Discussion
tooth wear, erosion
EROSION
In contrast to previous studies, when erosion and abrasion challenges were performed, the step height data of the natural and polished surfaces were not statistically different until the final experimental cycle. We therefore partially rejected the first null hypothesis. The step height for erosion on natural surfaces was significantly lower than that of the polished surfaces throughout all experimental the cycles, which supports the existing literature [Ganss et al. compared erosion depths on human natural enamel and polished enamel after 3 h of citric acid exposure We also observed significant differences in measured wear between the natural and polished enamel groups for erosion. After four cycles of erosion, the lesions on polished enamel were almost twice as deep as those on natural enamel surfaces. Standard polishing techniques remove the natural outer surface of enamel, making the exposed prisms more susceptible to acids SEM imagery facilitated investigation into the natural subsurface of enamel. The authors hypothesised the possibility of a distinct area of deteriorated enamel prisms beneath the region subjected to erosion, however this layer was not as clearly evident in the natural erosion only group, with only a subtle change in the definition of the prims extending to depths similarly observed by Austin et al. The limitation of this study resides primarily in the fact that it was an Despite the limitations, this study enabled an investigation into the early erosion and abrasion subsurface lesions on natural enamel samples. The findings support the evidence that the erosive tooth wear process on enamel is driven by the chemical wear and exacerbated by mechanical wear. It also supports that natural surfaces have a greater resistance to erosion based wear than polished enamel yet both appeared susceptible to mechanical forces following acid exposure.