Cone-beam computed tomography study of mandibular morphology and tooth compensation in asymmetrical patients.

INTRODUCTION: This study evaluated mandibular morphology and transverse dental compensation between symmetrical and asymmetrical subjects, allocated according to sagittal skeletal patterns. In addition, the hypothesis that mandibular morphology and dental compensations differed between symmetrical/asymmetrical groups and also among the different types of sagittal skeletal patterns was tested. METHODS: Cone-beam computed tomography images of 96 patients were included in this study and were divided into 2 groups according to the degree of menton deviation: a symmetrical group with deviation up to 2.0 mm (n = 48; mean age, 15 ± 6 years), and an asymmetrical group with deviation from 3.5 mm (n = 48; mean age, 16 ± 8 years). The 2 groups were divided in accordance with the ANB angle: Class I, II, and III. Skeletal and dental measurements were performed. Intergroup and intragroup analyses were carried out, using a 2-way analysis of variance to assess the interaction of factors: symmetry and sagittal skeletal pattern; and the Student t test for differences between deviated (Dv) and nondeviated (NDv) sides. RESULTS: Symmetrical/asymmetrical groups and Class I, II, and III groups were similar in relation to demographic aspects (P = 0.412 and P = 0.357 for sex and age, respectively). Asymmetrical patients had higher values for body length and mandibular ramus and condyle height on the NDv side (P = 0.011, P = 0.024, and P = 0.001, respectively). When comparing the different skeletal patterns, patients with a Class III relationship demonstrated higher values for mandibular ramus height. Intergroup analysis showed no differences in dental parameters. In the comparison between the sides, the asymmetrical group showed a significant difference in canine inclination (P = 0.008), mandibular ramus height (P = 0.004), condyle height (P = 0.010) and gonion to midsagittal plane distance (P = 0.018). CONCLUSIONS: Asymmetrical subjects showed higher values for canine inclination and mandibular body, ramus and condylar height on the NDv side. The hypothesis was partially confirmed that mandibular morphology and dental compensations are different between symmetrical/asymmetrical groups and among different sagittal skeletal patterns.

Three dimensional condylar positional and morphological changes following mandibular reconstruction based on CBCT analysis: a prospective study.

OBJECTIVE: This study aimed to evaluate the condylar positional changes following mandibular reconstruction with preservation of the condylar head using Cone-Beam Computed Tomography (CBCT). Also, to assess joint space changes and the overall volumetric space compared to the preoperative status. METHODOLOGY: This prospective study included 30 patients (60 joints) subjected to unilateral mandibular resection and reconstruction with preservation of the condylar head. The Helkimo index and preoperative (T1), two weeks postoperative (T2), and follow-up CBCTs (T3) after at least six months were gathered and processed to evaluate the condylar position and TMJ joint space using Anatomage Invivo 6. A student's t-test and repeated-measures ANOVA statistics were used. A P value of less than 0.05 was considered statistically significant. RESULTS: Thirty patients (14 males, 16 females) with a mean age of 40.01 ± 12.7 years (a range of 18.1-62.9 years) were included. On the tumor side, there were significant variances in the vertical and mediolateral condylar positions between the three-time points (T1, T2, T3). Immediately after the operation, the condyles were significantly displaced in a downward direction at T2, which became larger after the last follow-up period (T3) (p = 0.007). The condylar positions at the anteroposterior direction were relatively stable without significant differences between the three times points (p = 0.915). On the non-tumor side, the condylar positions were relatively stable in the mediolateral and anteroposterior positions. In the tumor side, all of the TMJ spaces were significantly increased in size following the mandibular reconstructions (T2 and T3). However, on the non-tumor side, the anterior, posterior, and medial joint spaces were significantly changed postoperatively. CONCLUSION: After mandibular reconstruction with condylar preservation, the condylar position and volumetric measurement immediately changed noticeably and continued to be a permanent change over time compared to relatively stable condyles on the non-tumor side. According to Helkimo index, patients become adapted to the postoperative changes without significant differences between the two sides.

Association of temporomandibular joint osteoarthrosis with dentoskeletal morphology in males: A cone-beam computed tomography and cephalometric analysis.

