Objective To develop, characterize and assess the in vitro effects of experimental niobium pentafluoride (NbF5) solutions on preventing dental caries. Materials and methods NbF5 solutions were developed and evaluated for fluoride concentration (after 1 and 6 months of preparation) and cytotoxicity (MTT for fibroblasts and preodontoblastic cells). Bovine enamel blocks (n = 176) were randomly assigned into groups of treatment: NbF5 (0.25%, 0.5%, and 1% corresponding to 1,263.75; 2,527.5; and 5,055 ppm F⁻), NaF (0.29%, 0.57%, and 1.13% with fluoride levels matched to NbF5), and controls (growth and sterility). The enamel blocks were partially covered and exposed to artificial saliva (1 h) before they were subjected to cariogenic challenge with a multispecies biofilm (37 °C; 24 h and 48 h) in culture medium enriched with 2% sucrose. The pH and total soluble fluoride (TSF) content of the medium were evaluated, and the enamel surface microhardness loss (%SML), volumetric roughness (Sa), tooth structure loss (TSL), and scanning electron microscopy (SEM) results were also evaluated. The data were analyzed by the Kruskal‒Wallis, Mann‒Whitney and Wilcoxon tests (p < 0.05). Results The fluoride concentrations remained stable across all storage periods with no significant variation, and similar stabilities were observed for both the NbF5 and NaF solutions. The viability of MTT fibroblasts ranged from 94% ± 3.2% for 0.25% NbF5 to 76% ± 2.9% for 1.0% NbF5, whereas for MTT preodontoblastic cells, it ranged from 89% ± 3.8–70% ± 4.1% for the same concentrations. In contrast, NaF maintained 100% viability for both cell types, indicating lower cytotoxicity than NbF5. The 1% NbF5 and 1.13% NaF solutions presented the highest pH values, with no significant difference between them (p > 0.05). Both compounds also resulted in comparable TSF release patterns, with higher concentrations resulting in lower TSF levels, suggesting greater fluoride uptake into the enamel. The 1% NbF5 (21.15 ± 10.12 and 37.31 ± 10.15) and 1.13% NaF solutions (22.12 ± 11.11 and 39.09 ± 13.24) presented the lowest %SMLs at 24 h and 48 h, respectively, with no significant difference between them (p > 0.05). Compared with those of the lower concentration groups, the Sa and TSL of the 1% NbF5 and 1.13% NaF groups also exhibited equivalent and superior preventive effects (p < 0.05). SEM and profilometry analysis confirmed similar enamel surface preservation in both the 1% NbF5 and the 1.13% NaF groups, with less porosity and mineral loss than in the other groups. Conclusion The in vitro results of the 1% NbF5 solution revealed the potential of niobium pentafluoride to prevent dental caries, demonstrating equivalent effectiveness to NaF in maintaining enamel integrity, pH stability, and fluoride uptake, although with slightly greater cytotoxicity at the cellular level. Clinical relevance  The 1% NbF5 solution had anticaries effects comparable to those of NaF, with stable fluoride release and acceptable biocompatibility, indicating its potential as an alternative compound for professional caries prevention.

Anticaries effects of the experimental solutions containing niobium pentafluoride

期刊论文
发表日期：

2025年9月30日

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Karla Lorene de França Leite,
Ana Beatriz Chevitarese,
Kenderson Santos Silva,
Andréa Vaz Braga Pintor,
Livia Rodrigues de Menezes,
Lucianne Cople Maia

摘要

Objective

To develop, characterize and assess the in vitro effects of experimental niobium pentafluoride (NbF₅) solutions on preventing dental caries.

Materials and methods

NbF₅ solutions were developed and evaluated for fluoride concentration (after 1 and 6 months of preparation) and cytotoxicity (MTT for fibroblasts and preodontoblastic cells). Bovine enamel blocks (n = 176) were randomly assigned into groups of treatment: NbF₅ (0.25%, 0.5%, and 1% corresponding to 1,263.75; 2,527.5; and 5,055 ppm F⁻), NaF (0.29%, 0.57%, and 1.13% with fluoride levels matched to NbF₅), and controls (growth and sterility). The enamel blocks were partially covered and exposed to artificial saliva (1 h) before they were subjected to cariogenic challenge with a multispecies biofilm (37 °C; 24 h and 48 h) in culture medium enriched with 2% sucrose. The pH and total soluble fluoride (TSF) content of the medium were evaluated, and the enamel surface microhardness loss (%SML), volumetric roughness (Sa), tooth structure loss (TSL), and scanning electron microscopy (SEM) results were also evaluated. The data were analyzed by the Kruskal‒Wallis, Mann‒Whitney and Wilcoxon tests (p < 0.05).

Results

The fluoride concentrations remained stable across all storage periods with no significant variation, and similar stabilities were observed for both the NbF₅ and NaF solutions. The viability of MTT fibroblasts ranged from 94% ± 3.2% for 0.25% NbF₅ to 76% ± 2.9% for 1.0% NbF₅, whereas for MTT preodontoblastic cells, it ranged from 89% ± 3.8–70% ± 4.1% for the same concentrations. In contrast, NaF maintained 100% viability for both cell types, indicating lower cytotoxicity than NbF₅. The 1% NbF₅ and 1.13% NaF solutions presented the highest pH values, with no significant difference between them (p > 0.05). Both compounds also resulted in comparable TSF release patterns, with higher concentrations resulting in lower TSF levels, suggesting greater fluoride uptake into the enamel. The 1% NbF₅ (21.15 ± 10.12 and 37.31 ± 10.15) and 1.13% NaF solutions (22.12 ± 11.11 and 39.09 ± 13.24) presented the lowest %SMLs at 24 h and 48 h, respectively, with no significant difference between them (p > 0.05). Compared with those of the lower concentration groups, the Sa and TSL of the 1% NbF₅ and 1.13% NaF groups also exhibited equivalent and superior preventive effects (p < 0.05). SEM and profilometry analysis confirmed similar enamel surface preservation in both the 1% NbF₅ and the 1.13% NaF groups, with less porosity and mineral loss than in the other groups.

Conclusion

The in vitro results of the 1% NbF₅ solution revealed the potential of niobium pentafluoride to prevent dental caries, demonstrating equivalent effectiveness to NaF in maintaining enamel integrity, pH stability, and fluoride uptake, although with slightly greater cytotoxicity at the cellular level.

Clinical relevance

The 1% NbF₅ solution had anticaries effects comparable to those of NaF, with stable fluoride release and acceptable biocompatibility, indicating its potential as an alternative compound for professional caries prevention.