Ultraviolet Illumination as an Adjunctive Aid in Dental Inspection*

Abstract

Tooth-colored resin fillings have become increasingly popular as restorative materials. Their presence in the dentition presents a challenge to the clinician and the forensic odontologist, as detection of the fillings can be difficult both visually and radiographically. As they necessarily form part of the unique dentition of an individual, recognition of the resins is important for forensic identification. Alternative light sources have been used with success in various fields of forensic science. In recent years small LED flashlights emitting at specific wavelengths in the ultraviolet light (UV) range have been developed. Their low cost, small size, and ready availability makes their use practical in both forensic dental inspection and clinical settings. UV inspection is of interest because enamel, dentin and dental materials all have differing fluorescent properties when illuminated by UV light. It was one goal of this research to quantitatively assess the fluorescence properties of modern restorative resins in order to predict their behavior during inspection using UV illumination. The second goal was to demonstrate practical use of UV in dental inspection with examples of how different materials fluoresce. Quantitative measurements were obtained for optical emission wavelength and intensity for 15 modern resins using a spectrophotometer. Results indicated that resin brands fluoresce at different wavelengths and with varying intensities. Practical use and comparison of the flashlights revealed that the most useful excitation wavelengths for resin detection were in the UVA range (365 and 380 nm). Porcelain restorations and composite resin fillings exhibited different responses to these two wavelengths and thus use of both is recommended for forensic dental inspection.

Forensic applications: Fluorescence properties of tooth-coloured restorative materials using a fluorescence DSLR camera

“…This aligns with results of previous studies analyzing composite resin materials [11,23] which showed that optimal excitation wavelengths for the composite resin materials used in their studies were in the range of 365 -380nm and 398 ± 5 nm, respectively. Fluorescence properties of materials in the mouth can be affected by the ingress of moisture as well as by degradation over time.…”

“…Ultraviolet light elicits green fluorescence while blue light elicits yellow fluorescence from healthy tooth enamel. Alterations in these patterns can be used to detect missing or decalcified tooth structure (in the case of dental caries), as well as the presence of a restorative material [11][12][13]. Human enamel exhibits three distinct luminescence peaks in the regions of 350-360, 405-410 and 440-450nm [14,15].…”

“…Light in the ultraviolet and visible violet range has been found useful for detection of resin restorations [4,11]. However historically, light sources used for eliciting such fluorescence were high-intensity fluorescent light sources and lasers.…”

Surfing the spectrum – what is on the horizon?

“…UV digital viewers and camcorders utilise 396nm UV-rays and can give resolution of 640 x 480 pixels. The UV-rays may be reflected or absorbed in surface layers and aid forensic medicine with detection of bitemarks and bruises 50 and the fluorescence properties identify dental materials 51 . Basal Cell Carcinomas can be recognised as dark patches and oral Squamous Cell Carcinoma may be discerned 52 .…”

Forensic odontology, part 1. Dental identification

“…8 However, it has been documented that these materials lose their organic components and fluorescence properties after exposure to temperatures above 300°C; 9 consequently, fluorescence may not reveal restorations in cases of high temperature incineration.…”