Comparison of knee joint and temporomandibular joint development in pig embryos.

Although the knee joint (KNJ) and temporomandibular joint (TMJ) all belong to the synovial joint, there are many differences in developmental origin, joint structure and articular cartilage type. Studies of joint development in embryos have been performed, mainly using poultry and rodents. However, KNJ and TMJ in poultry and rodents differ from those in humans in several ways. Very little work has been done on the embryonic development of KNJ and TMJ in large mammals. Several studies have shown that pigs are ideal animals for embryonic development research. Embryonic day 30 (E30), E35, E45, E55, E75, E90, Postnatal day 0 (P0) and Postnatal day 30 (P30) embryos/fetuses from the pigs were used for this study. The results showed that KNJ develops earlier than TMJ. Only one mesenchymal condensate of KNJ is formed on E30, while two mesenchymal condensates of TMJ are present on E35. All structures of KNJ and TMJ were formed on E45. The growth plate of KNJ begins to develop on E45 and becomes more pronounced from E55 to P30. From E75 to E90, more and more vascular-rich cartilage canals form in the cartilage regions of both joints. The cartilaginous canal of the TMJ divides the condyle into sections along the longitudinal axis of the condyle. This arrangement of cartilaginous canal was not found in the KNJ. The chondrification of KNJ precedes that of TMJ. Ossification of the knee condyle occurs gradually from the middle to the periphery, while that of the TMJ occurs gradually from the base of the mandibular condyle. In the KNJ, the ossification of the articular condyle is evident from P0 to P30, and the growth plate is completely formed on P30. In the TMJ, the cartilage layer of condyle becomes thinner from P0 to P30. There is no growth plate formation in TMJ during its entire development. There is no growth plate formation in the TMJ throughout its development. The condyle may be the developmental center of the TMJ. The chondrocytes and hypertrophic chondrocytes of the growth plate are densely arranged. The condylar chondrocytes of TMJ are scattered, while the hypertrophic chondrocytes are arranged. Embryonic development of KNJ and TMJ in pigs is an important bridge for translating the results of rodent studies to medical applications.

Effects of occlusion modification on the remodelling of degenerative mandibular condylar processes.

OBJECTIVE: The temporomandibular joint (TMJ) displays a high remodelling capability in response to occlusion changes. The purpose of the current study was to investigate the responses of TMJ condyles of growing mice to the installation of a unilateral anterior crossbite (UAC) prosthesis and the replacement of the UAC prothesis with a bilateral anterior elevation (BAE) prosthesis. MATERIALS AND METHODS: C57BL/6J mice were randomly assigned to the blank control and experimental groups. In mice in the experimental groups, UAC was created, while in others, BAE was created after the creation of UAC or removal of UAC. Changes in TMJ condylar cartilage and subchondral bone were assessed. RESULTS: The degradation of condylar cartilage induced by UAC was reversed by BAE, as evaluated by cartilage histochemical changes, collagen II-positive area, collagen X-positive chondrocytes and expression levels of Adamts-5, Mmp13, Tnf-α and Il-1ß. Subchondral bone was assessed based on the subchondral bone volume, the number of TRAP-positive cells and the Opg/Rankl ratio. CONCLUSION: The growing mouse TMJ condyle displays a high remodelling capability, which can be degenerative or rehabilitative in response to the creation of UAC and the replacement of UAC with BAE. Early correction of occlusion is beneficial for the recovery of degenerative condyles.

Relationship between mandibular condyle and articular eminence cortication with mandibular cortical index on cone-beam CT.

