Adsorption/desorption of amine fluorides to hydroxyapatite

Area of Science:

• Dental Materials Science
• Biochemistry
• Oral Microbiology

Background:

• Hydroxyapatite (HA) is the primary mineral component of teeth.
• Amine fluorides (AmF) are used in dental products for caries prevention.
• Understanding AmF interaction with HA is crucial for optimizing dental treatments.

Purpose of the Study:

• To investigate the adsorption and desorption of commercial amine fluoride (AmF) preparations onto hydroxyapatite (HA).
• To determine the influence of environmental factors (pH, ionic strength, temperature, saliva, albumin) on AmF-HA interactions.
• To assess the antibacterial potential of desorbed AmF.

Main Methods:

• Adsorption and desorption experiments of AmF 297 and AmF 335 onto HA.
• Investigation of variables including pH, ionic strength, temperature, and presence of saliva/albumin.
• Quantification of AmF levels using a surfactant electrode.
• Assessment of desorbed AmF's minimum inhibitory concentration (MIC) against oral bacteria.

Main Results:

• AmF 297 and AmF 335 demonstrated immediate and irreversible binding to HA across various conditions.
• Monovalent AmF 335 showed higher adsorption than divalent AmF 297.
• Desorbed AmF exhibited levels below the MIC for oral bacteria.
• Protein pre-adsorption had minimal impact on AmF adsorption/desorption.

Conclusions:

• AmF preparations bind strongly and irreversibly to HA, suggesting effective tooth surface interaction.
• Excess proteins in the oral environment likely inactivate AmF, rather than impeding its adsorption or antibacterial activity on tooth surfaces.
• The findings support the clinical efficacy of AmF in preventing dental caries.