Fluorescence as a Quantitative Indicator of Cariogenic Bacteria During Chemo-Mechanical Caries Excavation with BRIX 3000 in Primary Teeth

Minimally invasive treatment is increasingly successful in managing carious lesions in primary teeth, owing to the regenerative capacity of the dental pulp and the possibility to influence the pulp–dentin complex. Chemo-mechanical caries excavation (CME) with Brix 3000, a papain-based enzymatic agent, allows selective removal of infected dentin while preserving affected dentin for potential remineralization. Fluorescence-aided caries excavation (FACE) enables visualization of porphyrins produced by cariogenic microorganisms, guiding selective dentin removal. In this study, 42 children aged 4–7 years with ICDAS II code 05–06 lesions in primary molars were treated, and the correlation between fluorescence intensity and cariogenic microbial load was evaluated. CME was performed using Brix 3000, and residual dentin was categorized by fluorescence as red, red with pale-pink areas, pale-pink, or non-fluorescent. Microbiological samples were collected pre- and post-excavation, cultured under standardized laboratory conditions, and quantitatively analyzed. Results showed that higher fluorescence intensity corresponded to increased presence of S. mutans (ρ = 0.945, p < 0.001), while other species were present in lower quantities. CME with Brix 3000 significantly reduced microbial load, and fluorescence reliably indicated areas requiring removal. These findings demonstrate that combining FACE with Brix 3000 allows precise, minimally invasive caries removal in primary teeth, providing an objective method to guide tissue-preserving excavation while effectively controlling cariogenic microorganisms.