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Klop C, Schreurs R, De Jong GA, Klinkenberg ET, Vespasiano V, Rood NL, Niehe VG, Soerdjbalie-Maikoe V, Van Goethem A, De Bakker BS, Maal TJ, Nolte JW, Becking AG. An open-source, three-dimensional growth model of the mandible. Comput Biol Med 2024; 175:108455. [PMID: 38663350 DOI: 10.1016/j.compbiomed.2024.108455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/28/2024] [Accepted: 04/07/2024] [Indexed: 05/15/2024]
Abstract
The available reference data for the mandible and mandibular growth consists primarily of two-dimensional linear or angular measurements. The aim of this study was to create the first open-source, three-dimensional statistical shape model of the mandible that spans the complete growth period. Computed tomography scans of 678 mandibles from children and young adults between 0 and 22 years old were included in the model. The mandibles were segmented using a semi-automatic or automatic (artificial intelligence-based) segmentation method. Point correspondence among the samples was achieved by rigid registration, followed by non-rigid registration of a symmetrical template onto each sample. The registration process was validated with adequate results. Principal component analysis was used to gain insight in the variation within the dataset and to investigate age-related changes and sexual dimorphism. The presented growth model is accessible globally and free-of-charge for scientists, physicians and forensic investigators for any kind of purpose deemed suitable. The versatility of the model opens up new possibilities in the fields of oral and maxillofacial surgery, forensic sciences or biological anthropology. In clinical settings, the model may aid diagnostic decision-making, treatment planning and treatment evaluation.
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Affiliation(s)
- Cornelis Klop
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Movement Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands.
| | - Ruud Schreurs
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Movement Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands; Department of Oral and Maxillofacial Surgery 3D Lab, Radboud University Medical Centre Nijmegen, Radboud Institute for Health Sciences, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, the Netherlands
| | - Guido A De Jong
- Department of Oral and Maxillofacial Surgery 3D Lab, Radboud University Medical Centre Nijmegen, Radboud Institute for Health Sciences, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, the Netherlands
| | - Edwin Tm Klinkenberg
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Movement Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Valeria Vespasiano
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Movement Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Naomi L Rood
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Movement Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Valerie G Niehe
- Department of Radiology, Groene Hart Ziekenhuis, Bleulandweg 10, 2803 HH, Gouda, the Netherlands
| | - Vidija Soerdjbalie-Maikoe
- Department of Forensic Medicine and Pathology, Antwerp University Hospital, Drie Eikenstraat 655, 2650, Edegem, Belgium; Netherlands Forensic Institute, Department of Forensic Medical Research, Laan van Ypenburg 6, 2497 GB, The Hague, the Netherlands
| | - Alexia Van Goethem
- Department of Forensic Medicine and Pathology, Antwerp University Hospital, Drie Eikenstraat 655, 2650, Edegem, Belgium
| | - Bernadette S De Bakker
- Department of Obstetrics and Gynecology, Amsterdam UMC Location University of Amsterdam, Amsterdam Reproduction and Development Research Institute, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Thomas Jj Maal
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Movement Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands; Department of Oral and Maxillofacial Surgery 3D Lab, Radboud University Medical Centre Nijmegen, Radboud Institute for Health Sciences, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, the Netherlands
| | - Jitske W Nolte
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Movement Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
| | - Alfred G Becking
- Department of Oral and Maxillofacial Surgery, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam Movement Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
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Chalazoniti A, Lattanzi W, Halazonetis DJ. Shape variation and sex differences of the adult human mandible evaluated by geometric morphometrics. Sci Rep 2024; 14:8546. [PMID: 38609399 PMCID: PMC11014969 DOI: 10.1038/s41598-024-57617-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 03/20/2024] [Indexed: 04/14/2024] Open
Abstract
In cases of osseous defects, knowledge of the anatomy, and its age and sex-related variations, is essential for reconstruction of normal morphology. Here, we aimed at creating a 3D atlas of the human mandible in an adult sample using dense landmarking and geometric morphometrics. We segmented 50 male and 50 female mandibular surfaces from CBCT images (age range: 18.9-73.7 years). Nine fixed landmarks and 510 sliding semilandmarks were digitized on the mandibular surface, and then slid by minimizing bending energy against the average shape. Principal component analysis extracted the main patterns of shape variation. Sexes were compared with permutation tests and allometry was assessed by regressing on the log of the centroid size. Almost 49 percent of shape variation was described by the first three principal components. Shape variation was related to width, height and length proportions, variation of the angle between ramus and corpus, height of the coronoid process and inclination of the symphysis. Significant sex differences were detected, both in size and shape. Males were larger than females, had a higher ramus, more pronounced gonial angle, larger inter-gonial width, and more distinct antegonial notch. Accuracy of sexing based on the first two principal components in form space was 91 percent. The degree of edentulism was weakly related to mandibular shape. Age effects were not significant. The resulting atlas provides a dense description of mandibular form that can be used clinically as a guide for planning surgical reconstruction.
