Abstract
The authors. basic experiment has revealed the interesting phenomenon that the optical and the thermal reaction of carious dental structures to the Nd: YAG laser beam is essentially different from that of normal dental structures depending on their optical charcteristics. The result of this experiment hopefuly suggested the possibility of the dental caries detection applying the photo-thermal reaction of teeth against the laser irradiation, and this study was designed to realize this suggestion.
The basic method of this experiment was as follows: When a tooth crown surface was exposed to a very weak pulsed Nd-YAG laser shot, the surface temperature and the transmission of the laser in the tooth were measured with an infrared thermometer and the special thermocouples. These data were recorded simultaneously on a multi pen recorder with a pen offset compensator function. Comparative analysis on the data of carious teeth with that of normal teeth has revealed the dramatic result that carious teeth were clearly differentiated from normal teeth, and the affected area could also be observed with real-time thermography. This method is superior to conventional roentgenographic diagnosis for dental caries because of its complete safety and its high sensitivity for a fine primary caries that can not be detected by radiographic examination and it may lead to an exciting new dental caries examination.
