THE INFLUENCE OF MINERAL LOSS ON THE AUTOFLUORESCENT BEHAVIOR OF IN-VITRO DEMINERALIZED DENTIN

The aim of this study is to investigate the influence of demineralisat ion on the fluorescent properties of dentine. The fluorescence emissio n at 529 nm due to 515 nm excitation of in vitro demineralised lesions was determined with a micro-Raman spectroscope as a function of locat ion. Results were compared with the mineral loss profiles of the same lesions measured by microradiography. The root surfaces of 6 in vitro demineralised human third molars (lactic acid CMC gel, pH 5; six group s: 0, 4, 7, 14, 18 and 21 days) were used in the experiment. Thin slic es of +/-130 mu m were cut perpendicular to the tooth axis. The fluore scence scans corresponded to mineral loss profiles. Confocal microscop e images showed increasing fluorescence with increasing mineral loss. From these results it is concluded that this mineral loss causes an in crease in auto-fluorescence by a factor of at least 10, therefore the chromophore causing this green fluorescence must be organic in nature. De-quenching or modification of this fluorophore due to the demineral isation process is probably the cause for the increase of the green fl uorescence.