Electromyographic analysis of the masseter and temporalis muscles and bite force in a patient treated by functional maxillary orthopedics: a case report.

This case report evaluated electromyographic activity of the masseter and temporalis muscles and molar bite force, before and after with functional orthopedic. A 65 years woman presenting with orofacial pain symptoms, cervical tension, condyle subluxation and osteoarthrosis. The patient was diagnosed with temporomandibular dysfunction and treated with use of a Simões Network 9 modified type functional maxillary orthopedics appliance. The Myosystem BR1 apparatus was used to analyze the electromyographic activity of the masseter and temporalis muscles. The maximum molar bite force was measured with the digital dynamometer (Kratus). This study showed increased EMG activity of the masseter and temporalis muscles in postural conditions of mandible and molar bite force after 12 months of treatment. After twelve months of treatment, the patient had lack of pain symptoms as well as an improvement in the balance of the mastication muscles, as demonstrated by EMG activity and maximum molar bite force.

The influence of maxillary and mandibular osteoporosis on maximal bite force and thickness of masticatory muscles

The aim of this study was to examine the bite force and masseter and temporal muscle thickness in individuals with maxillary and mandibular osteoporosis. 72 individuals were distributed into two equal groups: (1) facial osteoporosis and (2) healthy controls. Bite force on the right and left molar regions was recorded with a dynamometer and the highest value out of three measurements was recorded as the maximal bite force. Muscle thickness was measured with a SonoSite Titan ultrasound scanner. Ultrasound images were obtained of the bilateral masseter and temporal muscles at rest and at maximal voluntary contraction. The means of the measurements in each clinical condition were analyzed with multivariate statistical analysis (SPSS 19.0). Student's t test indicated no significant difference for muscle thickness, but indicated significantly lower bite force values in the osteoporosis group (p>0.05). Lower bite force in individuals with facial bone loss demonstrates functional impact of osteoporosis on the complex physiological stomatognathic system.

Este estudo teve como objetivo analisar a forca de mordida e a espessura dos musculos masseter e temporal em individuos com osteoporose maxilar e mandibular. 72 individuos distribuidos em dois grupos equivalentes: (1) osteoporose facial e (2) controles saudaveis. Forca de mordida nas regioes de molar direita e esquerda foi gravada com o dinamometro e o valor mais alto das tres medidas foi registrado como a forca de mordida maxima. A espessura muscular foi mensurada com ultrassom SonoSite Titan. As imagens de ultrassom foram obtidas dos musculos masseter e temporais bilateral em repouso e em contracao voluntaria maxima. As medias das medidas em cada condicao clinica foram analisadas com a analise estatistica multivariada (SPSS 19.0). Teste t de Student nao revelou diferencas significativas para a espessura musculos, mas indicou valores significativamente mais baixos de forca de mordida no grupo com osteoporose (p> 0,05). Forca de mordida menor em individuos com perda ossea facial demonstra um impacto funcional da osteoporose na fisiologia complexa do sistema estomatognatico.

Analysis of Endodontist Posture Utilizing Cinemetry, Surface Electromyography and Ergonomic Checklists

The postural risk factors for dentists include the ease of vision in the workplace, cold, vibration and mechanical pressure in tissues, incorrect posture, functional fixity, cognitive requirements and work-related organizational and psychosocial factors. The objective was to analyze the posture of endodontists at the workplace. Eighteen right-handed endodontists aged 25 to 60 years (34±3) participated in the study. Electromyography, kinemetry, ergonomic scales (RULA and Couto's checklist) and biophotogrammetry were used to analyze the posture of endodontists during root canal treatment of the maxillary right first and second molars using rotary and manual instrumentation. The variations observed in the electromyographic activities during the performance of rotary and manual techniques suggest that the fibers of the longissimus region, anterior and medium deltoid, medium trapezium, biceps, triceps brachii, brachioradialis and short thumb abductor muscles underwent adaptations to provide more accurate functional movements. Computerized kinemetry and biophotogrammetry showed that, as far as posture is concerned, rotary technique was more demanding than the manual technique. In conclusion, the group of endodontists evaluated in this study exhibited posture disorders regardless of whether the rotary or manual technique was used.