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Affiliation(s)
- Aspasia Chalazoniti
- Department of Prosthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Wanda Lattanzi
- Department of Life Science and Public Health, Università Cattolica del Sacro Cuore, Rome, Italy
- Unit of Paediatric Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Demetrios J Halazonetis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
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Gillingham RL, Mutsvangwa TEM, van der Merwe J. Reconstruction of the mandible from partial inputs for virtual surgery planning. Med Eng Phys 2023; 111:103934. [PMID: 36792246 DOI: 10.1016/j.medengphy.2022.103934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/30/2022]
Abstract
Statistical Shape Models (SSMs) and Sparse Prediction Models (SPMs) based on regressions between cephalometric measurements were compared against standard practice in virtual surgery planning for reconstruction of mandibular defects. Emphasis was placed on the ability of the models to reproduce clinically relevant metrics. CT scans of 50 men and 50 women were collected and split into training and testing datasets according to an 80:20 ratio. The scans were segmented, and anatomical landmarks were identified. SPMs were constructed based on direct regressions between measurements derived from the anatomical landmarks. SSMs were developed by establishing correspondence between the segmented meshes, performing alignment, and principal component analysis. Anterior and bilateral defects were simulated by removing sections of the mandibles in the testing set. Measurement errors after reconstruction ranged from 1.07˚ to 2.2˚ and 0.66 mm to 2.02 mm for mirroring, from 0.45˚ to 3.67˚ and 0.66 mm to 2.54 mm for the SSMs, and from 1.74˚ to 5.01˚ and 0.64 mm to 2.89 mm for the SPMs. Surface-to-surface errors ranged from 1.01 mm to 1.29 mm and 1.06 mm to 1.33 mm for mirroring and SSMs, respectively. Based on the results, SSMs are recommended for VSP in the absence of normal patient anatomy.
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Affiliation(s)
- Ryan L Gillingham
- Department of Mechanical & Mechatronic Engineering, University of Stellenbosch, Stellenbosch, 7600, South Africa
| | - Tinashe E M Mutsvangwa
- Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, 7935, South Africa
| | - Johan van der Merwe
- Department of Mechanical & Mechatronic Engineering, University of Stellenbosch, Stellenbosch, 7600, South Africa.
