In-vivo study to evaluate the long-term (one -year) ability of glass ionomer cement to resist demineralization of enamel around orthodontic brackets

Enamel demineralization in the form of white spot lesions (WSLs) is a pervasive problem in orthodontics. These lesions can result in long-term aesthetic compromises and increased susceptibility to caries. Though detection by eyesight has traditionally been the most common way of diagnosing these lesions, the defect by then is often irreversible. Our aim is to reduce the prevalence of these lesions by exploring tools for earlier detection and by substantiating the salient effects of fluoride. To this end, we used Polarization Sensitive--Optical Coherence Tomography (PS-OCT) to investigate the long-term potential of a fluoride-releasing glass ionomer primer for minimizing prevalence of these lesions. We devised a split-mouth protocol for this study: the control tooth bracket was bonded with conventional composite, while the experimental tooth bracket was bonded with glass ionomer. We used PS-OCT to scan each tooth every 3 months for 1 year, and then analyzed the integrated reflectivity and lesion depth for each image. We obtained high-quality images of the enamel gingival to the bracket, and were able to track and quantify enamel integrity over time. Our results indicate that glass ionomer cements do not result in less demineralization when compared to composite controls over an extended period of time. Our study also highlights the important advantages PS-OCT has over traditional techniques for assessing enamel demineralization. These scans are capable of revealing how deep and severe white spot lesions are, thus making PS-OCT an attractive tool for future use in dental imaging.