Impact of voxel’s size on the possibility of second mesio-buccal canal (MB2) verification within the structure of upper molars based on cone-beam computed tomography data

Abstract

Introduction. It seems logical to assume that the increase in the prevalence of second mesio-buccal canal (MB2) identification within maxillary molars should be associated with smaller dimensional parameters of the CBCT-image voxel, however, discrepancies in the results of individual studies, as well as between those highlighted in experimental and systematic studies, argue for the need to conduct a corresponding comparative analysis of available data for the purpose of their further systematization and objective interpretation. Objective of the research. To analyze the data on the impact of the CBCT image voxel’s size parameters on the possibility of the second mesiobuccal canal verification within the structure of the maxillary molars. Materials and methods. The study was provided as a structured literature review with the target investigated parameters being presented by the voxel size of the CBCT image (as a potential determinant) and the established prevalence/probability of identification of MB2 canal based on the CBCT data (as a potential derivative). The analysis of the publications primary cohort was carried based on the title and content of the abstracts/summaries, after which those works that most closely corresponded to the purpose of this study were subjected to the detailed content analysis, the categories of which included the following: 1) the relationship between the voxel size and the prevalence of the MB2 canal identification according to the CBCT studies data; 2) differences in the frequency of of the MB2 canal identification at different initial voxel sizes according to the data of CBCT studies; 3) impact of different research designs on the prevalence of MB2 canal identification represented in their results considering different voxel sizes; 4) factors affecting the probability of identifying MB2 canal on the CBCT images at different voxel sizes. Results and discussions. The data aggregated during the literature review indicated that the probability of identifying MB2 canal according to the CBCT data with different voxel sizes, which are less than or equal to 0,2 mm, does not differ statistically, and such outcome is reliable when the voxel size is interpreted as the main determinant for MB2 canal prevalence variation based on CBCT data. Despite this, the probability of identifying the MB2 canal is affected by the condition of the MB1 canal, presence of artifacts, thickness of the slice during image analysis, experience of the operator, and features of used software. An increase in the voxel size of more than 0,2 mm can potentially have a critical impact on the changes of probability for MB2 canal verification within the structure of the maxillary molars according to the CBCT images. During the analytical processing of scientific publications, it was possible to identify a specific dependence, which was manifested in the fact that in those scientific works in which categorical data were targeted for research, more accurate results of CBCT examinations were associated with a higher resolution (smaller voxel size). Conclusions. In the conducted systematic reviews, no statistically substantiated differences were identified regarding the critical influence of the used different voxel size as a significant determinant for the variation of the second mesio-buccal canal prevalence within the structure of the maxillary molars, although, according to the data of individual studies, a trend towards a higher prevalence of identification of the MB2 canal was noted when using CBCT- protocols with a small voxel size, and in cases of using a voxel size ≤ 0,2 mm (compared to cases of using a voxel size > 0,2 mm).