Title:  Effects of soft-drinks and remineralising treatment on teeth assessed by morphological and quantitative X-ray investigations

Abstract:  Aim To morphologically and chemical-physically analyse both the surface and the subsurface of enamel undergoing soft-drink demineralisation and remineralisation treatment. Material and methods Fifteen human premolars were split and immersed in saline or three popular soft drinks, as demineralising agent, 15 minutes per day, for seven days at room temperature. Half of drink-processed teeth was then treated with casein phosphopeptide-amorphous calcium phosphate, as remineralising agent, for an additional seven days. The surface morphology was evaluated by stereomicroscope and scanning electron microscope (SEM). Teeth were then re-embedded and sectioned, and analysed under SEM and X-ray microprobe. Results Drink-processed teeth showed root pigmentation, opacification and deterioration of the superficial enamel. The enamel surface resulted greatly furrowed after drink processing, and apparently restored after remineralising treatment. However, in tooth sections, SEM showed always a subsurface demineralisation of dentine and enamel, in particular at the cementoenamel junction, also after reminalising treatment. The remineralising agent produced a partial remineralisation of the subsurface enamel, sometimes statistically significant, but not in hydroxyapatite stoichiometry. Conclusion Soft-drink erosion impaired not only the surface but also the subsurface enamel. The applied remineralising treatment, yielding some effects on surface and subsurface enamel reversing basically the decalcification process.