Search

Objective We wanted to evaluate the three-dimensional (3D) mandibular growth of Sprague-Dawley rats from 4th to 16th postnatal weeks with periodic and live micro-computed tomographic scanning. Design Twenty Sprague-Dawley rats were used for micro-CT scanning from 4th to 16th postnatal weeks. After 3D reconstruction of rat mandible, we performed the linear and angular measurements and the superimposition of the 3D models to evaluate the mandibular growth of rat. Results The results showed that the growth direction of the condylar and coronoid regions was superior primarily and posterior secondarily, while the condyle had minimal lateral growth. Moreover, the angular region was growing mainly toward the posterior and lateral direction, while the body and symphysis maintained small, incremental anterior-posterior growth. Conclusions We could evaluate the amount, rate, and direction of growth using the mandibular skeletal unit. Some reference points and measurements were more relevant in properly characterizing 3D growth of the mandible. Their growth rates were the greatest between 4th and 8th postnatal weeks, a period which seems most appropriate for studies of rat mandible growth. [ABSTRACT FROM AUTHOR]

Background and Purpose: Segmental, depressed fractures of the posterolateral maxillary sinus may occur as a result of trauma to the masticator space, previously described in association with mandibular fractures. The authors hypothesize that the fracture is due to a transient increase in pressure in the masticator space (blow out) and therefore should be seen in association with other regional fractures.Materials and Methods: Injuries of the masticator space were retrospectively identified by searching the imaging database from January 2014 to November 2014 for keywords that would identify regional trauma. The images were reviewed for segmental depressed fractures in the posterolateral aspect of the maxillary sinus accompanied by herniation of a variable amount of masticator space fat and/or muscle into the adjacent sinus. Three neuroradiologists reviewed the images and agreed by consensus on the presence or absence of a masticator space blowout fracture.Results: Forty-three zygomaticomaxillary complex (ZMC) fractures, 89 mandibular fractures, and 49 isolated zygomatic arch fractures were identified. While all of the ZMC fractures had a maxillary component, 3 of 43 (7.0 %) additional fractures met our fracture definition. Five of 89 (5.6 %) of the mandibular fractures and 6 of 49 (12.2 %) zygomatic arch fractures had an associated posterolateral maxillary fracture.Conclusions: Segmental depressed fracture of the posterolateral maxillary sinus is relatively common, occurring in conjunction with other regional injuries. The authors hypothesize that it is due to a transient increase in pressure in the masticator space and is a separate entity from other fractures of the region that may occur concurrently. [ABSTRACT FROM AUTHOR]

Introduction: A large number of disorders affecting the masticatory system can cause mouthopening restrictions. Among them is Jacob's disease, characterized by restricted jaw movements and caused by pressure of the mandible coronoid process, which is longer than normal in size, on the posterior aspect of the zygomatic arch, together establishing new joint formation. Observation: We present a case report of a 29-year-old male patient presenting limited mouth opening. Inter-incisal maximum mouth opening was 5 mm. On panoramic radiograph an elongated coronoid process of the mandible was evident. Computed tomography (CT) scans showed the relationship between the exophytic mass and the inner surface of the zygomatic arch. An extra-oral coronoidectomy was performed. A mouth opening of 55 mm was achieved intra-operatively. The post-operative period was without complications. The histopathological diagnosis was osteochondroma. Discussion: The clinical, radiological and histopathological characteristics and surgical approach to Jacob's disease are discussed. Conclusion: In a patient with a limitation of mouth opening, and without any temporo-mandibular joint disease, an examination of the coronoid process is required to identify hypertrophy ofthe coronoid process and to diagnose Jacob's disease. [ABSTRACT FROM AUTHOR]