PURPOSE: Mandibular condyle development can be evaluated with radiographic evaluation of subchondral cortical bone. The aim of this study is to investigate mandibular condyle cortication (MCC), articular eminence cortication (AEC) and mandibular cortical index (MCI) according to age and gender on CBCT, and relationship between each other. METHODS: CBCT scans of 520 patients (312 male and 208 female, age range 7-84) were retrospectively investigated to evaluate MCC, AEC and MCI. MCC and AEC were examined in sagittal section and MCI in panoramic reformatted image. MCC and AEC were classified as Type I, Type II and Type III according to density difference between the cortical bone enclosing condyle and articular eminence. Categorical variables were tested by Chi square. RESULTS: When MCC, AEC and MCI were compared, a significant relationship was detected (p < 0.05). According to age, there was a significant difference between MCC, MCI and AEC types with each other (p < 0.05). No significant discrepancy was found between gender and MCC, AEC and MCI (p > 0.05). CONCLUSIONS: This study evaluated the distribution of MCC, AEC, MCI according to age and gender and detected that these cortications were correlated. This result may be caused by anatomical proximity bone components and functional stimuli. Knowledge of these cortications can be important for accurate diagnosis of TMJ disorders and may also be helpful for prediction of osteoporotic changes.

Inhibition of Ihh Reverses Temporomandibular Joint Osteoarthritis via a PTH1R Signaling Dependent Mechanism.

The temporomandibular joint (TMJ), which is biomechanically related to dental occlusion, is often insulted by osteoarthritis (OA). This study was conducted to clarify the relationship between Indian hedgehog (Ihh) and parathyroid hormone receptor 1 (PTH1R) signaling in modulating the enhanced chondrocyte terminal differentiation in dental stimulated TMJ osteoarthritic cartilage. A gain- and loss-of-function strategy was used in an in vitro model in which fluid flow shear stress (FFSS) was applied, and in an in vivo model in which the unilateral anterior cross-bite (UAC) stimulation was adopted. Ihh and PTH1R signaling was modulated through treating the isolated chondrocytes with inhibitor/activator and via deleting Smoothened (Smo) and/or Pth1r genes in mice with the promoter gene of type 2 collagen (Col2-CreER) in the tamoxifen-inducible pattern. We found that both FFSS and UAC stimulation promoted the deep zone chondrocytes to undergo terminal differentiation, while cells in the superficial zone were robust. We demonstrated that the terminal differentiation process in deep zone chondrocytes promoted by FFSS and UAC was mediated by the enhanced Ihh signaling and declined PTH1R expression. The FFSS-promoted terminal differentiation was suppressed by administration of the Ihh inhibitor or PTH1R activator. The UAC-promoted chondrocytes terminal differentiation and OA-like lesions were rescued in Smo knockout, but were enhanced in Pth1r knockout mice. Importantly, the relieving effect of Smo knockout mice was attenuated when Pth1r knockout was also applied. Our data suggest a chondrocyte protective effect of suppressing Ihh signaling in TMJ OA cartilage which is dependent on PTH1R signaling.

Mechanobehavior and Ontogenesis of the Temporomandibular Joint.

Craniofacial secondary cartilages of the mandibular condyle and temporomandibular joint (TMJ) eminence grow in response to the local mechanical environment. The intervening TMJ disc distributes normal loads over the cartilage surfaces and provides lubrication. A better understanding of the mechanical environment and its effects on growth, development, and degeneration of the TMJ may improve treatments aimed at modifying jaw growth and preventing or reversing degenerative joint disease (DJD). This review highlights data recorded in human subjects and from computer modeling that elucidate the role of mechanics in TMJ ontogeny. Presented data provide an approximation of the age-related changes in jaw-loading behaviors and TMJ contact mechanics. The cells of the mandibular condyle, eminence, and disc respond to the mechanical environment associated with behaviors and ultimately determine the TMJ components' mature morphologies and susceptibility to precocious development of DJD compared to postcranial joints. The TMJ disc may be especially prone to degenerative change due to its avascularity and steep oxygen and glucose gradients consequent to high cell density and rate of nutrient consumption, as well as low solute diffusivities. The combined effects of strain-related hypoxia and limited glucose concentrations dramatically affect synthesis of the extracellular matrix (ECM), which limit repair capabilities. Magnitude and frequency of jaw loading influence this localized in situ environment, including stem and fibrocartilage cell chemistry, as well as the rate of ECM mechanical fatigue. Key in vivo measurements to characterize the mechanical environment include the concentration of work input to articulating tissues, known as energy density, and the percentage of time that muscles are used to load the jaws out of a total recording time, known as duty factor. Combining these measurements into a mechanobehavioral score and linking these to results of computer models of strain-regulated biochemical events may elucidate the mechanisms responsible for growth, maintenance, and deterioration of TMJ tissues.

