However, these methods usually differentiate dental caries or dental composites from healthy dental tissues by comparing the data obtained from those two different parts. In contrast, caries detection methods based on laser-induced breakdown spectroscopy (LIBS) enable absolute and quantitative analysis of elements contained in teeth. This method for elemental analysis is based on the spectral analysis of plasma emissions generated by the irradiation of high-powered laser pulses.13 LIBS is different from other element analysis methods such as inductively coupled argon plasma-atomic emission spectroscopy (ICP-AES),14 and LIBS needs no pretreatment of samples. Thus, it can analyze very small amounts in real time. Many groups have applied LIBS methods to biomedical applications because they can be used in vivo and are less invasive for diagnosis in a variety of soft and hard tissues.15–18 In dental applications, many groups have proposed LIBS methods for caries detection that analyze element contents in teeth,19,20 and some groups have shown results from in vivo studies.21 Enamel, which is the outermost layer of the tooth, is a biochemical composite whose components are made up of 96% inorganic materials [including minerals, hydroxyapatites (), and a small amount of various metals], 3% water, and 1% organics such as protein and fat. In the decayed parts of teeth, the amounts of these components vary in accordance with the degree of caries progress. Therefore, by analyzing these elements, one can detect caries and execute an accurate diagnosis of the decaying stages. These methods usually detect relatively strong emission lines of elements such as Ca and P in hydroxyapatite and C, Mg, Cu, and Sr in visible wavelengths. However, the sensitivity and accuracy were insufficient for detecting early caries.