Model for Assessing the Mineral Loss in Non-carious cervical lesions

Objectives:  To evaluate in vitro some factors that determine the mineral loss of enamel in a model that simulates the formation of some types of non carious cervical lesions using biomechanical tests.

Methods: 36 specimens of bovine dental enamel (n = 3) were prepared in the shape of sticks with a groove on dentin. Samples were kept in demineralized solution of citric acid buffered with KOH 1 M and adjusted to pH’s 5.0, 5.1, 5.2, 5.3, 5.5 and 7.0 during 5 days at temperature of 37° C. For each pH value, 3 samples were subjected to continuous flexural loading along the immersion period and other 3 samples from each pH group were submitted to immersion without loading. A quantitative light-induced fluorescence (QLF) evaluation of the enamel was made previously and after immersion in acid to verify whether white staining (generalized staining or localized at typical stress concentration sites) and/or cracking appeared after the period of immersion or not.

Results: Among the specimens not subjected to stress, all samples showed gradual mineral loss along time of solution exposure, except the samples on pH 7.0. Regarding the specimens subjected to stress, all samples presented higher localized mineral loss in the typical regions of stress concentration suggesting that stress can increase the mineral loss. 

Conclusions: The mineral loss of bovine dental enamel was increased by stress state. However, it would be necessary more research in order to confirm these findings.