Читать книгу Caries Excavation: Evolution of Treating Cavitated Carious Lesions - Группа авторов - Страница 41

The interaction of light with matter may lead to several specific phenomena: light can be reflected, or scattered (back-scattering or diffuse transmission), there can be transmission of the light, absorption with heat production or absorption with fluorescence [44]. Under the impact of suitable wavelengths, bacteria, or rather their porphyrins, can have a characteristic red fluorescence [45]. Fluorescence is thus an indirect measure of the degree of tooth demineralisation [46–48]. It is applicable on occlusal surfaces, smooth surfaces, and some devices also measure carious lesions in approximal surfaces [49].

There are pen-type devices that measure the red fluorescence locally in small areas and camera-based systems that can visualise the fluorescence for one or more tooth surfaces at once. One of the most popular pen-type fluorescence devices operates on a wavelength of about 650 nm and has a numeric output between 0 and 99 (DIAGNOdent pen, KaVo, Biberach, Germany). This device measures the fluorescence and allows for monitoring over time. In numerous studies a greater reliability was found for the pen-type fluorescence device compared to visual caries detection [49–51]. Among the camera-based systems, there are devices that visualise fluorescence qualitatively (e.g., Sopro, Acteon, La Ciotat, France), and other devices that have a quantitative output (e.g., Vistacam iX, Dürr, Bietigheim-Bissingen, Germany). There is a heterogeneous body of evidence derived from clinical studies [52]. While certain authors found that use of fluorescence devices increased the diagnostic accuracy [53–58], others found that it did not add to clinical decision making compared to visual inspection and radiography [59, 60], at least not in primary teeth [61].

Like radiography, fluorescence-based methods cannot detect surface cavitation, but they may add to the information on lesion depth. This might be helpful especially when radiography cannot be applied (repeatedly in children or pregnant women, anxious patients etc.) and visually dubious or conspicuous sites are present. One problem with fluorescence is the sensitivity to false positive results because of the inherent autofluorescence of biofilm, calculus, some prophylaxis pastes [62] or some filling materials [63, 64]. Fluorescence-based methods therefore require professional tooth cleaning before application, and – within the limits outlined above – they are most notably suitable for adjunct primary caries detection. Although thresholds have been published indicating the presence of enamel caries or dentine caries, the use of fluorescence-based methods is usually advocated as a “second opinion” device [46, 47], and treatment decisions should not be based on fluorescence measurements alone.