Cariotester, a new device for assessment of dentin lesion remineralization in vitro

Evaluation of a new hardness tester (Cariotester): Comparison with transverse microradiography for assessing the inhibitory effect of fluoride application on bovine root dentin demineralization

The objective of this study was to investigate the correlation between CT depth, indentation depth determined by a new hardness tester (Cariotester), and the transverse microradiography (TMR) parameters, i.e., lesion depth and mineral loss. For that purpose, this study evaluated the feasibility of using Cariotester as a root caries diagnostic system and capability of Cariotester to detect effect of fluoride application on inhibiting dentin demineralization. Fluorides were applied to bovine root dentin specimens, which were subsequently demineralized for 1-21 days and then CT depth and TMR parameters were assessed. There were significant correlations between CT depth and TMR parameters in fluoride and non-fluoride groups. There were significant differences between fluoride and non-fluoride groups for CT depth and TMR parameters respectively. Current results suggested that Cariotester may be capable of providing an objective evaluation of root caries progression and the fluoride effect on inhibiting dentin demineralization.

Measurement of surface hardness of primary carious lesions in extracted human enamel -measurement of Knoop hardness using Cariotester

The clinical feasibility of a novel device called a Cariotester was investigated by measuring the Knoop hardness (KHN) of white spot lesions diagnosed as ICDAS code 1, 2 or 3. To obtain an equation for converting the Cariotester indentation depth into the KHN, a regression analysis was performed between the depth and measured KHN for human enamel. The Cariotester was then used to measure the indentation depth for white spots (ICDAS code 1, 2 or 3) in extracted teeth, and the KHN values were determined using the above equation. The KHN was 219.9±19.7, 162.4±24.0 and 31.7±17.5 for code 1, 2 and 3 lesions, respectively, which was 30, 49 and 90% lower than that for healthy enamel. Using the formula reported in the literature, the mineral density was calculated to be 87.7 vol.% for healthy enamel, and 75.1, 66.1 and 35.5 vol.% for code 1, 2 and 3 lesions, respectively.

Formation and characterization of hypermineralized zone beneath dentine lesion body induced by topical fluoride in-vitro

OBJECTIVE

This in-vitro study aimed to evaluate and characterize the hypermineralized zone (Hyper-zone) formed beneath the remineralized dentine lesion body by transverse microradiography (TMR), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDS).

DESIGN

Demineralized bovine dentine specimens were treated with fluoride solutions (APF, NaF) and remineralized for 2-4 weeks. Then thin sections were prepared to characterize the Hyper-zone by TMR, EDS. Fractured specimen surfaces were observed by SEM.

RESULTS

TMR analysis revealed a higher mineral density at Hyper-zone than that of sound dentine (48vol%) ranging from 50 up to 61vol% and the thickness ranging from 197 to 344μm for 4-week specimens, while specimens without fluoride treatment did not show Hyper-zone. SEM pictures at Hyper-zone showed no evident crystal-like deposits in dentinal tubules and no notable difference when compared to that in sound dentine. EDS analysis demonstrated higher concentrations of Ca and P at Hyper-zone than those in sound dentine, which corresponded to the TMR profile, while the magnesium (Mg) concentration was low at this zone.

CONCLUSIONS

Demineralized dentine lesions exposed to fluoride and remineralization treatments exhibited Hyper-zone beneath the lesion body, in which the mineral density was higher than that of sound dentine. Possible mechanism for the formation of Hyper-zone was discussed by assuming removal of mineral regulators such as Mg and other organic substances from sound dentine during de-/remineralization processes.