DIAGNOSTIC VALUE OF TWO MODELS OF CONE-BEAM COMPUTED TOMOGRAPHY IN EVALUATION OF SIMULATED EXTERNAL ROOT RESORPTION: ANINVITRO STUDY

Voxel resolution and field of view of cone-beam computed tomography affect its diagnostic capability. The aim of this study was to compare two modes of CBCT (Sirona Dental Systems Inc, Bensheim, Germany) and (Sirona Dental Systems GmbH, Bensheim, Germany). Thirty small(0.5 mm in depth and 0.5 mmin diameter) and thirty large(1 mm in depth and 1 mmin diameter) cavities were simulated on the buccal surface of teeth at three levels in a random manner: 10 teeth with small cavities in the cervical and large cavities in the apical, 10 teeth with small cavities in the middle and large cavities in the cervical, 10 teeth with small cavities in the apical and large cavities in the middle thirds. The root was inserted in the socket, and CBCT scans were taken in both modes. The images were analyzed by two observers to diagnose the presence and the size of the cavity. The sensitivity and specificity of simulated cavities were analyzed. There was a significant difference between the two imaging modes in diagnosing the small cavities (P=0.02).The sensitivity of the “Inc mode ” in detecting the small cavities was lower than that of the “GmbH mode”. This study suggested that a smaller FOV and larger voxel size, for example 0.3, in Gmbh mode in comparison to 0.15 in the Inc mode of CBCT is preferred for the diagnosisof ERR