The introduction of cone-beam computed tomography (CBCT) for the maxillofacial imaging provided opportunities for dental practitioners to request multiplanar imaging. Currently CBCT is used during implant treatment-planning to measure accurately the height of bone available for implant placement to avoid serious problems e.g. compromising vital structure such as the inferior alveolar nerve during placement of implants. We present a physical method to assess the accuracy of measurements obtained from an i-CAT CBCT dental radiography unit used at king abdulaziz university hospital and to appraise the effect of voxel size on the accuracy of measurement by an i-CAT CBCT unit. Not significant difference was found between the physical and CBCT measurements for all the samples. The maximum measurements variation was + or -0.15 mm. Therefore, the linear measurements from i-CAT CBCT unit are accurate and the adjustment of the scan parameters like the FOV and voxel size will not significantly affect this accuracy.