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.

Discrepancia anteroposterior en registro de relación céntrica con apoyo central intraoral en cubetas rodetes acrílicas (BOPAYACU) e inducción manual en adultos mayores desdentados totales / Anteroposterior discrepancy in centric relation record with intraoral central support in acylic impaction cups (BOPAYACU) and manual induction in edentulous older adults

Objetivo: Comparar la discrepancia anteroposterior medida a nivel de la platina incisiva de 2 métodos de registro intermaxilar en la misma sesión que la im-presión definitiva en adultos mayores desdentados totales. Materiales y métodos. Se incluyeron en el es-tudio 20 pacientes (n=20) con edad promedio de 70 años. En cada uno de ellos se obtuvieron registros intermaxilares con cubetas rodete de acrílico: uno con inducción manual (IM) y otro autoinducido con el sistema de cubeta rodete de acrílico y apoyo central único utilizando una superficie palatina de registro curva (BYC). Los modelos fueron montados en un ar-ticulador Whip Mix modelo 2240 al que se le adicio-nó un dispositivo de papel milimetrado, Orthodent, a nivel de la platina incisiva, para registrar las dife-rencias existentes entre las posiciones obtenidas. El análisis estadístico se llevó a cabo mediante el cálcu-lo de intervalos de confianza (95%) para las diferen-cias medias y prueba de t de student para datos apa-reados (nivel de significancia: α<0,05). Resultados. En el plano mesiodistal a nivel de la platina incisiva se encontró diferencia estadísticamente significativa entre las dos variables de registro (p<0,001). A este nivel el BYC proporcionó registros más retrusivos que IM. Media aritmética (desviaciones estándar) en milímetros: 3,82 (2,1). Conclusión. El sistema de re-gistro con cubetas rodete acrílicas y BYC incorpora-do a las mismas proporciona un registro intermaxi-lar más retrusivo que IM en adultos mayores des-dentados totales cuando se realizan dichos registros en la misma sesión que la impresión definitiva (AU)

Objective: To compare the anteroposterior discre-pancy measured at the level of the incisal plate of 2 methods of intermaxillary registration in the same session as the definitive impression in fully edentu-lous older adults. Materials and methods. Twenty pa-tients (n=20) with an average age of 70 years were included in the study. On each of them, intermaxillary recordings were obtained with acrylic rims trays: one with manual induction (MI) and the other with a self-induced system and single central support using a curved recording palatal surface (BYC). The models were mounted in a Whip Mix model 2240 articula-tor to which an Orthodent graph paper device was added, at the level of the incisal plate, to record the di-fferences between the positions obtained. Statistical analysis was carried out by calculating confidence intervals (95%) for mean differences and T-student for paired data (significance level: α<0.05). Results. On the mesiodistal plane at the level of the incisal plate, a statistically significant difference was found between the two recording variables (p<0.001). At this level the BYC provided more retrusive recordings than MI. Arithmetic mean (standard deviations) in mi-llimeters: 3.82 (2.1). Conclusions. The registration system with acrylic rim trays and BYC incorporated into them provides a more retrusive intermaxillary registration than MI in fully edentulous older adults when such registrations are made in the same ses-sion as the final impression.(AU)

Posiciones Mandibulares de Referencia Clínica. Una Descripción Narrativa

RESUMEN: Las posiciones mandibulares se definen como la relación existente entre la mandíbula y la maxila observada durante su función, o bien posiciones de referencia clínica que pueden ser comparables con otras posiciones o movimientos. Se realizó una descripción narrativa de las posiciones de referencia mandibular de mayor interés clínico, donde se definen algunas de sus principales características; (1) la posición de máxima intercuspidación, está definida por el determinante anatómico dentario, tiene una adecuada reproducibilidad y sencilla ejecución, (2) la posición postural mandibular, es la menos estable, y está definida por el determinante fisiológico neuromuscular, siendo el resultado de la interacción de múltiples factores relacionados, (3) la relación céntrica fisiológica, se considera la posición más estable de la mandíbula, siendo repetible e independiente del contacto dentario, (4) la posición retruida ligamentosa, es una posición extrema por lo que no se considera fisiológica, está determinada por la tensión de la banda horizontal medial del ligamento temporomandibular, (5) la posición retruida de contacto, se describe como la posición mandibular cuando se producen los primeros contactos dentarios y la articulación temporomandibular (ATM) está en una posición retruida, se divide en forzada y no forzada, (6) la posición muscular de contacto es una posición regulada a través de diferentes mecanismos que permiten su estabilidad. Estas posiciones brindan una referencia clínica por medio de la cual se pueden evaluar distintos parámetros necesarios para de realizar diagnósticos y planificación de tratamientos, para ello es importante que el profesional tenga los conocimientos adecuados sobre las características que definen cada una de ellas, tales como su estabilidad y reproducibilidad, que son fundamentales al momento de su ejecución.

