Área de Céntrica, Revisión del Concepto. Una Revisión Narrativa / Central Area, Review of the Concept. A Narrative Review

La búsqueda de una oclusión ideal es uno de los principales objetivos de los tratamientos rehabilitadores. Para que esta se cumpla, es necesario que se presenten ciertas características, en base a esto, se ha constituido el concepto de "tríada en céntrica", que se define como la coincidencia entre la relación céntrica fisiológica (RCF), posición muscular de contacto (PMC) y posición de máxima intercuspidación (PMI), existiendo de esta forma un equilibrio morfofuncional óptimo de los diferentes componentes del sistema estomatognático. Así nace la necesidad de analizar los conceptos que involucren la relación existente entre las distintas posiciones mandibulares, dentro de estos conceptos encontramos el "área de céntrica", que debido a sus características, se le atribuye relevancia y utilidad clínica cuando se entiende su aplicación. El objetivo de este estudio fue analizar el concepto de área céntrica, actualizar los conceptos oclusales asociados y proponer nuevas metodologías para su evaluación. En ocasiones existen interferencias oclusales que impiden que la mandíbula continúe su recorrido habitual para llegar a determinada posición, estas interferencias se conocen como contactos prematuros, cuando estos existen, naturalmente la mandíbula se desvía hacia una posición de acomodo. El deslizamiento en céntrica se define como el movimiento de la mandíbula mientras se encuentra posición retruida de contacto no forzada, es decir, la posición de contacto que se produce cuando la mandíbula se cierra en RCF, hasta llegar a PMI, este deslizamiento se produce debido a la presencia de contactos prematuros, cuando no existen contactos prematuros, esta posición coincidirá con PMI. El área de céntrica se define como el deslizamiento de la mandíbula entre la posición retruída ligamentosa (PRL) y PMI. Idealmente, la PMI se da cuando los cóndilos están en RCF y coincide con la PMC, debe existir siempre un área de céntrica, pues fisiológicamente ninguna articulación adoptara naturalmente una posición extrema como la PRL.

The search for an ideal occlusion is one of the main objectives of rehabilitation treatments. For this to be fulfilled, some characteristics need to be present, based on this, the concept of "centric triad" has been constituted, which is defined as the coincidence between the physiological centric relation (CR), muscular contact position (MCP) and maximum intercuspal position (MIP), thus existing an optimal morphofunctional balance of the different components of the stomatognathic system. In this way, the need arises to analyze the concepts that involve the relationship between the different mandibular positions, within these concepts we find the "centric area", which due to its characteristics, it is attributed relevance and clinical utility when its application is understood. The objective of this study was to analyze the concept of centric area, update the associated occlusal concepts and propose new methodologies for its evaluation. Sometimes there are occlusal interferences that prevent the jaw from continuing its usual path to reach a certain position, these interferences are known as premature contacts, when they exist, the jaw naturally deviates towards a position of accommodation. Centric slide is defined as the movement of the mandible when it is in a retruded contact position unforced, that is, the contact position that occurs when the mandible closes in CR, until reaching MIP, this sliding occurs due to in the presence of premature contacts, when there are no premature contacts, this position will coincide with PMI. The centric area is defined as the slippage of the mandible between the retruded ligamentous position (RLP) and MIP. Ideally, the PMI occurs when the condyles are in CR and coincides with the MCP, there should always be a centric area, since physiologically no joint will naturally adopt an extreme position like PRL.

Oclusión basada en evidencia: rompiendo paradigmas / Occlusion based on evidence: breaking paradigms

La odontología basada en evidencias es una metodología que busca que las decisiones clínicas diarias que toman los profesionales en estomatología se encuentren fundamentadas en la evidencia científica, en ella se integran las experiencias clínicas, las necesidades, las preferencias del paciente y la evidencia clínicamente relevante más actual analizada por pares. Estos pilares son parte del proceso en la toma de decisiones para la atención al paciente. La odontología basada en evidencias surge de las exitosas experiencias obtenidas con el desarrollo e implementación de la medicina fundamentada en pruebas, al aplicar el método científico en la evaluación, planificación y toma de decisiones de las prestaciones sanitarias, sobre todo a través de los estudios controlados. En general, toda la práctica odontológica ha tenido grandes avances basados en evidencias, con hechos verídicos comprobados, pero los conceptos fundamentales de oclusión no han tenido una mejora cimentada en el conocimiento científico, prueba de ello es que se siguen ocupando teorías y conceptos de las filosofías de oclusión en la rehabilitación de muchos pacientes, seguimos creyendo en mitos y sofismas que no han podido ser demostrados. En esta revisión, demostramos los grandes avances en los conceptos de oclusión e invitamos a todos los odontólogos a romper los paradigmas de la oclusión antigua sin evidencias científicas y a utilizar las herramientas del método científico en la práctica clínica odontológica (AU)