Os fatores de risco posturais para cirurgiões dentistas incluem o acesso a visão no local de trabalho, frio, vibração, pressão mecânica nos tecidos, postura incorreta, alterações funcionais, requisitos cognitivos e fatores organizacionais e psicossociais relacionados com o trabalho. O objetivo é analisar a postura dos endodontistas no local de trabalho. Participaram dezoito endodontistas destros com idades entre as idades de 25 e 60 anos (34±3). Nesta pesquisa foi utilizado a eletromiografia, cinemetria, escalas de ergonomia (do RULA e Couto checklist) e biofotogrametria para analisar a postura dos endodontistas durante o preparo químico-mecânico do sistema de canais radiculares para primeiros e segundos molares superiores direitos, utilizando a instrumentação rotatória e manual. As variações observadas nas atividades eletromiográficas durante a execução das técnicas rotatórias e manuais sugerem que as fibras da região dos músculos longuíssimo, deltóide anterior e médio, trapézio médio, bíceps, tríceps braquial, braquiorradial e músculos abdutores curtos do polegar passaram por adaptações para promover movimentos funcionais mais precisos. A cinemetria e biofotogrametria computadorizada mostraram que a técnica rotatória foi mais exigente da postura corporal do que a técnica manual. Em conclusão, os endodontistas estudados apresentaram distúrbios de postura, independentemente da técnica utilizada, rotatória ou manual.

The effect of a Lucia jig for 30 minutes on neuromuscular re-programming, in normal subjects

The Lucia jig is a technique that promotes neuromuscular reprogramming of the masticatory system and allows the stabilization of the mandible without the interference of dental contacts, maintaining the mandible position in harmonic condition with the musculature in normal subjects or in patients with temporomandibular dysfunction (TMD). This study aimed to electromyographically analyze the activity (RMS) of the masseter and temporal muscles in normal subjects (control group) during the use of an anterior programming device, the Lucia jig, in place for 0, 5, 10, 20 and 30 minutes to demonstrate its effect on the stomatognathic system. Forty-two healthy dentate individuals (aged 21 to 40 years) with normal occlusion and without parafunctional habits or temporomandibular dysfunction (RDC/TMD) were evaluated on the basis of the electromyographic activity of the masseter and temporal muscles before placement of a neuromuscular re-programming device, the Lucia jig, on the upper central incisors. There were no statistically significant differences (p < 0.05) in the electromyographic activity of the masticatory muscles in the different time periods. The Lucia jig changed the electromyographic activity by promoting a neuromuscular reprogramming. In most of the time periods, it decreased the activation of the masticatory muscles, showing that this device has wide applicability in dentistry. The use of a Lucia jig over 0, 5, 10, 15, 20 and 30 minutes did not promote any statistically significant increase in muscle activity despite differences in the data, thus showing that this intra-oral device can be used in dentistry.

Electromyographic activity of masticatory muscles in women with osteoporosis

The purpose of this study was to analyze the electromyographic (EMG) activity and the maximal molar bite force in women diagnosed with osteoporosis in the maxillary and mandibular regions, considering the habits and conditions that lead to development of generalized skeletal bone loss, including on face bones, can disturb the functional harmony of the stomatognathic system. Twenty-seven women with mandibular and maxillary osteoporosis and 27 healthy controls volunteered to participate in the study. A 5-channel electromyographer was used. Muscle activity was evaluated by means of EMG recordings of the masticatory musculature (masseter and temporalis muscles, bilaterally) during the following clinical conditions: rest (5 s); right and left lateral excursions (5 s); protrusion (5 s); maximal dental clenching on Parafilm™ (4 s) and maximal voluntary contraction (4 s). This latter clinical condition was used as the normalization factor of the sample data. It was observed that individuals with osteoporosis presented greater EMG activity when maintaining mandible posture conditions and less activity during dental clenching and when obtaining maximal molar bite force. It may be concluded that facial osteoporosis can interfere on the patterns of masticatory muscle activation and maximal bite force of the stomatognathic system.

