The Sensitivity and Specificity of Bitewing Radiography

Objective: The objective of this cross-sectional study was to determine the sensitivity and specificity of bitewing radiography for diagnosis of simulated recurrent caries in teeth with class II amalgam and composite restorations in vitro. Materials & Method: the study was performed on 38 extracted posterior human teeth (26 premolars and 12 molars) with sound surfaces of both jaws. Standard proximal boxes were made with fissure dental bur in all approximal surfaces of the teeth. Lesions were created in half of the proximal boxes using round dental bur of 0.05 diameters at buccogingival margins. Defects were filled with sticky wax and preparations were restored with composite or amalgam randomly, providing 78 filled approximal surfaces to detect 38 secondary caries. 21 bitewing radiographs of teeth blocks were taken with soft tissue substitute phantom under standard conditions. The presence or absence of approximal carious lesions was evaluated by eight observers according to a five- point confidence scale. Sensitivity, specificity, positive and negative predictive value of the bitewing technique to detect all secondary caries and for each restoration material was calculated separately and observer responses were assessed with spearman s rho test. Results: The sensitivity values for bitewing radiography, composite and amalgam restorations were 0.41, 0.5 and 0.32 respectively, while the specificity values were 0.74, 0.7 and 0.77 respectively. The difference in detecting secondary approximal carious lesions between the restorative materials was not statistically significant. (p=0.2>0.05) Conclusion: This study suggests that there is no significant difference between amalgam and composite restorations in detecting small secondary caries.The sensitivity and specificity of bitewing radiography decreases when the secondary caries are very small (less than 1 mm in diameter),however this technique plays an important role in detecting very small secondary carious lesions under the restorations.