Evidence-based dentistry is a strategy that seeks to ensure that the daily clinical decisions made by the dental professional are based on scientific evidence. It integrates the clinical experience of the dentist, the needs and preferences of the patient, and the most current relevant clinical evidence. All three are part of the decision-making process for patient care. Evidence-based dentistry arises from the successful experiences obtained with the development and implementation of evidence-based medicine, applying the scientific method in the evaluation, planning and decision-making of health benefits, especially through controlled studies. In general, all dental practice has had great advances based on evidence, with proven true facts, but the fundamental concepts of occlusion have not had an improvement based on scientific knowledge, proof of this is that theories and concepts continue to be used. of the philosophies of occlusion in patient rehabilitation, we follow myths and sophisms that have not been demonstrated, in this review, we demonstrate the great advances in the concepts of occlusion and we know all dentists to break the paradigms of the old occlusion without scientific evidence (AU)

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.

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.

Desprogramación neuromuscular en paciente con maloclusión esquelética clase II previo a tratamiento ortodóncico-quirúrgico / Neuromuscular deprogramming in malocclusion class II patient before an orthodontic-surgery treatment

Los pacientes con problemas esqueléticos clase II que han terminado su crecimiento, generalmente, se tratan con cirugía ortognática o extracciones de piezas dentarias. Un objetivo del tratamiento es obtener estabilidad a largo plazo. El presente caso clínico es de un paciente masculino de 15 años de edad con clase II esquelética sagital que se realizó desprogramación neuromuscular con un plano de acrílico, que permitió determinar la verdadera discrepancia intermaxilar y obtener que la articulación temporomandibular estuviera en una posición estable en relación céntrica del paciente previo a su tratamiento ortodóncico prequirúrgico (AU)

In patients with class II skeletal problems who have finished their growth; they are treated with orthognathic surgery or dental extractions usually. One treatment goal is to obtain long-term stability. The present case report is of a 15 years old male patient with skeletal sagittal class II who underwent neuromuscular deprogramming with an acrylic plane, which allowed to determine the true skeletal discrepancy and achieve a stable position of the temporomandibular joint in centric relation before the orthodontic treatment (AU)

Ameloplastia positiva en relación céntrica como método auxiliar durante la finalización en el tratamiento de ortodoncia en un paciente bruxista / Positive ameloplasty in centric relationship as an auxiliary method during finalization in the orthodontic treatment in a bruxist patient

A continuación se presenta un caso de un paciente de 12 años de edad, con antecedente de bruxismo, con biotipo mesofacial, tercio inferior dolicofacial, hipertonicidad muscular en maseteros, cierre labial forzado con incompetencia labial de 4 milímetros con dolor en sinoviales anteriores inferiores. Los objetivos de tratamiento consistieron en lograr relajación muscular y promover un posicionamiento condilar ortopédicamente funcional y estable, realizar control vertical para disminuir gap interlabial, alinear líneas medias, mantener clase I molar bilateral, clase I canina bilateral y clase I incisiva, crear overjet y overbite adecuados, con recuperación estética y función del segmento anterior. Debido a eventos adversos durante la etapa de cierre de espacios, la clase molar y canina I no se logró, pero se aseguró mediante ameloplastias positivas la función y estética adecuadas para tener un tratamiento de ortodoncia estable a largo plazo (AU)

