A clinical application study of digital manufacturing simple intraoral Gothic arch-tracing device in determining the centric relation of complete dentures / 北京大学学报(医学版)

OBJECTIVE@#To verify the consistency between the digital manufacturing simple intraoral Gothic arch-tracing device and the traditional intraoral Gothic arch-tracing device in determining the centric relation of complete dentures restoration.@*METHODS@#Ten outpatients with edentulous jaws were selec-ted, and the centric relation of the patients was determined by digital manufacturing of simple intraoral Gothic arch-tracing device (T1) and traditional intraoral Gothic arch-tracing device (T2); the difference of clinical operation time between the two methods was recorded; the upper and lower edentulous jaw plaster models were scanned with two kinds of centric relation, the Standard Triangle Language (STL) files imported into Geomagic studio software to apply the best fitting of multiple points of the both upper jaw models, the fitted STL files imported into the 3 shape viewer software, and the maximum position deviations of the vertical, labial (buccal) and lingual directions of the mandibular midline area and molar areas in T1 and T2 groups measured. During the clinical complete dentures try-in, we observed whether there was midline deviation in the mouth of T1 group and T2 group, and whether the occlusion of posterior teeth was stable or not.@*RESULTS@#The mean time spent on determining the centric relation of T1 and T2 groups was (41.90±2.64) min, (57.50±2.37) min respectively. Paired t test was conducted in the two groups, P < 0.01 with significant statistical difference; The mean maximum position deviation between T1 group and T2 group of the midline mandibular region in labial lingual direction was (0.32±0.14) mm, that was (0.40±0.23) mm in vertical direction; the mean maximum position deviation of molar area in buccal lingual direction was (0.35±0.23) mm and that was (0.33±0.20) mm in vertical direction. In the vertical and horizontal directions, the maximum position deviation of mandibles between group T1 and group T2 was controlled within 0.5 mm. In the process of clinical complete dentures try-in, there was no deviation from the center line of dentures. There was not warping, swinging and other poor stability phenomena in T1 and T2 groups.@*CONCLUSION@#The digital manufacturing of simple intraoral Gothic arch-tracing device can be used to determine the centric relation of complete dentures, which can not only save time of clinical operation, but also ensure the accuracy of the centric relation.

Application of 3D Electromagnetic Articulography in Dentistry: Mastication and Deglutition Analysis. Protocol Report / Aplicación de la Articulografía Electromagnética 3D en Odontología: Análisis de la Masticación y Deglución. Reporte de Protocolo

ABSTRACT: The Stomatognathic System (SS) is an integrated and coordinated morphofunctional unit, consisting of skeletal, muscular, angiological, nervous, glandular and dental structures that work in harmony to perform different functions such as chewing, swallowing, speaking, breathing, tasting and esthetics. The study of SS physiology is crucial to achieving a correct maintenance of its normal function or restoration. Thus, we developed a protocol to record mandibular movement, chewing and swallowing (saliva and water) by using the 3D-electromagnetic articulograph AG501 at the Oral Physiology Laboratory of the Research Centre for Dental Sciences (CICO). This tool has been used for decades in speech and phonetic research and it is able to record, present and evaluate articulated structure movement data in real time. The articulograph provides an ordered data matrix (values ??for the x, y, z axes, among others) for the recorded movement, which is stored in binary files that can be processed by different software. One of these is MATLAB®, allowing us to perform a quick, clear and understandable analysis. The existence of a standardized methodology for recording allows an accurate description of the stages to perform different types of measurements according to the researcher's objective. This has opened the way for a new type of oral physiology analysis based on study reproducibility, which is considered one of the bases of scientific methodology.