ABSTRACT: Mandibular positions are defined as the existing relation between mandibula and maxilla during its function, or it can also be defined as clinical reference positions that may be comparable with other positions or movements. A narrative description of the mandibular reference positions of greatest clinical interest was made, where some of their main characteristics were defined; (1) maximum intercuspal position, is defined by de dental anatomical determinant, it has an adequate reproduction and simple execution, (2) the mandibular postural position, it is the least stable, and it is defined by the neuromuscular physiological elements, being the result of the interaction of multiple factors related, (3) the physiological centric relation is considered the most stable position of the mandible, being easy to repeat and independent of dental contact, (4) the retruded ligamentous position, is an extreme position so it is not considered physiological, and it is determinated by the tension of the medial horizontal band of the temporomandibular ligament, (5) retruded contact position is described as the mandibular position when the first dental contacts are produced and the temporomandibular joint (TMJ) is in a retruded position, it is divided into forced and non- forced, (6) the muscular contact position is a position regulated through different mechanisms that allows its stability. These positions provide a clinical reference by means of which different parameters required while diagnosing and planning treatments can be evaluated, this is why it is important for the Specialist to have specific knowledge about the characteristics that correspond to each one of them, such as its stability and reproducibility, which are fundamental at the time of its execution.

Centric relation registration with intraoral central bearing on curved vs. flat plates with rim trays in edentulous patients / Registro de relación céntrica con apoyo central intraoral en platinas curvas vs. rectas con cubetas rodete en edéntulos

ABSTRACT The aim of this study was to compare jaw relation record in the completely edentulous patient using acrylic rim trays with curved or flat registration plates or using the manual guidance technique. The study included 17 patients - 11 female and 6 male, average age 70 years. Three jaw relation records were taken during one session, in the same vertical dimension, using acrylic rim trays: (1) with manual guidance (IM), (2) with self-guided recording system with acrylic rim tray and central support using a curved plate (BYC) and (3) with self-guided recording system with acrylic rim tray and central support using a flat plate (BYR). The models were mounted on a Whip Mix 2240 articulator to which a condyle position device (Orthodent) was added to register, at the level of the condyle box and incisal table, the differences among the positions recorded with the different setups (IM, BYC and BYR). The distances were measured on millimeter paper provided by the recording system manufacturer. For statistical analysis, confidence intervals (95%) were calculated for the mean differences and Student's t-test for paired data (significance level: alpha<0.05). On both the mesiodistal plane and the vertical plane at the level of each condyle box and the incisal table, there were statistically significant differences among the three systems (p<0.001). At the level of incisal table, BYC and BYR provided more retrusive records than IM [arithmetic means (standard deviations) in millimeters: 3.82 (2.10) and 4.53 (2.18), respectively). The records obtained with BYR were significantly more retrusive with BYC [arithmetic mean (standard deviation) in millimeters: 1.41 (1.00)]. We reject the null hypothesis that proposes that all three registration systems described are clinically equivalent for establishing a jaw relation record in completely edentulous patients.