The following is a case of a 12-year-old patient, with a history of bruxism, with a mesofacial biotype, lower third of the facial area, muscular hypertonicity in the masseters, a forced labial closure with a 4-millimeter labial incompetence with pain in inferior anterior synoviums. Treatment objectives consisted of achieving muscle relaxation and promoting orthopedically functional and stable condylar positioning, perform vertical control to decrease interlabial gap, align midlines, maintain bilateral molar class I, bilateral canine class I and incisive class I, create adequate overjet and overbite, with aesthetic recovery and function of the anterior segment. Due to adverse events during the closing phase of spaces, the molar and canine I class was not achieved, but positive function and aesthetics were ensured by positive ameloplasties in order to have a long-term stable orthodontic treatment (AU)

Control vertical mediante bite block en relación céntrica / Vertical control through bite block in centric relation

Paciente femenina de ocho años y cuatro meses, con patrón esquelético de clase II severa y overjet de 10 mm, fue tratada con Bite-Block Céntrico como método de control vertical. Después de cinco meses de terapia con aparatología fija de primera fase se logró control vertical y reducción de las desviaciones de la clase esquelética. Posteriormente se continuó con tratamiento activo durante 18 meses, se dio de alta de la primera fase cuando los objetivos del tratamiento como alineación, nivelación, overbite y overjet fueron adecuados. Los registros postratamiento demostraron una buena estabilidad articular, oclusión funcional y una mejora en la estética facial. El montaje en céntrica postratamiento demuestra estabilidad condilar con el uso de Bite-Block Céntrico como método de control vertical (AU)

Female patient of eight years and four months, with skeletal pattern of severe class II and 10 mm overjet, was treated with Bite-Block Centric as a vertical control method. After five months of therapy with fixed appliances of the first phase, vertical control and reduction of the deviations of the skeletal class were achieved. Subsequently continued with active treatment for 18 months, was discharged from the first phase when the treatment objectives such as alignment, leveling, overbite and overjet appropriate. Post-treatment records showed good joint stability, functional occlusion and an improvement in facial aesthetics. The posttreatment centric assembly demonstrates condylar stability with the use of Centric Bite-Block as a vertical control method (AU)

Full mouth rehabilitation using removable prosthesis of patient with unstable mandible movements: A case report / 대한치과보철학회지

Patients with collapsed occlusal support and unilateral chewing show parafunctional mandibular movements, which can be complicated in older patients. Gothic arch tracing and split cast technique are used to confirm the deviation between centric relation and anterior habitual bite in patient who has oral dyskinesia and collapsed occlusion. Temporary denture as occlusal stabilization appliance was provided for stable occlusion and reproducible mandibular movement. Definitive denture was fabricated by lingualized occlusion concept.

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)

Restoration of patient accelerating anterior teeth wear by loss of posterior support: Case report / 대한치과보철학회지

Increased anterior teeth mastication following posterior teeth loss leads to greater anterior occlusal force. It may cause greater attrition of anterior teeth, traumatic force occlusion (TFO), also often followed by antagonist extrusion and occlusal disharmony. This clinical report describes the treatment for a 67-year-old female patient diagnosed with loss of both maxillary and left mandibular posterior teeth, severe attrition of maxillary and mandibular anterior teeth and extrusion of multiple teeth. A diagnostic cast was mounted on articular in centric relation (CR) position to evaluate vertical dimension (VD) and interspace. To provide adequate space for the prosthetic reconstructions, VD was increased by 3 mm on the anterior pin. And then diagnostic wax-up was completed upon that VD. Wax-up was converted to provisional restorations and verified in the patient's mouth and the final restorations were delivered. Clinical follow up examination held 3 months after temporary restoration owing to changes in vertical dimension revealed proper function in mastication without evidence of temporo-mandibular joint (TMJ) disorders. This clinical report presents successfully restoring severe attrition case with increasing vertical dimension resulting in satisfaction in esthetics and function.

Full mouth rehabilitation in patient with loss of vertical dimension and deep bite due to tooth wear / 대한치과보철학회지

Excessive tooth wear can cause irreversible damage to the occlusal surface and can alter the anterior occlusal relationship by destroying the structure of the anterior teeth needed for esthetics and proper anterior guidance. The anterior deep bite is not a morbid occlusion by itself, but it may cause problems such as soft tissue trauma, opposing tooth eruption, tooth wear, and occlusal trauma if there are no stable occlusal contacts between the lower incisal edge against its upper lingual surface. The most important goal of treatment is to form stable occlusal contact in centric relation. In this case report, patients with decrease in vertical dimension and anterior deep bite due to maxillary posterior tooth loss and excessive tooth wear were treated full mouth rehabilitation with increased vertical dimension to regain the space for restoration and improve anterior occlusal relationship and esthetics. The functional and aesthetic problems of the patient could be solved by the equal intensity contact of all the teeth in centic relation (CR), anterior guidance in harmony with the functional movement, and restoration of the wear surface beyond the enamel range.