Geometrically accurate and anatomically correct 3D models of the human bones are of great importance for medical research and practice in orthopedics and surgery. These geometrical models can be created by the use of techniques which can be based on input geometrical data acquired from volumetric methods of scanning (e.g., Computed Tomography (CT)) or on the 2D images (e.g., X-ray). Geometrical models of human bones created in such way can be applied for education of medical practitioners, preoperative planning, etc. In cases when geometrical data about the human bone is incomplete (e.g., fractures), it may be necessary to create its complete geometrical model. The possible solution for this problem is the application of parametric models. The geometry of these models can be changed and adapted to the specific patient based on the values of parameters acquired from medical images (e.g., X-ray). In this paper, Method of Anatomical Features (MAF) which enables creation of geometrically precise and anatomically accurate geometrical models of the human bones is implemented for the creation of the parametric model of the Human Mandible Coronoid Process (HMCP). The obtained results about geometrical accuracy of the model are quite satisfactory, as it is stated by the medical practitioners and confirmed in the literature. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to define the coronoid-condylar index (CCI). Materials and Methods: The material for studies comprised 26 patients. Thirteen patients were treated for bilateral coronoid hyperplasia. The remaining 13 patients were included in the control group. Based on 3D CT measurements, the coronoidcondylar index (CCI) was calculated and assessed statistically. Results: In patients with coronoid hyperplasia mean CCI was 1.25, while in the control group it was 1.00. Conclusion: The proposed CCI can be used for the evaluation of anomalies of the mandibular coronoid processes [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The three-dimensional (3D) asymmetric structure of the mandible makes it necessary to analyze both its size and angle. Currently the developing 3D analysis techniques are not able to perform the simultaneous linear and angular measurements. Our aim was to evaluate mandibular asymmetry using a vector-based system by constructing 3D vectors for the mandibular functional units. Material and methods: We analyzed the 3D computed tomography images of normal control (N = 27) and asymmetric mandibles (N = 40). We created 3D vectors for the condylar, coronoid, body, gonial, and symphyseal functional units and compared the corresponding pairs of 3D vectors by calculating vector operations. Results: The vector difference and other vector components represented the individual 3D architectural pattern and severity of the asymmetric mandible. The body unit contributed most to mandibular asymmetry followed by the condylar unit. Conclusions: The results indicate that 3D vector analysis can improve our understanding of the 3D architecture of asymmetric mandibles. This type of 3D vector analysis can be a useful tool for the comprehensive evaluation of its asymmetric mandibular structure. [Copyright &y& Elsevier]

Aims: The aim of the study was to evaluate the role of three-dimensional computed tomography (3D-CT) in the assessment of temporomandibular joint (TMJ) ankylosis and its importance in treatment planning. The objectives of study were to measure and assess the mediolateral extent of ankylosis mass in 3D-CT and to compare the extent with intraoperative assessment. The study was also aimed to measure the coronoid process elongation in 3D-CT and its significance in treatment planning. Materials and Methods: This prospective study included 3D-CT evaluation of 11 patients with TMJ ankylosis during the period of February 2006-October 2007. Results: The 3D-CT assessment provided the length of the coronoid process and the relation of vital structures including maxillary artery to the ankylosed mass. Measurement of ankylosed mass also aids in preoperative measurement of the graft required to reconstruct the defect following removal of the ankylosed mass. Conclusion: Our study concludes that 3D-CT is a useful tool in the diagnosis and treatment planning of TMJ ankylosis. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the hypothesis that a quantitative 3-dimensional computed tomography (CT) modeling technique that can measure size, shape, and proximal articular surface area can be used to develop formulas that could predict the volume and proximal surface area of the intact coronoid based on anatomical and demographic data available in patients with fracture of the coronoid process. Methods: We used a consecutive series of 50 CT scans with a slice thickness of 1.25 mm or less obtained in patients with fracture of the distal humerus, but no injury to the coronoid, to create 3-dimensional models. The volume and articular surface area of the coronoid were measured, and predictive formulas were based on anatomical measurements. We calculated gender using multiple linear regression. Results: There were significant correlations between total coronoid volume and coronoid articular surface area for coronoid width, radial neck diameter, radial head diameter, height, weight, and gender. Multiple linear regression modeling with the factors radial head diameter, radial neck diameter, coronoid width, height, weight, and gender resulted in formulas that could account for 71.8% of the variation in coronoid volume and 66.2% of the variation in coronoid articular surface area. The average relative percent difference was 1.32% for the coronoid volume and 0.68% for the coronoid articular surface area. Conclusions: The volume and articular surface area of the coronoid can be estimated based on anatomical measurements and gender. This may lead to better estimates of lost fragments when modeling the fractured coronoid and CT scan of the opposite limb is not available. [ABSTRACT FROM AUTHOR]