RESUMEN El objetivo de este estudio fue comparar el registro de la posición intermaxilar en el paciente desdentado total obtenido con el uso de cubetas rodete de acrílico y platinas de registro curva o recta y con la técnica de inducción manual. Se incluyeron en el estudio 17 pacientes, 11 mujeres y 6 varones con edad promedio de 70 años. En cada uno de ellos se obtuvieron en la misma sesión y en la misma dimensión vertical tres registros intermaxilares con cubetas rodete de acrílico: uno con inducción manual (IM), otro autoinducido con el sistema de cubeta rodete de acrílico y apoyo central único utilizando una superficie palatina de registro curva (BYC) y un tercero con este mismo sistema pero con la superficie palatina recta (BYR). Los modelos correspondientes fueron montados en un articula-dor Whip Mix modelo 2240 al que se le adicionó un dispositivo de posición condilar (Orthodent) para registrar, a nivel de la caja condílea y la platina incisiva, las diferencias existentes entre las posiciones obtenidas con cada una de las variantes de las platinas en las cubetas rodete acrílicas y la posición registrada con inducción manual. Las distancias fueron medidas sobre papel milimetrado provisto por el fabricante del sistema de registro. El análisis estadístico se llevó a cabo mediante el cálculo de intervalos de confianza (95%) para las diferencias medias y prueba de t de student para datos apareados (nivel de significancia: alfa<0,05). Tanto en el plano mesiodistal como en el vertical a nivel de cada caja condilea como en la platina incisiva, se encontró diferencia estadísticamente significativa entre las tres variables de registro (p<0,001). A nivel de las platinas incisivas tanto BYC como BYR proporcionaron registros más retrusivos que IM [medias aritméticas (desviaciones estándar) en milímetros: 3,82 (2,1°) y 4,53 (2,18), respectivamente). Los obtenidos con BYR fueron significativamente más retrusivos que en el grupo BYC [media aritmética (desviación estándar) en milímetros: 1,41 (1,00)]. Rechazamos la hipótesis nula que propone que los tres sistemas de registro expuestos son clínicamente equivalentes para establecer una posición de registro intermaxilar en desdentados totales.

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

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

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

Comparative Evaluation of Various Techniques to Record Centric Relation- A Literature Review.

The documentation of centric relation from the completely edentulous patient and transferring the same to the fully-adjustable articulator or semi-adjustable articulator is the most essential step, that helps in diagnosing, treatment planning, and fabrication of the complete denture prosthesis, that aids in enhancing the facial aesthetics, function, speech, and maintenance of the stomatognathic system. Recording of maxillomandibular relationship is the most critical step, the relation of mandible to maxilla creates more controversy than any other dental-related studies. Hence to re-establish the maxillomandibular relationship in a completely edentulous patient is the most difficult task. However, a historical literature review in dentistry reveals that there are numerous techniques, philosophies, and materials that can be manipulated and used to record the maxillomandibular relationship. The recording of centric and eccentric relationship of the mandible to maxilla can be done using various techniques like check bite record, intra-oral graphic recording, extra-oral graphic recording, functional recording, radiographic imaging and measurements based on anatomical landmarks, and computerized assessment of maxillomandibular relationship based on jaw movement tracking systems. The principle reason of recording maxillomandibular relationship in all the centric and eccentric relationship is to re-establish a maxillomandibular relationship without an error, as stated in literature review, that to initiate any treatment in dentistry it is must to record centric relation with proper guidance of mandibular jaw to maxillary jaw that should be in harmony with all the muscles of mastication and facial expression including the temporomandibular joint and bony structure, that helps to maintain the health and growth of the muscle tissues and bony structures. This article discusses the in-depth details of these techniques and methods used in recording centric jaw relations.

Comparação clínica entre diferentes técnicas para registro de relação central em indivíduos edêntulos / Clinical comparison between different techniques for //registering a central relation in edentulous individuals

