Assessment of Mineral Gain in White Spot Lesions Using CPP-ACP and CPP-ACFP in Different Clinical Protocols: A Proof of Concept Study

Subsurface remineralization can be promoted by the topical application of nanoparticles of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). To assess changes in enamel white spot lesions, an in situ proof-of-concept investigation was performed using 5 subjects (all of whom were healthy young adults) with a cross-over study design. Custom orthodontic brackets were attached to the buccal surfaces of the maxillary second premolar and first molar teeth. Each bracket had a recess that held a slab of enamel with a standardized 100 μm deep white spot lesion (WSL). Changes in mineral were evaluated in lesion cross sections using backscatter electron imaging (BSE) and electron probe microanalysis (EPMA). The following products were applied twice daily for 2 weeks: GC Tooth Mousse™ (CPP-ACP), Tooth Mousse Plus™ (CPP-ACFP), CPP-ACFP Mineral Enhanced (CPP-ACFP Enh), or the vehicle paste of CPP-ACFP containing 900 ppm fluoride. To ensure blinding, all products had identical flavours and packaging. For each subject, the products were used in a random sequence, with washout periods between products. Compared to the baseline situation, favourable changes in white spot lesions occurred with all products. Analysis of enamel samples in cross section showed improvements in mineral levels, as seen in BSE grey scale levels from the enamel surface through the lesion. These were accompanied by enhanced calcium and phosphorus levels as seen using EPMA. The ranking of products for subsurface mineral gain, from best to worst, was: CPP-ACFP = CPP-ACFP Enh > CPP-ACP > vehicle with fluoride. Rapid remineralization occurred in this clinical model, which is due to a combination of factors: the enamel slabs were located on tooth surfaces exposed to parotid saliva, the surfaces were brushed regularly to remove dental plaque biofilm, and compliance with twice daily topical use of products was high. Such model systems may be useful for screening new product formulations for their effect on enamel WSL.