Introduction

Dental caries involves dynamic cycles of demineralization and remineralization, affecting enamel mineral content. Dental caries in deciduous teeth pose a significant public health challenge, necessitating effective moni­toring of enamel mineral changes for prevention and treatment.

Objectives

To measure the phosphate/carbonate ratio (P/C ratio) in sound, demineralized, and remineralized deciduous enamel at various depths using spontaneous Raman spectroscopy (SpRS) and stimulated Raman scattering spectroscopy (SRS).

Material and methods

Thirty deciduous enamel specimens (5 × 5 mm) were prepared and divided into three groups: sound, demineralized (24 h and 48 h in a lactic acid solution, pH 5.0), and remineralized (15-day pH cycling model using fluoride treatment). SpRS was employed to measure P/C ratio at enamel surface, while SRS provided depth-resolved analysis at depths ranging from 0 to 100 µm.

Results

The results revealed that demineralization significantly decreased the P/C ratio, with significant reductions observed in superficial layers (0-20 µm) but no significant differences compared to sound enamel at deeper layers (30-100 µm). Following remineralization, the P/C ratio partially recovered, primarily in superficial layers. However, remineralization for 48 h-demin did not significantly restore the P/C ratio in superficial layers, with values remaining lower than for sound enamel. Both SpRS and SRS effectively detected these mineral changes, while SRS, in particular, provided depth-resolved analysis.

Conclusions

Demineralization significantly reduces the P/C ratio in deciduous enamel, with the greatest mine­ral loss occurring in superficial layers. Remineralization led to partial P/C ratio recovery, primarily in super­ficial layers, though full restoration of the original mineral composition was not achieved.