Silver diamine fluoride pretreatment enhances the protective effect of resin-modified glass ionomer restorations on adjacent dentin caries: an in vitro study.
Abstract
Objective
To investigate whether 38% silver diamine fluoride (SDF) pretreatment enhances the caries-preventive effect of resin-modified glass ionomer cement (RMGIC) restorations on adjacent root dentin in an in vitro model. MATERIAL AND
Methods
Human tooth blocks with box-shaped cavities were allocated into two groups: 38% SDF pretreatment followed by RMGIC restorations (Group SDF+RMGIC), and RMGIC restorations alone (Group RMGIC). Dentin specimens simulating adjacent tooth root surface were placed 1mm from the restored tooth blocks and underwent a 7-day cariogenic challenge with a cross-kingdom biofilm of Streptococcus mutans, Lacticaseibacillus casei and Candida albicans. The biofilm on the surfaces of dentin specimens were assessed by PMA-qPCR, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM), respectively. Dentin demineralization was assessed by micro-computed tomography (Micro-CT), SEM, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR), respectively.
Results
PMA-qPCR demonstrated lower microbial growth on dentin surfaces in Group SDF+RMGIC compared to Group RMGIC. CLSM showed that dead-to-live ratio in Groups SDF+RMGIC and RMGIC were 0.89 ± 0.04 and 0.49 ± 0.05, respectively (p<0.001). SEM revealed sparse biofilms with damaged microbial cells in Group SDF+RMGIC, whereas Group RMGIC exhibited dense and structurally intact biofilms. Micro-CT showed that lesion depths (µm) in Groups SDF+RMGIC and RMGIC were 120±9 and 249±11, respectively (p<0.001). SEM demonstrated less mineral loss and collagen exposure in SDF+RMGIC. XRD showed stronger and sharper hydroxyapatite reflections, while FTIR showed a lower amide I: HPO42- value ratio in SDF+RMGIC than in RMGIC (0.12 ± 0.03 vs 0.20 ± 0.06; p=0.01).
Conclusion
Within the limitations of this study, SDF pretreatment was associated with an enhanced caries-preventive effect of RMGIC restorations on adjacent root dentin. CLINICAL
Significance
SDF pretreatment before RMGIC restoration may enhance protection against dentin caries on adjacent tooth. This combined approach may be beneficial for patients at high risk caries.