OBJECTIVE: The objective of the study was to assess the differences in dentoskeletal morphology in males with and without temporomandibular joint osteoarthrosis (TMJOA). METHODS: Three hundred seventy-one male participants seeking orthodontic treatment were enrolled in this cross-sectional study. Each participant's osseous status was evaluated using cone-beam computed tomography (CBCT) and classified into normal (N = 104), indeterminate for TMJOA (N = 110) and TMJOA (N = 157) groups. The dentoskeletal characteristics were evaluated using cephalograms. Stratified analysis was performed based on age and skeletal pattern. Descriptive statistics and one-way analysis of variance were performed to investigate dentoskeletal differences among groups. P < .05 was considered statistically significant. RESULTS: The differences in posterior cranial base length, FMA, MP-OP, anterior facial height, articular angle, ramus height and L1-MP were statistically significant. After stratification by age, the differences in FMA, maxillomandibular angle, posterior facial height, facial height ratio, gonial angle and mandibular body length were statistically significant in adults. No statistical difference except for articular angle was observed in adolescents. After stratification by skeletal pattern, statistical differences were mainly apparent in skeletal Class II adults. CONCLUSION: Males with TMJOA showed a posteriorly positioned and backward-rotated mandible, especially in skeletal Class II adults. Compared with women, the craniofacial morphology of men is less affected by TMJOA. The association between TMJOA and craniofacial morphology also varied across different age groups and skeletal patterns. Prospective studies are required to clarify the cause-effect relationship between TMJOA and craniofacial morphology in males.

Relationship between the condyle morphology and clinical findings in terms of gender, age, and remaining teeth on cone beam computed tomography images

Aim: This study aimed to evaluate the relationship between clinical findings and some factors such as age, gender, and remaining teeth on the anatomy of the temporomandibular joint in order to diagnose normal variations from abnormal cases. Methods: In this cross-sectional study, cone-beam computed tomography (CBCT) images of 144 patients referring to Tabriz Dental School for various reasons were selected and evaluated. The different aspects of the clinical parameters and the morphology of the condyle were evaluated on coronal, axial, and sagittal views. The CBCT prepared using the axial cross-sections had been 0.5 mm in thickness. The sagittal cross-sections had been evaluated perpendicular to the lengthy axis of the condyle at a thickness of 1 mm and the coronal cross-sections had been evaluated parallel to the lengthy axis of the condyle at a thickness of 1 mm. Data were analyzed with descriptive statistical methods and t-test, chi-squared test, using SPSS 20. The significance level of the study was p < 0.05. Results: There was a significant relationship between the condyle morphology, number of the teeth, and mastication side (p = 0.040). There were significant relationships between the condyle morphology, age between 20-40, and occlusion class I on the all the three views (coronal, axial, sagittal) (p = 0.04), (p = 0.006), (p = 0.006). Also, significant relationships were found in the condyle morphology and location of pain according to age, the number of remaining teeth, and gender. (p = 0.046) (p = 0.027) (p = 0.035). Conclusion:There are significant relationships between the clinical symptoms and condyle morphology based on age, gender, and the number of remaining teeth. The clinical finding that has the most significant relationship between the condyle morphology, remaining teeth (9-16 teeth), all of the age range (20-80 year), and gender was mastication side

The effect of mandibular movement on temporomandibular joint morphology while eating French fries.

BACKGROUND: The preferred masticatory side was reported to be almost always the same as the affected side of the temporomandibular disorder. Unbalanced alterations of temporomandibular joint morphology were found to be associated with unilaterally masticatory habits. The aim of this study was to investigate the effect of the mandibular movement on the remodeling of temporomandibular joint during eating French fries using a 3D motion capture system. METHODS: Twelve volunteers with non-maxillofacial deformity and a healthy temporomandibular joint were recruited. The 3D models of the mandible and the maxilla were reconstructed according to computed tomography. The subjects were asked to eat French fries by unilaterally mastication, which was recorded by a 3D motion capture system. The trajectories of the incisors and the condyles and the condylar acceleration during unilateral mastication were analyzed. RESULTS: During incisal biting, there was no significant difference in the condylar trajectories between the left and right sides (P > 0.05). During unilateral mastication, the average displacement and acceleration of the masticatory condyles were significantly lower than those of the non-masticatory condyles (P < 0.05). The trajectory angles of the masticatory condyles were significantly steeper than those of the non-masticatory condyle (P < 0.05). During swallowing, there was no obvious movement of the mandible. CONCLUSIONS: Between both temporomandibular joints, unilateral mastication resulted in significant differences in the regions of the condylar movement within the articular fossa, and then caused different compressive regions of the temporomandibular joints. Thus, unilateral mastication might result in a significantly different pattern of temporomandibular joint remodeling between the two sides.

Comprehensive three-dimensional positional and morphological assessment of the temporomandibular joint in skeletal Class II patients with mandibular retrognathism in different vertical skeletal patterns.