Purpose: This study tests the hypothesis that 3-dimensional computed tomography (CT) reconstructions improve interobserver agreement on classification and treatment of coronoid fractures compared with 2-dimensional CT. Methods: A total of 29 orthopedic surgeons evaluated 10 coronoid fractures on 2 occasions (first with radiographs and 2-dimensional CT and then with radiographs and 3-dimensional CT), separated by a minimum of 2 weeks. Surgeons classified fractures according to the classifications of Regan and Morrey and of O''Driscoll et al., identified specific characteristics, recommended the most appropriate treatment approach, and made treatment recommendations. The kappa multirater measure (κ) was calculated to estimate agreement between observers. Results: Regardless of the imaging modality used, there was fair to moderate agreement for most of the observations. Three-dimensional CT improved interobserver agreement in Regan and Morrey''s classsication (κ3-dimensional = 0.51 vs κ2-dimensional = 0.40; p < .001) and O''Driscoll et al.''s classifications (κ3-dimensional = 0.48 vs κ2-dimensional = 0.42; p = .009). There were trends toward better reliability for 3-dimensional reconstruction in recognition of coronoid tip fractures (κ3-dimensional = 0.19, κ2-dimensional = 0.03; p = .268), comminution (κ3-dimensional = 0.41 vs κ2-dimensional = 0.29; p = .133), and impacted fragments (κ3-dimensional = 0.39 vs κ2-dimensional = 0.27; p = .094), and in surgeons'' opinions on the need for something other than screws or plate for surgical fixation (κ3-dimensional = 0.31 vs κ2-dimensional = 0.15; p = .138). Interobserver agreement on treatment approach was better with 2-dimensional CT (κ3-dimensional = 0.27, κ2-dimensional = 0.32; p = .015). Conclusions: Three-dimensional CT reconstructions improve interobserver agreement with respect to fracture classification compared with 2-dimensional CT. Type of study/level of evidence: Diagnostic III. [Copyright &y& Elsevier]

An unusual accidental displacement of a mandibular third molar crown into the parapharayngeal space in an adult female patient is reported. In combination with clinical examination, conventional and advanced radiographic techniques were utilised in order to locate the crown for retrieval surgery. Under general anaesthesia, an incision starting from buccal sulcus towards distobuccal angle of the second molar at gingival margin was extended to the coronoid process. The dislodged crown was found by means of blunt dissection and grasped with a pair of artery forceps and removed. [ABSTRACT FROM AUTHOR]

The mandible or the submaxilla is a "U"-shaped pivotal structure, considering the attachment of the muscles of mastication with relation to mastication itself. The coronoid process is a variably shaped beak-like projection at the anterosuperior aspect of the ramus. The anterior border of which is convex and continuous with that of the ramus. Posteriorly, the border is slightly concave and contributes to the mandibular notch. The entire border of the coronoid along with the medial surface provides attachment for the temporalis muscle. Previous studies have shown that the size and shape of the coronoid are correlated to the bite force required by an individual and is dependent upon the mechanical force acting upon it during development. However, little is known about the developmental program leading to the specification of the process. The relative size & shape of the coronoid process varies considerably across individuals. [ABSTRACT FROM AUTHOR]