Layered Caries Prevention Model: A Hypothesis

Abstract

Dental caries is the most prevalent preventable chronic disease, yet prevention is usually delivered as separate, product-based advice. We hypothesize that caries incidence falls further under a layered, risk-stratified model whose base layer is the frequency of fermentable-carbohydrate exposure, not any single agent. Layer 1 reduces daily acid challenges by consolidating eating occasions and lowering fermentable carbohydrate between meals. Layer 2 strengthens remineralization: twice-daily fluoride toothpaste (higher concentration at high risk), spitting without rinsing, a delay before eating or drinking, and adjunct remineralizing agents. Layer 3 adds clinician-applied fluoride varnish, silver diamine fluoride for active lesions, and pit-and-fissure sealants. A speculative fourth element is biofilm modulation with oral probiotics (including Bacillus subtilis natto, whose extracts inhibit Streptococcus mutans biofilm in vitro) and plant-derived agents (coconut oil pulling, mastic chewing gum, essential-oil rinses), tested only on plaque, gingivitis or bacterial counts. Because the layers act on different terms of the demineralization–remineralization balance, we propose their effects are partly additive, and that Layer 1 raises the benefit of Layers 2 and 3. Evidence is strongest for fluoride, then sealants, varnish and sugar restriction; moderate to low for silver diamine fluoride and remineralizing agents; and absent for single-meal or low-carbohydrate patterns, for B. subtilis in humans, and for caries outcomes with any Layer 4 agent. No trial has tested the combination. We state falsifiable predictions and feasible tests, including factorial and split-mouth designs. If supported, the model would enable risk-based, mechanism-ordered prevention.

Keywords: dental caries; prevention; silver diamine fluoride; remineralization; oral microbiome; dietary frequency