The Early Erosive and Abrasive Challenge: A Profilometric, Electron Microscopic and Microhardness Study Using Human, Bovine and Ovine Enamel.

AIM: This study aimed to test the null hypothesis that there are no significant differences in surface characteristics of eroded and abraded human, ovine and bovine enamel.

DESIGN: Twenty enamel slabs were prepared from bovine, human and ovine incisor crowns, and randomly assigned to one of 4 treatments: 30 second/4 minute immersion at 1%/6% w/v citric acid. Post-erosion, an oscillatory brush was used for 20 seconds. Roughness parameters, height change and scanning electron microscopy were measured at each stage.

RESULTS: Whilst the eroded surface became generally less rough after the abrasive challenge, there were significant tissue differences. Abraded microhardness was significantly increased compared to eroded values (P⟨0.001), Surface loss was also significantly different between tissue types (P⟨0.001). Bovine enamel showed similar trends to human enamel but was consistently harder and more resistant to surface change. Ovine enamel displayed little correlation with human enamel.Scanning electron microscopy images showed differences for each tissue that were consistent with the quantitative data.

CONCLUSIONS: The null hypothesis was rejected; neither bovine nor ovine enamel can be reliably used interchangeably with human enamel for erosion/abrasion studies.