Optimal Wavelengths for Multispectral Short Wavelength Infrared Transillumination and Reflectance Imaging for Caries...

Area of Science:

• Biophotonics
• Dental Imaging Technology

Background:

• Dental caries detection remains a challenge, necessitating advanced imaging techniques.
• Short Wavelength Infrared (SWIR) imaging offers potential for non-invasive caries visualization.

Purpose of the Study:

• To determine optimal SWIR wavelengths for multispectral transillumination and reflectance imaging of dental caries.
• To evaluate SWIR-OTR (Occlusal Transillumination and Reflectance) performance on proximal and occlusal surfaces.

Main Methods:

• In vitro analysis of 76 caries lesions using SWIR transillumination (1050, 1300, 1550 nm) and reflectance (1058, 1300, 1450, 1675 nm).
• Utilized a custom handheld probe for simultaneous SWIR-OTR image acquisition.
• Radiography and microcomputed tomography (μCT) used for lesion verification.

Main Results:

• Highest contrast for reflectance imaging was observed at 1450 nm and 1675 nm.
• Highest contrast for transillumination imaging was observed at 1050 nm and 1300 nm.
• Wavelengths >1400 nm significantly improved reflectance contrast.

Conclusions:

• Optimal SWIR wavelengths for caries detection are 1000-1300 nm for transillumination and >1400 nm for reflectance.
• Higher reflectance contrast is achieved with wavelengths beyond 1400 nm.
• Transillumination beyond 1300 nm is less effective due to water absorption causing contrast inversion.