The impact of dietary consistency on structural craniofacial components: Temporomandibular joint/condyle, condylar cartilage, alveolar bone and periodontal ligament. A systematic review and meta-analysis in experimental in vivo research.

OBJECTIVE: The aim of this systematic review was to provide a comprehensive synthesis of available evidence evaluating the effect of dietary loading on temporomandibular joint/condyle, condylar cartilage, alveolar bone of the mandible and the periodontal ligament in healthy mice and rats. DESIGN: Medline via PubMed, EMBASE and Open Grey databases were searched for published and unpublished literature. Search terms included "mandiblular condyle", "alveolar bone", "temporomandibular joint", "condylar cartilage", "periodontal ligament", "rat", "mice". After data extraction, risk of bias (SYRCLE) and reporting quality (ARRIVE) were assessed. Random effects meta-analyses were performed for the outcomes of interest where applicable. RESULTS: A total of 33 relevant articles were considered in the systematic review, while only 6 studies were included in the quantitative synthesis. Risk of Bias in all studies was judged to be unclear to high overall, while reporting quality was suboptimal. Comparing soft to hard diet animals, significantly reduced anteroposterior condylar length (4 studies, weighted mean difference: -0.40 mm; 95% CI: -0.47, -0.32; p < 0.001) and width (4 studies, weighted mean difference: -0.043 mm; 95% CI: -0.51, -0.36; p < 0.001) were found in rats. Decreased anteroposterior condylar dimensions were detected for mice as well (2 studies, weighted mean difference: -0.049; 95% CI: -0.56, -0.43; p < 0.001). CONCLUSIONS: Overall, there was strong evidence to suggest a significant effect of soft diet on reduced condylar dimensions in rodents; however, there is need for further high quality experimental studies to inform current knowledge on condylar cartilage, alveolar bone and periodontal ligament related outcomes.

Assessment of dentofacial growth deviation in juvenile idiopathic arthritis: Reliability and validity of three-dimensional morphometric measures.

INTRODUCTION: Patients with juvenile idiopathic arthritis (JIA) and involvement of the temporomandibular joint (TMJ) often experience abnormal facial growth. Three-dimensional (3D) assessment of dentofacial growth deviation has become more common with advancement and commercialization of imaging technologies. However, no standardized guidelines exist for interpretation of 3D imaging in patients with JIA. The aim of this study was to propose and validate morphometric measures for the 3D radiographic assessment of dentofacial growth deviation in patients with JIA to enhance: 1) Description of dentofacial growth deviation; 2) Treatment planning; 3) Longitudinal follow-up. METHODS: The study was conducted in a standardized sequential-phased approach involving: 1) Preliminary decision-making; 2) Item generation; 3) Test of content-validity; 4) Test of reliability; 5) Test of construct validity; 6) Establishment of final recommendations. RESULTS: Twenty-one morphometric measures were evaluated. Based on results of reliability and validity-testing including subjects with JIA (n = 70) and non-JIA controls (n = 19), seven measures received a "high recommendation" score. Those measures were associated with posterior mandibular height, occlusal cant, mandibular asymmetry, mandibular inclination, and anterior/posterior lower face height. Nine other measures were "moderately recommended" and five received a "somewhat recommendation" score. CONCLUSION: Seven morphometric measures were considered very useful in the 3D assessment of growth deviation in patients with TMJ disease associated with JIA. These variables can be used to standardize the description of dentofacial deformities and to plan corrective interventions.

