concordance Index was 0.68 (95% CI 0.60–0.76) in the training set and 0.67 (95% CI 0.59–0.74) in the validation set. The calibration belt indicated good calibration of the model ( p > 0.05). In this study, based on 36-month follow-up data in children at risk, we have developed and internally validated a nomogram to predict dentin caries on occlusal surfaces of FPMs. The findings suggest that nomogram approach may be a useful visual aid in clinical practice to facilitate informed decision-making; however, external validation in a large cohort study, transportability and applicability to different settings are needed.