Selective Caries Removal as a Restorative Strategy for Caries Management: Residual Dentin Quality After...

Background/Objectives: Advances in restorative caries management have shifted operative dentistry from complete caries excavation toward selective, tissue-preserving strategies that maintain remineralizable dentin and support adhesive restoration. Chemomechanical systems and self-limiting burs may reduce unnecessary dentin removal, but their effects on residual dentin quality remain relevant to restorative decision-making. This in vitro study compared Carisolv™, Papacarie^®, Smart Burs™, and conventional tungsten carbide burs with respect to caries removal time, residual bacterial load, laser fluorescence, Vickers microhardness, and scanning electron microscopy (SEM) features of residual dentin. Methods: Forty-eight extracted permanent molars were selected. Standardized class I cavities were prepared and subjected to an artificial caries protocol using a demineralizing solution for 240 h. A cariogenic biofilm model was then established using Streptococcus mutans. Specimens were allocated to four excavation groups: Carisolv™, Papacarie^®, Smart Burs™, and conventional carbide burs. Caries removal was performed according to each system, and the operative time was recorded. Residual bacterial contamination was estimated through colony-forming unit counts. Residual dentin was assessed using DIAGNOdent™ laser fluorescence, Vickers microhardness testing, and SEM at multiple magnifications. Results: Mean removal times were 2.82 ± 1.64 min for Carisolv™, 2.50 ± 1.15 min for Papacarie^®, 2.05 ± 0.70 min for Smart Burs™, and 0.61 ± 0.44 min for carbide burs. Residual bacterial growth was detected in all groups. Vickers microhardness values were 79.2 ± 24.66 VHN for Carisolv™, 79.6 ± 22.30 VHN for Papacarie^®, 83.4 ± 28.73 VHN for Smart Burs™, and 92.9 ± 24.66 VHN for intact dentin control. SEM revealed dentin morphology closer to the control after carbide bur excavation, partially obliterated tubules after Carisolv™, and more evident tubular obliteration after Papacarie^® and Smart Burs™. Conclusions: Chemomechanical excavation, particularly Carisolv™, generated a residual dentin substrate with microhardness values compatible with a conservative restorative approach, although with longer operative time than conventional burs. The findings support the role of selective caries removal in minimally invasive restorative protocols and highlight the need to connect residual dentin characteristics with adhesive performance, bioactive materials, and long-term restoration outcomes.