Este estudo teve como objetivo analisar a atividade eletromiográfica e a força de mordida molar máxima de indivíduos diagnosticados com osteoporose na região maxilar e mandibular, visto que os hábitos e condições que provocam o desenvolvimento de uma perda óssea generalizada no esqueleto, inclusive no esqueleto facial, podem causar distúrbios na harmonia funcional do sistema mastigatório. Vinte e sete indivíduos portadores de osteoporose na mandíbula e maxila e 27 voluntários sem a doença participaram deste estudo. Um eletromiógrafo de 5 canais foi utilizado. A avaliação da atividade muscular foi realizada por meio de registros eletromiográficos da musculatura mastigatória (músculos masseter e temporal, bilateralmente) durante as seguintes condições clínicas: Repouso (5 s); Lateralidades direita e esquerda (5 s); Protrusão (5 s); Apertamento dental máximo com parafilme (4 s) e a contração voluntária máxima (4 s), sendo que esta condição clínica foi utilizada como fator de normalização dos dados da amostra. Verificou-se que os indivíduos com osteoporose apresentaram maior atividade eletromiográfica durante a manutenção das condições posturais da mandíbula e menor atividade durante o apertamento dental e na obtenção da força de mordida molar máxima. Conclui-se que a osteoporose na região dos ossos da face pode interferir nos padrões de ativação da musculatura mastigatória e na força de mordida máxima do sistema estomatognático.

Using overdenture on implants and complete dentures: effects on postural maintenance of masticatory musculature

Aims: Thanks to advances in osseointegration, oral rehabilitation specialists have had the option of using implants to improve retention and stability in treatments with complete dentures. This study compared the masticatory muscle electromyographic activity in implant-supported overdenture wearers, complete denture wearers and dentate individuals. The electromyographic activity of the right and left masseter muscles, and the right and left anterior temporalis muscles was analyzed in 10 implant-supported overdenture wearers (Group 1), 10 conventional complete denture wearers (Group 2), and 10 dentate individuals (Group 3), with mean age of 65 years, at rest and during postural position maintenance. The analysis was performed using the MyoSystem-Br1 electromyographer with differential active electrodes. Analysis of variance tests were carried out to compare the groups and muscles and revealed different electromyographic values that were statistically significant at 1% significance level. Duncan’s pos-hoc test showed that Group 3 presented the smallest values (pd”0.01). The electromyographic contraction pattern was similar between Groups 1 and 3 (p>0.01), and hyperactivity of anterior temporalis muscles was observed in Group 2 (pd”0.01). Conclusions: dentate individuals had smaller electromyographic values of masticatory muscles and the overdenture use caused electromyographic contraction patterns similar to those of dentate individuals in both positions.

Anatomic variation of cranial parasympathetic ganglia

Having broad knowledge of anatomy is essential for practicing dentistry. Certain anatomical structures call for detailed studies due to their anatomical and functional importance. Nevertheless, some structures are difficult to visualize and identify due to their small volume and complicated access. Such is the case of the parasympathetic ganglia located in the cranial part of the autonomic nervous system, which include: the ciliary ganglion (located deeply in the orbit, laterally to the optic nerve), the pterygopalatine ganglion (located in the pterygopalatine fossa), the submandibular ganglion (located laterally to the hyoglossus muscle, below the lingual nerve), and the otic ganglion (located medially to the mandibular nerve, right beneath the oval foramen). The aim of this study was to present these structures in dissected anatomic specimens and perform a comparative analysis regarding location and morphology. The proximity of the ganglia and associated nerves were also analyzed, as well as the number and volume of fibers connected to them. Human heads were dissected by planes, partially removing the adjacent structures to the point we could reach the parasympathetic ganglia. With this study, we concluded that there was no significant variation regarding the location of the studied ganglia. Morphologically, our observations concur with previous classical descriptions of the parasympathetic ganglia, but we observed variations regarding the proximity of the otic ganglion to the mandibular nerve. We also observed that there were variations regarding the number and volume of fiber bundles connected to the submandibular, otic, and pterygopalatine ganglia.

