Pathogenesis and modifying factors of dental erosion.

Dental erosion is caused by acidic solutions which come into contact with the teeth. Because the critical pH of dental enamel is approximately 5.5, any solution with a lower pH value may cause erosion, particularly if the attack is of long duration, and repeated over time. Saliva and salivary pellicle counteract the acid attacks but if the challenge is severe, a total destruction of tooth tissue follows. Ultrastructural studies have shown that erosive lesions are seen in prismatic enamel as characteristic demineralization patterns where either the prism cores or interprismatic areas dissolve, leading to a honeycomb structure. In aprismatic enamel the pattern of dissolution is more irregular and areas with various degrees of mineral loss are seen side by side. In dentin the first area to be affected is the peritubular dentin. With progressing lesions, the dentinal tubules become enlarged but finally disruption is seen also in the intertubular areas. If the erosion process is rapid, increased sensitivity of the teeth is the presenting symptom. However, in cases with slower progression, the patient may remain without symptoms even though the whole dentition may become severely damaged. Regarding the role of causative agents, present data does not allow the ranking of different acids with regard to their potential of causing erosion. Neither is there consensus as to how effective fluorides are in preventing the progression of erosive lesions, or how the chemical and structural factors of tooth tissue in general might modify this pathological process.