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Fuessinger MA, Metzger MC, Rothweiler R, Brandenburg LS, Schlager S. Cranial reconstruction evaluation - comparison of European statistical shape model performance on Chinese dataset. Bone Rep 2022; 17:101611. [PMID: 36120645 PMCID: PMC9478677 DOI: 10.1016/j.bonr.2022.101611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose Morphological variability of the skull is an important consideration for cranioplasty and implant design. Differences in morphology of the skull based on the ethnicity are known. In a previous study we could show the accuracy and benefits of virtual reconstructions based on a statistical shape model (SSM) for neurocranial defects. As the SSM is trained on European data, the question arises how well this model fares when dealing with patients with a different ethnic background. In this study we aim to evaluate the accuracy and applicability of our proposed method when deploying a cranial SSM generated from European data to estimate missing parts of the neurocranium in a Chinese population. Methods We used the same data and methods as in our previous study and compared the outcomes when applied to Chinese individuals. A large unilateral defect on the right side and a bilateral defect were created. The outer surface of the cranial table was reconstructed from CT scans, meshed with triangular elements, and registered to a template. Principal component analysis together with Thin Plate Spines (TPS) deformation was applied to quantify modes of variation. The mesh to mesh distances between the original defects´ surfaces and the reconstructed surface were computed. Results Comparing the Chinese test group with the European control group, regarding the entire defect the analysis shows no significant difference for unilateral defects (test vs. control group/0.46 mm ± vs. 0.44 mm). Reconstruction of bilateral defects exhibited only in slightly higher prediction errors than those of unilateral defects (0.49 mm ± vs. 0.45 mm). Conclusion The proposed method shows a high accuracy that seems to be ethnical independent - with low error margins for virtual skull reconstruction and implant design. Clinical relevance: Metallic objects may severely impact image quality in several CBCT devices. Statistical shape modelling enables automatic skull reconstruction for computer assisted surgery Despite a Caucasian database, the statistical shape model can provide accurate results for other ethnic groups. The results facilitate the development of reconstruction algorithms, as the data basis can be kept smaller
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Affiliation(s)
- Marc Anton Fuessinger
- Department of Oral and Maxillofacial Surgery, Albert-Ludwigs University Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany
| | - Marc Christian Metzger
- Department of Oral and Maxillofacial Surgery, Albert-Ludwigs University Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany
| | - Rene Rothweiler
- Department of Oral and Maxillofacial Surgery, Albert-Ludwigs University Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany
| | - Leonard Simon Brandenburg
- Department of Oral and Maxillofacial Surgery, Albert-Ludwigs University Freiburg, Hugstetterstr. 55, 79106 Freiburg, Germany
| | - Stefan Schlager
- Department of Physical Anthropology, Albert-Ludwigs University Freiburg, Hebelstr. 29, 79104 Freiburg, Germany
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Vallabh R, Zhang J, Fernandez J, Dimitroulis G, Ackland DC. The morphology of the human mandible: A computational modelling study. Biomech Model Mechanobiol 2019; 19:1187-1202. [PMID: 30826909 DOI: 10.1007/s10237-019-01133-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 02/16/2019] [Indexed: 11/29/2022]
Abstract
Cephalometric methods have been used to evaluate morphometric measurements of the mandible and quantify sex-related anatomical features; however, most studies to date employ a limited set of location-specific measurements without considering the entire three-dimensional anatomy of the mandible. The aims of this study were to develop statistical shape models (SSMs) of partially edentulous male and female mandibles to evaluate inter-subject morphological variability and secondly to assess the effectiveness of discrete clinical morphometric measurements in prediction of complete three-dimensional mandible geometry. Computed tomography images of forty partially edentulous female and twenty-five male subjects were obtained, and SSM developed using mesh fitting, rigid body registration and principal component analysis. Analysis of female and male SSMs showed that the variation along their first principal components was size-related. Sex-differentiating pure shape variations were found along the first principal component of size-normalised SSM and were observed to be most prominent in the symphysis and posterior ramus regions of the mandible. Seven morphometric measurements were found to characterise female and male shape prediction optimally. The capability to rapidly generate accurate patient-specific shape-predictive models of the mandible may be useful for implant development and pre-operative planning, particularly in the absence of bony structures following trauma or tumour resection.
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Affiliation(s)
- Ravin Vallabh
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ju Zhang
- Auckland Bioengineering Institute, University of Auckland, Auckland, 1010, New Zealand
| | - Justin Fernandez
- Auckland Bioengineering Institute, University of Auckland, Auckland, 1010, New Zealand.,Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - George Dimitroulis
- Department of Surgery, St Vincent's Hospital, Fitzroy, VIC, 3065, Australia
| | - David C Ackland
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, 3010, Australia.
