Comparison of Diagnostic Ability of Conventional Film and Storage Phosphor Plate in Detecting Proximal Caries with Direct Measurements by Stereomicroscope: A Diagnostic Test Evaluation.

Background: Radiography plays an important role in detection of interproximal caries. The aim of study is to compare diagnostic ability of conventional film and photostimulable phosphor (PSP) with direct measurement using stereomicroscope in detecting proximal caries.

Methodology: In this descriptive study - diagnostic test evaluation, 200 proximal surfaces of 100 extracted human posterior teeth were radiographed with dental X-ray unit. Evaluation of conventional and digital radiographs was performed twice by three observers. Carious lesions were classified based on a four-point scale (R0-R3) suggested by Abesi . Weighted kappa coefficients were calculated to assess intra- and interobserver agreement for each image set. Indices of diagnostic ability calculation were based on the first readings of the three observers. The scores were compared with the histological gold standard using receiver operating characteristic (ROC) analysis to evaluate diagnostic ability.

Results: Intraobserver kappa coefficients calculated for each observer for each method of detecting caries ranged from 0.914 to 0.956. Interobserver kappa coefficients for each image set ranged from 0.8788 to 0.9583. The sensitivity and specificity of film for the first observer were 77.5% and 78.3% and for PSP were 77.5% and 80%, respectively. ROC analysis revealed that there were no statistically significant results ( > 0.05) between Az values for the two detection methods.

Conclusion: PSP plate should be preferred over conventional films in detecting cavitated proximal caries. Further studies with more noncavitated proximal surfaces are required to conclusively establish the diagnostic ability of PSP over conventional film.