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Diagnostic ultrasound for the imaging of teeth: a comparison between experimental results and simulation models

Diagnostic ultrasound is being applied to teeth in order to detect cavities, decay, fractures and even early indication of abscesses. Ultrasonic waves are particularly sensitive to tight cracks and interface conditions between layers-dental features often difficult to interpret from X-ray images. Most importantly, due to its nonionizing nature, ultrasound acquires a potential advantage over conventional X-ray imaging. When ultrasonic waves are used at low intensity levels, they do not cause any health risks. This paper presents the results of laboratory experiments conducted on extracted human second and third molars using a low-intensity, high-frequency setup. Three cases have been examined: an intact tooth, a tooth containing an amalgam restoration, and a tooth containing a machine-side-drilled hole in order to mimic a cavity at the enamel-dentin interface. However, due to this paper length limitation only the first two cases are presented. A- and C-scans have been acquired in this study. Initial analysis of these results reveals similarities to those produced earlier by finite element and transmission-line methods insofar the identification of the different layers in the host teeth, and that such results could be used to realize the design of appropriate transducers and equipment for dentistry applications.