The development of test methods for the assessment of live tooth site susceptibility to erosion could be valuable for clinical determinations of treatments to prevent hard tissue loss. Objectives: The aim of this study was to evaluate in vitro the potential of a dynamic flow erosion susceptibility test (DFEST) which may be later applied in situ. Methods: Polished enamel blocks (4 per treatment group) were cycled in NaF fluoridated dentifrice and saliva to establish a surface representative of clinical tooth presentation. Windows of enamel were isolated and exposed to flow solutions of erosion buffers comprised of citric acid (CA) (150 mM, 300 mM), pH (2.3, 3.0), flow rate (2 ml/min, 4 ml/min) and time of challenge (1 min, 2 min, 4 min) respectively. Flow erosion was controlled by distance to tooth surface and angulation of erosion media flow - matching simulated use in a clinical setting. Collected “erosion challenge” eluents were analyzed by atomic absorption spectroscopy for calcium and the depth of etched enamel was back calculated from enamel density. SEM was carried out on eroded surfaces. Results: Enamel damage from in vitro modeling treatments ranged from 2-12µm. The time of erosive challenge was clearly correlated with enamel loss, though CA and pH effects exhibited dependence to flow rate of treatment. For 1 min treatment at 2ml/min results included (pH/CA): 2.3/150=3.8µm; 3.0/150=2.0µm; 2.3/300=12.0µm; 3.0/300=4.0µm. SEM revealed patterns of prism disclosure. Conclusions: These data suggest that a dynamic flow erosion susceptibility test (DFEST) may be possible for clinical application and possibly even present an alternative for clinical erosion assessment.