Enamel Remineralization with Novel Bioactive Glass Air Abrasion

Abstract

Enamel demineralization or white spot lesions (WSLs) are a frequent complication associated with fixed appliance–based orthodontic treatment. The remineralization potential of a novel fluoride-containing bioactive glass (QMAT3) propelled via an air abrasion system was compared with Sylc glass and artificial saliva on artificially induced WSLs. Thirty extracted human premolars were randomly assigned into 3 groups (n = 10) per method of treatment and scanned with optical coherence tomography and noncontact profilometer in the 4 enamel states: sound, demineralized, after glass propulsion, and after immersion in artificial saliva. Knoop hardness testing was also performed. Twenty additional prepared teeth samples were also randomly selected for examination by scanning electron microscopy and energy-dispersive X-ray spectroscopy (2 teeth per technique) under each of the 4 enamel conditions. 19F MAS-NMR (magic angle spinning–nuclear magnetic resonance) was also used to detect the type of apatite formed on the enamel surface. Significant enamel remineralization with surface roughness and intensity of light backscattering similar to that of sound enamel was observed following treatment with QMAT3. In addition, mineral deposits were detected on the remineralized enamel surfaces, forming a protective layer and improving its hardness. This layer was rich in calcium, phosphate, and fluoride; 19F MAS-NMR confirmed the formation of fluorapatite. This finding is particularly beneficial since fluorapatite is more chemically stable than hydroxyapatite and has greater resistance to acid attack. Hence, a promising fluoride-containing bioactive glass for enamel remineralization has been developed, although further clinical evaluation and refinement is required.