As reabilitações protéticas baseadas em técnicas adequadas podem promover um melhor desempenho, conforto e longevidade à prótese, com o intuito de restabelecer o equilíbrio muscular e articular com o seu uso. Uma das etapas da reabilitação é o registro da relação central (RC) do indivíduo. Para que este registro seja feito, a literatura descreve diversas técnicas aplicáveis, partindo de métodos fisiológicos, guiados ou gráficos. Infelizmente, não existe um consenso se diferentes técnicas para registro da RC oferecem resultados semelhantes. Diante disto, o objetivo deste estudo foi comparar a semelhança entre diferentes técnicas para registro da RC em indivíduos edêntulos, levando em consideração a posição condilar em relação à cavidade glenóide no sentido anteroposterior e o tempo para realização de cada registro, adotando-se uma técnica inicial como controle (técnica do arco gótico extra oral) e uma posição fixada em articulador como referência. Foram incluídos no estudo 12 voluntários (2 homens e 10 mulheres, idade média de 68,58 anos) desdentados bimaxilares usuários de prótese total insatisfatória, considerando critérios de inclusão específicos. Diferentes técnicas foram analisadas pelo posicionamento em um articulador personalizado para mensurar movimentos no sentido anteroposterior, sendo elas: arco gótico extra oral (AGEO), deglutição (D), manipulação frontal associada ao levantamento da língua (MFLL) e arco gótico intra oral (AGIO). Todos os registros foram realizados pelo mesmo operador no mesmo período do dia, com intervalo de 30 minutos entre cada registro e o tempo para realização de cada técnica foi mensurado. Os dados relacionados à confiabilidade das técnicas e o tempo de realização das mesmas foram submetidos à Análise de Variância um fator, seguido do teste de Tukey. Todas as análises foram realizadas com significância de 5%. Considerando as medidas da posição condilar do lado direito, houve diferença estatística (P < 0,05) no registro da técnica D em relação ao registro de AGEO, onde a mandíbula posicionou-se mais anteriorizada. No lado esquerdo, não houve diferença estatística entre os grupos. O registro das técnicas MFLL e AGIO não mostrou diferença estatisticamente significativa em comparação à técnica AGEO em relação a posição de registro da RC em ambos os lados. Em relação ao tempo para realizar cada registro, as técnicas AGEO e AGIO apresentaram diferenças significativas em relação as técnicas D e MFLL, despendendo maior tempo. Pode-se concluir que a técnica D apresentou maior diferença quando comparada às técnicas MFLL e AGIO sobre a posição condilar, onde esta posicionou-se retruída. Os registros de AGEO, MFLL e AGIO não apresentaram diferenças significativas, bem como entre as técnicas D e AGEO. Considerando-se semelhança posição condilar em cada técnica registrada e tempo para execução, as técnicas MFLL mostrou-se adequada, por promover menor tempo clínico ao paciente durante o registro e ser estatisticamente semelhante ao controle. A técnica D também mostrou-se interessante, apresentando-se semelhante ao controle, com erro padrão equilibrado e fisiologicamente confortável ao paciente. Mais estudos precisam ser realizados sobre o comportamento das estruturas do sistema estomatognático quanto quando ao registro de posição condilar protruido ou retruido a longo prazo(AU)

Prosthetic rehabilitation based on appropriate techniques can promote better performance, comfort and longevity to the prosthesis, in order to restore muscle and joint balance with its use. One of the stages of rehabilitation is the registration of the individual's central relationship (CR). For this record to be made, the literature describes several applicable techniques, starting from physiological, guided or graphic methods. Unfortunately, there is no consensus on whether different techniques for recording CR offer similar results. In view of this, the aim of this study was to compare the similarity between different techniques for recording CR in edentulous individuals, taking into account the condylar position in relation to the glenoid cavity in the anteroposterior direction and the time to perform each record, adopting a technique initial as a control (extra oral gothic arch technique) and a position fixed on the articulator as a reference. Twelve volunteers (2 men and 10 women, mean age 68.58 years) were included in the study, toothless bimaxillary users of unsatisfactory complete dentures, considering specific inclusion criteria. Different techniques were analyzed by positioning in a personalized articulator to measure movements in the anteroposterior direction, namely: extra oral gothic arch (AGEO), swallowing (D), frontal manipulation associated with tongue lifting (MFLL) and intra oral gothic arch (AGIO ). All records were made by the same operator at the same time of the day, with an interval of 30 minutes between each record and the time to perform each technique was measured. The data related to the reliability of the techniques and the time they were performed were submitted to one-way analysis of variance, followed by the Tukey test. All analyzes were performed with a 5% significance level. Considering the measurements of the condylar position on the right side, there was a statistical difference (P <0.05) in the registration of technique D in relation to the registration of AGEO, where the mandible was positioned more anteriorly. On the left side, there was no statistical difference between the groups. The registration of the MFLL and AGIO techniques showed no statistically significant difference compared to the AGEO technique in relation to the CR registration position on both sides. Regarding the time to perform each record, the AGEO and AGIO techniques showed significant differences in relation to the D and MFLL techniques, spending more time. It can be concluded that technique D presented a greater difference when compared to the techniques MFLL and AGIO on the condylar position, where it was retracted. The records of AGEO, MFLL and AGIO showed no significant differences, as well as between the techniques D and AGEO. Considering the similarity of the condylar position in each registered technique and time for execution, the MFLL techniques were shown to be adequate, as they promote less clinical time for the patient during registration and are statistically similar to the control. Technique D was also interesting, being similar to the control, with balanced standard error and physiologically comfortable to the patient. More studies need to be carried out on the behavior of the structures of the stomatognathic system regarding the recording of protruded or retracted condylar position at long term(AU)