BACKGROUND: Only a few studies have used 3D cone-beam computed tomography (CBCT) analysis to evaluate the positional and morphological characteristics of the temporomandibular joint (TMJ) in adults with skeletal Class II. No studies have focused on the case of skeletal Class II with mandibular retrognathism in different vertical skeletal patterns. As a result, this study aimed to evaluate and compare the position and morphology of TMJ in adults with skeletal Class II with mandibular retrognathism in different vertical skeletal patterns to the position and morphology of TMJ in the normal Chinese adult population in three dimensions. METHODS: This retrospective study analyzed CBCT images of 80 adult patients. Subjects with skeletal Class II with a normal sagittal position of the maxilla and mandibular retrognathism were classified according to the mandibular angle and facial height ratio into three groups of 20 subjects each: hypodivergent, normodivergent, and hyperdivergent groups, as well as a control group of 20 subjects. The following 3D measurements of TMJ were evaluated: (1) position, parameters, and inclination of the mandibular fossa; (2) position, parameters, and inclination of the mandibular condyle; (3) condyle centralization in their respective mandibular fossae; (4) anterior, posterior, superior, and medial joint spaces; and (5) 3D volumetric measurements of the TMJ spaces. Measurements were statistically analyzed by one-way ANOVA test, followed by Tukey's post hoc test. RESULTS: Significant differences were found in the hyperdivergent and hypodivergent groups compared with the normal group in the vertical and anteroposterior mandibular fossa position, vertical condylar inclination, and condylar width and length. The hyperdivergent group showed the significantly highest condylar inclination with the midsagittal plane; anterior and superior positioning of the condyle; smallest anterior, superior, and medial joint spaces; and largest volumetric total joint space relative to the two other groups. CONCLUSIONS: The condyle-fossa position and morphology differ with various vertical facial patterns in individuals with skeletal Class II mandibular retrognathism. These differences could be considered during TMD diagnosis and orthodontic treatment.

Automated cortical thickness measurement of the mandibular condyle head on CBCT images using a deep learning method.

This study proposes a deep learning model for cortical bone segmentation in the mandibular condyle head using cone-beam computed tomography (CBCT) and an automated method for measuring cortical thickness with a color display based on the segmentation results. In total, 12,800 CBCT images from 25 normal subjects, manually labeled by an oral radiologist, served as the gold-standard. The segmentation model combined a modified U-Net and a convolutional neural network for target region classification. Model performance was evaluated using intersection over union (IoU) and the Hausdorff distance in comparison with the gold standard. The second automated model measured the cortical thickness based on a three-dimensional (3D) model rendered from the segmentation results and presented a color visualization of the measurements. The IoU and Hausdorff distance showed high accuracy (0.870 and 0.928 for marrow bone and 0.734 and 1.247 for cortical bone, respectively). A visual comparison of the 3D color maps showed a similar trend to the gold standard. This algorithm for automatic segmentation of the mandibular condyle head and visualization of the measured cortical thickness as a 3D-rendered model with a color map may contribute to the automated quantification of bone thickness changes of the temporomandibular joint complex on CBCT.

Mandibular ramus height and condyle distance asymmetries in individuals with different facial growth patterns: a cone-beam computed tomography study.

PURPOSE: This study aimed to quantify mandibular ramus height and condylar distances asymmetry indexes in adult patients with different vertical facial growth pattern using Cone Beam computed tomography (CBCT). METHODS: An observational cross-sectional study was conducted by using CBCT of 159 patients (mean age 26.36 ± 5.32 years). Vistadent 3D® software was used to determine the facial pattern in 3 groups (N = 53): hypodivergent, normodivergent and hyperdivergent-by Ricketts VERT index. Mandibular ramus height and the condylar linear distance in relation to the median sagittal plane were evaluated. The asymmetry index was calculated considering the right and left sides. Data were analyzed by generalized linear models and Tukey post-hoc test (α = 0.05). RESULTS: Significantly lower values were found for the left and right mandibular ramus height in the hyperdivergent skeletal pattern (P < 0.05). There was no statistically significant difference for condylar and intercondylar distances among the facial groups (P > 0.05). Asymmetry indexes (mandibular ramus height and condylar distance) were similar, and no statistically significant differences were found among the skeletal patterns. In most subjects, the severity of mandibular ramus height asymmetry varied from light to not clinically significant independently of the facial type. CONCLUSION: The findings suggest that vertical facial growth pattern not affected the asymmetry index of mandibular ramus height and the intercondylar distance. The results also demonstrated significantly shorter mandibular ramus height for the hyperdivergent skeletal pattern individuals.

Postoperative Anatomic Position of Mandibular Free Flap Neocondyles Affects Patient Symptoms.

