Introduction In this study, we present a novel classification method for individual assessment of midpalatal suture morphology. Methods Cone-beam computed tomography images from 140 subjects (ages, 5.6-58.4 years) were examined to define the radiographic stages of midpalatal suture maturation. Five stages of maturation of the midpalatal suture were identified and defined: stage A, straight high-density sutural line, with no or little interdigitation; stage B, scalloped appearance of the high-density sutural line; stage C, 2 parallel, scalloped, high-density lines that were close to each other, separated in some areas by small low-density spaces; stage D, fusion completed in the palatine bone, with no evidence of a suture; and stage E, fusion anteriorly in the maxilla. Intraexaminer and interexaminer agreements were evaluated by weighted kappa tests. Results Stages A and B typically were observed up to 13 years of age, whereas stage C was noted primarily from 11 to 17 years but occasionally in younger and older age groups. Fusion of the palatine (stage D) and maxillary (stage E) regions of the midpalatal suture was completed after 11 years only in girls. From 14 to 17 years, 3 of 13 (23%) boys showed fusion only in the palatine bone (stage D). Conclusions This new classification method has the potential to avoid the side effects of rapid maxillary expansion failure or unnecessary surgically assisted rapid maxillary expansion for late adolescents and young adults.

Objectives-To evaluate the registration of 3D models from cone-beam CT (CBCT) images taken before and after orthognathic surgery for the assessment of mandibular anatomy and position.Methods-CBCT scans were taken before and after orthognathic surgery for ten patients with various malocclusions undergoing maxillary surgery only. 3D models were constructed from the CBCT images utilizing semi-automatic segmentation and manual editing. The cranial base was used to register 3D models of pre-and post-surgery scans (1 week). After registration, a novel tool allowed the visual and quantitative assessment of post-operative changes via 2D overlays of superimposed models and 3D coloured displacement maps.Results-3D changes in mandibular rami position after surgical procedures were clearly illustrated by the 3D colour-coded maps. The average displacement of all surfaces was 0.77 mm (SD = 0.17 mm), at the posterior border 0.78 mm (SD = 0.25 mm), and at the condyle 0.70 mm (SD = 0.07 mm). These displacements were close to the image spatial resolution of 0.60 mm. The average interobserver differences were negligible. The range of the interobserver errors for the average of all mandibular rami surface distances was 0.02 mm (SD = 0.01 mm).Conclusion-Our results suggest this method provides a valid and reproducible assessment of craniofacial structures for patients undergoing orthognathic surgery. This technique may be used to identify different patterns of ramus and condylar remodelling following orthognathic surgery.

Three-dimensional (3D) imaging techniques can provide valuable information to clinicians and researchers. But as we move from traditional 2-dimensional (2D) cephalometric analysis to new 3D techniques, it is often necessary to compare 2D with 3D data. Cone-beam computed tomography (CBCT) provides simulation tools that can help bridge the gap between image types. CBCT acquisitions can be made to simulate panoramic, lateral, and posteroanterior cephalometric radioagraphs so that they can be compared with preexisting cephalometric databases. Applications of 3D imaging in orthodontics include initial diagnosis and superimpositions for assessing growth, treatment changes, and stability. Three-dimensional CBCT images show dental root inclination and torque, impacted and supernumerary tooth positions, thickness and morphology of bone at sites of mini-implants for anchorage, and osteotomy sites in surgical planning. Findings such as resorption, hyperplasic growth, displacement, shape anomalies of mandibular condyles, and morphological differences between the right and left sides emphasize the diagnostic value of computed tomography acquisitions. Furthermore, relationships of soft tissues and the airway can be assessed in 3 dimensions.To routinely benefit from 3-dimensional (3D) imaging, which can provide stacks of axial, lateral, and anteroposterior slices, clinicians need userfriendly tools to construct virtual 3Dmodels. These can be used in initial diagnosis and assessing changes as a result of treatment. Although shape analysis tools have become more readily available, most current software requires some computer expertise.As new tools are developed, we can navigate away from the limitations of conventional cephalometrics, but we still need to allow comparisons to previously acquired cephalograms. 1 It is important to be able to use superimpositions and current images to evaluate growth changes. Various techniques for the reconstruction of 3D computed tomography (CT) images have been used in diagnosis, treatment planning, and simulation. [2][3][4][5][6][7][8][9][10][11] However, image superimposition for the assessment of changes with treatment poses many challenges. These challenges refer to registration and homology issues and also to the difficulty of landmark locations on anatomic surfaces. [12][13][14][15][16] NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript location in each of the 3 planes of space. We describe superimposition methods that do not depend on landmarks or planes but, rather, compare the cranial base structures voxel by voxel of each CT acquisition. These procedures allow us to calculate the rotation and translation parameters between 2 time-point images, display the superimposed 3D virtual models, and measure the distances between the 3D model's surfaces. CONE-BEAM CT DEVICESNewTom 3G (Aperio Services, Sarasota, Fla), i-CAT (Imaging Sciences International, Hatfield, Pa), and CB MercuRay (Hitachi Medical Corporation, Tokyo, Japan) are the conebeam (CB) CT (CBCT) sc...

Introduction-In this cephalometric investigation, we analyzed the treatment effects of boneanchored maxillary protraction (BAMP) with miniplates in the maxilla and mandible connected by Class III elastics in patients with Class III malocclusion.

Objective-To evaluate reliability in 3D landmark identification using Cone-Beam CT.Study Design-Twelve pre-surgery CBCTs were randomly selected from 159 orthognathic surgery patients. Three observers independently repeated three times the identification of 30 landmarks in the sagittal, coronal, and axial slices. A mixed effects ANOVA model estimated the Intraclass Correlations (ICC) and assessed systematic bias.Results-The ICC was >0.9 for 86% of intra-observer assessments and 66% of inter-observer assessments. Only 1% of intra-observer and 3% of inter-observer coefficients were <0.45. The systematic difference among observers was greater in X and Z than in Y dimensions, but the maximum mean difference was quite small. Conclusion-Overall, the intra-and inter-observer reliability was excellent. 3D landmark identification using CBCT can offer consistent and reproducible data, if a protocol for operator training and calibration is followed. This is particularly important for landmarks not easily specified in all three planes of space.Three-dimensional cephalometry has long been proposed as the ideal for orthodontic diagnosis, treatment planning, and follow-up of the patients. 1 Diagnosis, treatment planning, and assessment of change over time have been routinely based on landmark based analysis in 2D cephalometry. 1 CORRESPONDING AUTHOR: Lucia H.S. Cevidanes, DDS, MS, PhD, UNC School of Dentistry, Assistant Professor, Department of Orthodontics, 201 Brauer Hall, UNC School of Dentistry, Chapel Hill, NC, 27599-7450, Phone: (919) 3578603, Email: cevidanl@dentistry.unc.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. The use of Cone-Beam CT (CBCT) in dentistry offers great potential for 3D diagnosis and treatment planning compared to CT. 5-16 However, the development of three-dimensional landmark-based cephalometric analysis requires definition of 3D landmarks on complex curving structures, which is not a trivial problem. As Bookstein 16 noted, there is a lack of literature about suitable operational definitions for the landmarks in the 3 planes of space (coronal, sagittal, and axial). Practical considerations of identification errors, coupled with an essential need for biological relevance and a balanced representation of components of the craniofacial form, limit the number and nature of landmarks available for analysis. Historically landmarks, such as Articulare, were used because of the ease in landmark location on the 2D cephalometric projections, but these projected superimposed structures do not exist in the actual 3D facial structure. For these reasons, the...