Constant vs static solution approach for remineralization of dentin

Objective: Remineralization of dentin is critical to prevent the advance of caries lesions in affected teeth, and provide improved preventive and conservative dental care. Recent work has suggested that the biomechanical recovery of demineralized dentin is related to the association of mineral within the collagen structure, thus we hypothesize that it is indicative of successful remineralization. In this study we compared two remineralization approaches to gain insight into the mechanisms of mechanical recovery of carious dentin. Methods: Dentin specimens demineralized with a 0.05M acetate containing 2.2mM CaPO₄ (pH=5.0, 8 hours), were remineralized using either the constant solution composition approach or a static solution remineralization approach, for up to five days(n=3). Remineralizing solutions had 1.5mM calcium and 0.9mM phosphate with degree of saturation of 10.6. Before and after remineralization, elastic moduli(E) of the specimens were measured by AFM nanoindentation in hydrated conditions. SEM and AFM images and Raman spectroscopy analyses were also included. Results: Mean values of E were subjected to ANOVA and Tukey HSD(p<0.05). Specimens remineralized with the static solution approach showed no recovery of mechanical properties as compared with the initial artificial caries lesions (0.3±0.1GPa) after one (0.2±0.1GPa), three (0.7±0.5GPa) or five days (1.7±0.9GPa). Specimens remineralized with the constant solution composition approach gave values statistically higher than the carious dentin after one (9.6±2.5GPa) and three (7.2±2.1GPa) days; after five days (11.6±2.4GPa) the properties recovered up to about 60%, but were still statistically different from normal dentin (20±1.9GPa). All of the samples remineralized with the constant composition approach gave values statistically higher than the specimens remineralized with the static solution approach for each day. Conclusion: In summary, we concluded that slow and continuous mineral formation provided improved formation of mineral within the demineralized dentin matrix and therefore was suggested to be a superior approach for remineralization of carious dentin. Support-NIH/NIDCRR01DE16849