Three-dimensional Frankfort horizontal plane for 3D cephalometry: a comparative assessment of conventional versus novel landmarks and horizontal planes (original) (raw)
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Objective: was to compare the reliability of six Frankfurt Horizontal planes versus the true Horizontal plane in adults having normal occlusion and balanced facial profile.Material and Methods: CBCT images were collectedfrom thirty seven Egyptian adult subjects using the I-CAT CBCT machine and Anatomage 5.3 software to generate 3D volumetric reconstructions.A newly constructed coordinate reference system that depends on the true vertical was used for accurate measurements.Six different Frankfurt planes were constructed and were compared to the true Horizontal plane.Results:The intra-observer, inter-observer reliability for landmarks showed high concordance with identical ICC and CCC exceeding 0.751 and 0.78 respectively.All the Frankfurt constituting points showed high reproducibility with high correlation values varied from 0.776 to 0.999 in the intra-observer readings and exceeded 0.994 in the inter-observer readings. All proposed Frankfurt planes showed insignificant difference in their mean cant that varied from 0.7 to 1.2 to the true Horizontal plane. All planes showed no statistical significant difference from True Horizontal plane (p > 0.05)on their comparison with the True Horizontal plane using McNamaras' analysis.Conclusions: All six Frankfurt horizontal planes constructed on 3D volumetric surface were reliable as horizontal reference planes.
Direct 3D Cephalometric Analysis Performed on CBCT
Journal of Information Technology & Software Engineering, 2012
Engineering is an international, peer-reviewed journal publishing an overview of IT research and algorithmic processes that create, describe and transform information to formulate suitable abstractions to model complex systems.
Journal of the Korean Association of Oral and Maxillofacial Surgeons, 2014
Objectives: The aim of this study was to verify the concordance of the measurement values when the same cephalometric analysis method was used for two-dimensional (2D) cephalometric radiography and three-dimensional computed tomography (3D CT), and to identify which 3D Frankfort horizontal (FH) plane was the most concordant with FH plane used for cephalometric radiography. Materials and Methods: Reference horizontal plane was FH plane. Palatal angle and occlusal plane angle was evaluated with FH plane. Gonial angle (GA), palatal angle, upper occlusal plane angle (UOPA), mandibular plane angle (MPA), U1 to occlusal plane angle, U1 to FH plane angle, SNA and SNB were obtained on 2D cephalmetries and reconstructed 3D CT. The values measured eight angles in 2D lateral cephalometry and reconstructed 3D CT were evaluated by intraclass correlation coefficiency (ICC). It also was evaluated to identify 3D FH plane with high degree of concordance to 2D one by studying which one in four FH planes shows the highest degree of concordance with 2D FH plane. Results: ICCs of MPA (0.752), UOPA (0.745), SNA (0.798) and SNB (0.869) were high. On the other hand, ICCs of gonial angle (0.583), palatal angle (0.287), U1 to occlusal plane (0.404), U1 to FH plane (0.617) were low respectively. Additionally GA and MPA acquired from 2D were bigger than those on 3D in all 20 patients included in this study. Concordance between one UOPA from 2D and four UOPAs from 3D CT were evaluated by ICC values. Results showed no significant difference among four FH planes defined on 3D CT. Conclusion: FH plane that can be set on 3D CT does not have difference in concordance from FH plane on lateral cephalometry. However, it is desirable to define FH plane on 3D CT with two orbitales and one porion considering the reproduction of orbitale itself.
Cephalometric measurements from 3D reconstructed images compared with conventional 2D images
The Angle Orthodontist, 2011
Objective: To assess whether the values of different measurements taken on three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) are comparable with those taken on two-dimensional (2D) images from conventional lateral cephalometric radiographs (LCRs) and to examine if there are differences between the different types of CBCT software when taking those measurements. Material and Methods: Eight patients were selected who had both an LRC and a CBCT. The 3D reconstructions of each patient in the CBCT were evaluated using two different software packages, NemoCeph 3D and InVivo5. An observer took 10 angular and 3 linear measurements on each of the three types of record on two different occasions. Results: Intraobserver reliability was high except for the mandibular plane and facial cone (from the LCR), the Na-Ans distance (using NemoCeph 3D), and facial cone and the Ans-Me distance (using InVivo5). No statistically significant differences were found for the angular and linear measurements between the LCRs and the CBCTs for any measurement, and the correlation levels were high for all measurements. Conclusion: No statistically significant differences were found between the angular and linear measurements taken with the LCR and those taken with the CBCT. Neither were there any statistically significant differences between the angular or linear measurements using the two CBCT software packages. (Angle Orthod. 2011;81:856-864.)
Use of an anatomical mid-sagittal plane for 3-dimensional cephalometry: A preliminary study
Purpose: Cone-beam computed tomography (CBCT) is widely used for 3-dimensional assessments of cranio-maxillofacial relationships, especially in patients undergoing orthognathic surgery. We have introduced, for reference in CBCT cephalometry, an anatomical mid-sagittal plane (MSP) identified by the nasion, the midpoint between the posterior clinoid processes of the sella turcica, and the basion. The MSP is an updated version of the median plane previously used at our institution for 2D posterior-anterior cephalometry. This study was conducted to test the accuracy of the CBCT measures compared to those obtained using standard posterior-anterior cephalometry. Materials and Methods: Two operators measured the inter-zygomatic distance on 15 CBCT scans using the MSP as a reference plane, and the CBCT measurements were compared with measurements made on patients' posterioranterior cephalograms. The statistical analysis evaluated the absolute and percentage differences between the 3D and 2D measurements. results: As demonstrated by the absolute mean difference (roughly 1 mm) and the percentage difference (less than 3%), the MSP showed good accuracy on CBCT compared to the 2D plane, especially for measurements of the left side. However, the CBCT measurements showed a high standard deviation, indicating major variability and low precision. conclusion: The anatomical MSP can be used as a reliable reference plane for transverse measurements in 3D cephalometry in cases of symmetrical or asymmetrical malocclusion. In patients who suffer from distortions of the skull base, the identification of landmarks might be difficult and the MSP could be unreliable. Becoming familiar with the relevant software could reduce errors and improve reliability.