Glândula submandibular de ratos com envelhecimento: observações ao microscópio eletrônico de varredura de alta resolução / Submandibular gland of rats with ageing: observations with high resolution scanning electron microscopy

As características tridimensionais dos componentes intracelulares de células acinares e de ductos foram reveladas usando o método ósmio-DMSO-ósmio. As amostras foram maceradas em solução de tetróxido de ósmio diluído após a fratura na solução de dimetil sulfoxido. As lamelas do retículo endoplasmático granular são reveladas entremeadas por várias mitocôndrias. As lamelas do retículo endoplasmático granular são localizados ao redor dos núcleos na porção basal e estas estruturas são observadas em imagens tridimensionais de microscopia eletrônica de alta resolução.

The three-dimensional characteristics of the intracellular components of acinar and ductal cells were revealed using the osmium-DMSO-osmium method. The samples were macerated in diluted osmium after fractured in DMSO solution. The stacks of the rough endoplasmic reticulum are revealed intermingling by several mitochondria. The lamellae of the rough endoplasmic reticulum are located around the nuclei at basal portion and these structures are shown in three-dimensional HRSEM images.

Evaluation of ocular prosthesis biofilm and anophthalmic cavity contamination after use of three cleansing solutions

In addition to an initial socket discomfort, ocular prosthesis (OP) installation may allow the adherence of fungi and/or bacteria due to the superficial characteristics of the prosthesis' material, use of inadequate cleansing solutions and methods, or because the void located between the internal portion of the prosthesis and the anophthalmic cavity (AC) mucosa. Objective: The aim of this study was to evaluate OP biofilm formation and the level of contamination of the internal portion of the OP and the AC in 24 patients. Material and Methods: Material was collected from the AC at the beginning of the study and 15 days after cleansing of the OP with 3 cleansing solutions: a neutral liquid soap, a multiuse solution for contact lens (Complete) and 0.12 percent chlorhexidine (Periogard). The collected materials were sowed in Petri dishes containing selective media for aerobic and facultative microorganisms, specifically staphylococci (Hipersalt agar with egg yolk), aerobic microorganisms (Brain Heart Infusion Blood Agar), streptococci (Mitis salivarius Agar), gram-negative bacilli (MacConkey Agar) and yeasts (Chromagar CandidaTM), incubated at 35°C or 37°C and the number of colony forming units were counted. Data were analyzed statistically by ANOVA, Friedman's test and Spearman's correlation. Results: Aerobic microorganisms, gram-negative bacilli and S. aureus were found in the OP biofilm and in the AC. There was statistically significant difference (p<0.05) between the number of microorganisms before and after the use of the cleansing solutions. Conclusion: There was positive correlation with respect to the microorganisms present in the OP biofilm and AC for the 4 proposed treatments, indicating that the decrease of OP contamination leads to AC contamination as well.

Use of the Fonseca's questionnaire to assess the prevalence and severity of temporomandibular disorders in brazilian dental undergraduates

This study to assessed the prevalence of signs and symptoms of temporomandibular disorders (TMD) by means of the frequency distribution of data for 218 dentistry students from a Brazilian public university using the Fonseca's questionnaire. The group consisted of 96 men and 122 women, with an average age of 20 years. Of the students, 53.21 percent showed some level of TMD: 35.78 percent mild TMD 11.93 percent moderate and 5.5 percent severe. Women were the most affected group, with 63.11 percent showing some level of TMD, against 40.62 percent of men. When considering only severe TMD, women are approximately 9 times more affected than men. Students with any level of TMD showed marked characteristics: 76.72 percent considered themselves tense people; 71.55 percent reported to clench or grind their teeth; 65.52 percent reported clicking of the temporomandibular joint; 64.66 percent reported frequent headache and 61.21 percent neck pain. In conclusion, clinical signs and symptoms of TMD can occur in young population and this information is of great importance for the early diagnosis of the dysfunction.