Importance: Mandibular condyle reconstruction with vascularized free flaps can re-establish form and function after resection. However, no reports have been published regarding the postoperative anatomic seating of these reconstructions. Objective: To use postoperative axial imaging to determine whether condylar reconstructions migrate and correlate their ultimate location with postoperative symptoms. Design, Setting, and Participants: A prospectively maintained database of free flap cases performed between 2006 and 2019 at a single institution was queried. Twenty-one consecutive patients who underwent reconstructions that involved the mandibular condyle who also had postoperative axial imaging were selected for review. Distances were measured from the reconstructed condyle to the lateral, superior, and posterior aspect of the temporomandibular joint (TMJ), and correlated with postoperative symptoms and jaw function. Main Outcomes and Measures: Condyle displacement, postoperative diet, jaw pain, trismus, and malocclusion. Results: In total, 57% of patients had 1 cm or greater displacement of the condylar reconstruction from the TMJ in at least one vector. Anterior displacement of condyle by >1 cm was associated with jaw misalignment (42.8%) and clicking (14.3%) [odds ratio (OR) 37.3, 95% confidence interval (CI) 1.6-866.9, p = 0.024]. However, 83.3% of these patients were able to return to a normal diet and denied dysphagia. All edentulous patients had acceptable anteroposterior alignment, but 42.8% of dentulous patients had anterior displacement >1 cm (p = 0.12). Inferior displacement >1 cm was associated with dysphagia (OR 23, 95% CI 1.07-494.6, p = 0.04), but not pain or trismus. Eleven patients had multiple postoperative computed tomography scans, on average 21 months apart. The reconstructed location was stable in all 11 patients. Conclusions and Relevance: Patients undergoing free flap reconstruction of the mandibular condyle often return to normal diet, even when their reconstructions do not sit perfectly within the TMJ. Anterior displacement of the neocondyle may be more common in dentulous patients due to stress on the joint from chewing and produces some dysfunction and misalignment. Inferior displacement of the neocondyle may result in dysphagia. The reconstructed condyles are unlikely to migrate over time.

Análise morfológica comparativa do côndilo mandibular e outras estruturas da mandíbula e base do crânio em maloclusões classe I, II e III esqueléticas / Comparative morphological analysis of the mandibular condyle and other structures of mandible and cranial base in class I, II and III skeletal malocclusions

O objetivo deste estudo foi comparar o volume condilar em indivíduos com diferentes maloclusões esqueléticas. Também foram realizadas análises das semelhanças morfológicas entre o côndilo mandibular e outras estruturas da mandíbula e base do crânio, por meio de medidas lineares e volumétricas. Essas análises foram realizadas usando Tomografia Computadorizada de Feixe Cônico (TCFC), modelos tridimensionais de côndilos mandibulares e sínfise mandibular de 58 indivíduos foram construídos, e os volumes e áreas foram mensurados. A amostra foi dividida nos seguintes grupos: Classe I (0 ≤ ANB ≥ 4,5°) (n=18), Classe II (ANB > 4,5°) (n=21) e Classe III (ANB < 0°) (n=19). Dezesseis pontos de referência do tecido duro na mandíbula e base do crânio foram identificados por um operador treinado e calibrado. Foram obtidas as distâncias 3D entre os pontos e as projeções nos três planos do espaco (x, y e z). A comparação do volume condilar entre os lados direito e esquerdo foi realizada pelo teste de Wilcoxon (Classe I) e Test t pareado (Classe II e III) e a comparação inter-grupos foi realizada com o teste ANOVA/Tukey (a=0,05). Análises de correlação de Pearson e regressão linear foram realizadas para avaliar a relação entre o volume dos côndilos e a sínfise mandibular, e o volume dos côndilos e as medidas lineares realizadas na mandíbula e base do crânio. Não foi observada diferença estatisticamente significativa entre os volumes condilares dos lados direito e esquerdo em diferentes maloclusões esqueléticas (Classe I: p=0,728; Classe II: p=0,741 e Classe III: p=0,155). Indivíduos de classe III apresentaram maior volume condilar (Classe III: 1990,85 ± 559,42) em comparação aos indivíduos de classe I e II (Classe I: 1835,22 ± 552,15; Classe II: 1725,47 ± 394,64), embora a diferença não tenha sido estatisticamente significativa (p=0,214). Houve uma correlação significativa, mas moderada, entre os volumes condilares e as medidas lineares da sínfise mandibular (p <0,01). Conclui-se que os volumes condilares não variam significativamente em diferentes padrões esqueléticos sagitais e, entre os lados direito e esquerdo. A relação entre o volume condilar e a sínfise mandibular foi moderada e equações de regressão foram desenvolvidas para estimar o volume condilar. (AU)

The aim of this study was to compare the condylar volume in individuals with different skeletal classes. Analyzes of the morphological similarities between the mandibular condyle and other structures of the mandible and cranial base were also performed, using linear and volumetric measurements. These analyzes were performed using Cone Beam Computed Tomography (CBCT), three-dimensional models of mandibular condyles and mandibular symphysis of 58 individuals were constructed, and volumes and areas were measured. The sample was divided into the following groups: Class I (0 ≤ ANB ≥ 4.5 °) (n = 18), Class II (ANB> 4.5°) (n = 21) and Class III (ANB <0 °) (n = 19). Sixteen hard tissue reference points in the mandible and cranial base were identified by a trained and calibrated operator. 3D distances were obtained between the points and the projections in the three planes of the space (x, y and z). The comparison of the condylar volume between the right and left sides was performed by the Wilcoxon test (Class I) and the paired t-test (Class II and III) and the inter-group comparison was performed with the ANOVA / Tukey test (a = 0, 05). Pearson's correlation analyzes and linear regression were performed to assess the relationship between condylar volume and mandibular symphysis, and condylar volume and linear measurements. There was no statistically significant difference between condylar volumes on the right and left sides in different skeletal malocclusions (Class I: p = 0.728; Class II: p = 0.741 and Class III: p = 0.155). Class III individuals had a higher condylar volume (Class III: 1990.85 ± 559.42) compared to Class I and II individuals (Class I: 1835.22 ± 552.15; Class II: 1725.47 ± 394, 64), although the difference was not statistically significant (p = 0.214). There was a significant, but moderate, correlation between condylar volumes and linear measurements of the mandibular symphysis (p <0.01). It is concluded that the condylar volumes do not vary significantly in different sagittal skeletal patterns and, between the right and left sides. The relationship between the condylar volume and the mandibular symphysis was moderate and regression equations were developed to estimate the condylar volume. (AU)

