In this paper, using light-emitting diodes operating in the near ultraviolet spectral regions, fluorescence imaging and spectroscopy techniques were incorporated into studying fluorescence properties of healthy and cariousv human dentine samples. | TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 18, SOÁ K4- 2015 Application of fluorescence technique in studying dental caries Pham Thi Hai Mien Tran Van Tien Huynh Quang Linh Ho Chi Minh city University of Technology, VNU-HCM (Manuscript Received on August 01st, 2015, Manuscript Revised August 27th, 2015) ABSTRACT: The aim of the present study was to investigate the fluorescence properties of sound teeth and teeth with different types of lesions. Using light-emitting diodes operating in the near ultraviolet (UVA) spectral regions for excitation, the obtained fluorescence images and spectra of carious teeth were different from sound teeth spectra due to the presence of bacteria Streptococcus mutans producing metabolites called porphyrins. The sound teeth showed the blue fluorescence with broad emission spectra from 410 nm to 650 nm (maxima at 450 nm, 500 nm and 520 nm), while the carious regions illuminated the red light with three new peaks at 625 nm, 650 nm and 690 nm. The intensity of the red fluorescent signal depends on the density of the bacteria. Based on the red fluorescence emitted by porphyrins, not only the surface lesions but also the caries hiding under the enamel layer can be detected by UVA exciting. These results provide the ability to apply fluorescence technique in the development of an early dental diagnostic tool with a number of advantages such as safety, mobility, low cost and rapid test time. Key words: fluorescence, dental caries, early diagnosis. 1. INTRODUCTION Dental caries is one of the most popular diseases of humans worldwide. In Vietnam, according to statistics of Vietnam Odonto – Stomatology Association, dental caries affects 75% of the population. The detection of carious lesions has been primarily a visual process, based principally on clinical-tactile inspection and radiographic examination [1]. Visual-tactile examination has been widely used in dental clinics for detecting carious lesions on all surfaces. A major shortcoming of .
