RADIOGRAPHIC CONTRAST TO DIFFERENTIATE CAVITATED FROM NON-CAVITATED DENTAL CARIES

DESCRIPTION (provided by applicant): This project relates directly to the PHS 2011-2, Omnibus Solicitation for SBIR/STTR Grant Application page NIDCR 110: Development of instrumentation for early caries detection and comparison studies on specificity andselectivity with respect to current clinical practice. The proposed test is intended to enable dentists to differentiate between cavitated and non-cavitated tooth decay in the areas where teeth are in contact (interproximal surfaces). In these areas, dentists cannot visually inspect for caries, and currently bitewing X- rays (BWs) only correctly detect the presence of enamel decay 15-25% of the time. This low sensitivity can lead to late treatment resulting in unnecessarily large fillings crowns, pain, root canals, and possible later loss of teeth. The proposed method will use a liquid radiographic contrast agent, which will be applied in the interproximal regions immediately before dentists perform routine BW X-rays. A tooth with a cavity (hole) will appear opaque on the radiograph whereas a healthy or non-cavitated decay patch will not. No increase in radiation, purchase of extra equipment or extensive training are required. It is anticipated the final product will be inexpensive to use. The lack of extra radiation, capital expenditure or major training should reduce the barriers for dentists to adopt the test which is anticipated to increase the overall diagnostic accuracy of BWs from about 58% to 90%. Hypothesis: Use of radiographic contrast will increase detection of early interproximal cavitated decay from a sensitivity of 15-25% to 90% and specificity will remain at about 90%. Method: 41 subjects between 14-40 years who require a posterior tooth extraction will be recruited. From pre- existing screening BWs potential subjects will be identified with at least one interproximal radiolucency in the tooth for extraction or on the adjacent teeth surfaces. Tooth surfaces will be cleaned with air-water spray and floss. Two BWs will be exposed (control). Teeth will be dried with air. Contrast liquid will be applied in the interproximal spaces and excess removed. Two more BWs will be exposed (test). The subject will have the diseased tooth removed. The interproximal surfaces of the adjacent teeth and extractedtooth will be examined directly by visual inspection and gently with a sharp probe. Any cavities detected will be photographed and the size of the opening recorded. Three dentists will identify cavities from the blinded control and test BWs in a randomized order. 10% will be reread. The accuracy of non-contrast to contrast BWs will be compared to direct inspection. PUBLIC HEALTH RELEVANCE: This project will test the use of radiographic contrast with existing X-ray examinations to increase the accuracy for detecting early decay cavities (holes) between teeth in the interproximal areas. Existing methods (direct visual inspection, use of sharp explorers, and conventional bitewing radiographs) have a combined accuracy of only 58% - the proposed methodis anticipated to increase accuracy to 90%. This will assist detection and monitoring of decay, likely reducing the late caries diagnosis that can cause large fillings, crowns, root canals and/or tooth loss, and also reducing unnecessary filling by betterenabling dentists to track the progression of decay and detect if it has stopped.