Avaliou-se a prevalência de sinais e sintomas de disfunção temporomandibular (DTM) através da distribuição da freqüência de dados obtidos em 218 estudantes de Odontologia da FORP-USP usando o questionário Fonseca. A amostra foi dividida em 96 homens e 122 mulheres (idade média=20 anos). 53,21 por cento apresentaram algum grau de DTM, sendo 35,78 por cento DTM leve, 11,93 por cento moderada e 5,5 por cento severa. As mulheres foram mais afetadas; 63,11 por cento apresentaram algum grau de DTM contra 40,62 por cento dos homens. Considerando somente DTM severa, as mulheres foram cerca de 9 vezes mais afetadas que os homens. Os estudantes com DTM em qualquer grau apresentaram características marcantes como: 76,72 por cento se consideram pessoas tensas; 71,55 por cento apertam ou rangem os dentes; 65,52 por cento têm ruídos na ATM; 64,66 por cento apresentam dor de cabeça com freqüência e 61,21 por cento dor na nuca ou torcicolo. Conclui-se que sinais e sintomas de DTM estão presentes em população jovem, sendo estes importantes para o diagnóstico precoce da disfunção.

Transmission Electron Microscopy Study of the Neonatal Rat Tongue Mucosa Treated with Special Attention to the Bacteriae on the Epithelial Cell Membrane

RESUMEN: A través de miscroscopía electrónica de transmisión se examinaron las células del epitelio de la mucosa lingual de ratas Wistar recién nacidas. Los tejidos fueron fijados en solución de Karnovksy modificada e incluidos en resina Spurr. Se obtuvieron delgados cortes de 90 nm y se observaron al microscopio electrónico de transmisión Jeol 1010. Se encontró que las células epiteliales queratinizadas escamosas de la mucosa lingual expuestas al cadmio, presentaron grupos de numerosas bacterias las cuales estaban fijadas a las superficies de las membranas celulares. Los cocos y bacilos estaban fijados a las membranas celulares organizadas en pilas o columnas o al azar, como se aprecia claramente en las imágenes obtenidas a través de la microscopía electrónica de transmisión. Las imágenes mostraron que las bacterias estaban fijadas por estructuras fibrilares desde una a otra y desde las memebranas de las células epiteliales a las bacterias. El grupo control demostró que en las membranas celulares no era evidente la presencia de cadmio.

Electromyographic analysis of the orbicularis oris muscle in oralized deaf individuals

A eletromiografia, como método de estudo, tem sido bastante utilizada e vem contribuindo para elucidar o desempenho da musculatura peribucal em vários processos fisiológicos como a mastigação, deglutição e fala, e é um instrumento importante na análise das bases fisiopatológicas das mudanças que ocorrem nesta musculatura. Muitos trabalhos têm sido conduzidos em pacientes com deficiência auditiva e de fala, mas nenhum deles avaliou a musculatura responsável pela fala. Este estudo comparou medidas eletromiográficas dos fascículos superior e inferior do músculo orbicular da boca em indivíduos portadores de deficiência auditiva neurossensorial profunda (surdos) com indivíduos clinicamente normais (ouvintes). A análise eletromiográfica foi realizada em 20 indivíduos, de ambos os sexos, com idade média de 18,5 anos, divididos em dois grupos: o primeiro grupo constituído por 10 indivíduos portadores de deficiência auditiva neurossensorial profunda bilateral e o segundo por indivíduos clinicamente normais. Cinco condições clínicas foram avaliadas: sucção, sopro, projeção e compressão labial e emissão da sílaba "Pa". Verificou-se que os pacientes surdos apresentaram hiperatividade muscular em todas as condições clínicas analisadas, e que o fascículo inferior do músculo orbicular da boca apresentou os níveis mais altos de atividade eletromiográfica, sugerindo a necessidade de um tratamento fonoaudiológico, com enfoque em motricidade oral.