Research progress on the relationship between centric relation and orthodontic treatment / 华西口腔医学杂志

Centric relation (CR) is one of the core research contents in orthodontics, prosthodontics, and gnathology, acting as an important physiological factor in reconstructing the occlusion and adjusting the occlusal relationship. For over a century, CR is still a controversial subject in dentistry. CR has been redefined for several times, and recently, its application has been widened in orthodontics, including orthodontic diagnosis, clinical examination and analysis, and treatment goals. The purpose of this article is to review the definition of CR, its relationship with malocclusion, and the application of this relationship in orthodontic treatment.

Maxillary anterior prosthetic treatment concerning anterior guidance of a patient who lost stable holding contact / 대한치과보철학회지

Recently, many patients undergo anterior prosthetic treatment for esthetic reasons. In some patients complain about functional reasons such as inaccurate pronunciation and occlusal discomfort after the treatment. Anterior teeth are important esthetically but in the occlusal point of view, anterior guidance is the second most important factor in occlusion, next to centric relation. Failure to determine an appropriate anterior guidance might lead to posterior occlusal interference, which can highly affect the stability of the posterior teeth. Also, discomfort might occur if the customized interior guidance is not in harmony with the patient's envelope of function. The patient in this case complained of overall discomfort in the maxillary anterior area after prosthetic treatment. The expressed difficulty in pronunciation, unstable occlusion due to lack of stable holding contact and discomfort of the facial muscles. Maxillary anterior prostheses were refabricated through systematic diagnosis and treatment and thus, this case presents esthetical and functional satisfaction to both the patient and the dentist.

Application of RW-splint in clinical diagnosis of classⅡ1 malocclusion patients / 口腔疾病防治

Objective @# To investigate whether the RW-splint could be used to guide or determine the CR position of the lower jaw so as to provide help for the later diagnostic design.@*Methods@#20 class ⅡⅠ malocclusion patients were recruited in orthodontic department of Foshan Stomatological Hospital. They were treated by RW-splint for half a year before orthodontic treatment. The overjet of anterior teeth were recorded before and after treatment. @*Results @#The overjet of anterior teeth was (6.792 ± 0.795) mm before treatment and (7.720 ± 0.930) mm after half a year's treatment. The overjet of anterior teeth had significant difference (t=6.319, P <0.01). The overjet change of anterior teeth between before treatment and half year after treatment was (0.928 ± 0.657) mm. @* Conclusion @#The RW-splint wearing before treatment can be used to guide or determine the mandible in the CR position.

Hinge axis - location, clinical use and controversies

The hinge axis is an imaginary line around which the condyles can rotate without translation. Terminal hinge position is the most retruded hinge position and it is significant because it is a learnable, repeatable and recordable position that coincides with the position of centric relation. There are many schools of thought regarding hinge axis. The proponents of Gnathology say that there is one transverse hinge axis common to both condyles which can be accurately located. The proponents of transographics claim that each condyle has a different transverse hinge axis and that a transograph is the only instrument that can duplicate this. Still others claim that an exact duplication of jaw movement is not possible on any machine. The aim of this article is to throw light on location, clinical use and controversies of hinge axis.

Relación entre el espesor del registro interoclusal en céntrica y el error oclusal en la posición retruída de contacto en el articulador semiajustable de tipo arcon / Relation between the thickness of the interocclusal centric registration and occlusal error in the retruded contact position in an arcon semiadjustable articulator

