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.

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.

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.

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...

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...

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.

Estrogen via estrogen receptor beta partially inhibits mandibular condylar cartilage growth.

OBJECTIVE: Temporomandibular joint (TMJ) diseases predominantly afflict women, suggesting a role for female hormones in the disease process. However, little is known about the role of estrogen receptor (ER) signaling in regulating mandibular condylar cartilage growth. Therefore, the goal of this study was to examine the effects of altered estrogen levels on the mandibular condylar cartilage in wild type (WT) and ER beta Knockout (KO) mice. MATERIALS AND METHODS: 21-day-old female WT (n = 37) and ER beta KO mice (n = 36) were either sham operated or ovariectomized, and treated with either placebo or estradiol. The mandibular condylar cartilage was evaluated by histomorphometry, proliferation was analyzed by double ethynyl-2'-deoxyuridine/bromodeoxyuridine (EdU/BrdU) labeling, and assays on gene and protein expression of chondrocyte maturation markers were performed. RESULTS: In WT mice, ovariectomy caused a significant increase in mandibular condylar cartilage cell numbers, a significant increase in Sox9 expression and a significant increase in proliferation compared with sham operated WT mice. In contrast, ovariectomy did not cause any of these effects in the ER beta KO mice. Estrogen replacement treatment in ovariectomized WT mice caused a significant decrease in ER alpha expression and a significant increase in Sost expression compared with ovariectomized mice treated with placebo. Estrogen replacement treatment in ovariectomized ER beta KO mice caused a significant increase in Col2 expression, no change in ER alpha expression, and a significant increase in Sost expression. CONCLUSION: Estrogen via ER beta inhibits proliferation and ER alpha expression while estrogen independent of ER beta induces Col2 and Sost expression.

Three-dimensional longitudinal changes in craniofacial growth in untreated hemifacial microsomia patients with cone-beam computed tomography.

INTRODUCTION: The purpose of this study was to evaluate the concept that the affected and contralateral sides do not grow at the same rate in patients with hemifacial microsomia. Changes in the cranial base, maxilla, mandible, and occlusal plane were evaluated on 3-dimensional images from cone-beam computed tomography data in untreated patients. METHODS: Six patients were classified as having mandibular Pruzansky/Kaban type I, IIA, or IIB hemifacial microsomia. Cone-beam computed tomography (MercuRay; Hitachi, Tokyo, Japan) scans were taken before orthodontic treatment during both growth and postpuberty periods. RESULTS: The cranial base as defined by the position of the mastoid process was in a different position between the affected and contralateral control sides. The nasomaxillary length or height was shorter on the affected side for all 6 patients with hemifacial microsomia regardless of its severity, and it grew less than on the contralateral control side in 5 of the 6 patients. The occlusal plane angle became more inclined in 4 of the 6 patients. The mandibular ramus was shorter on the affected side in all patients and grew less on the affected side in 5 of the 6 patients. The mandibular body grew slower, the same, or faster than on the control side. CONCLUSIONS: The cranial base, position of the condyle, lengths of the condyle and ramus, and positions of the gonial angle and condyle can vary between the affected and contralateral control sides of patients with hemifacial microsomia, with the ramus and nasomaxillary length usually growing slower than they grow on the control side. These results suggest that many factors affect the growth rate of the craniofacial region and, specifically, the mandible in patients with hemifacial microsomia.

The Sarnat studies in craniofacial biology.

Dr. Bernard Sarnat is one of plastic surgery's greatest laboratory investigators. His contributions to our understanding of modern craniofacial molecular biology are immense. His landmark studies continue to influence the way we approach and treat patients today. This article outlines his classic investigations of the craniofacial skeleton, with particular interest in lower face, midface, and upper face development; cranial suture and cranial base biology; and tooth and dental development. In this article, a brief summary of Dr. Sarnat's investigations are followed by how these data have had an important clinical impact.

Growth factors, genes, bone proteins and apoptosis in the temporomandibular joint (TMJ) of children with ankylosis and during disease recurrence.

