The detection of simulated periapical lesions in human dry mandibles with cone-beam computed tomography: a dose reduction study.

AIM: To assess in an ex vivo model the accuracy of detection of simulated periapical lesions using two cone-beam computed tomography (CBCT) dose modes and periapical radiography. METHODOLOGY: Small and large artificial periapical lesions were created with burs at the base of the socket of eleven mandibular molars, in seven human dry mandibles. Digital periapical radiographs, 360 degrees and 180 degrees rotations CBCT scans with standard dose and dose reduction (DR) modes were obtained before and after periapical lesions were prepared. Six blinded examiners scored the presence/absence of lesions. Inter- and intra-examiner reliability were determined. Sensitivity, specificity, positive predictive values and negative predictive values and receiver operating characteristic (ROC) area under the curve (overall accuracy) were determined for each modality. RESULTS: The mean sensitivity and specificity of both CBCT rotations with dose reduction mode were higher compared to that of standard dose CBCT scans. The ROC Az mean values for periapical radiographs, 360 degrees scan with standard dose and dose reduction and 180 degrees scans with standard dose and dose reduction were 0.62, 0.94, 0.95, 0.95 and 0.97, respectively. No significant difference in the diagnostic accuracy of CBCT scans taken with standard and dose reduction modes, whilst their accuracy was significantly higher than periapical radiographs. CONCLUSIONS: Using dose reduction with 360 degrees and 180 degrees CBCT scans demonstrated good diagnostic accuracy in the detection of simulated periapical lesions whilst reducing the radiation dose by 54% and 51%, respectively, compared to conventional settings. Clinical evaluation is now needed to determine whether this is applicable to patients.