Ultra-Violet and Infrared Digital Photography of Dental Materials

The sensitivity of digital cameras to ultraviolet (UV) and near-infrared (NIR) is widely recognized. However, most cameras have an NIR filter over the charged-coupled device (CCD) for protection and lenses also have a coating that diminishes UV interference. Recently a new digital camera utilizes innovative CCD technology to see light from the UV, visible and IR portion of the spectrum. Previously, such cameras are mainly in the hands of professional photographers and a small niche in the forensic, cosmetic and personal skin care industry. Objectives: The purpose of this study was to evaluate the application of such new technology in the dental field. Methods: A forensic camera (Fuji, IS Pro) which can detect light from the spectrum of approximately 380 nm-1000 nm was used with an AF-S VR Micro-Nikkor 105 mm f/2.8G IF-ED lens and a series of UV and IR filters. The filters included Digital Filter PECA 900 (wratten filter #18A), 902 (wratten filter #70), 904 (wratten filter #87), 906 (wratten filter #87A), 908 (wratten filter #87B), 910 (wratten filter #87C), 912 (wratten filter #88A), 914 (wratten filter #89B) and 916 (IR & UV blocking filter for visible light). Three different materials - an extracted tooth, traditional feldspathic porcelain (VMK) and a hybrid composite (Point 4, Kerr) were photographed under various light sources which included incandescent light, infrared 830 nm, UVA 320-400 nm and a pair of Ultraviolet Modified Vivitar 285HV Flashes. Results: Examples as shown in Figure 1. Conclusions: IR image capturing is easier and requires less specialize equipment than UV. The protective coating on Micro-Nikkor lens reduced the UV signal and dictated longer exposure time. Focus shifting for UV is also a problem. The camera and the associated software allows for immediate review of image. The camera offer good potential in detecting features beyond the visible range.