Lesion progression can be assessed using sound enamel slabs subjected to cycles of acid challenges and salivary remineralization in vitro, or by in situ testing with patients drinking beverages that deliver acid challenges to enamel slabs worn in an appliance (Figure 15). Using the same methods, the efficacy of preventive measures to inhibit lesion progression can be assessed. Lesion progression in enamel and dentin can be measured using microradiography, contact profilometry, and non-contact (optical) profilometry; the latter two additionally measure surface roughness. A fourth option, confocal laser scanning microscopy (CLSM), measures total lesion progression and the softened zone of mineral caused by an erosive acid. A recent study compared CLSM, contact profilometry and non-contact profilometry and found all three methods gave similar results in measuring the loss of enamel.63
Human enamel specimens mounted into appliances worn for human in situ erosion prevention studies.