Remineralization patterns in artificial dentin caries lesions treated with fluoride- and tricalcium phosphate-based varnishes or silver diamine fluoride: an in vitro micro-CT study.

OBJECTIVES

To compare the effects of 5% sodium fluoride (NaF) varnish, tricalcium phosphate (TCP) varnish, NaF/TCP varnish, and 30% silver diamine fluoride (SDF) on artificial dentin caries lesions through the assessment of lesion depth, mineral redistribution, and superficial mineralization.

METHODS

Artificial dentin caries lesions were created in bovine root dentin blocks and randomly assigned to five groups (n = 12): Control, 5% NaF varnish, TCP varnish, NaF/TCP varnish, and 30% SDF. After treatment, specimens underwent 7 days of pH cycling. Mineral concentration profiles obtained by micro-CT were used to determine integrated mineral concentration (ΔIMC), lesion depth, mean lesion mineral concentration (Rvol%), and maximum mineral concentration in the surface zone (SZmax). Data were analyzed by two-way repeated-measures ANOVA and Tukey's test (α = 0.05).

RESULTS

All treatments promoted remineralization or reduced lesion progression compared with the Control group (p < 0.001). The 5% NaF varnish showed the highest ΔIMC and Rvol% values and the lowest lesion depth (p < 0.05). TCP varnish reduced lesion depth but produced limited mineral recovery. NaF/TCP varnish exhibited high SZmax values, indicating greater superficial mineral accumulation without proportional increases in ΔIMC or Rvol%. SDF reduced lesion depth and increased SZmax compared with the Control group but showed lower integrated mineral recovery than 5% NaF.

CONCLUSION

The agents produced distinct remineralization patterns. The 5% NaF varnish promoted the most effective and homogeneous response, TCP mainly limited lesion progression in depth, NaF/TCP favored superficial mineralization, and SDF promoted lesion stabilization with moderate superficial mineral reinforcement.

CLINICAL SIGNIFICANCE: These findings indicate that professional remineralizing therapies may require repeated applications because agents do not act uniformly in dentin caries lesions. The 5% NaF varnish promoted the most homogeneous mineral recovery, whereas TCP, NaF/TCP, and SDF produced distinct effects on lesion depth, superficial mineralization, and stabilization, supporting treatment-specific clinical decision-making.