Factors influencing the development of dental erosion in vitro: enamel type, temperature and exposure time

The influence of temperature, duration of exposure, and enamel type on the development and progression of dental erosion has been determined. Three experiments were devised as follows. Eroded lesions were produced on enamel samples with orange juice: (1) at different temperatures; (2) for different lengths of time; and (3) on bovine permanent, human deciduous and human permanent enamel. Lesion parameters (mineral loss and lesion depth) were quantified using transverse microradiography. Both lesion parameters were significantly lower at 4 degrees C when compared with 20 degrees C and 37 degrees C, and at 20 degrees C when compared with 37 degrees C. Lesion parameters increased significantly as the length of exposure increased, and were positively correlated (r=0.98, P<0.05) to the exposure time. Both parameters were significantly greater in bovine enamel than human permanent and deciduous enamel, and in human deciduous than permanent enamel. Lesion progression, as measured by mineral loss, was in the ratio 2.0:1.5:1.0 for bovine:human deciduous:human permanent, and by lesion depth, 1.7:1. 3:1.0. In conclusion, the erosiveness of orange juice was less pronounced at a lower temperature, and increased with an increased exposure time. Erosion progressed twice as fast in bovine permanent than in human permanent enamel, and 1.5 times more rapidly in human deciduous than in permanent enamel.