Selective Role of Discoidin Domain Receptor 2 in Murine Temporomandibular Joint Development and Aging.

Temporomandibular joint (TMJ) disorders are often associated with development of osteoarthritis-like changes in the mandibular condyle. Discoidin domain receptor 2 (DDR2), a collagen receptor preferentially activated by type I and III collagen found in the TMJ and other fibrocartilages, has been associated with TMJ degeneration, but its role in normal joint development has not been previously examined. Using Ddr2 LacZ-tagged mice and immunohistochemistry, we found that DDR2 is preferentially expressed and activated in the articular zone of TMJs but not knee joints. To assess the requirement for Ddr2 in TMJ development, studies were undertaken to compare wild-type and smallie ( slie) mice, which contain a spontaneous deletion in Ddr2 to produce an effective null allele. Analysis of TMJs from newborn Ddr2slie/slie mice revealed a developmental delay in condyle mineralization, as measured by micro-computed tomography and histologic analysis. In marked contrast, knee joints of Ddr2slie/slie mice were normal. Analysis of older Ddr2slie/slie mice (3 and 10 mo) revealed that the early developmental delay led to a dramatic and progressive loss of TMJ articular integrity and osteoarthritis-like changes. Mutant condyles had a rough and flattened bone surface, accompanied by a dramatic loss of bone mineral density. Mankin scores showed significantly greater degenerative changes in the TMJs of 3- and 10-mo-old Ddr2slie/slie mice as compared with wild-type controls. No DDR2-dependent degenerative changes were seen in knees. Analysis of primary cultures of TMJ articular chondrocytes from wild-type and Ddr2slie/slie mice showed defects in chondrocyte maturation and mineralization in the absence of Ddr2. These studies demonstrate that DDR2 is necessary for normal TMJ condyle development and homeostasis and that these DDR2 functions are restricted to TMJ fibrocartilage and not seen in the hyaline cartilage of the knee.

Temporomandibular Joint Imaging.

The temporomandibular joint (TMJ) is an anatomically and biomechanically complex structure. Understanding how this structure grows and functions is essential to accurate radiographic evaluation. This article discusses the anatomy, function, and growth and development of the TMJ and how growth changes can affect the morphology of the craniofacial structures. Accordingly, the radiographic appearance of the entities that may alter the TMJ are discussed, including developmental, degenerative, inflammatory, and traumatic changes. Both osseous imaging and soft tissue imaging are shown.

Development of the Pediatric Temporomandibular Joint.

This article focuses on the embryologic development and growth of the temporomandibular joint (TMJ) and touches on the development and growth of surrounding structures. Aberrations in structures surrounding the TMJ can affect its development as well. The normal adult anatomy of the TMJ is described as well as common malformations. The clinical ramifications of a malformed TMJ are also discussed in order to understand future necessary consultants involved in the care of these patients.

Acquired Abnormalities of the Temporomandibular Joint.

Mandibular growth is a complex process that involves the "functional matrix," an interaction of the muscles of mastication, occlusion, and jaw function. Although not a typical growth center, the mandibular condyle has a significant effect on the ultimate size, shape and function of the mandible and secondarily on overall facial form. Acquired temporomandibular joint (TMJ)/condylar abnormalities, such as juvenile idiopathic arthritis, idiopathic condylar resorption, TMJ ankylosis, and condylar hyperplasia, often result in facial deformity and functional deficits. Accurate diagnosis is critical for the clinician to assess potential progression of deformity, predict prognosis, and plan treatment.

Morphological and functional maturity of the oral jaws covary with offspring size in Trinidadian guppies.

