Fluoride release from dental cements and composites: a mechanistic study

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Glass-ionomer cements (GICs) and resin-modified GICs are known for fluoride release, offering anticariogenic benefits.
• Composite resins typically exhibit limited fluoride release, potentially hindering their therapeutic effects.
• Optimizing fluoride release from dental restorative materials is crucial for enhanced caries prevention.

Purpose of the Study:

• To compare the fluoride release profile of an experimental composite containing HEMA with commercial GICs, resin-modified GICs, and composite resins.
• To analyze the kinetics and mechanisms governing fluoride release from these dental materials.

Main Methods:

• Prepared disc specimens of an experimental composite (78 wt% filler, 22 wt% resin including HEMA) and three commercial materials.
• Incubated specimens in deionized water at 37°C with agitation for up to 284 days.
• Quantified fluoride release using a fluoride-ion specific electrode at various time points.

Main Results:

• The experimental composite exhibited the highest fluoride release rate within the first day, significantly decreasing by day 7.
• Commercial GICs and resin-modified GICs demonstrated significantly higher release rates than both experimental and commercial composites after the initial period.
• Fluoride release kinetics across all materials were accurately modeled by a two-term equation: rapid dissolution followed by sustained diffusion.

Conclusions:

• Incorporating HEMA into the experimental composite's polymer matrix enhanced short-term fluoride release through increased hydrophilicity and dissolution.
• This initial burst release may establish a fluoride reservoir, potentially beneficial if sustained by subsequent slower release.
• Further research is needed to confirm the long-term efficacy and clinical relevance of this fluoride release profile.