When the Tooth Is No Longer Enough: A Question-Driven Journey from Dental Caries to Complex Networks

Abstract

Traditionally, dental research has framed its questions around units of observation such as lesions, teeth, or specific oral diseases. However, empirical findings may reveal the limitations of these units, requiring broader explanatory lenses. This critical review reconstructs a scientific trajectory organized around eight research questions. The findings shifted the unit of inquiry from the caries lesion to the disease process and to individual, social, and behavioral contexts, oral disease burden, syndemic frameworks, and complex disease networks. Evidence that carious dentin could be retained without compromising restoration performance challenged lesion-centered intervention, while differences in fluoride effectiveness and caries polarization revealed the importance of social and behavioral conditions. Caries and periodontal indicators subsequently converged into the Chronic Oral Disease Burden construct across life stages. Associations with inflammatory, nutritional, metabolic, mental, and vascular conditions then extended the frontiers beyond the mouth. Throughout this trajectory, sugars remained a thread, shifting from a major causal factor for dental caries to a shared behavioral risk factor across oral and systemic conditions. Within the complex NCD network, dental caries emerged as a hub across the life course; when we incorporated its determinants, socioeconomic disadvantage, high free sugar consumption, and insulin resistance emerged as key connecting nodes. Because caries is among the earliest NCDs, these findings raise a question requiring prospective investigation: Could early childhood caries serve as a sentinel marker of broader NCD trajectories across the life course? The disease remains the same; what changes is the question-driven lens through which we examine it.