Large size of individual offspring is routinely selected for in highly competitive environments, such as in low-predation populations of the Trinidadian guppy (Poecilia reticulata). Large guppy offspring outcompete their smaller conspecifics, but the functional mechanisms underlying this advantage are unknown. We measured jaw kinematics during benthic feeding and cranial musculoskeletal morphologies in neonates and juveniles from five populations of Trinidadian guppy and found that both kinematics and morphologies vary substantially with neonatal size. Rotation at the intramandibular joint (IMJ), but not the quadratomandibular joint (QMJ), increases with size among guppy offspring, from 11.7° in the smallest neonates to 22.9° in the largest neonates. Ossification of the cranial skeleton varies from 20% in the smallest neonates to 90% in the largest. Relative to standard length (SL; jaw tip to caudal fin base distance), the surface area of jaw-closing musculature scales with positive allometry (SL2.72) indicating that muscle growth outpaces body growth. Maximum gape also scales with positive allometry (SL1.20), indicating that larger neonates are capable of greater jaw excursions. These findings indicate that size is not the sole adaptive benefit to producing larger offspring; maturation provides a potential functional mechanism underlying the competitive advantage of large offspring size among Trinidadian guppies.

Tuberculose e suas manifestações na ATM: uma revisão de literatura / Tuberculosis and its manifestations in TMJ: a literature review

A disfunção temporomandibular tem caráter multifatorial e merece uma abordagem diferenciada tanto para seu diagnóstico quanto seu tratamento, sendo frequentemente recomendada a atuação de uma equipe multidisciplinar. Várias são as manifestações que podem acometer as articulações temporomandibulares decorrentes de patologias sistêmicas. Dentre estas, a tuberculose raramente as acomete, mas a ocorrência de manifestações extrapulmonares vem crescendo nos últimos anos. Estima-se que a tuberculose acometa 8.8 milhões de pessoas ao ano, levando 1.45 milhões destas ao óbito. O objetivo desta revisão foi levantar dados e informações para profissionais da área da saúde, em especial os Cirurgiões Dentistas,para um correto e precoce diagnóstico, uma vez que a detecção correta da patologia possibilita tratamento adequado e previne o surgimento de alterações graves na forma e função das articulaçõesenvolvidas.

Temporomandibular disorders are a multifactorial disease, that deserves a special approachfor its diagnosis and treatment, and a multidisciplinary team is suggested. Various systemic pathologies have a TMJ manifestation. Among these diseases, tuberculosis rarely has a temporomandibularjoint occurrence, but extra pulmonary manifestation is increasing in the last years.About 8,8 million people are affected by tuberculosis each year, and 1,45 million die because ofit. The objective of this review is collect data and information for health professional, in special Dentists, in order to clarify the relationship between TMD and tuberculosis, early diagnosis and correct treatment, once that the correct identification of this patology can provide adequate treatment and prevents for more severe complications.

[PECULIARITIES OF THE STRUCTURE OF THE TEMPOROMANDIBULAR JOINT IN INDIVIDUALS WITH DIFFERENT DIRECTION OF GROWTH OF THE FACIAL PART OF THE SKULL].

The characteristics of the structure of the temporomandibular joint (TMJ) in individuals with different direction of growth of the facial part of the skull were studied. Cone beam computed tomography data were analyzed in 16 young (mean age 29±7 years) orthodontic patients (32 joints) before treatment, which had class II dentition ratio. The patients were divided into 2 groups (4 men and 4 women in each): with strongly expressed vertical and horizontal types of facial growth. In patients with a vertical type of facial growth, the reduction of the size of joint spaces was noted in anterior, posterior, upper, oral and buccal parts of TMJ. In patients with a vertical type of facial growth anterior articular angle was smaller than in those with a horizontal growth type. The data obtained indicate the relationship of the structure of TMJ and the direction of growth of the facial part of the skull.

Differences in skeletal components of temporomandibular joint of an early medieval and contemporary Croatian population obtained by different methods.