RESUMEN: El Sistema Estomatognático es una unidad morfo-funcional integrada y coordinada, constituida por estructuras esqueléticas, musculares, angiológicas, nerviosas, glandulares y dentales que actúan en armonía para realizar diferentes funciones como la masticación, deglución, fonoarticulación, respiración, degustación y estética. Es importante el estudio de la fisiología del SE para lograr un correcto mantenimiento de su función normal, o para la restauración de este. Es así como en el Laboratorio de Fisiología Oral del Centro de Investigación en Ciencias Odontológicas (CICO) hemos desarrollado un protocolo para el registro del movimiento mandibular, masticación y deglución (saliva y agua), utilizando el articulógrafo electromagnético 3D AG501, el cual ha sido utilizado desde hace décadas en la investigación del habla y la fonética y que es capaz de grabar, presentar y evaluar en tiempo real datos del movimiento de estructuras articuladas. El articulógrafo provee de una matriz de datos ordenados (valores para los ejes x, y, z, entre otros) para el movimiento registrado, el cual se almacena en archivos binarios que pueden procesarse a través de diferentes softwares. Uno de ellos es MATLAB®, el cual nos permite realizar un análisis de forma rápida, clara y comprensible. La existencia de una estandarización metodológica de registro, permite describir de forma exacta las etapas para llevar a cabo distintos tipos de mediciones según el objetivo del investigador. De esta forma se abre la puerta a una nueva forma de análisis en la fisiología oral que se sustenta en la reproducibilidad de la investigación que es considerada una de las bases de la metodología científica.

Influence of Class II Elastics on Centric Relation and Centric Occlusion Discrepancy after Orthodontic Treatment / Influencia de los Elásticos de Clase II sobre la Discrepancia de Relación Céntrica para la Oclusión Céntrica Después del Tratamiento Ortodóncico

ABSTRACT: The objective of this study was to verify the influence of the use of Class II intermaxillary elastics on centric relation (CR) to centric occlusion (CO) occlusal discrepancy. A total of 30 patients had been at the contention stage for at least three months were divided in two groups: G1 - 15 had been submitted to intramaxillary orthodontic mechanics only, and G2 - 15 had used Class II intermaxillary elastics. Distances of horizontal and vertical overlap and the distance or coincidence of the mandibular dental midline in relation to the maxillary midline were measured in CR and CO positions. Intergroup comparisons were performed using the Mann-Whitney test. No statistically significant differences (P>0.05) were found between G1 and G2. Both in the horizontal and vertical directions, these discrepancies were smaller than or equal to 1mm in 96.66 % of the patients. In the transverse plane, there was no discrepancy in 63.33 % of the patients, and in 33.33 % these discrepancies were equal to 0.5 mm. The use of Class II elastic didn't be capable of increasing the occlusal discrepancies between CR and CO.

RESUMEN: El objetivo de este estudio fue verificar la influencia del uso de los elásticos intermaxilares Clase II en la discrepancia oclusal entre la relación céntrica (RC) y la oclusión céntrica (OC). Un total de 30 pacientes que permanecieron en la fase de contención durante al menos tres meses se dividieron en dos grupos: G1 - 15 fueron sometidos solamente a la mecánica ortodóncica intramaxilar, y G2 - 15 habían utilizado elásticos de clase II intermaxilar. Se midieron las distancias de traslapo horizontal y vertical y la distancia o coincidencia de la línea mediana dentaria mandibular con respecto a la línea mediana maxilar en las posiciones RC y OC. Las comparaciones entre grupos se realizaron mediante la prueba de Mann-Whitney. No se encontraron diferencias estadísticamente significativas (P> 0.05) entre G1 y G2. Tanto en las direcciones horizontal como vertical, estas discrepancias fueron menores o iguales a 1 mm en el 96,66 % de los pacientes. En el plano transversal, no hubo discrepancia en el 63,33 % de los pacientes, y en un 33,33 % estas discrepancias fueron iguales a 0,5 mm. El uso de la clase II elástica no logró aumentar las discrepancias entre RC y OC.

