Comparing the accuracy of voxel sizes of different sizes of computed tomography with cone beam in the detection of marginal gaps in all-ceramic and metal-ceramic fixed prostheses

Abstract

Introduction Diagnosing the marginal gap in fixed ceramic and metal-ceramic prostheses is very important in preventing complications after treatment. Cone ray computed tomography is one of the most important tools in diagnosing these gaps. However, CBCT settings and setup can be effective in its diagnostic accuracy. Voxel size is one of the most important parameters of a CBCT device, whose dimensions can be effective in the accuracy of measuring anatomical landmarks. The aim of this study was to compare two voxel sizes of 0.15 and 0.3 mm in detecting the marginal gap of all-ceramic and full-ceramic veneers. Materials and methods In this laboratory study, 36 extracted human teeth will be fixed in a wax mold and examined. 36 samples will be placed in two groups (18 samples in each group) and metal-ceramic veneers were used in one group and full-ceramic veneers were used in the next group. Then, each group was divided into three groups of 6 (gaps of 0.5, 1, and 1.5 mm). CBCT images of restored samples were prepared in two voxel sizes of 0.15 and 0.3 mm. Gaps observed in the images were measured by the software in a room without light pollution. Independent t-test was used to compare the size accuracy between two dimensions of 0.15 and 0.3 mm. To compare the accuracy of the measurements in two dimensions (0.30 and 0.15) in comparison with metal-ceramic and all-ceramic subgroups (gaps), two-way analysis of variance and appropriate post hoc tests were used. The significance level in all tests will be considered less than 0.05. Results The results showed that in the 0.5 metal-ceramic gap, the measurement accuracy in the 0.15 dimension was equal to 0.433 and in the 0.3 dimension it was equal to 0.366, which is a statistically significant difference between the accuracy of the CBCT size of 0.15 and There was 0.3 (p=0.049). But in Gap 0.5 all ceramic; There was no significant difference between the two measurement dimensions of CBCT (p=0.213). . The results of our analysis showed that the average accuracy of measurements is different between different gaps (0.5, 1 and 1.5) and this difference is also statistically different (P=0.001). In other words, the measurement accuracy is different depending on the type of gap.

Conclusion: Our results show that the voxel accuracy of different CBCT sizes in measuring the marginal gaps of all-ceramic and metal-ceramic veneers is different, and this difference is especially true for 0.3 mm gaps. Therefore, it is recommended to use smaller voxel sizes to measure smaller marginal gaps in order to be more accurate.