21 February 2023

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Remineralization of molar incisor hypomineralization with a hydroxyapatite toothpaste

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This randomized, double-blind, crossover, in-situ study, compared the efficacy of toothpastes based on microcrystalline hydroxyapatite (HAP; fluoride-free) or fluoride, in remineralizing molar incisor hypomineralization (MIH).

Methods

Two lesion-bearing enamel blocks were produced from each of 30. extracted permanent molars diagnosed with MIH. Sixty produced blocks were randomly assigned to two groups: 20% HAP or 1450 ppm fluoride toothpaste.

Each group was subdivided into, etched (n = 20), with lesion surface treated with 32% phosphoric acid-etchant for 5 s, and unetched (n = 10). Blocks were cemented into intra-oral appliances (two blocks/appliance) worn full-time by 15 subjects.

Subjects used the toothpastes in a two-phase crossover manner, lasting 14 days per phase, after one-week washout period. Baseline and post-treatment mineral density (MD) was quantified using microcomputed tomography.

Results

Overall, both groups showed statistically significant net-gain when MD was compared pre-treatment and post-treatment. HAP: pre-treatment (1.716 ± 0.315) and post-treatment (1.901 ± 0.354), fluoride: pre-treatment (1.962 ± 0.363) and post-treatment (2.072 ± 0.353).

Independent t-test demonstrated a practically significantly (≥10%) higher percentage remineralization with HAP toothpaste (26.02 ± 20.68) compared with fluoride toothpaste (14.64 ± 9.60). Higher percentage remineralization was observed in etched than unetched samples.

Conclusion

The tested toothpaste based on hydroxyapatite can remineralize MIH lesions. Pre-treating the tooth surface with acid-etchant enhanced remineralization.

Amaechi, B.T., Farah, R., Liu, J.A. et al. "Remineralization of molar incisor hypomineralization (MIH) with a hydroxyapatite toothpaste: an in-situ study." BDJ Open 8, 33 (2022). https://doi.org/10.1038/s41405-022-00126-4