Objetivo. Relacionar el espesor del registro interoclusal en céntrica con el error oclusal en la posición retruída de contacto en el articulador semi ajustable, tipo arcon. Materiales y métodos. Se utilizó un juego de modelos de 42 alumnos de la asignatura de Oclusión de una universidad particular, con oclusión clase I, dentición natural, completa hasta segunda molar, libres de signos-síntomas de trastornos temporomandibulares, y con contacto prematuro unilateral y posterior perfectamente verificable. Para reproducir la posición retruída de contacto, se tomaron tres registros de relación céntrica (espesores de 1, 2 y 3 mm). Se observaron tres contactos prematuros a los que se les denominó A1, B1, C1 de acuerdo a los tres registros usados, su ubicación se registró usando folio de 8 µm y cinta de 12 µm. Se cuantificó el error oclusal usando un calibrador digital. Resultados. El error oclusal fue de 0,0 mm,0,46 mm, y 2,01 mm, para el registro A, B y C, respectivamente. El test de Friedman determinó que hay diferencias significativas en el error oclusal presentado por los tres tipos de registro (p=0,00). La prueba de signo de rangos de Wilcoxon, demostró que existen diferencias significativas en el error oclusal ocurrido entre los pares de registros...

Objective. To relate the thickness of the centric interocclusal record with occlusal error in retruded contact position in arcon type se-miadjustable articulator. Materials and methods. A set of 42 casts of occlusion students were taken from a private university presenting occlusion Class I, natural and complete dentition to second molar, free of signs and symptoms of temporomandibular disorders, and with premature and unilateral contact perfectly verifiable. To reproduce the retruded contact position three centric relation records were taken with different thicknesses of 1. 2 and 3 mm. Tree premature contacts were observed and were called A1, B1, C1, according to the three records used, its location were recorded using foil tape of 8 and 12 pm. Occlusal error was quantified using a digital caliper. Results. The occlusal error was 0.0 mm, 0.46 mm and 2.01 mm, for the record A, B and C, respectively. Friedman test determined a significant difference in occlusal errors introduced by the three record types (p = 0.00). Wilcoxorf s Sign Test Rank showed significant differences in the occlusal error that occurred between pairs of records A...

Evaluación de dos técnicas para el registro de relación céntrica mandibular: arco gótico versus céntrica de poder / Assessment of two techniques for the recording of mandibular central relationship: gothic arch versus power centric relation

La búsqueda de la verdadera posición mandibular con respecto a la cavidad glenoidea y la relación de los otros componentes que constituyen la articulación temporomandibular conocida como relación céntrica (RC) son esenciales para el diagnóstico, tratamiento y estabilidad del mismo. El propósito del estudio fue evaluar dos técnicas para el registro de RC (técnica céntrica de poder y técnica del arco gótico) con objeto de determinar el método más eficaz para brindar mayor veracidad en el registro, dado que, en nuestra institución, se han experimentado algunas inconsistencias durante la obtención de registros en pacientes con malformaciones o discrepancias esqueléticas considerables. Se evaluaron quince pacientes sistémicamente sanos, clase ósea II, de entre 13 y 17 años de edad, ocho del sexo femenino (53.4%) y siete del sexo masculino (46.6%). Se realizaron treinta montajes en un articulador semiajustable utilizando ambas técnicas, se monitorearon los cambios a nivel condilar utilizando el indicador de posición axial condilar (IPAC). Los resultados mostraron que no hubo diferencias significativas; sin embargo, los cambios sagitales, verticales y transversales fueron mayores con la técnica del arco gótico.

The search for the true mandibular position with respect to the glenoid fossa and the relationship of the other components which constitute the temporomandibular joint known as centric relation (CR) are essential factors for its diagnosis, treatment and stability. The aim of the present study was to assess two techniques used for recording CR: power centric technique and gothic arch technique, with the purpose of determining the most effective method to confer greater accuracy to the recording. This was triggered by the fact that in our institution some inconsistencies had been detected when taking records of patients afflicted with considerable skeletal discrepancies or malformations. Fifteen healthy skeletal class II patients were assessed. Patients' ages ranged from 13 to 17 years. Eight patients were female (53.4%) and seven male (46.6%). Using both techniques, thirty mountings were performed in a semi-adjustable articulator, condylar changes were monitored using axial condylar position indicator (API). Results revealed no significant differences, nevertheless, observed transversal, vertical and saggital changes were greater with the gothic arch technique.

Prosthetic rehabilitation for a patient with CO-MI discrepancy

Centric occlusion-maximum intercuspation (CO-MI) discrepancy is one of main causes of evoking premature contact and resultant mandibular shift. These non-physiological conditions can induce temporomandibular disease, periodontitis, and non-carious cervical lesion. Therefore, if CO-MI discrepancy exists in patients who need extensive prosthetic rehabilitation, it must be corrected and then physiological occlusion must be restored. This report describes the treatment procedure of removing CO-MI discrepancy and prosthetic rehabilitation in a patient with 3.5 mm discrepancy, multiple caries and periodontitis. Proper mandibular position and modified opening & closing movement were confirmed by ARCUSdigma II and transcranial radiograph.