UNLABELLED: AIM OF STUDY was complex detection of appearance and distribution of growth factors, facial bone growth stimulating genes, ground substance proteins and apoptosis in bone of ankylotic TMJ in primary and repeatedly operated children. MATERIALS AND METHODS: Ankylotic tissue was obtained during the arthroplastic surgery from two 6 years old children (boy and girl) with osseous type of disease. The girl underwent the repeated surgery in TMJ due to the same diagnosis in age of 12 years. Ankylotic tissue was proceeded for detection of BMP2/4, TGFß, Msx2, osteopontin, osteocalcin immunohistochemically, and apoptosis. RESULTS demonstrated massive bone formation intermixed by neochondrogenesis the lack of BMP 2/4, but abundant number of TGFß-containing cells in bone of all tested cases. Despite rich osteopontin positive structures in bone obtained from both - primary and repeated surgery, osteocalcin demonstrated variable appearance in 6 years aged children, but was abundant in joint 5 years later during disease recurrence. Expression of Msx2 varied widely before, but with tendency to decrease stabilized until few positive cells in bone of 12 years old girl. Apoptosis practically was not detected in primarily operated TMJ, but massively affected the supportive tissue in girl with recurrent ankylosis. CONCLUSIONS: The lack of BMP2/4 expression in ankylotic bone proves the disorders in cellular differentiation with simultaneous compensatory intensification of cellular proliferation and/or growth by rich expression of TGFß leading to the remodelling of TMJ. Mainly rich distribution of osteocalcin and osteopontin indicate the intensive mineralization processes of ankylotic bone. Persistent Msx2 expression is characteristic for the supportive tissue of recurrent ankylosis of TMJ and indicates the persistent stimulation of bone growth compensatory limitated by massive increase of programmed cell death.

Tissue interaction is required for glenoid fossa development during temporomandibular joint formation.

The mammalian temporomandibular joint (TMJ) develops from two distinct mesenchymal condensations that grow toward each other and ossify through different mechanisms, with the glenoid fossa undergoing intramembranous ossification while the condyle being endochondral in origin. In this study, we used various genetically modified mouse models to investigate tissue interaction between the condyle and glenoid fossa during TMJ formation in mice. We report that either absence or dislocation of the condyle results in an arrested glenoid fossa development. In both cases, glenoid fossa development was initiated, but failed to sustain, and became regressed subsequently. However, condyle development appears to be independent upon the presence of the forming glenoid fossa. In addition, we show that substitution of condyle by Meckel's cartilage is able to sustain glenoid fossa development. These observations suggest that proper signals from the developing condyle or Meckel's cartilage are required to sustain the glenoid fossa development.

Indian hedgehog roles in post-natal TMJ development and organization.

Indian hedgehog (Ihh) is essential for embryonic mandibular condylar growth and disc primordium formation. To determine whether it regulates those processes during post-natal life, we ablated Ihh in cartilage of neonatal mice and assessed the consequences on temporomandibular joint (TMJ) growth and organization over age. Ihh deficiency caused condylar disorganization and growth retardation and reduced polymorphic cell layer proliferation. Expression of Sox9, Runx2, and Osterix was low, as was that of collagen II, collagen I, and aggrecan, thus altering the fibrocartilaginous nature of the condyle. Though a disc formed, it exhibited morphological defects, partial fusion with the glenoid bone surface, reduced synovial cavity space, and, unexpectedly, higher lubricin expression. Analysis of the data shows, for the first time, that continuous Ihh action is required for completion of post-natal TMJ growth and organization. Lubricin overexpression in mutants may represent a compensatory response to sustain TMJ movement and function.

