Caries diagnosis by observation of Autofluorecence of dental caries using a Laser Fluorescence System

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 16591908
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Conservative dentistry
• Research Institution: Niigata University
• Principal Investigator: OKAMOTO Akira Niigata University, Medical and Dental Hospital, Lecturer, 医歯学総合病院, 講師 (10143786)
• Co-Investigator(Kenkyū-buntansha): KODAMA Linlin Niigata University, Institute of Medicine and Dentistry, Assistant, 医歯学系, 助手 (10272824)
• Project Period (FY): 2004 – 2006
• Keywords: autofluorescence / dental caries / Streptococcus mutans / 走査型共焦点レーザ顕微鏡 / 口腔内細菌

Research Abstract

The purpose of this study was to examine whether Streptococcus mutans (S.mutans) is implicated in the generation of autofluorescence (AF) detected in carious lesions. Enamel surfaces and dentin cavities of extracted human teeth were subjected to artificial caries generation by exposing either to a culture medium containing S. mutans or to a lactic acid buffer. AF from the lesions were detected with confocal laser scanning microscopy or fluorescence microscopy at various excitation wavelengths. Results demonstrated that S. mutans-induced enamel and dentin lesions exhibited increased AF in the red and green spectral regions, with the signal stronger in the red region. In the blue region, however, AF signals in the corresponding area was below the background level. Significantly weaker or virtually no AF intensification was detected in lactic acid-demineralized lesions at any excitation wavelengths. Neither bacterial cells nor culture media generated any AF. These results indicate that, although the presence of S. mutans may be a prerequisite for the emission of AF signals from carious lesions, certain interaction of S. mutans with exposed tooth matrix elements may also be required for generation and/or unmasking of fluorophore(s).