Pop-Cola Acids and Tooth Erosion: AnIn Vitro,In Vivo, Electron-Microscopic, and Clinical Report

Abstract

Introduction. Manufactured Colas are consumed universally as soft drinks. Evidence about the acid contents of Cola-beverages and its effects on teeth is rare.Aim. To assess (i) cola acidity and buffering capacityin vitro, (ii) tooth erosion after swishing with colasin vivo(iii) scanning electronmicroscopic effectson teeth of colas, and tooth-brush abrasion, and (iv) report aclinical caseof erosion from cola consumption.Materials and Methods. (i) We measured six commercially available pop “Cola beverages”, pH, and buffering capacities using a pH-Mettler Automatic Titrator, with weak solution of Sodium Hydroxide (ii) two cohorts, onewith teeth, the secondwithout teethrinsed with aliquots of Cola for 60 seconds. Swished cola samples tested for calcium and phosphorus contents using standardized chemical analytical methods (iii) enamel, dentine, and the enamel-cemental junction from unerupted extracted wisdom teeth were examined with a scanning electron microscope after exposure to colas, and tested for tooth-brush abrasion; (iv) a clinical case of pop cola erosion presentation, are all described.Results. Comparisons among pop colas testedin vitroreveal high acidity with very low pH. Buffering capacities in millilitres of 0.5 M NaOH needed to increase one pH unit, to pH 5.5 and pH 7 are reported. Rinsingin vivowith pop cola causes leeching of calcium from teeth; SEM shows dental erosion, and pop-cola consumption induces advanced dental erosion and facilitates abrasion.Conclusions. (i) Pop-Cola acid activity is below the critical pH 5.5 for tooth dissolution, with high buffering capacities countering neutralization effects of saliva; (ii) calcium is leeched out of teeth after rinsing with pop colas; (iii) SEM evidence explains why chronic exposure to acid pop colas causes dental frangibles; (iv) aclinical caseof pop-cola erosion confirms this.