Study about the development of the temporomandibular joint in the human fetuses / Estudio del desarrollo de la articulacion temporomandibular en fetos humanos

The temporomandibular joint (TMJ) is a highly specialized articulation that differs from all the other synovial articulations for many reasons. In children, different from what we observe in adults, these articulations have rarely been studied under the morphofunctional aspect, mainly in the embryonary and fetal stages. In this study 10 fetuses with ages varying from 16 to 39 weeks of intrauterine life were used, and it could be observed that the fibers and thickness of the articular disc, as well as the articular capsule and the condylar process, suffer modifications according to age. It was also observed that the superior head of the lateral pterygoid muscle inserts itself in the articular disc and capsule in all the ages studied. Also, the maturation of the articular tissues, especially of the articular disc, as well as, the associated muscles, suggests that the TMJ was able to carry out mandibular movements since the 24th week of intrauterine life.

La articulación temporomandibular (ATM) es una articulación altamente especializada que se distingue de todas las otras articulaciones sinoviales por muchas razones. En los niños, a diferencia de lo que se observa en los adultos, estas articulaciones muy pocas veces han sido estudiadas en el aspecto morfofuncional, principalmente, en las etapas embrionaria y fetal. Se utilizaron 10 fetos con edades que variaban entre 16 a 39 semanas de vida intrauterina. Se pudo observar que las fibras y espesor del disco articular, así como la cápsula articular y el proceso condilar. Sufren modificaciones en función de la edad. También se observó que la parte superior del músculo pterigóideo lateral se inserta en el disco y en la cápsula articular en todas las edades estudiadas. Por otra parte, la maduración de los tejidos articulares, especialmente del disco articular, así como, de los músculos asociados, sugiere que la ATM es capaz de llevar a cabo los movimientos mandibulares, desde la 24 ª semana de vida intrauterina.

Alterações cefalométricas presentes em crianças e adolescentes com desordens da ATM nas diferentes classificações sagitais de má oclusão / Cephalometric changes present in children and adolescents with TMJ disorders with different classes of malocclusions

INTRODUÇÃO: o acometimento da ATM por alterações degenerativas e deslocamentos do disco articular demonstrou ser um fator de risco para a identificação de indivíduos com padrões hiperdivergentes de crescimento facial. OBJETIVOS: avaliar diferenças entre as médias encontradas para as variáveis cefalométricas em crianças com DTM articular e grupo controle, nas diferentes classificações sagitais de má oclusão (Classe I, II e III de Angle). MÉTODO: foram incluídos crianças e adolescentes com idade máxima de 17 anos, divididos em grupo experimental (n = 30) com diagnóstico de DTM articular, segundo o eixo I do RDC/TMD para crianças e adolescentes, igualmente divididos em 3 sub-grupos (n= 10) de acordo com a classificação da má oclusão presente e grupo controle (n = 30) sem DTM, pareados por gênero, índice de maturidade esquelética vertebral cervical e classificação da má oclusão. Foram traçadas telerradiografias laterais e as estruturas craniofaciais e suas relações foram divididas em: base do crânio, maxila, mandíbula, relações intermaxilares, relações esqueléticas verticais e relações dentárias. As diferenças encontradas entre as médias, para cada uma das variáveis, foram avaliadas pela aplicação do teste estatístico t de Student para amostra independentes. RESULTADOS: o grupo experimental Classe I apresentou S.N.Ar (p = 0,05) aumentado, o grupo experimental Classe II apresentou S.N.Ar (p = 0,006) e NperpA (p = 0,037) diminuídos e S.Ar.Go (p = 0,045) aumentado e o grupo experimental Classe III apresentou N.A.P (p = 0,045), 1.NB (p = 0,001) e 1-NB (p = 0,017) aumentados e 1.1 (p = 0,004) diminuído, todos em relação aos seus respectivos controles CONCLUSÃO: as diferenças foram mais significantes nos pacientes com má oclusão de Classe II e de Classe III.

