When dentists notice teeth with tiny “white-spot” lesions or areas of mildly decalcified enamel, they usually ask themselves the obvious questions: How deep is the lesion? Will it progress to full-blown decay, or will the lesion remineralize on its own? The problem is there are no obvious answers. Currently available dental imaging technologies cannot provide high enough resolution to answer any of these questions, and this shortcoming has led to attempts to adapt powerful industrial imaging tools to the everyday needs of the dentistís office. Among the technologies now under development is optical coherence tomography, or OCT. A product of the telecommunications industry, OCT measures the optical reflection of low coherence light sources focused on the tooth enamel. A team of National Institute of Dental and Craniofacial Research grantees has published a series of papers over the past few years on OCT imaging of tooth enamel, and in the March 2006 issue of the journal Caries Research, they provide new data on a variant technique called polarization-sensitive OCT (PS-OCT). This technique records spatially resolved changes in polarized light backscatter from the tooth enamel. Studying artificial caries on the toothís occlusal surfaces, the scientists show that PS-OCT has a number of advantages over conventional OCT. One advantage is an increased contrast to differentiate between areas of normal and demineralized enamel; another is its more straightforward approach to quantifying carious lesions.
(Source: National Institute of Dental and Craniofacial Research Web site, Science News in Brief, accessed March 20, 2006)