Diagnóstico cefalométrico de la relación sagital intermaxilar, ángulo ANB y pruebas alternativas: artículo de revisión / Cephalometric diagnosis of intermaxillary sagittal relationship, ANB angle and alternative tests: a review article

La manifestación clínica de la relación sagital entre los maxilares superior e inferior ha sido utilizada de forma fiable y válida, hasta la actualidad. El objetivo de este trabajo ha sido realizar una revisión histórica y análisis del estado arte del Ángulo ANB como prueba diagnóstica gold estándar de la relación sagital intermaxilar necesaria para decidir el tipo de tratamiento ortodóncico u ortopédico a aplicar, así como un estudio de los diferentes factores que pueden afectar la validez de este test de diagnóstico, además de hacer una revisión de pruebas diagnósticas alternativas propuestas por diferentes autores, establecer su funcionalidad en la toma de decisiones clínicas terapéuticas. Se realiza una revisión de las diferentes metodologías estadísticas como estudios de correlación y uso del análisis deCaracterística Operativa Relativa (ROC), que observa la sensibilidad y la especificidad de la prueba y es un indicador de su habilidad diagnóstica. Esta revisión sistemática se la ha realizado en base a información bibliográfica (1952-2015) a través de Biblioteca virtual, en Postgrado de Ortodoncia de la Facultad de Odontología de la Universidad de Buenos Aires.

The clinical manifestation of anteroposterior relationship between the upper and lower jaws has been used in a reliable and valid untiltoday. The aim of this study was to conduct a historical review and state of the art analysis of ANB angle as a diagnostic gold standardsagittal intermaxillary relationship needed to decide the type of orthodontic or orthopedic treatment to apply, and a study of the differentfactors that can affect the validity of the diagnostic test, in addition to a review of alternative diagnostic tests proposed by differentauthors, establish their functionality in making therapeutic clinical decisions. Reviews of the different statistical methodologies ascorrelation studies and analyzes of Relative Operating Characteristic (ROC) were performed, noting the sensitivity and specificity of thetest, being an indicator of its diagnostic utility. This systematic review has made based on bibliographic information (1952-2015) through Virtual Library in Orthodontics Graduate School of Dentistry at the University of Buenos Aires.

Thickness and marking quality of different occlusal contact registration strips

Objectives Evaluate the thickness and the marking quality of different occlusal contact registration strips (OCRS) and a possible correlation between them. Material and Methods The following OCRS were selected: Accufilm II, BK20, BK21, BK22, BK23, BK28, and BK31. The thickness was measured in three points of the OCRS with an electronic measuring device (TESA), and the mean was calculated. To produce the marks on the strips, composite resin specimens were adapted to a universal testing machine (Versat 2000) with 40 kgf load cell at a speed of 1.0 mm/min. The mark images were photographed with a stereoscopic microscope (Stemi SV11) and processed and analyzed by the 550-Leica Qwin® analyzer. Results Values (μm) found in the 1st and 2nd thickness measurements were: Accufilm II - 16.4 and 14.2; BK20 - 10.0 and 8.1; BK21 - 9.5 and 8.0; BK22 - 9.7 and 8.7; BK23 - 9.8 and 7.9; BK28 - 12.8 and 10.0; and BK31 - 8.4 and 8.0, respectively. The mean (mm2) values found in the mark areas were: Accufilm II - 0.078; BK20 - 0.035; BK21 - 0.045; BK22 - 0.012; BK23 - 0.022; BK28 - 0.024; and BK31 - 0.024. The results were submitted to the Kruskal-Wallis (p<0.05) and Pearson’s correlation tests. Conclusions Only in the 2nd measurement, the OCRS thickness observed was similar to the value indicated by the manufacturers; the Accufilm II and the BK28 strips showed the better marks; and no correlation was found between the thickness and the marking area. .

Comparación de la posición condilar entre dos técnicas de registro de relación céntrica mediante tomografía espiral / Condylar position comparison between two centric relation recording methods, by means of a spiral tomography technique

Objetivo: El objetivo de este estudio fue comparar la variación de la posición del cóndilo mandibular entre la técnica de registro de relación céntrica auto-inducida de tipo activa y otra de manipulación mandibular de tipo chin-point. Método: En una muestra por conveniencia de 9 sujetos (4 hombres y 5 mujeres), se estudiaron un total de 18 articulaciones témporomandibulares determinando la variación de la posición condilar con el uso de imágenes obtenidas mediante tomografía espiral, utilizando para ambas técnicas un deprogramador anterior de Neff para estandarizar el grosor del material de registro. Resultados: Se observó que con la técnica chin-point, el cóndilo adopta una posición más posterior (55.6 por ciento) y superior (72.2 por ciento) respecto a la auto-inducida de tipo activa, con diferencias estadísticamente significativas (p<0.001, t-test). En promedio se observó que la técnica chin-point produjo una magnitud de desplazamiento de 1.5mm en dirección cefálica y 1.1mm hacia posterior, tomando como referencia la posición registrada con la técnica auto-inducida de tipo activa. Conclusiones: La técnica chin-point produce una posición condilar más posterior y superior que la técnica auto-inducida de tipo activa.