Effect of denture quality on perioral muscle activity during speech / Efeito da qualidade da dentadura no músculo peribucal durante a atividade da fala

This study aimed to evaluate the electromyographic activity of the orbicularis oris muscle in patients using clinically inadequate conventional dentures before and after the insertion of clinically acceptable new convencional denture. Six patients, using inadequatedentures, were asked to pronounce the syllables PAH, BAH, MAH, SAH, FAH, VAH, MEE and the word MISSISSIPI. During this activity, we analyzed the Electromyographic activity of the orbicularis oris muscle. This was done before and after changing the inadequate denture for a acceptable new denture. A K6-I EMG Light Channel SurfaceElectromyograph was used (Myo-tronics Co). Results were analyzed by repeated measures ANOVA, with 3 sources of variation (Syllables, Muscles, and Clinical Conditions). ANOVA revealed higher electromyographic readings in the mandibular fascicle of the orbicular oris muscle, as compared to those of the maxillary fascicle (F = 79.02;P<0.01). The comparison regarding clinical conditions indicated higher electromyographic values after insertion of acceptable new denture (F= 32.64; P<0.01). Clinical condition after the implantation of a new well-adapted complete denture revealed higher electromyographicactivity levels than those measured with the use of maladapted complete dentures

Efectos del Albendazol en el Hígado de Feto de Rata: Estudios Morfológico y Morfométrico / Effects of Albendazole on Rat Fetuses Liver: Morphologic and Morphometric Studies

El objetivo del presente trabajo fue caracterizar morfológica, morfométrica y estereológicamente las alteraciones causadas por la administración de albendazol en ratas preñadas en el hígado de los fetos. Fueron usadas ratas Wistar, que recibieron entre los días 9 y 11 de la preñez, una dosis diaria de 5 mg/kg de peso de albendazol. Las ratas control recibieron volumen semejante de suero fisiológico en los mismos días. Al 20 día, las ratas fueron sacrificadas por inhalación de éter, siendo retirados los fetos e inmediatamente fijados en alfac por 24 h. Los fetos, úteros y placentas, luego de fijados, fueron secados en papel de filtro y pesados en balanza de precisión, siendo medidos los cordones umbilicales con nonio. Los cuerpos de los fetos fueron seccionados longitudinalmente e incluidos en parafina. Los cortes seriados de 6 µm de espesor, fueron teñidos con hematoxilina y eosina. Además del examen histopatológico, fueron utilizadas técnicas histométricas. Los resultados obtenidos, en las condiciones experimentales, sugieren que la exposición prenatal al albendazol actúa directamente en la embriogénesis, causando malformaciones como agenesia del rabo y fetos hidrópicos. En los fetos sin malformaciones, la droga causó retardo del desarrollo fetal, caracterizado por reducción de peso corporal, peso de la placenta y longitud del cordón umbilical, así como alteraciones estructurales hepáticas, reflejadas en hepatocitos menores con núcleos menores y citoplasma más escaso y aumento de la densidad numérica. Los megacariocitos eran mayores, con núcleos lobulados grandes, con mayor volumen relativo. Los sinusoides ocuparon un volumen relativo semejante en los fetos de los dos grupos estudiados. Los fetos tratados, además de las malformaciones, mostraron aspectos que sugieren inmadurez al ser comparados con los controles.

