Laser light transmission in teeth: a study of the patterns in different species

Aim The aim of this study was to investigate the pattern of light transmiss ion through teeth of different species and to examine laser light propagati on within enamel from various animal sources. Methodology Sectioned teeth from five species pig, horse, sheep, cat and ra t - were evaluated. Samples were illuminated individually by a helium-neon laser light from the buccal surface using a probe 0.5 mm in diameter placed at varying angles between 60 and 120 degrees C. The pattern of light trans mission was observed macroscopically. Further evaluation of laser pulpal or igin. light transmission in enamel was achieved using confocal microscopy. Results In each species, light was transmitted through the tooth to the pul p, but in the cat and the rat, light was also transmitted to the far side o f the tooth. Despite the different patterns of enamel in the species, light was transmitted through enamel to dentine. Conclusion Light from a laser Doppler probe appeared to reach the dental pu lp in all the species; however, in the mammals with smaller teeth, light ma y also have been able to reach the periodontium and thus the reflected sign al may not be entirely of dentine.