A panoramic study of the morphology of mandibular condyle in a sample of population from Basrah City / Estudio panorámico de la morfología del cóndilo mandibular en una muestra de población de la ciudad de Basora

SUMMARY: The study aims to evaluate the morphological variation of mandibular condyle This analysis was composed of 450 digital orthopantomograms taken for routine investigation to assess the morphology of 900 condylar heads. Condylar morphology was classified into four types (oval, bird beak, diamond and crooked finger). Most common occurring shape were evaluated, symmetry of condylar shape and most common combinations of the condylar shapes present in population were assessed. Out of 900 mandibular condyle, type 1(oval) of condyle was the most commonly appearing shape (56 %), followed by type 3 (diamond), type 2(bird beak) and finally type 4 (crooked finger). Symmetry was seen in 74.2 % of the total sample with the oval-oval was the most commonly occurring. Routine use of orthopantomography can assist dentist in assessment of condylar morphology alterations. Oval shape was the most common in all age groups in males and females. More studies on Iraqi population evaluating mandibular condyle are needed to provide standardized values for mandibular anatomical parts.

RESUMEN: El objetivo del presente estudio fue evaluar la variación morfológica del cóndilo mandibular. El análisis se realizó en 450 ortopantomogramas digitales en una investigación de rutina para evaluar la morfología de 900 cabezas condilares. La morfología condilar se clasificó en cuatro tipos (ovalada, pico de pájaro, diamante y dedo torcido). Se evaluó la forma más común de ocurrencia, la simetría de la forma condilar y las combinaciones más comunes en la población. De 900 cóndilos mandibulares, el tipo 1 (ovalado) de cóndilo apareció con mayor frecuencia (56 %), seguido del tipo 3 (diamante), el tipo 2 (pico de pájaro) y finalmente el tipo 4 (dedo torcido). Se observó simetría en el 74,2 % de la muestra total, siendo el óvalo-óvalo el que se presentó con mayor frecuencia. El uso rutinario de la ortopantomografía puede ayudar al dentista a evaluar las alteraciones de la morfología condilar. La forma ovalada fue la más común en todos los grupos etarios en hombres y mujeres. Se necesitan más estudios sobre la población iraquí que evalúen el cóndilo mandibular para proporcionar valores estandarizados para evaluar la anatomía mandibular.

Características anatómicas-funcionales que orientan la posición del cóndilo en la fosa mandibular en una relación céntrica: una descripción narrativa / Anatomical functional characteristics that guide the condylar position in mandibular fossa a centric relation: narrative description

RESUMEN: La Relación Céntrica (RC) es un concepto que busca definir la posición ideal del cóndilo de la mandíbula en la fosa mandibular, siendo esta posición muy discutida en la literatura y ha ido cambiado con los avances en conocimiento y tecnología. Tomándose en la actualidad en consideración elementos anatómicos esenciales que son utilizados como guía para el clínico. La importancia de poder reconocer esta posición radica en la correcta ejecución tanto de procedimientos diagnósticos como de tratamiento en diversas áreas de la odontología. Existen elementos anatómicos de la articulación temporomandibular (ATM) que nos ayudarían a comprender mejor el concepto de RC, entre estos destacan que la condensación ósea de las superficies articulares funcionales y su recubrimiento por fibrocartílago; la porción media del disco articular, desprovista de vasos y nervios; el techo de la fosa mandibular que puede llegar a ser extremadamente delgado por lo cual no se consideraría un área para soportar carga; la prolongación posterior del disco articular (DA) que es altamente vascularizada e inervada. El DA se encuentra íntimamente relacionado con estructuras como el ligamento temporomandibular o lateral y la cabeza superior del músculo pterigoideo lateral que permitirían junto a los elementos anteriormente mencionados el adecuado funcionamiento de la ATM. El correcto aprendizaje y utilización de estos conceptos contribuirá a lograr un mejor ejercicio del desarrollo profesional de estudiantes y profesionales del área de la odontología.

