Functional remineralization of dentin artificial caries lesions via poly-L-aspartic acid‑calcium complexes

Dental caries is a common oral disease and lacks an effective recovery method. The objective of the study was to investigate the remineralization efficiency of polyelectrolyte‑calcium complexes pre-precursor (PCCP) and polymer-induced liquid-like precursors (PILP) processes on mechanical and biochemical properties of dentin artificial caries lesions (ACLs) evaluated with micro-CT, SEM, TEM, ATR-FTIR, Raman spectra and nanoindentation. The human dentin ACLs were prepared with the depth of 100-120 μm. The intact dentin served as positive control and the dentin ACLs as negative control. The dentin ACLs were either incubated in poly-L-aspartic acid‑calcium suspension (PAsp-Ca, 4 g/L-5.44 M) followed by phosphate solution (0.325 M), and further incubated in artificial saliva serving as PCCP group, or in PAsp-stabilized amorphous calcium phosphate solution serving as PILP group. The micro-CT and SEM findings with EDX indicated that mineral contents of the dentin ACLs were dramatically increased in PCCP group, but, to some degree in PILP group. TEM and nanoindentation results showed that a heavy remineralization of dentin ACLs was obtained via PCCP process with an obvious recovery of mechanical properties while a poor remineralization via PILP process. In conclusion, the PCCP process is a promising strategy for functional remineralization of dentin caries lesions.