Reproducibility of Maxillofacial Anatomic Landmarks on 3-Dimensional Computed Tomographic Images Determined with the 95% Confidence Ellipse Method

Abstract

Objective: To assess the plotting reproducibility of landmarks on 3-dimensional computed tomography (3D-CT) images through use of the 95% confidence ellipse in order to propose sufficiently stable coordinate systems for 3D-CT measurements. Materials and Methods: Six dentists plotted 19 landmarks twice on 3D-CT images. Scatterplots and the 95% ellipses were produced 3-dimensionally, and the areas of the ellipses were calculated for evaluating the reproducibility of landmarks. [Or], and true porion [Po]) that are frequently used as reference points on cephalograms, Ba showed the smallest areas for all three coordinate axes, indicating high reproducibility. The coronoid process (CP) and the tooth-related landmarks showed relatively high reproducibility. Conclusion: Sufficiently stable coordinate axes could be proposed for different treatments and studies.

Reproducibility of landmark identification in the jaw and teeth on 3-dimensional cone-beam computed tomography images

“…Not only the accuracy but also the reliability or reproducibility of 3D measurements have been verified to be sufficient for clinical use. 10,[13][14][15][16][17][18][19][20][21] In many stud- ies, 10,[17][18][19][20] however, the reliability has been tested for measurements of the length or angle created by two or three landmarks, and therefore we cannot exactly identify which landmark is unstable when reliability of the length or angular measurement is insufficient. To solve this problem, the reliability should be evaluated for identifying landmarks themselves.…”

“…21 The landmarks related to the jaw and teeth, which were plotted on the axial CT slice, showed relatively wide variations, probably because of the application of 2D cephalometric definitions to 3D images. However, this method allows us to visually interpret the variability of landmark identification.…”

“…10,[17][18][19][20] In this regard, we modified and proposed the 95% confidence ellipse method for 3D images obtained by CT or CBCT. 21,22 The purpose of the present study was to compare the reproducibility of landmark identification on 3D CBCT images between two procedures through the use of the 95% confidence ellipse method. One procedure was based on traditional 2D cephalometric definitions, and the other was tentatively proposed for the landmarks related to the jaws and teeth on 3D images.…”

A 3D computerized tomography study of changes in craniofacial morphology of Portuguese skulls from the eighteenth century to the present

“…By this method the influence and relationship could be evaluated not only in the linear measurement, but also in the projection of the A point and B point to the medial plane. Surprisingly, 70.1 % of the variation of the SNA angle in the eighteenth century could be explained by the orthogonal A variable, whereas in the nineteenth 42] and reproducibility [16,31] by applying a different computer-based software such as the one used in this study. Multiple regressions associated with the stepwise method regression analysis were used in the present study to identify the important craniofacial measurements that influenced the architecture of Portuguese skulls.…”

Espessura de tecidos moles nos diferentes tipos faciais: estudo em tomografias computadorizadas cone-beam

“…Observadores treinados podem reproduzir, satisfatoriamente, a localização de pontos cefalométricos bem definidos, em imagens tridimensionais de diversas naturezas (26,38,88,(94)(95)(96). A posição da cabeça durante a execução do exame não prejudica a interpretação de imagens tomográficas, como ocorre em exames radiográficos tradicionais, tão pouco diminui a precisão de medidas lineares realizadas em modelos tridimensionais (90-92, 94, 97, 98).…”