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Van Osch K, Allen D, Gare B, Hudson TJ, Ladak H, Agrawal SK. Morphological analysis of sigmoid sinus anatomy: clinical applications to neurotological surgery. J Otolaryngol Head Neck Surg 2019; 48:2. [PMID: 30635049 PMCID: PMC6329078 DOI: 10.1186/s40463-019-0324-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 01/02/2019] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVES The primary objective of this study was to use high-resolution micro-CT images to create accurate three-dimensional (3D) models of several intratemporal structures, and to compare several surgically important dimensions within the temporal bone. The secondary objective was to create a statistical shape model (SSM) of a dominant and non-dominant sigmoid sinus (SS) to provide a template for automated segmentation algorithms. METHODS A free image processing software, 3D Slicer, was utilized to create three-dimensional reconstructions of the SS, jugular bulb (JB), facial nerve (FN), and external auditory canal (EAC) from micro-CT scans. The models were used to compare several clinically important dimensions between the dominant and non-dominant SS. Anatomic variability of the SS was also analyzed using SSMs generated using the Statismo software framework. RESULTS Three-dimensional models from 38 temporal bones were generated and analyzed. Right dominance was observed in 74% of the paired SSs. All distances were significantly shorter on the dominant side (p < 0.05), including: EAC - SS (dominant: 13.7 ± 3.4 mm; non-dominant: 15.3 ± 2.7 mm), FN - SS (dominant: 7.2 ± 1.8 mm; non-dominant: 8.1 ± 2.3 mm), 2nd genu FN - superior tip of JB (dominant: 8.7 ± 2.2 mm; non-dominant: 11.2 ± 2.6 mm), horizontal distance between the superior tip of JB - descending FN (dominant: 9.5 ± 2.3 mm; non-dominant: 13.2 ± 3.5 mm), and horizontal distance between the FN at the stylomastoid foramen - JB (dominant: 5.4 ± 2.2 mm; non-dominant: 7.7 ± 2.1). Analysis of the SSMs indicated that SS morphology is most variable at its junction with the transverse sinus, and least variable at the JB. CONCLUSIONS This is the first known study to investigate the anatomical variation and relationships of the SS using high resolution scans, 3D models and statistical shape analysis. This analysis seeks to guide neurotological surgical approaches and provide a template for automated segmentation and surgical simulation.
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Affiliation(s)
- Kylen Van Osch
- Schulich School of Medicine & Dentistry, Western University, London, Ontario, N6A 5C1, Canada
| | - Daniel Allen
- Department of Electrical and Computer Engineering, Western University, London, Ontario, N6A 5C1, Canada
| | - Bradley Gare
- Department of Electrical and Computer Engineering, Western University, London, Ontario, N6A 5C1, Canada
| | - Thomas J Hudson
- Schulich School of Medicine & Dentistry, Western University, London, Ontario, N6A 5C1, Canada
| | - Hanif Ladak
- Department of Medical Biophysics, Western University, London, Ontario, N6A 5C1, Canada
| | - Sumit K Agrawal
- Department of Otolaryngology - Head and Neck Surgery, Western University, London, Ontario, N6A 5C1, Canada.
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Automatic analysis algorithm for acquiring standard dental and mandibular shape data using cone-beam computed tomography. Sci Rep 2018; 8:13516. [PMID: 30202001 PMCID: PMC6131388 DOI: 10.1038/s41598-018-31869-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 08/29/2018] [Indexed: 01/15/2023] Open
Abstract
This study aims to introduce a new algorithm developed using retrospective cone-beam computed tomography (CBCT) data to obtain a standard dental and mandibular arch shape automatically for an optimal panoramic focal trough. A custom-made program was developed to analyze each arch shape of randomly collected 30 CBCT images. First, volumetric data of the mandible were binarized and projected in the axial direction to obtain 2-dimensional arch images. Second, 30 patients’ mandibular arches were superimposed on the center of the bilateral distal contact points of the mandibular canines to generate an average arch shape. Third, the center and boundary of a panoramic focal trough were obtained using smoothing splines. As a result, the minimum thickness and transition of the focal trough could be obtained. If this new algorithm is applied to big data of retrospective CBCT images, standard focal troughs could be established by race, sex, and age group, which would improve the image quality of dental panoramic radiography.