Objective: The aim of this study was to compare the mandibular condylar position between two centric relation recording methods: Active self-induced type and chin-point manipulation. Method: In a convenient sample of 9 subjects (5 females and 4 males), the condylar position variation was determined in the 18 temporomandibular joints by means of a spiral tomography radiographic technique. To standardize the thickness of the registration material, a Neff anterior deprogramming appliance was used. Results: It was observed that with the chin-point technique, the condyle adopted a significantly more superior (72.2 percent) and posterior (55.6 percent) position compared to the active self-induced technique (p<0.001, t-test). Regarding magnitudes, chin-point produced an average of 1.5mm cephalic and 1.1mm posterior displacements, using the position obtained with the active self-induced technique as a reference. Conclusions: Chin-point technique generates a more superior and posterior condylar position that the one determined by the active self-induced.

Registro de mordida neuromuscular para ortopedia con Tens / Neuromuscular bite recording for orthopedics with Tens

El propósito de este artículo es difundir la odontología neuromuscular, su fundamento, filosofía y en esta oportunidad, aplicarla a la toma del registro de mordida para la confección de aparatología de ortopedia funcional.

Moldagem de transferência e registro interoclusal: técnica diferenciada / Transfer molding and interocclusal record: differentiate technique

O sucesso da reabilitação oral depende de precisão tanto na moldagem quanto na montagem no articulador. Quando temos uma prótese em rebordo de extremidade livre, com grandes espaços edêntulos, a intercuspidação torna-se sujeita a erros e um registro estável e preciso da relação interoclusal é necessário. O objetivo desse artigo é apresentar uma técnica de moldagem de transferência que, ao unir os cilindros para a moldagem, já realizamos o registro interoclusal, obtendo o modelo de trabalho e o registro para o correto relacionamento entre os modelos no mesmo procedimento clínico. A técnica é conveniente, de fácil manuseio e garante bons resultados clínicos (como pode ser observado no resultado final), e poucos ajustes foram necessários para a finalização do trabalho protético

The success of oral rehabilitation depends on the accuracy, both in impression and cast mounting on an articulator. When we have prosthesis in the free end edge, with large edentulous spaces, intercuspation becomes subject to errors and a stable and accurate record of the interocclusal relationship is recquired. The aim of this paper is to present a implant impression technique that, while splinting the cylinders to prepare the impression already makes the interocclusal record, getting the working model and the record for the correct relationship between the models in the same clinical step. The technique is convenient, easy to use and provides good clinical results as observed in final results, requiring only few adjustments for the completion of the prosthetic work

Métodos de registro de la relación céntrica: ¿Son una necesidad en el diagnóstico y tratamiento de ortodoncia? / Recording methods for centric relation: are they a need in orthodontics

Esta revisión bibliográfica se refiere a los métodos de registro de la Relación Céntrica (RC) con un recorrido de la literatura desde 1921a la actualidad en busca de aclarar su definición. Esta controvertida posición cráneo mandibular lleva a una evolución en las técnicasde su registro.El objetivo es describir los métodos de registro, clasificarlos, aportar conocimiento y demostrar su necesidad en el momento del diagnósticoy el plan de tratamiento de acuerdo a las definiciones más aceptadas de RC.

This literature review analyzes the methods of recording Centric Relation (CR) with a previous revision throughout the years seekingto clarify its definition.This controversial craniomandibular position has gone through many changes in it’s registration techniques. A description of the techniquesis made until arriving to the most recent ones according the current accepted definition. The aim is to describe the methods ofrecording, classify them and provide information in order to choose a method in orthodontics diagnosis and treatment, and demostrateits need according to the most accepted definition of Centric Relation.