The objective of the present work was to characterize morphological, morphometrical and stereologically the hepatic alterations in rat fetuses, caused by the administration of albendazole during pregnancy. They were obtained fetuses of Wistar rats, which received in days 9, 10 and 11 of pregnancy a daily dose of 5 mg/Kg body weight of albendazole. The control rats received injections of saline in the same days. At the 20th day, the rats were sacrificed by anesthetic ether inhalation, the fetuses were removed and immediately fixed in alfac for 24 h. All the fetuses, uteri and placentas, after fixed, was dried in filter paper and weighed in a precision scale, whereas the umbilical cords were measured with a vernier. The bodies were longitudinally cut and embedded in paraffin. Six mm-thick serial sections were stained with hematoxylin and eosin. In addition to the histopatologic examination, histometric technics were used. The obtained results, in the used experimental conditions, suggest that prenatal exposition to albendazole directly acts on the embryogenesis, causing malformations, like agenesia of the tail and hydropic fetuses. In those fetuses without malformations, the drug acts on the fetal growth, causing modifications characterized by reduced body weight, placental weight and size of the umbilical cord, as well as structural alterations of the hepatic tissue, translated by smaller hepatocytes with smaller nuclei, and scanty cytoplasm but increased number density. The megacariocytes were more volumous, with greater lobulated nuclei, occupying a higher relative volume. The sinusoids occupied a similar relative volume in the fetuses of both studied groups. The treated fetuses, in addition to the malformations appeared to be immature, when compared to the controls.

Effects of cigarette smoke on the Meckel's cartilage of rat fetus: morphologic, morphometric and stereologic study

O objetivo deste estudo foi investigar os efeitos da fumaça de cigarros sobre o desenvolvimento da cartilagem mandibular (cartilagem de Meckel) do embrião de rato. Quando inalado por ratas Wistar, entre o 9º e o 12º dia de prenhez, a fumaça de cigarros (5/dia) provocou retardo do crescimento intrauterino, com fetos e placentas menores. Nos fetos do grupo experimental, o exame histopatológico revelou uma cartilagem de Meckel pouco desenvolvida, com condroblastos menores apresentando citoplasma escaso com núcleos mais pálidos, esféricos e centrais, assim como uma matrix cartilaginosa mais abundante. A análise morfométrica revelou que as lacunas da cartilagem de Meckel eram menores nos fetos do grupo experimental, não apresentando alteração significativa de sua forma. Os resultados sugeriram que a fumaça de cigarros inalada pelas ratas prenhes durante o período de organogênese induziu retardo tanto do crescimento quanto da diferenciação celular na cartilagem de Meckel dos fetos.

Educational material of dental anatomy applied to study the morphology of permanent teeth

O objetivo deste trabalho é de apresentar um material didático que permita ao aluno de odontologia, identificar com maior facilidade, as características morfológicas dos dentes permanentes assim como entender mais facilmente a oclusão dos dentes. Para isto, foram confeccionados macromodelos de dentes permanentes sem desgaste, que foram obtidos da seguinte maneira: foram esculpidos macromodelos em cera; posteriormente estes foram moldados com alginato e os moldes foram preenchidos com gesso pedra e resina acrílica. Os macromodelos de gesso pedra foram montados em oclusão em uma base de cera #7 sendo obtidas desta maneira as arcadas superior e inferior. Estas arcadas montadas em cera foram moldadas novamente e o molde foi preenchido com gesso pedra, obtendo então as duas arcadas totalmente em gesso. Os autores concluíram que os macromodelos permitem uma melhor visualização das características morfológicas dos dentes permanentes bem como da oclusão; os alunos conseguem esculpir dentes permanentes em cera, com maior facilidade, quando observam macromodelos.

