Fluorescent diagnostics using aluminum phthalocyanine nanoparticles as a detection method for enamel microcracks

Abstract

Early diagnosis of caries and enamel microcracks is of great importance for the prevention of the destruction of healthy tooth enamel. It was reported that aluminum phthalocyanine in the form of nanoparticles (nAlPc) can be used for fluorescent diagnostics of tooth enamel microcracks.A model compound with the nAlPc colloid and Protelan MST-35 were prepared for the development of the method of laser-induced fluorescent diagnostics (FD). Two groups of human teeth were used to research the interaction between the nAlPc colloid and the model compound for the detection of microcracks and the areas of accumulation of pathogenic microflora on the enamel surface. A Student’s two-sample unequal variances t-test was used to check whether the means of the coefficient of diagnostics contrast (kdc) between two groups of samples was significantly different. Experimental studies were conducted using a laser electronic spectro-analyser and a fluorescence video imaging system.The results of the studies of the nAlPc colloid interaction with the surface enamel of the tooth enamel ex vivo in the first group showed that in 3 min a low-intensity nAlPc fluorescence was observed. This was due to a slight activation of the surface molecules of nAlPc by a pathogenic microflora. Measurements of the interaction of the model compound (nAlPc colloid with the Protelan MST-35 and supplementary components) with the tooth enamel has shown that the high-intensity AlPc molecule fluorescence appears in the enamel microcracks 3 min after application. The high intensity of the fluorescence is accounted for by a preliminary activation of nAlPc by the surfactant as they meet pathogenic microflora. Statistical analysis of the results revealed a statistically significant difference between the kdc of the studied groups (α = 0.05).It has been concluded that the developed method of laser-induced FD of tooth enamel makes it possible to detect the hidden microcracks on the enamel surface and the hidden accumulation areas of the pathogenic microflora using the model compound.