Fluoride release from dental cements and composites: A mechanistic study

Chan, Wailan D.; Yang, Lifang; Wan, Wankei; Rizkalla, Amin S.

doi:10.1016/j.dental.2005.04.028

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Volume 22, Issue 4 , Pages 366-373, April 2006

Fluoride release from dental cements and composites: A mechanistic study

Wailan D. Chan
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ont., Canada N6A 5C1
Lifang Yang
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ont., Canada N6A 5C1
Wankei Wan
- Department of Chemical & Biochemical Engineering, The University of Western Ontario, London, Ont., Canada N6A 5C1
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ont., Canada N6A 5C1
Amin S. Rizkalla
- Department of Chemical & Biochemical Engineering, The University of Western Ontario, London, Ont., Canada N6A 5C1
- Division of Biomaterials Science, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ont., Canada N6A 5C1
- Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ont., Canada N6A 5C1
- Corresponding author. Address: Division of Biomaterials Science, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ont., Canada N6A 5C1. Tel.: +1 519 661 2111x86086/82212; fax: +1 519 661 3416.

Received 26 October 2004; accepted 7 April 2005.

Summary

Objectives

The purpose of this study was (1) to compare the fluoride release profile of an experimental composite to commercial GICs, resin-modified GICs, and composite resins; (2) to assess the fluoride release process.

Methods

Commercial materials (n=3) were prepared according to manufacturers' directions. The experimental composite (n=3) consisted of 78wt% filler and 22wt% resin. The resin consisted of 19wt% BisGMA, 38wt% UDMA, 19wt% TEGDMA, and 24wt% HEMA. Disc specimens were placed into 25ml of deionized water in sealed polyethylene vials and shaked at 1.4Hz at 37°C. Fluoride release was measured using a fluoride-ion specific electrode at different time intervals up to 284 days.

Results

The fluoride release rate of the experimental composite demonstrated the highest rate of release within the first day (p=0.05), but decreased significantly by day 7. Release rates of the commercial glass-ionomer cements and resin-modified glass-ionomer cements thereafter were significantly higher than the experimental and commercial composites at p=0.05. Among the materials studied, cumulative fluoride release is adequately described by a two-term equation consisting of an initial fluoride release via a rapid dissolution process followed by a long-term diffusive release.

Significance

An increase in the hydrophilicity of the polymer matrix through the introduction of HEMA improved the fluoride release over the short term during which dissolution occurs. Such a release behavior could be beneficial if it results in a fluoride reservoir that could be maintained by a prolonged slower release thereafter.

Keywords: Glass-ionomer cements, Resin-modified glass-ionomer, Resin composite, Fluoride release profile, HEMA, Kinetics, Diffusion coefficient