SUMMARY: The Central Relation (CR) is a concept that defines the ideal position of the mandibular condyle in the mandibular fossa. The position has been the subject of much discussion in the literature, noting changes as advancements in knowledge and technology are achieved. Thus, certain essential anatomical elements that are used as a guide for the clinician, are taken into account. The importance of being able to identify this position lies in the correct execution of both diagnostic and treatment procedures in various areas of dentistry. There are anatomical elements of the temporomandibular joint (TMJ) that improve understanding of the CR concept. These include: Bone condensation of the functional articular surfaces and their fibrocartilage coating; the middle portion of the joint disc, devoid of vessels and nerves. The roof of the mandibular fossa can become extremely thin, so it would not be considered an area to support load; the posterior prolongation of the articular disc (AD) Which is highly vascularized and innervated. The AD is also closely related to structures such as the temporomandibular or lateral ligament and the superior head of the lateral pterygoid muscle. Along with the previously described elements, this would allow proper functioning of the TMJ. The correct learning and use of these concepts contributes to a better exercise in the professional development of students and professionals in the area of dentistry.

Assessment of mandibular characteristics in patients affected with ß-thalassaemia major: A retrospective case-control study.

OBJECTIVE: Thalassemia is the most common hereditary blood disorder across the world. This study aimed to identify some mandibular features of thalassaemic patients and compare them with unaffected counterparts. MATERIAL AND METHODS: This retrospective case-control study was carried out on lateral cephalograms of 60 subjects (26 males, 34 females) with class II malocclusion and age range of 11 to 15 years. The control group consisted of 60 non-thalassaemic subjects with class II malocclusion and similar chronological age, gender and vertical facial dimension. Based on the Jarabak index, the case and control subjects were classified into hyperdivergent, normodivergent and hypodivergent growth patterns. Four linear (ramus height, ramus width, mandibular depth, and antegonial notch depth) and 3 angular (symphyseal angle, gonial angle, and mandibular arc angle) cephalometric parameters were measured to represent mandibular morphology. The data were analysed using Chi-square test and Student's t-test. RESULTS: No significant difference was found in linear measurements between thalassaemic patients and controls. The symphysis angle was significantly greater and the mandibular arc angle was significantly smaller in the total thalassaemic sample than the control individuals (P<0.001 and P=0.004, respectively). The difference in symphysis angle was significant in both hyperdivergent and normodivergent subjects (P=0.004 and P=0.002, respectively), whereas the difference in mandibular arc angle was only significant in the normodivergent subgroup P=0.001). CONCLUSIONS: The smaller mandibular arc angle in the thalassaemic sample suggests a more superior than posterior growth direction of condyles compared with healthy individuals. The difference in symphyseal angle represents inherent differences in chin morphology between thalassaemic subjects and controls.

Correlation between patient complaint, temporomandibular disorder diagnosis and mandible head morphology

The aim of this study was to evaluate the correlation between patient complaints, clinical diagnosis of temporomandibular disorder (TMD) based on the diagnostic criteria for TMD, and morphology of the mandibular condyle obtained by cone-beam computed tomography (CB-CT). Data were collected from 40 patients. The anatomy of the mandibular condyle was assessed using CB-CT, the diagnosis of TMD according to diagnostic criteria for TMD, and patients' complaints was registered at the appointment. Data were explored and all statistical references were completed in bicaudal tests, with 95% confidence level (α=0.05). The Chisquared test was used with Bonferroni correction (z-tests). Main complaints found were grouped as muscular, articular, muscular and articular, or headache and articular symptoms. Clinical diagnosis of TMD involved myalgia, local myalgia, myofascial pain, myofascial pain with reference, myofascial pain with arthralgia, arthralgia, or disc displacement with reduction. At least one joint showed condylar flattening, erosion, sclerosis, or osteophytes. No correlation was observed between main complaints, clinical diagnosis, and morphology of the mandibular condyle in all comparisons. The findings suggest that due to the absence of clinical and morphological correlation, CB-CTs should be requested only in specific cases, when doubt remain after careful TMD diagnosis, to avoid their over-indication(AU)

Anatomy of the lateral pterygoid muscle and its relationship with temporomandibular disorders. A literature review

The lateral pterygoid muscle is a chewing muscle that is found bilaterally in the cranial region. Anatomically, the lateral pterygoid muscle is made up of two bellies, an upper belly and a lower belly. Its anatomical description present in the scientific lit-erature showed that there is an anatomical differ-ence or variation, mainly the insertions of the up-per belly of the lateral pterygoid muscle at the level of the temporomandibular joint, and specifically in the disc and articular condyle, although distribu-tions are reported similarly. They are not entirely accurate in smaller quantities: some articles re-ported variations in the insertion of the lower belly and others the appearance of a third belly of the lateral pterygoid muscle or medial belly. As men-tioned above, a high number of studies that presented some type of lateral pterygoid muscle vari-ation was associated with some type of temporo-mandibular disorders of the joint or some of its in-tra or extra-articular components. A review of the literature in scientific databases was carried out after the selection of the scientific articles, which were analyzed in full text, and the relationship between the anatomy of the lateral pterygoid muscleand the temporomandibular disorders was sought

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CBCT Analysis of Changes in Dental Occlusion and Temporomandibular Joints before and after MEAW Orthotherapy in Patients with Nonlow Angle of Skeletal Class III.

