Comparative assessment of 638-nm Diode laser photobiomodulation against chemical remineralizing agents for primary caries-affected dentin: Mechanistic investigation of photothermal effects on bonding substrate quality

AIMS: to investigate the influence of contemporary remineralizing agents, i.e., sodium fluoride (naf), casein phosphopeptide-amorphous calcium phosphate (cpp-acp), diode laser (dl), and theobromine on the microhardness (mh) and shear bond strength (sbs) of one-step self-etch (se) adhesive to the caries-affected primary molars. MATERIALS AND METHODS: 100 extracted primary mandibular molars with carious lesions in dentin, classified as level 5, according to the international caries detection and assessment system, were considered. the teeth were disinfected, followed by the removal of infected dentin. all teeth were allocated into five groups based on the remineralization technique (n = 20). group 1 (untreated cad), group 2 (naf), group 3 (cpp-acp), group 4 (dl), and group 5 (theobromine). a digital vickers hardness tester was used to assess mh (n = 10). the composite was built on cad, and the samples were thermocycled (n = 10). sbs and failure mode testing were performed using a universal testing machine and a stereomicroscope, respectively. one-way anova and post hoc tukey determined significant differences in mh and sbs between the investigated groups (p˂0.05). RESULTS: cpp-acp-pretreated cad samples displayed the highest mh (195.11±20.13) and sbs (9.27± 0.23 mpa). untreated samples exhibited the lowest mh (164.26±11.02) and sbs (7.77± 0.22 mpa). there was no significant difference in the mh and sbs of cad treated with naf, cpp-acp, and theobromine (p˃0.05). CONCLUSION: Applying remineralizing agents such as sodium fluoride, casein phosphopeptide-amorphous calcium phosphate, or theobromine to caries-affected dentin in primary molars enhances shear bond strength and microhardness before restoration with a self-etch adhesive.