Photothermal Radiometry and Modulated Luminescence: The Canary System

The Canary System is a nonionizing caries detection procedure to aid detecting, quantifying, monitoring, and recording changes in structure of tooth tissues. It investigates the status of the crystal structure of the tooth tissue by using Photothermal Radiometry and Luminescence (PTR-LUM) technology that measures converted heat (PTR) and light (luminescence or LUM) signatures emitted from the tooth surface when a pulsed laser is shone on the tooth. A Canary Number, created from an algorithm combining the four signals measured by the system, is directly linked to the status of the tooth crystal structure. As an aid to the conventional visual and radiographic assessment of the teeth, PTR-LUM can be used to perform the following functions as a second step in the lesion detection and monitoring process: (1) investigate suspect sites for “hidden caries” in pits/fissures, proximal surfaces, underneath and around restorations, beneath sealants, and clear resin infiltrants; (2) obtain the estimate of the severity of the caries lesion in terms of depth and breadth, as Canary Number, to facilitate treatment decision; (3) measure and record the initial quantitative value of the demineralization, as Canary Number; (4) enable quantitative monitoring of changes in lesion activities (progress or remineralization) over time during nonoperative management; (5) help detect and measures cracks and erosion in teeth; and (6) use the integrated intra-oral camera to capture the image of the examined surface/lesion for future reference with Canary Numbers on the images. Data is stored on The Canary Cloud for ongoing monitoring and analysis. Full description of The Canary System and the technique of using it in practice for clinical detection and monitoring of caries are given in this chapter.