Changes in mineral density and fluoridated apatite formation of artificial root caries using fluoridated toothpastes with or without bioactive glass

Abstract Objectives To explore the potential mineral exchange and fluoridated apatite formation within the artificial root carious lesions (ARCLs) subsurface using different toothpastes either containing 5,000ppm-F, 1,450ppm-F or bioactive glass (BG) with 540ppm-F. Material and Methods The crowns of three extracted sound teeth were removed. Subsequently, roots were divided into four parts (n = 12). Each sample was randomly allocated into one of four groups: Group-1(Deionised water); Group-2(BG with 540ppm-F); Group-3(1,450ppm-F) and Group-4(5,000ppm-F). ARCLs were developed using demineralisation solution (pH4.8). The 13-day pH-cycling for samples included demineralisation solution (6hrs) and remineralisation solution (pH7) for 16hrs. Standard tooth brushing twice a day with an assigned toothpaste was carried out during pH-cycling. XMT was performed for each sample at baseline, following ARCLs and after 13-day pH-cycling. Samples were then analysed using SEM/EDX and 19 F-MAS-NMR. Results XMT showed an increase in mineral contents in the ARCL areas for each toothpaste group after 13-day pH-cycling, however there was mineral loss in subsurface for all groups. SEM showed the occlusion of dentinal tubules on the root surfaces in all toothpaste groups. 19 F-MAS-NMR confirmed the partial/full fluoridated apatite formation in all groups, interestingly the presence of more fluorapatite was evident in the Groups-3 and 4. Conclusion All toothpastes were potentially effective to increase mineral density on surface while mineral loss in subsurface. The 5,000ppm-F toothpaste had a superior effect with respect to mineral density increase by promoting fluorapatite formation in comparison to the BG with 540ppm-F and 1,450ppm-F groups. Clinical Relevance: Toothpaste containing BG with 540ppm-F, 5000ppm-F and 1450ppm-F toothpastes are likely to manage root caries.