Estudio preliminar de patrones de mordedura según forma del cráneo, mediante el análisis morfológico y morfométrico de semiarcadas dentarias de perro doméstico (Canis familiaris) con fines de identificación / Preliminary study of bite patterns according to skull shape, by morphological and morphometric analysis of dental semi arcs of domestic dog (Canis familiaris) for identification

La Odontología forense es una rama de las Ciencias Forenses que se utiliza para establecer la identidad de una víctima o victimario mediante el estudio de las huellas de mordeduras, estimación de edad cronológica, entre otros. Dada la inexistencia de este tipo de estudios en Chile y la magnitud que alcanza el problema de mordidas de perros en Chile, se compararon los patrones de huellas de mordedura según forma del cráneo, mediante el análisis morfológico y morfométrico de semiarcadas dentarias de perro doméstico (Canis familiaris) con fines médico legal. Para ello se obtuvieron modelos dentarios en yeso e impresiones de huellas de mordedura en cera de tres razas puras: Bóxer, Dálmata y Ovejero Alemán. Las mediciones contemplaron la distancia máxima externa entre caninos superiores e inferiores y la distancia máxima externa entre incisivos superiores e inferiores. Los principales resultados muestran que sólo la distancia máxima entre caninos superiores permitiría identificar la raza en forma estadísticamente significativa (p0,05) en los modelos de yeso. En el estudio ciego y desde el punto de vista morfométrico se identificaron especialmente los Dálmata con un alto grado de sensibilidad y especificidad. Un poco menor y en forma variable se observó en Bóxer y Ovejero Alemán. El estudio morfológico permitió identificar e individualizar al 100 por ciento de los perros. Por tanto los métodos morfométricos y morfológicos son herramientas complementarias para identificar e individualizar a un posible perro agresor.

Forensic dentistry is a branch of Forensic Sciences used to establish the identity of a crime victim or perpetrator, among these studies are bite marks and dental chronological age studies. In the absence of such studies in Chile and considering the widespread problem of dog bites in Chile, bite patterns were compared according to skull shape, by morphological and morphometric analysis of dental semi arcs of domestic dog (Canis Familiaris) for medico legal purposes. Plaster dental models and impressions of bite marks were obtained of three pure breeds: Boxer, Dalmatian and German shepherd. Measures included he maximum external distance between upper and lower canine, and maximum external distance between upper and lower incisors. Main results show that only the maximum distance between upper canine would allow statistically significant race identification, (p0.05) in cast models. In a blind study and from a morphometric point of view, Dalmatians were identified with a high rate of sensitivity and specificity. A somewhat lesser and variable form was observed in Boxer and German Shepherd. The morphological study allowed identification and individualization of 100 percent of dogs. Therefore, both morphological and morphometric methods are useful and complementary tools to identify and individualize a potentially aggressive dog.

Comparative evaluation of condylar position in symptomatic (TMJ dysfunction) and asymptomatic individuals.

Context: The etiopathogenesis of temporomandibular joint (TMJ) disorders has been attributed to multiple factors and, while the importance of centric relation (CR) has been acknowledged in dental literature, the role of condylar position and CR-CO (CO-centric occlusion) discrepancy in TMJ dysfunction (TMD) has been a source of controversy. Aim: To establish the relationship between condyle position and TMD. Setting and Design: This was a case-control study to evaluate condylar displacement and interarch CR-CO discrepancy in symptomatic subjects (with TMD) and compare them with asymptomatic subjects. Materials and Methods: Forty subjects were screened for TMD based on Helkimo index and grouped into asymptomatic and symptomatic groups. CR was registered using the modified Roth power centric bite registration after neuromuscular deprogramming. Models thus mounted on an Advanced Dental Design (AD2) articulator were evaluated for interarch CR-CO discrepancy. The condylar position discrepancy was recorded on a device MCD (measured condylar deviation). Statistical Analysis: The Student's t test was used to test statistical significance. The paired t test and the unpaired t test were used for comparing results within and between the groups. Pearson correlation coefficient was used to find out the correlation between MCD measurements and dental three-dimensional (3D) model analysis measurements. The Chi-square test was used to evaluate the qualitative data. Results: The average vertical and horizontal condylar displacements were significantly greater in the symptomatic group than in the asymptomatic group. There were significant deviations at the level of the occlusion in both groups. Conclusion: Condyle position may play a significant role in the etiopathogenesis of TMJ disorders.