The temporomandibular joint (TMJ) is one of the most complex joints in the human body. The anatomical configuration of the TMJ allows for a large range of mandibular movements as well as transmission of masticatory forces and loads to the skull base. The measurements of the TMJ's anatomical structures and their interpretations contribute to the understanding of how pathological changes, tooth loss, and the type of diet (changing throughout human history) can affect biomechanical conditions of the masticatory system and the TMJ. The human TMJ and its constituent parts are still the subject of extensive investigation and comparisons of measurement methods are being made in order to determine the most precise and suitable measurement methods. The aim of this study has been to examine the morphology of skeletal components of TMJ of an early medieval population (EMP) in Croatia and to compare measured values with TMJ values of the contemporary Croatian population (CP) using various methods of measurement. The study was performed on 30 EMP specimens - human dry skulls, aged from 18 to 55 years, and 30 CP human dry skulls, aged from 18 to 65 years. Only fully preserved specimens (in measured areas) were included. The articular eminence (AE) inclination was measured in relation to the Frankfurt horizontal using two methods. Also, the AE height (glenoid fossa depth) and the length of the curved line - highest to the lowest point of the AE were measured. Measurements were performed on lateral skull photographs, panoramic radiographs and lateral cephalograms using VistaMetrix software on skull images. The results were statistically analyzed using SPSS statistical software. No statistically significant differences were obtained for AE parameters between the EMP and CP populations independent of age and gender. However, statistically significant (p<0.05) differences were revealed when comparing results of three different measuring methods. It could not be determined which of the used measurement methods is the most accurate due to the different results obtained as well as the presence of possible shortcomings and limitations of the various methods (measuring points are difficult to determine and/or they are not clearly observed in the investigated images to be precisely marked and measured; distortion and magnification of structures on radiographic images are present). Therefore, due to the limitations of this study, the obtained results could serve only as orienting information.

Genetic Influences on Temporomandibular Joint Development and Growth.

The temporomandibular joint (TMJ) is a small synovial joint at which the mandible articulates with the skull during movements involved in speaking and mastication. However, the secondary cartilage lining its joint surfaces is indicative of a very different developmental history than limb cartilages. This review summarizes our current knowledge of genes that regulate the formation of primary components of the TMJ, as well as genes that regulate postnatal growth of the TMJ. Although the TMJ is regulated by some of the same genes that are important in limb joints, others appear unique to the TMJ or have different actions. Runx2, Sox9, and members of the TGF-ß/BMP family are critical drivers of chondrogenesis during condylar cartilage morphogenesis, and Indian hedgehog (Ihh) is important for formation of the articular disc and cavitation. Osterix (Osx) is a critical regulator of endochondral bone formation during postnatal TMJ growth.

Changes in collagens and chondrocytes in the temporomandibular joint cartilage in growing rats fed a liquid diet.

The temporomandibular joint (TMJ) of growing rats fed a soft diet is reported to be smaller in size and to have thinner condyle and glenoid fossa cartilage than rats fed a solid diet. The aim of this study was to determine the effect of a soft diet on the collagens and chondrocytes in the growing TMJ cartilage. Forty-eight male Wistar rats were divided into a control group fed a solid diet and an experimental group fed a liquid diet for 1-8 weeks. After the experimental period, the TMJs were harvested and examined histologically, immunohistochemically for collagen types I, II, and X, and with transmission electron microscopy. The condylar cartilage in the experimental rats showed weak immunoreactions for three types of collagens compared with the controls. The ultrastructure had fewer fine collagen fibrils in the experimental rats compared with that of the controls. The glenoid fossa cartilage in the experimental rats showed narrower Alcian blue-positive areas than the control staining. The immunoreactions for three types of collagen in the experimental rats were also weaker than those of the controls. The chondrocytes in the experimental rats appeared dark, had extended thin cytoplasmic processes, and had formed gap junctions, as assessed by transmission electron microscopy. Fewer fine collagen fibrils, but thick bands of collagen fibrils were observed in the glenoid fossa of the experimental cartilage. The results of the present study showed that a liquid diet had deleterious effects on the quality and quantity of collagens and chondrocytes in the TMJ cartilage in growing rats.

