Calcium fluoride formation on sound enamel using fluoride solutions with and without lactate

Area of Science:

• Dental materials science
• Fluoride chemistry
• Biomineralization

Background:

• Fluoride treatments are crucial for preventing dental caries.
• Understanding calcium fluoride (CaF2) formation kinetics on enamel is vital for optimizing treatment efficacy.
• The role of pellicle and lactate in fluoride uptake requires further investigation.

Purpose of the Study:

• To investigate the formation of CaF2 on bovine enamel using neutral fluoride solutions.
• To evaluate the influence of pellicle coating and lactate on CaF2 deposition.
• To determine CaF2 formation during clinically relevant treatment durations.

Main Methods:

• Bovine enamel blocks (coated and uncoated) were treated with neutral fluoride solutions (0.26 mol/l F) with and without 0.1 mol/l lactate for 0-60 minutes.
• Alkali-soluble calcium (Ca), phosphate (PO4), and fluoride (F) were quantified after treatment.
• Surface analysis utilized scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS).

Main Results:

• Fluoride recovery increased over time, while calcium levels remained stable.
• Pellicle-coated enamel showed lower fluoride recovery compared to uncoated enamel.
• Lactate addition promoted cuboidal crystal formation resembling CaF2 but did not increase overall fluoride recovery.
• CaF2 was confirmed after 24-hour treatments, but not definitively during shorter clinical application times.

Conclusions:

• CaF2 formation on enamel is a time-dependent process.
• Pellicle layer may impede fluoride uptake.
• Lactate's role in CaF2 morphology warrants further study, but its impact on short-term fluoride uptake is limited.
• Directly demonstrating CaF2 formation during brief clinical applications remains challenging.