Single step approach to make diagnostic impressions of both the arches and face bow transfer: A novel technique.

Context: Mounting the maxillary and mandibular dentulous casts for Diagnostic purpose requires many steps (including making maxillary and mandibular impressions, face-bow transfer, and bite registration) or many appointments. A simple new technique of doing all of this together without compromising on the accuracy can save time over the conventional mounting procedure. Aim: To compare the accuracy of a new technique of a single-step diagnostic mounting procedure with that of the conventional diagnostic mounting procedure. Materials and Methods: Ten dentulous patients with the full complement of teeth and without any history of temporomandibular disorder and orthodontic treatment were selected for this study. A detachable metal triple tray to replace the fork part of the face bow fork that further could be attached to face bow was fabricated. Dual-arch impressions and face-bow transfer were made in these subjects using this modified triple tray. These mountings were compared with the ones done with the conventional mounting procedure. Five linear measurements (using stable reference points on the articulator and the cast) were made and the values obtained by both the methods were compared. Statistical Analysis: The Student's 't' test for statistical analysis was used in this study. Results: The measurement values obtained by the single-step method were almost similar to the ones obtained by the conventional method. The various mean measurements for the single step and conventional methods were 37.7 ± 6.8 and 38.5 ± 6.5 mm; 70.0 ± 4.4 and 70.1 ± 4.2 mm; 57.0 ± 4.9 and 57.3 ± 4.2 mm; 71.3 ± 4.5 and 71.0 ± 4.6 mm; and 58.7 ± 2.5 and 58.3 ± 2.3 mm; respectively. The differences between the values obtained by the conventional and single-step methods were not statistically significant. Conclusion: The single-step procedure of diagnostic mounting can be used as an alternative to the conventional method, without compromising the quality of mounting.

Avaliação de marcas de mordidas em alimentos produzidas por próteses dentárias / Evaluation of bite marks made by dental prostheses in foods

O estudo de marcas de mordidas em alimentos é uma importante vertente da Odontologia Legal, pois através do seu emprego é possível identificar ou excluir suspeitos de atos criminosos. O objetivo deste trabalho foi avaliar a viabilidade de identificação através de marcas de mordidas em alimentos, realizadas por próteses dentárias. A amostra foi composta por 10 (dez) pares de próteses, confeccionadas em um laboratório e montadas em um articulador tipo charneira. Após numeração das mesmas e dos alimentos, foi realizado um sorteio. Em seguida, procedeu-se a realização das mordidas nos alimentos (quatro chocolates, quatro queijos e duas bananas), sem o conhecimento dos pesquisadores. Modelos de gesso das próteses e dos alimentos mordidos foram confeccionados, utilizando alginato e gesso pedra. Em seguida, empregou-se a técnica da análise métrica. Nesta etapa realizou-se a mensuração do diâmetro mésio-distal de cada dente nos modelos dos alimentos e das próteses, utilizando um paquímetro digital. Posteriormente, foi feita comparação direta do alimento mordido com os modelos das próteses. Dos dez alimentos mordidos foi possível identificar com precisão a prótese responsável pela impressão dentária em 7 deles. Entretanto, no queijo 01 e 02 e no chocolate 03 não foi possível identificar o autor, mas excluir 8, 5 e 8 suspeitos, respectivamente. De acordo com os resultados obtidos pode-se comprovar que é possível a identificação de marcas de mordidas produzidas por próteses, contribuindo assim com as perícias realizadas na área de Odontologia Legal.

A influência da base craniana nas discrepâncias esqueléticas

Este trabalho de revisão de literatura apresenta como objetivo definir-se, através de seu crescimento e desenvolvimento específico, as alterações na forma e na deflexão da base craniana podem ser consideradas fatores etiológicos primários na determinação das maloclusões de Angle...