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Raith S, Rauen A, Möhlhenrich SC, Ayoub N, Peters F, Steiner T, Hölzle F, Modabber A. Introduction of an algorithm for planning of autologous fibular transfer in mandibular reconstruction based on individual bone curvatures. Int J Med Robot 2018; 14. [PMID: 29423929 DOI: 10.1002/rcs.1894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 12/20/2017] [Accepted: 12/30/2017] [Indexed: 11/08/2022]
Abstract
BACKGROUND Reconstruction of the mandible with autologous transplants is a challenging task and current computer-aided surgical planning remains cumbersome. Thus, the aim of the present study was to create an automated computational approach for this procedure. METHODS The developed algorithm is based on curves following characteristic anatomical features. Geometrical data from a physiological mandible and a fibula were used to generate six different defects, and geometrical accordance was investigated to demonstrate the applicability of the method with different reconstruction parameters (n = 309). RESULTS The method proved to be applicable, it recognized given clinical constraints and the values of accordance could be used to quantify the success of reconstructions. CONCLUSIONS With the present approach, the complex three-dimensional task of mandibular reconstruction was simplified, and thus it allows implementation in clinical routine. The computational planning that is proposed may be used to design cutting guides or as geometrical input data for real-time navigated surgery.
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Affiliation(s)
- Stefan Raith
- Department of Oral and Maxillofacial Surgery, RWTH Aachen University Hospital, Aachen, Germany
| | - Alexandra Rauen
- Department of Oral and Maxillofacial Surgery, RWTH Aachen University Hospital, Aachen, Germany
| | - Stephan Christian Möhlhenrich
- Department of Oral and Maxillofacial Surgery, RWTH Aachen University Hospital, Aachen, Germany.,Department of Orthodontics, RWTH Aachen University Hospital, Aachen, Germany
| | - Nassim Ayoub
- Department of Oral and Maxillofacial Surgery, RWTH Aachen University Hospital, Aachen, Germany
| | - Florian Peters
- Department of Oral and Maxillofacial Surgery, RWTH Aachen University Hospital, Aachen, Germany
| | - Timm Steiner
- Department of Oral and Maxillofacial Surgery, RWTH Aachen University Hospital, Aachen, Germany
| | - Frank Hölzle
- Department of Oral and Maxillofacial Surgery, RWTH Aachen University Hospital, Aachen, Germany
| | - Ali Modabber
- Department of Oral and Maxillofacial Surgery, RWTH Aachen University Hospital, Aachen, Germany
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Planning of mandibular reconstructions based on statistical shape models. Int J Comput Assist Radiol Surg 2016; 12:99-112. [PMID: 27393280 DOI: 10.1007/s11548-016-1451-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/16/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE The reconstruction of large continuity defects of the mandible is a challenging task, especially when the shape of the missing part is not known prior to operation. Today, the surgical planning is based mainly on visual judgment and the individual skills and experience of the surgeons. The objective of the current study was to develop a computer-based method that is capable of proposing a reconstruction shape from a known residual mandible part. METHODS The volumetric data derived from 60 CT scans of mandibles were used as the basis for the novel numerical procedure. To find a standardized representation of the mandible shapes, a mesh was elaborated that follows the course of anatomical structures with a specially developed topology of quadrilaterals. These standard meshes were transformed with defined mesh modifications toward each individual mandible surface to allow for further statistical evaluations. The data were used to capture the inter-individual shape variations that were considered as random field variations and mathematically evaluated with principal component analysis. With this information of the mandibular shape variations, an algorithm was developed that proposes shapes for reconstruction planning based on given residual mandible geometry parts. RESULTS The accuracy of the novel method was evaluated on six different virtually defined continuity defects that were each created on three mandibles that were not part of the initial database. Virtual reconstructions showed sufficient accuracy of the algorithm for the planning of surgical reconstructions, with average deviations toward the actual geometry of [Formula: see text] mm for small missing parts and 5 mm for large hemi-lateral defects. CONCLUSIONS The presented algorithm may be a valuable tool for the planning of mandibular reconstructions. The proposed shapes can be used as templates for computer-aided manufacturing, e.g., with 3D printing devices that use biocompatible materials.
