Variations in Dentists' Thresholds for Restorative Treatment of Active Non-Cavitated Carious Lesions: A Multinational Cross-sectional Study.

Objectives: To assess patterns across 21 countries in dentists' thresholds for initiating operative treatment of active non-cavitated carious lesions and to evaluate the influence of caries risk, clinician characteristics, and geographic variation on decision-making in accordance with current guidelines.

Methods: A cross-sectional, vignette-style web-based survey was conducted between June and October 2023 across 21 countries. A standardized questionnaire, comprising theoretical radiographic scenarios of occlusal and approximal active non-cavitated carious lesions at four progressive stages (E1,E2,EDJ,D1), was distributed to general dentists and specialists. Respondents selected the radiographic threshold at which they would initiate invasive treatment for patients with low and high caries risk. Guideline-concordant benchmarks were predefined as D1 for low-risk and EDJ/D1 for high-risk; any earlier choice was coded as overtreatment. Cumulative-link mixed models estimated determinants of thresholds; guideline concordance was summarized descriptively.

Results: A total of 3,680 dentists provided 7,360 valid responses. High caries risk significantly predicted earlier intervention (occlusal OR= 0.34; approximal OR= 0.38, p<0.001). Female dentists and restorative specialists were more conservative, while age showed no significant effect. Overall guideline adherence was low (22.7% in low-risk and 32.7% in high-risk scenarios). Substantial inter-country variation was observed; Bangladesh and Portugal showed highest adherence, while Kazakhstan and Colombia demonstrated overtreatment tendencies.

Conclusions: Despite global promotion of minimally invasive dentistry, overtreatment of enamel lesions remains widespread. Addressing systemic, educational, and policy-level barriers is essential to improve adherence to evidence-based, risk-informed caries management.

Clinical Significance: This multinational study highlights substantial variability and premature intervention in caries management across countries. Identifying patterns of overtreatment and guideline discordance informs dental education and policy, emphasizing the urgent need to reinforce minimally invasive, risk-based strategies in clinical practice across participating countries.