This study focus on the changes of the position and morphology of jaw and condyle after MEAW (the multiloop edgewise arch wire) treatment in adults with a nonlow angle (mean angle or high angle SN - MP > 27°) of skeletal class III (mild to moderate skeletal classs III means -5° < ANB < 0°) malocclusions measured by CBCT (cone beam computed tomography). Twenty adult patients (aged 17-26) with a nonlow angle of skeletal class III malocclusions were selected in this study taken orthodontic treatment by MEAW. CBCT was taken before and after the treatment to analyze the changes of the jaw and condyle. After treatment, the angle of L7-MP decreased 12.2°, L6-MP decreased 10.5°, L1-MP decreased 8.8° (P < 0.001 for each) and U1-SN increased (P < 0.05). There was no significant changes between anterior and posterior APDI index and between anterior and posterior spaces of the TMJ (temporomandibular joint) (P > 0.05). The linear ratio of the TMJ was the LR > 12 before treatment, while it was -12 < LR < 12 after treatment; however, there was no statistically significant difference between them (P > 0.05). There was also no significant change in anterior and posterior position and morphology of the condyle within the joint fossa after the treatment by MEAW in this study. MEAW technology in correcting the class III with nonlow angle patients mainly relies on the compensation of distally and posterior mandibular teeth, rather than the mandible and condyle moving backward to establish a neutral occlusal. This study was approved by the institutional ethics committee of the Second Hospital of Tianjin Medical University (No. KYJJ2013002).

Evaluation of 2 ultrasonic indicators as predictors of difficult laryngoscopy in pregnant women: A prospective, double blinded study.

BACKGROUND: Ultrasonic measurements of tongue thickness and condylar translation were recently introduced to predict difficult laryngoscopy in non-obstetric patients. We designed the present study to evaluate the performance of these two ultrasonic indicators in predicting difficult laryngoscopy in healthy parturients. METHODS: The 119 parturients undergoing elective cesarean delivery were enrolled. Tongue thickness and condylar translation measured by ultrasonography, and Modified Mallampati test (MMT) score, inter-incisor distance (IID) and modified Cormack-Lehane grading system (MCLS) were measured and recorded before anesthesia. The primary outcome was difficult laryngoscopy defined as MCLS 3 or 4. The association between these variables and difficult laryngoscopy were analyzed by using multivariable logistic regression and receiver operating characteristic (ROC) curve. RESULTS: Compared to the Easy Laryngoscopy Group, the tongue thickness was significantly higher and the condylar translation and IID were significantly lower in the Difficult Laryngoscopy Group. Tongue thickness and condylar translation but not MMT score and IID were proved to be two independent predictors for difficult laryngoscopy by multivariate logistic regression, with the odds ratios of 2.554 (95% confidence interval (CI), 1.715 to 3.802) and 0.457 (95% CI, 0.304 to 0.686). The area under the ROC curve to predict difficult laryngoscopy for tongue thickness was 0.93 (95% CI, 0.88-0.98) and for condylar translation was 0.77 (95% CI, 0.67-0.86), which were significantly higher than those for MMT score (0.67, 95% CI, 0.56-0.77) and IID (0.65, 95% CI, 0.55-0.76). CONCLUSIONS: Compared with MMT and IID, tongue thickness and condylar translation measured by ultrasonography appear to be better indicators for predicting difficult laryngoscopy in parturients.The trial was registered at the Chinese Clinical Trial Registry (ChiCTR)(www.chictr.org), registration number ChiCTR-ICR-1800019991.

Dimension and morphology of the mandibular condyle in class I patients in cone beam computed tomography / Dimensión y morfología del cóndilo mandibular en pacientes de clase I en tomografía computarizada de haz cónico

To evaluate the anterior-posterior (A-P)/medial-lateral (M-L) dimension, and morphology of the mandibular condyle in patients aged 18 to 65 years with Class I skeletal pattern on Cone Beam CT scans. Materials and Methods: Seventy one scans were evaluated using RealScan 2.0 software. The dimension was determined by points A (most anterior in the sagittal plane), P (most posterior in the sagittal plane), M (most interior in the coronal plane), L (most exterior in the coronal plane). The morphology of the condyle was evaluated in two coronal and sagittal planes, being classified as: round, flat, convex or mixed. The size of the condyle was analyzed by descriptive statistics and the morphology by frequency distribution. For the bivariate analysis, the Student's t-test was applied. Results: Measurements were obtained for the A-P diameter of the right condyle (RC) (8.72mm ± 1.25mm) and the left condylar (LC) (8.50mm ± 1.50mm), the M-L diameter of the RC (19.24mm ± 2.03mm) and the LC (18.97mm ± 1.87mm). There were significant differences in the male M-L dimension of the LC compared to the female (p=0.002). The most prevalent morphology of RC (35.21) and IQ (23.94) in the coronal plane was round. Conclusion: The A-P dimension of the right and left condyle is similar in both genders; however, there are differences in the M-L dimension of the left male condyle. The most prevalent morphology of the right and left condyle was round in the sagittal plane with the exception of the coronal plane.

