2017 Volume 60 Issue 5 Pages 245-254
Purpose: To compare the pathological structure with the recognition accuracy of caries-infected dentin using blue light with a wavelength of approximately 405 nm and evaluate it in relation to the qualitative and quantitative localization of Streptococcus mutans.
Methods: Five molars extracted from different people with dentin caries were thinly sliced to obtain sections containing the caries region, and the boundary between sound dentin and caries-infected dentin identified by red fluorescence induced by blue light was compared with the pathological structure identified by transmitted light under a stereoscopic microscope. Furthermore, by using immunostaining via anti-WapA immunoglobulin G, the boundaries between sound dentin and caries-infected dentin were observed.
Results: The boundary between sound dentin and caries-infected dentin identified with blue light was confirmed in a mixed layer of the pioneer bacteria layer and the turbid layer. The boundary between these layers was distinctly identified by immunostaining and was roughly in agreement with the boundary indicated by blue light. A real-time polymerase chain reaction method revealed that the number of S. mutans in the pioneer bacteria layer was significantly higher (p<0.05) than that in the turbid layer. The red fluorescence induced by blue light with a wavelength of approximately 405 nm characterized a fluorescence spectrum with peaks at around 620 and 680 nm.
Conclusion: This study demonstrated that blue light at a wavelength of approximately 405 nm could accurately detect S. mutans in caries-infected dentin.
