Dental erosion is the loss of tooth enamel through direct attack by acids — not by bacterial decay, but by chemical dissolution of the mineral surface. The acids come from outside, in fizzy drinks, fruit juices, sports drinks, and wine, or from inside, in the repeated vomiting of eating disorders or the reflux of gastric acid. Each acid exposure softens the enamel surface; brushing too soon afterwards scrubs the softened layer away, which is why dentists advise waiting before brushing. Early erosion looks like a smooth, glassy dulling of the teeth; advanced cases expose the yellow dentine beneath and cause sensitivity. Prevention is dietary as much as dental: limit acidic drinks, don’t swish or hold them in the mouth, and let saliva — the mouth’s natural buffer — do its remineralising work between exposures.