Fabrication of fixed partial dentures using functionally generated path technique and double casting.

Harmonious occlusion is a critical requirement for successful oral rehabilitation. Conventional techniques of construction have been unsuccessful in producing a prosthesis that can be inserted without intraoral occlusal adjustment. This article discusses the use of functionally generated path technique with double casting to fabricate fixed partial dentures. The merits of this approach and the technique involved are discussed in detail.

A comparative study of inter-abutment distance of dies made from full arch dual-arch impression trays with those made from full arch stock trays: An in vitro study.

Objectives: The dual-arch impression technique is convenient in that it makes the required maxillary and mandibular impressions, as well as the inter-occlusal record in one procedure. The accuracy of inter-abutment distance in dies fabricated from dual-arch impression technique remains in question because there is little information available in the literature. Materials and Methods: This study was conducted to evaluate the accuracy of inter-abutment distance in dies obtained from full arch dual-arch trays with those obtained from full arch stock metal trays. Results and Conclusion: The metal dual-arch trays showed better accuracy followed by the plastic dual-arch and stock dentulous trays, respectively, though statistically insignificant. The pouring sequence did not have any effect on the inter-abutment distance statistically, though pouring the non-working side of the dual-arch impression first showed better accuracy.

Comparative study of intermaxillary relationships of manual and swallowing methods

This study compared the mandibular displacement from three methods of centric relation record using an anterior jig associated with (A) chin point guidance, (B) swallowing (control group) and (C) bimanual manipulation. Ten patients aged 25-39 years were selected if they met the following inclusion criteria: complete dentition (up to the second molars), Angle class I and absence of signs and symptoms of temporomandibular disorders and diagnostic casts showing stability in the maximum intercuspation (MI) position. Impressions of maxillary and mandibular arches were made with an irreversible hydrocolloid impression material. Master casts of each patient were obtained, mounted on a microscope table in MI as a reference position and 5 records of each method were made per patient. The mandibular casts were then repositioned with records interposed and new measurements were obtained. The difference between the two readings allowed measuring the displacement of the mandible in the anteroposterior and lateral axes. Data were analyzed statistically by ANOVA and Tukey's test at 5 percent significance level. There was no statistically significant differences (p>0.05) among the three methods for measuring lateral displacement (A=0.38 ± 0.26, B=0.32 ± 0.25 and C=0.32 ± 0.23). For the anteroposterior displacement (A=2.76 ± 1.43, B=2.46 ± 1.48 and C=2.97 ± 1.51), the swallowing method (B) differed significantly from the others (p<0.05), but no significant difference (p>0.05) was found between chin point guidance (A) and bimanual manipulation (C). In conclusion, the swallowing method produced smaller mandibular posterior displacement than the other methods.

Este estudo comparou o deslocamento mandibular a partir de 3 métodos de registro da relação cêntrica usando um jig anterior associado com: (A) guia da ponta do mento; (B) deglutição grupo controle (C) manipulação bimanual. As moldagens dos arcos maxilares e mandibulares foram feitas com hidrocolóide irreversível. Os modelos de estudo de cada paciente foram obtidos e montados em máxima intercuspidação como uma posição de referência no microscópio. Foram obtidos 5 registros de cada método em 10 pacientes. Os modelos mandibulares foram reposicionados com os registros interpostos e novas medidas foram obtidas. A diferença entre as duas leituras permitiu a medida do deslocamento mandibular nos eixos ântero-posterior e laterais. ANOVA não demonstrou diferença estatisticamente significativa entre os 3 métodos em relação ao registro do deslocamento lateral (A = 0,38 ± 0,26, B = 0,32 ± 0,25 e C = 0,32 ± 0,23). Quanto ao deslocamento anteroposterior, ANOVA e o teste de Tukey (a=0,05) indicaram diferença estatisticamente significante entre os três métodos (A=2,76 ± 1,43, B=2,46 ± 1,48 e C=2,97 ± 1,51). Não houve diferença estatisticamente significante entre A e C. A deglutição propiciou menor deslocamento mandibular posterior que os outros métodos.