Full mouth rehabilitation of a patient with difficulties in guiding centric relation: A case report / 대한치과보철학회지

The Gothic arch tracing method using a Gothic arch tracer which is one of the centric relation recording methods can reproduce mandibular movement more accurately by describing the path of mandibular curvilinear motion. This case reports that we have satisfactory results by recording reproducible centric relation using a gothic arch tracing method in a patient who has difficulty to induce centric relation by operator due to parafunctional movement.

Ajuste oclusal por desgaste seletivo: um novo conceito em terminologia e técnica / Occlusal adjustment for selective grinding: a new concept in terminology and technique

O ajuste oclusal é uma técnica amplamente utilizada para modificar a superfície oclusal a superfície oclusal dos dentes, a fim de restabelecer o equilíbrio oclusal, articular e neuromuscular. Entretanto, sua indicação deve ser específica, considerando-se um procedimento irreversível. Nesse contexto, diversos autores têm abordado a sequência clínica para a realização do ajuste oclusal, embora o uso de diferentes nomenclaturas e técnicas torne-o um procedimento de difícil compreensão aos cirurgiões-dentistas. Assim, o objetivo desse trabalho é discutir os principais aspectos relacionados ao ajuste oclusal em dentes naturais por meio do desgaste seletivo, propondo uma abordagem simplificada da técnica, considerando-se uma avaliação funcional e dinâmica da oclusão

The occlusal adjustment is a technique widely used to modify the occlusal surface occlusal surface of the teeth in order to restore the occlusal, articular and neuromuscular equilibrium. However, its indication should be specific, considering that it is an irreversible procedure. In this context, several authors have addressed the clinical sequence to perform the occlusal adjustment, although the use of different nomenclatures and techniques makes it a difficult understand procedure to dentists. Thus, the aim of this study is to discuss the main aspects related to occlusal adjustment in natural teeth through selective grinding, proposing a simplified approach of the technique, considering a functional and dynamic occlusion assessment

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.

Comparison of condylar displacement between three biotypological facial groups by using mounted models and a mandibular position indicator / 대한치과교정학회지

OBJECTIVE: Facial-type-associated variations in diagnostic features have several implications in orthodontics. For example, in hyperdivergent craniofacial types, growth imbalances are compensated by displacement of the condyle. When diagnosis and treatment planning involves centric relation (CR), detailed knowledge of the condylar position is desirable. The present study aimed to measure condylar displacement (CD) between CR and maximum intercuspation in three facial types of an asymptomatic orthodontic population. METHODS: The study was conducted in 108 patients classified into three groups of 36 individuals each (27 women and 9 men; mean age, 20.5 years), based on the following facial patterns: hyperdivergent, hypodivergent, and intermediate. To quantify CD along the horizontal and vertical axes, the condylar position was analyzed using mounted casts on a semi-adjustable articulator and a mandibular position indicator. The Student t-test was used to compare CD between the groups. RESULTS: Vertical displacement was found to be significantly different between the hyperdivergent and hypodivergent groups (p < 0.0002) and between the hyperdivergent and intermediate groups (p < 0.0006). The differences in horizontal displacement were not significant between the groups. In each group, vertical CD was more evident than horizontal displacement was. CONCLUSIONS: All facial types, especially the hyperdivergent type, carried a significantly high risk of CD. Therefore, the possibility of CD should be carefully evaluated and considered in the assessment of all orthodontic cases in order to accurately assess jaw relationships and avoid possible misdiagnosis.