Effect of cadmiun on rat maxillary moral junctional epithelium during lactation: efecto del cadmio sobre el epitelio de la zona de union maxilo-molar de ratas durante la lactancia

El cadmio presente en el aire, agua potable y alimentos, afecta la salud de las poblaciones, principalmente en regiones altamente industrializadas. El cadmio afecta la función placentaria, puede atravesar la barrera placentaria y alterar directamente el desarrollo fetal. Puede ser también excretado en la leche. El organismo es particularmente susceptible a la exposición al cadmio durante el período perinatal. Fue estudiado el efecto de la exposición continua, durante la lactancia, a agua potable conteniendo bajos niveles de cadmio, sobre el epitelio de la zona de unión maxilo-molar. Ratas hembras recibieron agua potable ad libitum conteniendo 300mg/l de CdCl2 durante todo el período de lactancia. Los controles recibieron un volumen similar de agua sin cadmio. Ratas lactantes (21 días de edad) fueron sacrificadas con dosis letal de anestésico, sus cabezas separadas, fijadas en alfac por 24 h y la región palatina seccionada frontalmente, al nivel de los primeros molares. Los cortes de 6 µm de espesor fueron teñidos con hematoxilina y eosina. Se estimaron los parámetros nucleares del epitelio, así como los volúmenes citoplasmático y celular, relación núcleo/citoplasma, densidad numérica y superficial y grosor epitelial. El peso medio fue 34,86g para los controles y 18,56g para los tratados. Histológicamente, el epitelio fue más fino, con células más abundantes y menores. El cadmio indujo hipotrofia epitelial, indicando una acción directa sobre la mucosa oral, además de retardo del desarrollo de las crías.

Bilaminar zone: anatomical aspects, irrigation and inervation

The temporomandibular joint, a synivial joint of great importance in dentistry, consists of articular surfaces, ligaments, and the articular disk. The posterior region of the disk or bilaminar zone consists of upper layer that is attached to the posterior wall of the mandibular head and forms the posterior limit of the disk. Lesions in this regions caused by distention, trauma or pressure can lead to luxation of the disk and temporomandibular disorders that may or may not be accompanied by degenerative alterations. In this work, we examined the anatomy of the bilaminar zone, as well as its irrigation and innervation. Five human heads fixed in 10 por cento formalin underwent medial sagittal sectioning followed by dissecting. The bilaminar zone was irrigated by the superficial temporal artery and anterior tympanic and deep auricular arteries. Innervation of this region was by the sensorial terminations of the auriculotemporal nerve. These finding indicated that the bilaminar zone was located in a innervated and vascularized area in the posterior region of the disk.

Estudo eletromiográfico da má-oclusão Classe II, durante tratamento com reabilitação dinâmica funcional dos maxilares / Electromyographic study in patients with Class II malocclusion, during treatment with funcional dynamic rehabilitation of jaw

Este estudo foi realizado com o objetivo de investigar a atividade eletromiográfica (EMG) dos músculos temporal (porção anterior) e masseter em portadores de má-oclusão Classe II de Angle, durante tratamento ortopédico funcional com a técnica Reabilitação Dinâmica e Funcional doa Maxilares (RDFM). Foram avaliados dez pacientes com dentição mista, na faixa etária de seis a doze anos (média 8,6), nas condições experimentais: 1) Apertamento em Máxima Intercuspidação Habitual (AMIH); 2)Apertamento Molar Bilateral com Rolete de Algodão (AMBA); 3)Apertamento Máximo com Aparelho (AAPA); e 4) Mastigação Habitual (MH). Os registros eletromiográficos foram executados no ato da instalação da aparatologia, após seis meses e um ano de tratamento com eletrodos bipolares de superfície posionados bilateralmente na porção anterior do músculo temporal e no músculo masseter. As atividades médias dos músculos estudados foram analisadas estatisticamente pela Análise de Variância e teste complementar de Tukey. Pelos resultados concluiu-se que: as funções estudadas mostraram aumento significativo na atividade muscular após um ano de tratamento; não houve diferença estatística entre as condições AMIH, AMBA e AAPA, porém estas foram significativamente diferentes da MH; e a atividade EMG do músculo masseter foi estatisticamente maior que a da porção anterior do músculo temporal