Effects of a liquid diet on the temporomandibular joint of growing rats.

OBJECTIVE: The aim of the present study was to clarify the effects of a liquid diet on the temporomandibular joint (TMJ) in growing rats. MATERIALS AND METHODS: Twenty-four male Wistar rats were weaned at 21 days and divided into control and experimental groups (12 in each group). Control rats were fed a solid diet and experimental rats were fed a liquid diet from 1 to 8 weeks. After injection with 5-bromo-2'-deoxyuridine (BrdU), the animals were perfused and the heads were removed. Serial coronal sections of the TMJ were stained with hematoxylin and eosin, or BrdU immunohistochemistry was done (12 rats in each group). Three dimensions and the thicknesses of the cartilage layers of the TMJ were measured, and cell proliferation in the TMJ was examined. RESULTS: After 4 weeks, the height and width of the mandibular fossa and the width and length of the mandibular condyle were smaller in the experimental groups than in the control groups. The cartilage layer in these areas was also thinner at 4 weeks. The BrdU levels in the intermediate zone of the mandibular fossa (at 4 weeks) and the mandibular condyle (at 1 and 4 weeks) were lower in the experimental groups than in the controls. CONCLUSION: These findings suggest that the growth of the mandibular fossa and mandibular condyle of rats was inhibited by the low proliferative activity of intermediate zone cells induced by liquid feeding.

Avaliação em 3D da cabeça da mandíbula em crianças portadoras de mordida cruzada posterior unilateral por meio de tomografia computadorizada de feixe cônico / 3D evaluation of the condyle in children with unilateral posterior cross bite using Cone Beam Computed Tomography

Durante o desenvolvimento da oclusão, a instalação de maloclusões podem resultar em desarmonias dento faciais de natureza e severidade diversas, podendo provocar alterações no desenvolvimento crânio facial, dentre as estruturas envolvidas as Articulações Temporo Mandibulares (ATM), podem sofrer alguma influência, dessa forma a avaliação desta região, no aspecto morfológico e funcional, constituí tema de interesse, sempre que levados em conta os aspectos funcionais da oclusão. A relação entre a forma e a função, tanto das cabeças da mandíbula, bem como o contorno da fossa mandibular com as maloclusões ainda é controversa e não está compreendida por completo, porém a literatura sobre o assunto, demonstra correlação entre a instalação de maloclusões e modificações neste sistema, mesmo que algumas alterações não sejam de ordem estatística e em amostras de indivíduos em tenra idade, as mesmas podem comprometer o desenvolvimento adequado em indivíduos adultos ou mesmo adultos jovens.

Tendo como propósito nesse estudo a avaliação das cabeças da mandíbula quanto ao volume e superficíe dos lados direito e esquerdo, cruzado e não cruzado, a amostra selecionada foi de 20 indivíduos com mordida cruzada posterior unilateral, com idades entre 06 e 09 anos de idade, utilizando imagens de tomografia computadorizada por feixe cônico, imagens obtidas por um equipamento modelo i- Cat, sendo utilizado na reformatação e manipulação das imagens o programa computacional - NemoCeph 3D® versão 11.5. Nas medições propostas para esse estudo, utilizou-se o teste t pareado de Student para amostras com distribuição normal. Na observação das tabelas e seus respectivos gráficos, podemos verificar que na comparação entre os lados direito e esquerdo, e cruzado e não cruzado das cabeças da mandíbula, com relação ao volume e superfície, existem diferenças numéricas entre elas, porém não pode ser observado diferenças estatísticas significantes, nessa amostra especifica com a metodologia empregada para esse estudo. Assim foi possível concluir que nas Mordidas Cruzadas Posteriores Unilaterais as cabeças da mandíbula tanto em seu volume como em sua superfície não apresentaram diferenças estatisticamente significantes na amostra estudada.

