Background: Silver diamine uoride (SDF) is widely accepted as a dentinal caries arresting agent because of its effectiveness, easy handling, and short working time. When dealing with uncooperative patients, a reduced working time is desired. As SDF has been known to interact with light, the effects of light curing (LC) on SDF have not been investigated. This study aimed to compare mean mineral density difference and surface morphology between 10-and 60-second(s) SDF-applied dentin carious lesions and similarly SDF-treated teeth with additional 20s LC.Methods: Forty primary molar blocks with natural dentin carious lesions were measured for baseline lesion depth and mineral density at baseline using Image-Pro Plus software. Samples were distributed into 4 groups; 38% SDF applied for 1) 10s (10SDF), 2) 60s (60SDF), 3) 10s+LC (10SDF+LC), and 4) 60s+LC (60SDF+LC), then underwent a 7-day bacterial pH-cycling. Dentin carious lesions' mean mineral density difference was re-evaluated by digital subtraction radiographic analysis. Surface morphology and elemental pro le were assessed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The mean mineral density difference of the dentin lesions was analyzed using two-way ANOVA, generalized linear models analysis.Results: Light curing was the only factor affecting the mean mineral density difference (p=0.007). Mean mineral density differences in 10SDF+LC and 60SDF+LC groups were signi cantly higher than those without light curing (p=0.041 and 0.041, respectively). The 60SDF+LC group showed a signi cantly higher mean mineral density difference than the 10SDF group (p=0.010), while the 10SDF+LC group was not different from the 60SDF group (p=1.00). Scanning electron microscopy showed denser mineral content layers, which likely were silver and chloride, in 10SDF+LC and 60SDF+LC groups than 10SDF and 60SDF groups, respectively. Conclusion: Shortened application time with light curing enhanced SDF remineralization similarly to a conventional method. This could be valuable for managing dentin caries in young or uncooperative children and special-needs patients by reducing the SDF application time by 50% of the American Academy of Pediatric Dentistry recommendation while maintaining an adequate SDF remineralization effectiveness.

Dental pulp cells release adenosine triphosphate (ATP) in response to intrapulpal pressure and the amount released depends on the magnitude of the pressure. ATP regulates the differentiation of stem cells into adipocytes and osteoblasts. However, it is unknown whether extracellular ATP influences the stemness and osteogenic differentiation of stem cells from human exfoliated deciduous teeth (SHEDs). Therefore, this study investigated the effects of extracellular ATP at a low (0.1 mM) and high (10 mM) concentration on the stemness and osteogenic differentiation of SHEDs. Cells were cultured in either growth medium or osteogenic medium with or without 0.1-10 mM ATP. In growth medium, both concentrations of ATP increased the mRNA expression of pluripotent and osteogenic markers. In contrast, in osteogenic medium, 0.1 mM ATP enhanced in vitro mineralization, whereas 10 mM ATP inhibited this process. In addition, 10 mM ATP stimulated the mRNA expression and activity of ectonucleotide pyrophosphatase/phosphodiesterase (ENPP), an enzyme that regulates the phosphate/pyrophosphate ratio. Thus, depending on the growth condition and its concentration, ATP stimulated stemness and in vitro mineralization or inhibited mineralization. In growth medium, both ATP concentrations stimulated pluripotent and osteogenic marker gene expression. However, in osteogenic medium, a biphasic effect was found on in vitro mineralization; the low concentration stimulated, whereas the high concentration inhibited, mineralization. We propose that ATP released due to mechanical stress modulates the stemness and differentiation of SHEDs.

Background To compare the mean mineral density (MMD) and examine the remineralization of carious dentin after cavity disinfection with chlorhexidine gluconate (CHX) and restoration with high viscosity glass ionomer cement (H-GIC) in vitro. Methods Selective caries removal to leathery dentin was performed in 40 extracted primary molars. The samples were scanned using micro-computed tomography (micro-CT) to determine the MMD baseline and randomly divided into 4 groups (n = 10): Equia™ group, applied dentin conditioner and restored with H-GIC (Equia Forte™), CHX-Equia™ group, disinfected the cavity with 2% CHX before applying dentin conditioner and restored with H-GIC (Equia Forte™), Ketac™ group, restored with H-GIC (Ketac Universal™) and CHX-Ketac™ group, disinfected the cavity with 2% CHX before restored with H-GIC (Ketac Universal™). The samples underwent micro-CT scanning post-restoration and post-pH-cycling to determine their respective MMDs. One sample from each group was randomly selected to analyze by scanning electron microscopy (SEM). Results The MMD gain in the 4 groups post-restoration was significantly different between the Equia™ and CHX-Ketac™ groups (oneway ANOVA with Post hoc (Tukey) test, P = 0.045). There was a significant difference in MMD gain post-restoration between the Equia™ and CHX-Equia™ groups (Independent t-test, P = 0.046). However, the Ketac™ and CHX-Ketac™ group’s MMD were similar. The SEM images revealed that the CHX-Ketac™ group had the smallest dentinal tubule orifices and the thickest intertubular dentin among the groups. However, the CHX-Equia™ group had thicker intertubular dentin than the Equia™ group. Conclusion Applying 2% CHX on demineralized dentin enhances the remineralization of the dentin beneath the restoration.

Background: Silver diamine fluoride (SDF) is widely accepted as a dentinal caries arresting agent because of its effectiveness, easy handling, and short working time. When dealing with uncooperative patients, a reduced working time is desired. As SDF has been known to interact with light, the effects of light curing (LC) on SDF have not been investigated. This study aimed to compare mean mineral density difference and surface morphology between 10-and 60-second(s) SDF-applied dentin carious lesions and similarly SDF-treated teeth with additional 20s LC. Methods: Forty primary molar blocks with natural dentin carious lesions were measured for baseline lesion depth and mineral density at baseline using Image-Pro Plus software. Samples were distributed into 4 groups; 38% SDF applied for 1) 10s (10SDF), 2) 60s (60SDF), 3) 10s+LC (10SDF+LC), and 4) 60s+LC (60SDF+LC), then underwent a 7-day bacterial pH-cycling. Dentin carious lesions’ mean mineral density difference was re-evaluated by digital subtraction radiographic analysis. Surface morphology and elemental profile were assessed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The mean mineral density difference of the dentin lesions was analyzed using two-way ANOVA, generalized linear models analysis.Results: Light curing was the only factor affecting the mean mineral density difference (p=0.007). Mean mineral density differences in 10SDF+LC and 60SDF+LC groups were significantly higher than those without light curing (p=0.041 and 0.041, respectively). The 60SDF+LC group showed a significantly higher mean mineral density difference than the 10SDF group (p=0.010), while the 10SDF+LC group was not different from the 60SDF group (p=1.00). Scanning electron microscopy showed denser mineral content layers, which likely were silver and chloride, in 10SDF+LC and 60SDF+LC groups than 10SDF and 60SDF groups, respectively.Conclusion: Shortened application time with light curing enhanced SDF remineralization similarly to a conventional method. This could be valuable for managing dentin caries in young or uncooperative children and special-needs patients by reducing the SDF application time by 50% of the American Academy of Pediatric Dentistry recommendation while maintaining an adequate SDF remineralization effectiveness.