INTRODUCTION: the involvement of TMJ through degenerative changes and displacements of the articular disc proved to be an important risk factor when identifying individuals with vertical facial growth patterns. PURPOSES: to evaluate differences between cephalometric variables in children with articular TMD and a control group, checking the variations in relation to the different patterns of malocclusion (Class I, II and III). METHOD: the study included children and adolescents of up to a maximum age of 17, who were divided up into an experimental group (n=30) diagnosed with articular TMD, diagnosed in accordance with the RDC/TMD axis I for children and adolescents, and a control group (n=30) without TMD, further paired by gender, stage of cervical vertebral skeletal maturity and class of malocclusion. Lateral cephalogram was carried out and both the craniofacial structures and their relations were separated into: the cranial base, maxillary, mandible, intermaxillary relations, vertical skeletal relations and dental relations. The differences found between the means, for each of the variables, were evaluated through the application of the Student t statistical test for independent samples. RESULTS: the Class I experimental group presented increased S.N.Ar (p=0.05). The Class II experimental group presented reduced S.N.Ar (p=0.006) and NperpA (p=0.037) and increased S.Ar.Go (p=0.045). The Class III experimental group presented increased N.A.P (p=0.045), 1.NB (p=0.001) and 1-NB (p=0.017) and reduced 1.1 (p=0.004). CONCLUSION: differences were more significant in those patients who presented Class II and III malocclusions.

Immunocytochemical localization of caveolin-3 in the synoviocytes of the rat temporomandibular joint during development.

Caveolins -- caveolin-1, -2, -3 (Cav1, 2, 3) -- are major components of caveolae, which have diverse functions. Our recent study on the temporomandibular joint (TMJ) revealed expressions of Cav1 and muscle-specific Cav3 in some synovial fibroblast-like type B cells with well-developed caveolae. However, the involvement of Cav3 expression in the differentiation and maturation of type B cells remains unclear. The present study therefore examined the chronological alterations in the localization of Cav3 in the synovial lining cells of the rat TMJ during postnatal development by immunocytochemical techniques. Observations showed immature type B cells possessed a few caveolae with Cav1 but lacked Cav3 protein at postnatal day 5 (P5). At P14, Cav3-immunopositive type B cells first appeared in the synovial lining layer. They increased in number and immunointensity from P14 to P21 as occlusion became active. In immunoelectron microscopy and double immunolabeling with heat shock protein 25 (Hsp25) and Cav3, coexpressed type B cells developed rough endoplasmic reticulum and numerous caveolae, while the Cav3-immunonegative type B cell with Hsp25 immunoreaction possessed few of these. Results suggest that Cav3 expression, which is closely related to added functional stimuli, reflects the differentiation of the type B synoviocytes.

Metric analysis of the upper space of the temporomandibular joint (TMJ) in pigs (Sus scrofa domestica) for evaluation of the pig as a model for arthroscopic TMJ surgery.

Minimally invasive arthroscopic surgery of the temporomandibular joint (TMJ) is more technically demanding than procedures in Larger joints. The acquisition of adequate arthroscopic skills for TMJ surgery requires extensive specialized training that can hardly be obtained from patients. In order to introduce a proper animal model for TMJ arthroscopy, this study focuses on the morphology of the upper joint cavity of pigs at different ages. Plastic casts of the upper joint cavity were obtained from a mixed-sex sample of eight unfixed juvenile pig heads. The morphometric evaluation of these plastic casts revealed that the TMJ of pigs with a body weight of about 30 kg resemble the situation of the human TMJ best, and thus may serve as a model for arthroscopic exercises and examinations of the TMJ.

Articulación temporomandibular desarrollo de un método para estudiar la morfología y relación de las estructuras duras / Joint temporomandibular development of a method to study the morphology and relation of the hard structures

Diferentes métodos han sido propuestos para analizar la posición del cóndilo mandibular. Los mismos se basaron en el estudio del espacio articular existente entre la superficie de la cabeza del cóndilo y la cavidad glenoidea. en todos estos métodos se consideró siempre como sanas e ideales a las estructuras articulares, las cuales hoy en día sabemos que pueden no serlo. El cóndilo mandibula es una estructura que puede sufrir alteraciones de forma y éste al ser empleado como estructura de referencia, podría estar alterando la interpretación del métdo de medición. Por dicha razón, nuestro objetivo es desarrollar un nuevo método, que permita estudiar la relación de las estructuras duras que conforman la articulación, buscando referencias que se encuentren alejadas de la zona de medición. El mismo permitiría revelar una relación antero-posterior y un comportamiento rotacional a través del estudio del eje del cóndilo

