Tactile perception of roughness to assess activity in artificial initial caries lesions with a novel force-controlled probe

Abstract Roughness-tactile perception is part of activity assessment in initial-caries-lesions. Hypothesizing that a probe's design influences this examiner's assessment, four probes were designed. The aims of this study were to select the probe with highest inter-/intra-examiners' roughness-assessment agreement and to determine its diagnostic accuracy on artificial initial-caries lesions. A pilot study was conducted with trained dentists to select one controlled-pressure probe design (n = 4) by assessing roughness on known-roughness metal plaques with 5-point Likert scale. Diagnostic accuracy of roughness assessment was conducted with the selected controlled-pressure probe and the WHO-probe on sound and artificial initial-caries-lesion (n = 20) human enamel blocks. Intra-class correlation coefficients (ICCs) and quadratic weighted-Kappa scores were used to assess examiners' reproducibility and Multilevel Poisson models to determine diagnostic accuracy between both probes controlling for confounding variables. The probe design with the highest inter/intra-examiner's agreement (ICC = 0.96) was selected for subsequent analyses. Unadjusted sensitivity, specificity and accuracy values were for the controlled-pressure and the WHO probes: 71.1%,90.6%,81.2%, and 67.4%,84.6%,75.8%, respectively (p > 0.05). Examiner remained the most important factor influencing diagnostic accuracy. While this study did not show significantly higher diagnostic accuracy of the designed controlled-pressure vs. the WHO-probe when used by trained dentists, all over roughness-assessment accuracy and reproducibility were high.

Pathogenesis of dental fluorosis: biochemical and cellular mechanisms / Patogénesis de la fluorosis dental: mecanismos bioquímicos y celulares

Abstract. The mechanisms involved in the development of dental fluorosis are still unknown. The development of in vivo and in vitro models using biologically relevant concentrations of fluoride for the emergence of fluorosis has allowed suggesting hypotheses that contribute to the understanding of the mechanisms that produce this defect in enamel development, with high prevalence in Colombia. This topic review presents an update on the normal mechanisms of the formation of enamel and how they are affected by exposure to high concentrations of fluoride. This is a thorough review of the deleterious effects of fluoride on the cells and the extracellular matrix, especially during the maturation stage, resulting in a delay of the removal of the protein matrix of amelogenins, as well as the appearance of mottled enamel-a characteristic of dental fluorosis. Finally, it shows the perspectives of the study of this defect in enamel development from biochemistry and cellular and molecular biology.

RESUMEN. Los mecanismos involucrados en el desarrollo de la fluorosis dental aún no se conocen a cabalidad. El desarrollo de modelos in vivo e in vitro que utilizan concentraciones de fluoruro biológicamente relevantes para la aparición de fluorosis ha permitido el planteamiento de hipótesis que aportan cada vez más al conocimiento de los mecanismos que generan este defecto del desarrollo del esmalte, de alta prevalencia en Colombia. Esta revisión presenta una actualización sobre los mecanismos normales de la formación del esmalte y cómo estos se ven afectados por la exposición a altas concentraciones de fluoruro. Se presenta una revisión en detalle de los efectos deletéreos del fluoruro sobre las células y sobre la matriz extracelular, especialmente durante la etapa de maduración, que tendrán como consecuencia el retraso de la remoción de la matriz proteica de amelogeninas y se traducirá en la apariencia de esmalte moteado, característica de la fluorosis dental. Por último, se muestran las perspectivas del estudio de este defecto del desarrollo del esmalte desde la bioquímica y la biología celular y molecular.