Microhardness Indentations on Artificial White Spot Lesions

Abstract

In this study, Knoop hardness experiments on artificial carious enamel (pH 5.0, 4.5 and 4.0) are presented with the load perpendicular to the subsurface lesion. The results show that for human and bovine enamel the indentation length is proportional to the square root of the load. The proportionality constant is numerically estimated for all pH values for human and bovine enamel. The indentation measurements reflect the decalcification despite the presence of surface layer covering the lesion.

Fluoride dose-response of human and bovine enamel artificial caries lesions under pH-cycling conditions

“…V-SMH and K-SMH were recorded and changes vs. lesion baseline calculated for both Knoop and Vickers indenter types as follows: ΔSMH = SMH post -SMH base . The authors refrained from calculating changes in indentation lengths as this is uncommon for Vickers and for the sake of clarity, although some previous studies [4,13,21,22] highlighted linear correlations between Knoop indentation lengths vs.…”

“…it is more readily available, easier to obtain due to ethical aspects, its larger size allows for the preparation of specimens with a more uniform enamel thickness, and its lack of prior cariogenic challenges and topical and systemic fluoride exposure should, at least in theory, provide a tissue of lesser biological variation than HE. Several morphological and compositional differences between the two tissues have been reported and were summarized recently [2]: BE is more porous [3], softer [4] contains more carbonate [5], but less fluoride [6] than HE. Their prism arrangement differs [7,8], especially in the inner third of the enamel [9], and crystallites are larger [10] but prism diameters smaller [9] in BE.…”

“…Among those techniques are the 'gold standard' transverse microradiography (TMR), Knoop and Vickers microhardness either used perpendicular (K-SMH, V-SMH) or parallel to the hard tissue surface, polarized light and confocal laser scanning microscopy (both used parallel to the surface), and quantitative light-induced fluorescence (used perpendicular to the surface). Researchers have either shown good [4,21,22] or poor correlations [23,24] between TMR and SMH, depending on the extent of demineralization and lesion mineral distribution. However, previous 5 laboratories approximately monthly; however, determinations of origin, exact age and other characteristics of the donor (human or animal) are impossible due to the large number of teeth received.…”

Comparison of Knoop and Vickers surface microhardness and transverse microradiography for the study of early caries lesion formation in human and bovine enamel

“…[9][10] Data from more recent studies (employing different baseline lesions among them) highlighted very strong linear correlations between IL(Knoop) and integrated mineral loss (ΔZ) in situ 11 and in vitro, 12 although other studies did not. [13][14] The reasons for this discrepancy could be manifold, such as the mineral content and density of the surface zone, extensive subsurface demineralization, differences in mineral distribution, and presence of laminations etc.…”

Estudo do efeito da saliva e do flúor, in situ, na recuperação da superfície do esmalte dentário desmineralizado submetido à profilaxia com jato de bicabornato de sódio

“…Entretanto, o esmalte bovino é mais poroso, portanto, apresenta uma taxa de difusão e desmineralização mais rápida, o que permite a realização de pesquisas em um menor tempo 3,8,22,27,36 .…”