Establishing the maxillary occlusal plane as a requisite for placement of an immediate implant-supported fixed prosthesis in the mandible: a case report / Estabelecimento do plano oclusal na maxila como pré-requisito para a colocação de uma prótese fixa imediata implanto-suportada na mandíbula: relato de caso

Introdução: Em pacientes com bruxismo, a atrição pode resultar em desgaste oclusal excessivo que excederá o mecanismo compensatório e ocorrerá uma perda de dimensão vertical de oclusão. Objetivo: O propósito deste artigo é mostrar a importância do restabelecimento de um adequado plano oclusal no arco não restaurado por meio de uma overlay fixa de acrílico, compatível com o tratamento protético do arco a ser reabilitado. A recuperação do plano oclusal do paciente na maxila com uma overlay de resina acrílica numa apropriada dimensão vertical de oclusão simultaneamente com uma prótese fixa na mandíbula, suportada por 5 implantes dentais é detalhada. Conclusão: Quando há um severo desgaste devido ao atrito dental em um dos arcos, é importante restabelecer o plano oclusal e as curvas de compensação simultaneamente com a restauração protética do arco a ser reabilitado.

Introduction: In patients with Bruxism, the attrition can result in excessive occlusal wear that exceeds the compensatory mechanism and loss of occlusion vertical dimension occurs. Objective: The purpose of this article is to show the importance of re-establishing an adequate occlusal plane for the non treated arch by means of a fixed acrylic overlay, compatible with the prosthetic treatment of the arch to be rehabilitated. An upper maxillary fixed acrylic overlay restored the patient’s occlusal plane in an appropriate vertical dimension of occlusion together with a fixed prosthesis in the mandible, supported by five dental implants. Conclusion: When there is severe wear due to dental attrition in one of the arches, it is important to re-establish the occlusal plane and compensation curves in conjunction with the prosthetic treatment of the arch to be rehabilitated.

Identification of occlusal prematurity by clinical examination and cone-beam computed tomography

The aim of this study was to evaluate the ability to identify occlusal prematurity by images from paraxial slices of cone-beam computed tomography (CBCT). For such purpose, a pilot study was performed in which 16 asymptomatic young patients were subjected to a clinical examination, including a careful occlusal analysis and then individual deprogrammer devices (“Lucia's JIG”) were fabricated. Premature contacts were clinically identified in centric relation (CR) for each patient by jaw manipulation and interocclusal marking with articulating paper (Accufilm). Subsequently, these devices were adjusted in CR and used during the tomographic exams in such a way that CBCT in CR could be obtained. After routine processing, the images were analyzed in order to identify occlusal prematurity on the displayed images by 30 professionals divided according to areas of activity (occlusion specialist, general practitioner and radiologist; n=10 per area) and time of professional experience (less than 5, between 5 and 10, and over 10 years). By comparing the premature contacts identified in the clinical analysis and CBCT images, an agreement index between these two variables was calculated. Data were analyzed statistically by ANOVA and Scott-Knott test (α=0.05). The results showed that the identification of occlusal prematurity by paraxial CBCT slices was proven to be a method of average reliability.

O objetivo deste estudo foi avaliar a capacidade de identificação de prematuridades oclusais por meio de imagens obtidas de cortes paraxiais de tomografias computadorizadas de feixe cônico. Para este fim, realizou-se um estudo piloto em que 16 pacientes jovens assintomáticos foram submetidos ao exame clínico, incluindo análise oclusal criteriosa, e em seguida foram confeccionados dispositivos desprogramadores individuais (“JIG de Lucia”). Mediante manipulação mandibular e marcação interoclusal com papel carbono (Accufilm) identificou-se clinicamente o contato prematuro em relação cêntrica (RC) de cada paciente. Posteriormente estes dispositivos foram ajustados na posição de contato cêntrico e utilizados durante os exames tomográficos para que se pudessem obter imagens tomográficas na posição de relação cêntrica. Após o processamento das imagens, estas foram analisadas com o intuito de identificar prematuridades oclusais nas imagens visualizadas por 30 profissionais divididos de acordo com as áreas de atuação (Oclusão, Clínica Geral e Radiologia, n=10 para cada área) e tempo de exercício profissional (<5; entre 5 e 10; e >10 anos). Mediante comparação entre os contatos prematuros identificados na análise clínica oclusal e as imagens tomográficas apontadas pelos profissionais como áreas de contatos prematuros, foram calculados os índices de concordância entre essas duas variáveis. Os dados obtidos foram analisados estatisticamente pela Análise de Variância ANOVA e teste de Scott-Knott (α=0,05). Os resultados deste estudo demonstraram que a identificação de prematuridades oclusais por meio de cortes paraxiais de tomografias computadorizadas de feixe cônico mostrou-se como um método de confiabilidade média.