Two- and three-dimensional imaging modalities for the detection of caries.A comparison between film, digital radiography and tuned aperture computedtomography (TACT (TM))

Objectives: To compare the diagnostic performance provided by two- (film an d digital radiography) and three-dimensional imaging modalities (TACT slice s and TACT pseudoholograms) in the detection of primary caries. Methods: Forty-two extracted human posterior teeth were mounted and imaged with conventional film and direct digital radiography. Free-hand positionin g of a dental X-ray source was used for all exposures. From the digital ima ges, iteratively restored TACT slices and TACT pseudoholograms were generat ed. Film images were viewed on a viewbox, Digital format images were viewed on a high-resolution monitor. Eight observers used a five-point scale to s core the presence or absence of occlusal and proximal caries using the four Image modalities. Observers' assessments were compared with the histologic al examination of tooth sections. Possible differences in ROG curve areas a mong image modalities, observers, and surfaces were assessed by ANOVA. Intr a- and interobserver reliability as indicated by intraclass correlation was also calculated. Results: There were no statistically significant differences between the di agnostic performances of film, digital radiography, TACT slices and TACT ps eudoholograms in the detection of caries (P = 0.310). Intraclass correlatio n indicated the highest concordance both within and between observers when film was used for the evaluation. Conclusions: Under the experimental conditions of this study, three-dimensi onal TACT images did not improve caries detection over him or digital radio graphy. Further research should investigate the effects of imaging variable s on TACT's diagnostic efficacy.