ACCURACY OF LINEAR MEASUREMENTS OF THIN CORTICAL BONE ON EXPERIMENTAL SURGICAL DEFECTS IN CBCT IMAGES WITH DIFFERENT EXPOSURE PROTOCOLS: AN IN VITRO STUDY

BACKGROUND Diagnostic imaging is mandatory for the assessment of osseous defects in the jaws. Traditional imaging has offered much over the decades in the evaluation of these defects but is limited because of its 2D nature. The introduction of cone beam computed tomography (CBCT), a 3D radiographic technique with interactivity, high resolution, and high accuracy, has provided solutions in the evaluation of such lesions OBJECTIVE(S) The purpose of this in vitro investigation was to evaluate the accuracy of representation of experimental surgical defects with CBCT using different exposure parameters. Moreover, the study aims to assess the effect of different exposure protocols on the accuracy of representation of experimental surgical defects. STUDY DESIGN Surgical defects were prepared in 8 pig jaw mandibular segments. The thickness of the cortical bone around the defects was measured in predetermined areas using the measurement tools of the CBCT software. In total, 48 locations were measured for bone thickness. The pig jaw specimens were imaged with 6 different exposure protocols created by altering voxel size, kilovoltage peak, and milliamperage. The measurements were made by 2 experienced examiners using the original scanner software. The evaluation of the surgical defects was completed in 4 rating sessions; a fifth rating session was included for intraobserver reliability assessment. RESULTS There were statistically significant differences in the estimation of cortical bone thickness around experimental surgical defects in certain sites among the variable exposure protocols; however, the differences were too small to be clinically important. The intra- and interobserver reliability values were very high, confirming the diagnostic value of CBCT in different exposure settings. DISCUSSION/CONCLUSIONS The accuracy of lineal cortical bone measurements with CBCT was high, even in lower dose protocols, a finding that is in line with the ALADA (as low as diagnostically acceptable) concept.