Evaluar la dimensión antero- posterior (A-P)/medio-lateral (M­L), y la morfología del cóndilo mandibular en pacientes de 18 a 65 años con patrón esquelético Clase I en tomografías computarizadas Cone Beam. Material y Métodos: 71 tomografías fueron evaluadas mediante el software RealScan 2.0. La dimensión fue determinada por los puntos A (más anterior en el plano sagital), P (más posterior en el plano sagital), M (más interno en el plano coronal), L (más externo en plano coronal). Se evaluó la morfología del cóndilo en dos planos coronal y sagital, clasificándose en: redonda, aplanada, convexa y mixta. La dimensión del cóndilo fue analizada por estadística descriptiva y la morfología mediante distribución de frecuencias. Para el análisis bivariado, se aplicó la prueba de t de Student. Resultado: Se obtuvieron las medidas del diámetro A-P del cóndilo derecho (CD) (8,72mm ± 1,25mm) y el izquierdo (CI) (8,50mm ± 1,50mm), el diámetro M-L del CD (19,24mm ± 2,03mm) y el CI (18,97mm ± 1,87mm). Hubo diferencias significativas en la dimensión M-L del CI del sexo masculino en comparación al femenino (p=0.002). La morfología más prevalente del CD (35,21) y CI (23,94) en plano coronal fue de tipo redonda. Conclusión: La dimensión A-P del cóndilo derecho e izquierdo es similar en ambos sexos; sin embargo, existen diferencias en la dimensión M-L del cóndilo izquierdo del sexo masculino. La morfología del cóndilo derecho e izquierdo más prevalente fue la redonda en plano sagital a excepción del plano coronal.

Endosteal blood supply of the mandible: anatomical study of nutrient vessels in the condylar neck accessory foramina.

PURPOSE: In the mandible, the condylar neck vascularization is commonly described as mainly periosteal; while the endosteal contribution is still debated, with very limited anatomical studies. Previous works have shown the contribution of nutrient vessels through accessory foramina and their contribution in the blood supply of other parts of the mandible. Our aim was to study the condylar neck's blood supply from nutrient foramina. METHODS: Six latex-injected heads were dissected and two hundred mandibular condyles were observed on dry mandibles searching for accessory bone foramina. RESULTS: Latex-injected dissections showed a direct condylar medular arterial supply through foramina. On dry mandibles, these foramina were most frequently observed in the pterygoid fovea in 91% of cases. However, two other accessory foramina areas were identified on the lateral and medial sides of the mandibular condylar process, confirming the vascular contribution of transverse facial and maxillary arteries. CONCLUSIONS: The maxillary artery indeed provided both endosteal and periosteal blood supply to the condylar neck, with three different branches: an intramedullary ascending artery (arising from the inferior alveolar artery), a direct nutrient branch and some pterygoid osteomuscular branches.

Evaluation of condyle-fossa relationships in adolescents with various skeletal patterns using cone-beam computed tomography.

OBJECTIVES: To evaluate the condyle-fossa relationship in adolescents with various skeletal patterns using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT images obtained in 120 adolescent patients were used for this study. The patients were divided into 3 groups according to 3 criteria: (1) age (early, middle, and late adolescence); (2) facial height ratio or Jarabak quotient (hyperdivergent, normodivergent, and hypodivergent); and (3) ANB classification (Class I, Class II, and Class III). Temporomandibular joint space (TMJS: AS, anterior space; SS, superior space; PS, posterior space; MS, medial space; LS, lateral space), width and depth of the condyle (MLT, mediolateral thickness; APT, anteroposterior thickness), articular slope (ArS) and vertical height of the fossa (VHF) were measured and compared using CBCT. RESULTS: Differences in condyle-fossa relationships were not significantly different between male and female adolescents, but were significantly different (P < .05) between left and right sides. The mean values showed no statistical differences according to age and skeletal pattern. Most measurements in the sagittal view showed that SS was the greatest, and the mean ratio of AS to SS to PS was 1.00 to 1.27 to 1.19, respectively. The mean values of coronal MS and LS were not significantly different. CONCLUSIONS: There were almost no statistical differences in the TMJS in adolescents across various factors except between left and right sides.