Comparing Different Methods to Assess Erosive Lesion Depths and Progression in vitro

Abstract

The aim of this study was to compare the precision and accuracy of 5 different methods applied to assess surface substance loss or changes in surface microhardness (SMH) on the same enamel surfaces after repeated acid exposures. Ground specimens from human molars were exposed to 0.01 M HCl (pH 2.2) for 6 min × 2 and measurements performed 3 times to estimate precision. The accuracies (systematic errors) were calculated against the manufacturer’s calibration standard. Lesion depth progression was from 94 to 110%, related to repeated acid exposure. The precisions/accuracies were: WLI (white light interferometry), 0.5/0.4%; SP (stylus profilometry), 4.7/0.7%; OP (optical profilometry), 1.4/12%; AAS (atomic absorption spectroscopy), 0.4/17% (measured calcium loss was converted to lesion depth). The correlation between WLI and SP was R² = 0.98, and between WLI and OP it was R² = 0.85. SMH gave information on qualitative changes of the surface (precision: 5.5%, accuracy: 4.0%). WLI performed best in precision and accuracy, but SP, OP and AAS are all relevant methods for analysing lesion depths and progression, SMH seems suitable for analysing minor changes in surface enamel only.

Diagnostic accuracy of proximal enamel subsurface demineralization and its relationship with calcium loss and lesion depth

“…Although the determination of lesion depth by use of calcium loss is an indirect method, it was shown to be a reliable method for analysing the progression of etch depth related to successive acid exposures on the same enamel surfaces. 28 It was also demonstrated that this method was comparable to the direct methods such as white light interferometry and light profilometry. 28 If one considers the definition of caries as a demineralization/remineralization imbalance leading to net mineral loss, mineral loss should be the parameter of a carious lesion that should be measured.…”

“…28 It was also demonstrated that this method was comparable to the direct methods such as white light interferometry and light profilometry. 28 If one considers the definition of caries as a demineralization/remineralization imbalance leading to net mineral loss, mineral loss should be the parameter of a carious lesion that should be measured. However, considering the direction of progression and the relationship between the defence reaction of the tooth and depth of progression, depth of mineral loss may be as relevant as volume of mineral loss.…”

“…28 ; r 5 0.97, p 5 0.03). Stereomicroscopic and SEM observations revealed lesions from superficial to deeper layers of enamel ( Figures 5 and 6).…”

Effects of brushing timing after erosive challenge on enamel loss <i>in situ</i>: White light interferometer and nanoindentation study

“…Previous studies have quantified the characteristics of enamel exposed to erosive wear using various methods. A white light interferometer (WLI) is a type of computerized optical interference microscopy that has been used to analyze substance loss of enamel after acid exposure in laboratory and in situ dental erosive studies 9,10) . It has been shown that WLI is able to operate with an accuracy down to 20 nm for measurements on polished enamel surfaces 10) .…”

“…A white light interferometer (WLI) is a type of computerized optical interference microscopy that has been used to analyze substance loss of enamel after acid exposure in laboratory and in situ dental erosive studies 9,10) . It has been shown that WLI is able to operate with an accuracy down to 20 nm for measurements on polished enamel surfaces 10) . Moreover, nanoindentation is a useful method to detect very small changes in surface hardness at the early stages of in situ eroded enamel.…”