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 ex periments were devised as follows. Eroded lesions were produced on enamel s amples with orange juice: (1) at different temperatures; (2) for different lengths of time; and (3) on bovine permanent, human deciduous and human per manent enamel. Lesion parameters (mineral loss and lesion depth) were quant ified using transverse microradiography. Both lesion parameters were signif icantly 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 posit ively correlated (r = 0.98, P < 0.05) to the exposure time. Both parameters were significantly greater in bovine enamel than human permanent and decid uous enamel, and in human deciduous than permanent enamel. Lesion progressi on, as measured by mineral loss, was in the ratio 2.0:1.5:1.0 for bovine:hu man deciduous:human permanent, and by lesion depth, 1.7:1.3:1.0. In conclus ion, the erosiveness of orange juice was less pronounced at a lower tempera ture, and increased with an increased exposure time. Erosion progressed twi ce as fast in bovine permanent than in human permanent enamel, and 1.5 time s more rapidly in human deciduous than in permanent enamel.