A novel non-destructive technique for qualitative and quantitative measurement of dental erosion in its entirety by porosity and bulk tissue-loss.

OBJECTIVE To explore the potential of combining non-contact profilometry(NCP) and confocal laser scanning microscopy(CLSM) data to measure the entire erosive process non-destructively and to validate findings using inductively coupled plasma-atomic emission spectroscopy(ICP-AES), scanning electron microscopy(SEM) and surface microhardness(SMH) using the same samples throughout. METHODS Polished bovine enamel samples(n = 35) were divided into groups(7/group) with similar SMH values. Samples underwent individual erosive challenges(1% citric acid,pH3.8) for 1,5,10,15 or 30 min under stirring and aliquot extracts were analysed for Ca and P by ICP-AES. SMH was used to measure erosive softening. Profilometry was used to assess bulk volume loss(BVL). Images were captured by SEM. Samples were stained with rhodamine-B(0.1 mM,24 h) and images captured by CLSM. Image processing was used to determine changes in fluorescent volume for the first 10 µm(ΔFV10) for each enamel sample which were combined with BVL to calculate total lesion volume(TLV). ANOVA, linear regression and Pearson correlation analysis were used where applicable. RESULTS Surface softening, [Ca],[P],BVL and ΔFV10µm increased with acid erosion duration which were significant by 10 min(P < .01). The Ca:P ratio increased to 1.57 then decreased after 5 min erosion suggesting a sub/surface phase change, which was observed by SEM and CLSM showing significant changes to the enamel surface and subsurface morphology with time. Combination of BVL and ΔFV10 as TLV strengthened the significant correlations with [Ca],[P],and SMH(P < .01). CONCLUSION This novel combination of CLSM and NCP allows for concurrent non-destructive quantification of the entire erosive process by mineral loss, and qualitatively characterise microstructural changes during dental erosion.