Lagos de Melo Larissa Pereira, Oenning Anne Caroline Costa, Nadaes Mariana Rocha, Nejaim Yuri, Neves Frederico Sampaio, Oliveira Matheus Lima, Freitas Deborah Queiroz
Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas (UNICAMP), São Paulo, Brazil.
Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas (UNICAMP), São Paulo, Brazil.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2017 Aug;124(2):183-190. doi: 10.1016/j.oooo.2017.03.008. Epub 2017 Mar 15.
The aim of the study was to assess the influence of cone beam computed tomography (CBCT) acquisition parameters on the evaluation of mandibular third molars and their relationship to the mandibular canal.
Eight dry human mandibles with 13 mandibular third molars were scanned with one CBCT unit. Voxel size (0.2 and 0.3 mm), field of view (FOV) size (12 × 8.5 cm and 5 × 5 cm), and number of basis images (450 and 720) were the variables studied. Two examiners evaluated the images, and the resulting data were compared through McNemar, McNemar-Bowker, and Student t tests. Additionally, dosimetry was determined for all protocols tested, and radiation doses were compared through analysis of variance.
The variables did not influence evaluation of mandibular third molars, except for voxel size, when assessing contact between the tooth and the mandibular canal (P = .021). Although FOV and number of basis images affected radiation dose, voxel size did not.
FOV size and number of basis images did not influence the evaluation of mandibular third molars and their relationship to the mandibular canal in the CBCT unit used. Conversely, smaller voxel size affected the assessment of contact between the tooth and the mandibular canal. In units in which voxel size does not influence radiation dose, the most appropriate CBCT protocol is the one using a smaller voxel size and delivering the lowest radiation dose to the patient.
本研究旨在评估锥形束计算机断层扫描（CBCT）采集参数对下颌第三磨牙评估的影响及其与下颌管的关系。
使用一台CBCT设备对8具带有13颗下颌第三磨牙的干燥人类下颌骨进行扫描。研究的变量包括体素大小（0.2和0.3毫米）、视野（FOV）大小（12×8.5厘米和5×5厘米）以及基础图像数量（450和720）。两名检查者对图像进行评估，并通过McNemar检验、McNemar - Bowker检验和Student t检验对所得数据进行比较。此外，还对所有测试方案进行了剂量测定，并通过方差分析比较辐射剂量。
在评估牙齿与下颌管之间的接触时，除体素大小外，其他变量均不影响下颌第三磨牙的评估（P = 0.021）。虽然视野和基础图像数量会影响辐射剂量，但体素大小不会。
在所用的CBCT设备中，视野大小和基础图像数量不影响下颌第三磨牙的评估及其与下颌管的关系。相反，较小的体素大小会影响对牙齿与下颌管之间接触的评估。在体素大小不影响辐射剂量的设备中，最合适的CBCT方案是使用较小体素大小并为患者提供最低辐射剂量的方案。