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Wang WH, Xu B, Zhang BJ, Lou HQ. Temporomandibular joint ankylosis contributing to coronoid process hyperplasia. Int J Oral Maxillofac Surg 2016; 45:1229-33. [PMID: 27173825 DOI: 10.1016/j.ijom.2016.04.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/13/2016] [Accepted: 04/25/2016] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to investigate the association between coronoid process hyperplasia and temporomandibular joint (TMJ) ankylosis and to analyze the pathological mechanism and clinical significance of coronoid process hyperplasia. Forty-four patients treated for TMJ ankylosis between January 2007 and December 2014 were studied retrospectively; 176 patients with normal TMJs served as controls. The original DICOM data were used to reconstruct the jaw, and a three-dimensional cephalometric analysis (SimPlant Pro software version 11.04) was performed to assess the association between the severity of TMJ ankylosis and the height of the coronoid process. The height of the coronoid process was 20.41±5.00mm in the case group and 14.86±2.67mm in the control group; there was a significant difference between the two groups (P<0.001). Long-standing TMJ ankylosis contributes to coronoid process hyperplasia. Therefore, attention should be drawn to the coronoid process in patients with TMJ ankylosis. A coronoidectomy together with arthroplasty is recommended in patients with TMJ ankylosis.
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Affiliation(s)
- W H Wang
- Department of Oral and Maxillofacial Surgery, Affiliated Stomatology Hospital of Kunming Medical University, Kunming, China.
| | - B Xu
- Department of Oral and Maxillofacial Surgery, Affiliated Stomatology Hospital of Kunming Medical University, Kunming, China
| | - B J Zhang
- Department of Oral and Maxillofacial Surgery, Affiliated Stomatology Hospital of Kunming Medical University, Kunming, China
| | - H Q Lou
- Department of Oral and Maxillofacial Surgery, Affiliated Stomatology Hospital of Kunming Medical University, Kunming, China
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Katkar RA, Kummet C, Dawson D, Moreno Uribe L, Allareddy V, Finkelstein M, Ruprecht A. Comparison of observer reliability of three-dimensional cephalometric landmark identification on subject images from Galileos and i-CAT cone beam CT. Dentomaxillofac Radiol 2013; 42:20130059. [PMID: 23833319 DOI: 10.1259/dmfr.20130059] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Recently, there has been increasing interest in the use of cone beam CT (CBCT) for three-dimensional cephalometric analysis and craniofacial reconstruction in orthodontic and orthognathic surgical treatment planning. However, there is a need to redefine the cephalometric landmarks in three dimensional cephalometric analysis and to demonstrate the reproducibility of landmark identification on the type of CBCT machine being used. METHODS CBCT images of 20 subjects aged 15-25 years were selected, ten each from Galileos(®) (Sirona Dental Systems Inc., Bensheim, Germany) and Next Generation i-CAT(®) (Imaging Sciences International, Hatfield, PA). 2 observers located 18 landmarks on each subject twice using Dolphin-3D v. 11 software (Dolphin Imaging and Management Systems, Chatsworth, CA). Inter- and intraobserver reliability was assessed using Euclidean distances and linear mixed models. RESULTS Overall, the intra- and interobserver reliability was excellent for both machines. The landmarks Gonion, Nasion, Orbitale and Anterior Nasal Spine (ANS) showed the greatest median Euclidean distances for both intra- and interobserver measurements. There were significant observer effects in the unified models for Sella, Menton and all six dental landmarks. For Sella, the distances between the measures were significantly smaller (more closely spaced) on the i-CAT machine than on the Galileos in both intra- and interobserver measurements. CONCLUSIONS The intra- and interobserver reliability was excellent for both machines. Some of the landmarks were not as reproducible as others. Which machine produced the highest reliability depended on the landmark considered.
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Affiliation(s)
- R A Katkar
- Department of Oral and Maxillofacial Radiology, University of Florida, College of Dentistry, Gainesville, FL
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