Objective: The aim of this study is to assess the effect of different CBCT voxel sizes on the soft tissue thickness measurements in a variety of maxillary and mandibular regions.
Methods: Two thicknesses (less than 2.0 mm and more than 2.0 mm) of pink baseplate wax as simulated soft tissue were overlaid on a maxilla and mandible of a dry human skull. The thicknesses were measured with a digital caliper as the physical measurements. The skull was scanned using CBCT with four different voxel sizes (0.20, 0.25, 0.30 and 0.4 mm). CBCT measurements were compared to the physical measurements. Intraclass Correlation Coefficient was used to assess both intra- and inter-observer reliability. Significance was considered to be 5% (P ≤ 0.05).
Results: Results showed a significant difference between the CBCT measurements using the 0.3 and 0.4 mm voxel sizes scans compared to the physical measurements when wax thickness was less than 2.0 mm. On the other hand, no significant difference was found for the CBCT measurements using the four voxel sizes when thickness was greater than 2.0 mm.
Conclusions: CBCT scans with voxel sizes of 0.3 mm and 0.4 mm provide accurate simulated soft tissue measurements when the thickness is more than 2.0 mm. However, when greater visualization of details are required, scans with lower voxel sizes is required. Therefore, in a clinical situation, it is of great importance to customize the resolution protocol according to the accuracy needed.