Morfología y morfometría del disco de la articulación témporomandibular en fetos y adultos humanos / Morphology and morphometry of the temporomandibular joint disc in human fetus and adults

RESUMEN: La articulación témporomandibular (ATM) humana, sinovial y bicondílea, es un conjunto de estructuras que permite la relación anatómica y funcional entre el hueso temporal y la mandíbula. Esta articulación permite realizar los movimientos mandibulares y las funciones del sistema estomatognático. Uno de los elementos de la ATM es el disco articular, que divide a la articulación en dos compartimientos y relaciona el proceso condilar con la fosa mandibular y con la eminencia articular del hueso temporal. Con el propósito de obtener información de la morfometría del disco articular, se analizaron y midieron 10 discos articulares de individuos adultos, de una edad promedio de 60 años, y 10 discos articulares de fetos con más de 28 semanas de gestación. La forma del disco articular de la ATM de adultos corresponde a las descripciones de la literatura y el disco articular del feto muestra una zona retrodiscal poco desarrollada. El promedio de las medidas del disco articular de la ATM de fetos, en el diámetro ántero-posterior (DAP) fue de 6,77mm y el diámetro transversal (DT) de 9,23mm. Las mediciones efectuadas en el plano sagital determinaron que el espesor en la zona anterior (EZA) es de 1 mm; en la zona media (EZM) de 0,59 mm y el espesor de la zona posterior (EZP) de 1,72 mm. En el adulto, el promedio de las medidas del disco corresponden en el DAP a 14,46 mm y en el DT a 20,08 mm. Las dimensiones tomadas en el plano sagital señalan que el EZA es de 2,39mm; el EZM es 1,60mm y el EZP es 3,29 mm. Fue estadísticamente significativa la correlación de DT y DAP del disco articular en el feto (p=< 0.005). En el disco adulto se determinó una correlación para EZA,EZM y EZP (p=< 0.005). Las variaciones en las dimensiones del disco de la articulación témporomandibular pueden atribuirse al crecimiento de los elementos articulares, a la función masticatoria, a la presencia o ausencia de piezas dentarias, lo que se manifestaría en una modelación del espesor del disco, principalmente en la zona posterior.

Development of the articular cavity in the rat temporomandibular joint with special reference to the behavior of endothelial cells and macrophages.

Previous developmental studies on the temporomandibular joint (TMJ) have proposed several hypotheses on the formation of its articular cavity. However, detailed information is meager. The present study examined the formation process of the articular cavity in the rat TMJ by immunocytochemistry for CD31, RECA-1, and ED1, which are useful cellular markers for endothelial cells and monocyte/macrophage lineages, respectively. The upper articular cavity formation had begun by embryonic day 21 (E21) and was completed at postnatal day 1 (P1) in advance of the lower cavitation; the latter took place from P1 to P3. The occurrence and distribution pattern of the CD31-, RECA-1-, and ED1-positive cells differed between the upper and lower articular cavity-forming areas: the ED1-positive cells exclusively occurred in the area of the prospective upper articular cavity prior to its formation, while no ED1-positive cell appeared in the lower cavity-forming area. In contrast, the CD31- and RECA-1-positive endothelial cells were restricted to the lower cavity-forming area (never the prospective upper cavity) at E19 and diminished thereafter. Throughout the cavity formation, we failed to find any apoptotic cells in the cavity formation area, indicating no involvement of apoptosis in the cavity formation in TMJ. The present findings on the behaviors of endothelial cells and ED1-positive cells show a possibility of different mechanism in the cavity formation between the upper and lower articular cavities in the rat TMJ. The appearance of ED1-reactive cells and temporal vascularization may play crucial roles in the upper and lower articular cavity formation, respectively.