Quantitative electromyographic assessment of facial muscles in cross-bite female children / Avaliação eletromiográfica quantitativa de músculos faciais em crianças do sexo feminino com mordida cruzada

The electromyography has been widely used as a diagnostic method for facial muscle conditions. The aim of this study was to determine the RMS (Root Mean Square) value of the electromyographic signal of facial muscles in children with normal occlusion or cross-bite as well as to verify a possible clinical application of this parameter. “Normal group” was composed of female children with normal occlusion and “cross-bite group” was composed of female children with cross-bite. We performed quantitative electromyographic analysis of masseter and temporal muscles at rest and with maximum biting force. Our results showed that the occlusion modifications affect normal masticatory muscle function, and that the quantitative electromyography is an important tool to help diagnosing the malocclusion in female children. Considering the analysis of the results, we verified that the electromyographic rest activity of the masseter or temporal muscles in cross-bite female children is higher in relation to the rest activity of normal occlusion female children. We concluded that the RMS value of the masseteric and temporal electromyographic signal has a diagnostic value to discriminate female children with cross-bite from those with normal occlusion.

A eletromiografia tem sido amplamente utilizada como método diagnóstico de disfunções de músculos da face. O objetivo deste estudo foi determinar a tensão RMS do sinal eletromiográfico de músculos da face de crianças do sexo feminino com oclusão normal ou com mordida cruzada, visando avaliar uma possível aplicação clínica deste parâmetro. O “grupo normal” foi composto por crianças do sexo feminino com oclusão normal e o “grupo mordida cruzada”por crianças do sexo feminino com diagnóstico de mordida cruzada. Foram realizadas análises eletromiográficas quantitativas dos músculos masseter e temporal nas condições de repouso e em máxima contração voluntária isométrica (MCV). Considerando a relação da tensão RMS do sinal eletromiográfico no repouso e em MCV, nossos resultados mostraram que variações de oclusão influenciam a função muscular mastigatória normal e que a eletromiografia quantitativa é uma ferramenta útil para auxiliar o diagnóstico de alterações oclusais em crianças do sexo feminino. Encontrou-se maior atividade eletromiográfica em repouso dos músculos masseter e temporal em crianças do sexo feminino com mordida cruzada em relação às com oclusão normal. Concluímos que a tensão RMS do sinal eletromiográfico massetérico e temporal tem valor diagnóstico para discriminar crianças do sexo feminino com mordida cruzada em relação às com oclusão normal.

Avaliação das dimensões programáveis dos articuladores semi-ajustáveis / Assessment of the programmable dimensions of the semi-adjustable articulador

O articulador semi-ajustável tem o propósito de reproduzir as relações maxilomandibulares estáticas e, parcialmente, as dinâmicas. No entanto, parte destas características depende da qualidade da fabricação dos aparelhos. O objetivo foi aferir os componentes responáveis pela determinação do ângulo de Bennett (AB), da eminência articular (EA) e da distância intercondilar (DI) do articulador semi-ajustável (ASA) Dentflex...

Comparison between two methods to record occlusal contacts in habitual maximal intercuspation

This research evaluated two techniques to record the occlusal contacts in habitual maximal intercuspation obtained in models mounted in semi adjustable articulator and in the mouth using an eight-micrometer carbon paper and sensors (T-Scan II). It was selected a sample of twenty five people, male and female, ages between twenty and twenty five years old with natural dentition. The collected data were visually and statistically evaluated by means of the Spearman coefficient. The results showed that the carbon paper as material used for the occlusal contact records enabled to determine exactly the quantity and its locations in the occlusal surface. However, it did not provide the information on the sequence, time and intensity on how these occur. The T-Scan system enabled to determine the quantity, the sequence and the exact time that they occur, however the system did not determine the exact location of the contacts over the teeth occlusal surface. It was observed that in both methods, the quantity of the occlusal contacts recorded in the mouth was higher than the ones obtained in the articulator and that the sensor thickness did not interfere in the reproduction of the quantity of dental contacts in comparison to the carbon paper.