During the development of occlusion, malocclusions installation may result in disharmony dento facial nature and various severity, can cause changes in craniofacial development, among the structures involved in the temporomandibular joints mandibular (ATM), may suffer some influence, thus the evaluation of this region, the morphological and functional aspect, constitutes topic of interest, when taken into account the functional aspects of occlusion. The relationship between form and function, both the heads of the jaw, as well as the outline of the mandibular fossa with malocclusion remains controversial and is not fully understood, but the literature on the subject shows correlation between the installation of malocclusions and modifications to this system, even if some changes are not of statistical order and samples from individuals at an early age, they can compromise the proper development in adults and even young adults. With the intent of this study was to evaluate the heads of the jaw as the volume and surface of the right and left sides, crossed and uncrossed, the selected sample of 20 subjects with unilateral posterior cross bite, aged from 06 to 09 years old, using computed tomography cone beam, images obtained by a device model i-Cat, being used in reformatting and manipulation of images the computer program - NemoCeph 3D® version 11.5.

The proposals measurements for this study, we used the paired t-test of Student for samples with normal distribution. The observation of the tables and their graphs, we can see that the comparison between the right and left sides, and crossed and uncrossed the heads of the mandible in relation to the volume and surface, there are numerical differences between them, but can not be observed differences statistically significant, this sample specifies the methodology used for this study. Thus it was concluded that the Unilateral Posterior Crossbites the heads of the jaw in both its volume and its surface showed no statistically significant differences

Efeitos da remoção do disco e cartilagem articular no crescimento e microarquitetura óssea da mandíbula de ratos: análise por microtomografia / Effects of articular disc and cartilage removal on mandible of growing rats: a micro-computed tomography study

Alterações na articulação emporomandibular (ATM) comumente geram desequilíbrios musculares que estão associados à alterações no tecido ósseo. Esta articulação pode sofrer a influência de traumas, fatores congênitos ou desordens de crescimento. Estudos sobre alterações de crescimento do complexo maxilomandibular decorrentes de problemas da ATM são escassos. O objetivo deste trabalho foi avaliar por meio da microtomografia os efeitos da remoção do disco articular e a remoção conjugada do disco e cartilagem articular no crescimento e na microarquitetura óssea da mandíbula de ratos. Trinta ratos da raça Wistar com um mês de idade foram divididos em três grupos: CTR (controle operado); RD (remoção de disco articular) e RDC (remoção conjugada do disco e cartilagem articular). Apenas o lado direito foi operado; o lado esquerdo permaneceu intacto. Após dois meses de acompanhamento, os ratos foram sacrificados e as hemimandíbulas escaneadas em microtomógrafo A remoção do disco articular e a remoção conjugada do disco e cartilagem articular alteram o volume e microestrutura do osso trabecular da mandíbula de ratos jovens. Estas duas intervenções provocaram uma queda na qualidade de parâmetros da microestrutura do trabeculado do processo angular e diminuição do crescimento da hemimandíbula do lado operado.

Changes in the temporomandibular joint (TMJ) lead to muscle dysfunctions that are associated with bone changes. This joint region can be influenced by trauma, congenital factors or growth disorders. Studies linking TMJ problems and growth alterations are scarce. The aim of this study was to evaluate the effects of the articular disc removal or articular disc and cartilage removal on the bone microarchitecture and mandibular growth of young rats. Thirty Wistar rats (one month old) were divided into three groups: CTR (sham operated); RD (disc removal) and RDC (disc and cartilage removal). Only the right side was operated, keeping the left side intact. After two months, the rats were sacrificed and the mandibles scanned on micro-CT for quantitative analysis. Some microstructural parameters were altered by the disc removal or disc and cartilage removal. The right side presented lower growth than the left side.