RESUMEN
UNLABELLED: BACKGROUND DATA AND OBJECTIVES: Nd:YAG laser radiation has been applied in treatment of dentine hypersensitivity; dentine melt created after irradiation on a tooth surface can occlude open dentinal tubules. Different conditions (energy of pulses, number of successive irradiations, and type of dye agent) have been reported in the literature. In our study, different conditions are compared and the most suitable ones are suggested. METHODS: One hundred nine dentine samples prepared from extracted human third molars in the form of 2- or 3-mm thick discs and facets from an outer convex surface of a root were irradiated by pulses with duration 0.3 ms and beam diameter 0.3 or 0.6 mm. The laser repetition rate was 15 Hz. Energies per pulse have been changed from 20 mJ to 250 mJ (the corresponding energy densities rho are 22 and 275 J/cm(2) for the beam diameter of 0.3 mm). Dyes including tartrazine, carmine indigo, erythrosin, and methylene blue have been used to cover dentine surfaces and to increase absorption of laser radiation. Irradiated dentine surfaces have been investigated using scanning electron microscopy. RESULTS: Sealing of open dentinal tubules can be accomplished even without dyes, provided that a sufficiently intense laser radiation level is used. To avoid damage to the dentine's surface the use of dyes is necessary. Erythrosin has been found to be the best agent, and closing of dentinal tubules occurred after four doses of irradiation with 30-mJ pulses with a beam diameter of 0.6 mm (energy density rho = 8.25 J/cm(2), total energy density rho(T) = 33 J/cm(2)). The upper limit has been reached using four doses of irradiation by 90-mJ pulses with a beam diameter of 0.3 mm (rho = 99 J/cm(2), rho(T) = 396 J/cm(2)). CONCLUSIONS: Occluding dentinal tubules can safely and effectively be accomplished using pulsed Nd:YAG laser radiation provided that the dentine surface is covered with erythrosin solution.
Asunto(s)
Permeabilidad de la Dentina/efectos de la radiación , Sensibilidad de la Dentina/prevención & control , Dentina/efectos de la radiación , Terapia por Láser , Dentina/ultraestructura , Eritrosina/administración & dosificación , Eritrosina/uso terapéutico , Colorantes Fluorescentes/administración & dosificación , Colorantes Fluorescentes/uso terapéutico , Humanos , Técnicas In Vitro , Microscopía Electrónica de Rastreo , NeodimioRESUMEN
Dentin of human teeth is a vital hydrated tissue. It is strongly sensitive to dehydration and drying that are commonly used in preparation of samples for scanning electron microscopy. Experience in examination of dentine surfaces of extracted human third molars using contact mode atomic force microscopy under moist conditions is described. The examined dentine surfaces are modified by laser radiation produced by a pulsed Nd:YAG laser that leads to sealing of open dentinal tubules under suitable conditions that are reached after covering dentine surfaces with dye agents. Out of four investigated dye agents erythrosin solution in water has been found the most suitable and the lower and upper limits of pulse energies for sealing of dentinal tubules have been set.
Asunto(s)
Grabado Dental/métodos , Dentina/efectos de la radiación , Dentina/ultraestructura , Terapia por Láser/métodos , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Dentina/efectos de los fármacos , Permeabilidad de la Dentina , Eritrosina/farmacología , Humanos , Terapia por Láser/instrumentación , Propiedades de SuperficieRESUMEN
Atomic force microscopy (AFM) as one the technique of Scanning Probe Microscopy is useful for imaging of surface structure. This method can yield three-dimensional high-resolution topographic images of sample surfaces by using a scanning technique for conductors and insulators on atomic scale. It is based upon mapping of atomic-forces on a surface of an investigated sample. The method is useful not only in physics and chemistry; it can be also applied in biological fields. Special construction of AFM scanner enables to follow biological samples in liquid environments. Artifacts caused by dehydration of samples are removed this way. Dentin of human teeth is a vital hydrated tissue. It is strongly sensitive to dehydration and drying that are commonly used in preparation of samples in examinations by Scanning Electron Microscopy (SEM). We describe our experience in examination of dentin surfaces of extracted human third molars using contact method of AFM under moist conditions.