Crush absorbing energy of white spot lesions measured by indentation tests

Abstract

White spot lesions are clinically detectable areas of demineralized enamel that often form during orthodontic treatment. Fluoride has been shown to prevent demineralization from occurring. Mechanical properties of white spot lesions are not well characterized. Bovine enamel slabs, with and without fluoride treatment, were placed under demineralization conditions. Through a series of microindentations at incremental loads, mechanical strength was measured using a novel method, specific volume absorbing energy (SVAE). SVAE is equal to work energy divided by the indentation volume. The supra-surface area (outermost 5 μm) of enamel slabs with fluoride demonstrated decreased mechanical strength compared to enamel slabs without fluoride. Fluoride may not impart protection over long periods of demineralization.