DETECTION OF DENTAL DECAY AND ITS EXTENT USING AC-IMPEDANCE SPECTROSCOPY

Dental caries (decay), the most prevalent of diseases, represents a he alth problem of immense proportions(1). It principally affects posteri or (back) teeth on occlusal (biting) and approximal (adjacent contacti ng) surfaces. Caries starts as a subsurface demineralization of enamel , may progress to the underlying dentine and, eventually, to cavitatio n of the surface. Accurate diagnosis before cavitation would permit ta rgeted preventive treatment, thereby significantly improving dental he alth and reducing the need for expensive drilling and filling. Inacces sibility of caries initiation sites and recent changes in lesion morph ology contribute to the relatively poor accuracy of conventional diagn ostic methods(2). Among alternative techniques, measurements of electr ical resistance(3-5) have shown the most promise. Here we described ne w experimental technique that demonstrates an outstanding 100% correla tion between a.c. impedance measurements of whole teeth and the actual extent of approximal caries in vitro. Only relatively minor modificat ions should be required to transfer the technique to in vivo applicati ons.