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.

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.

Rehabilitation of a patient with atrophic ridges using gothic arch tracing and nonpressure impression: a case report

Flabby ridges adversely affect the stability of complete dentures. For the management it is suggested that soft tissues reconditioned before making definitive dentures, and modified impression techniques used for the flabby ridges. Also, correct record of centric relation is important in complete dentures. This case of 67-year-old edentulous female patient had atrophied ridges on the mandible and the flabby ridge on the maxilla. Treatment dentures were fabricated using gothic arch tracing method and tissue conditioner. Definitive dentures were made using window opening impression technique, the gothic arch tracing method, and lingualized occlusion. The patient was satisfied with the function and esthetic quality of the new prostheses.

Agreement between 2 raters' evaluations of a traditional prosthodontic practical exam integrated with directly observed procedural skills in Egypt / 보건의료교육평가

PURPOSE: This study aimed to assess the agreement between 2 raters in evaluations of students on a prosthodontic clinical practical exam integrated with directly observed procedural skills (DOPS). METHODS: A sample of 76 students was monitored by 2 raters to evaluate the process and the final registered maxillomandibular relation for a completely edentulous patient at Mansoura Dental School, Egypt on a practical exam of bachelor’s students from May 15 to June 28, 2017. Each registered relation was evaluated from a total of 60 marks subdivided into 3 score categories: occlusal plane orientation (OPO), vertical dimension registration (VDR), and centric relation registration (CRR). The marks for each category included an assessment of DOPS. The marks of OPO and VDR for both raters were compared using the graph method to measure reliability through Bland and Altman analysis. The reliability of the CRR marks was evaluated by the Krippendorff alpha ratio. RESULTS: The results revealed highly similar marks between raters for OPO (mean= 18.1 for both raters), with close limits of agreement (0.73 and −0.78). For VDR, the mean marks were close (mean= 17.4 and 17.1 for examiners 1 and 2, respectively), with close limits of agreement (2.7 and −2.2). There was a strong correlation (Krippendorff alpha ratio, 0.92; 95% confidence interval, 0.79–0.99) between the raters in the evaluation of CRR. CONCLUSION: The 2 raters' evaluation of a clinical traditional practical exam integrated with DOPS showed no significant differences in the evaluations of candidates at the end of a clinical prosthodontic course. The limits of agreement between raters could be optimized by excluding subjective evaluation parameters and complicated cases from the examination procedure.

All-on-4 implant restoration with full-digital system preserving existing occlusion: A case report / 대한치과보철학회지

In edentulous patients, implant - supported fixed prosthesis treatment has been proved to be useful, but involves complex treatment process. On the other hand, in the modern dentistry, digital technology has been developed day by day and it has expanded its range to the implant restoration of edentulous patients. In this case, a digital system was used for all stages of diagnosis, surgery, design and fabrication of provisional implants fixed prosthesis restoration in 66-year-old mandibular edentulous patients. In the preoperative diagnosis stage, a provisional restoration was designed based on the mucosal scan using the intraoral scanner and the stable occlusion of prefabricated complete denture of the patient. After flapless implant surgery using the surgical guide, the prefabricated interim restoration was connected to the implant and used as immediate provisional restoration. The final restoration was designed and fabricated by transferring the vertical dimension and the centric relation of the provisional restoration with stable occlusion using digital technology. We report a simple protocol of implant treatment in edentulous patients by using digital techniques to preserve the patient's vertical dimension and occlusion.

A case of full mouth rehabilitation with orthodontic treatment in patient with extensive tooth erosion and wear using monolithic zirconia prostheses / 대한치과보철학회지

Extensive dental erosion and wear will cause serious loss of function and aesthetics in the mouth. In order to recover this condition, careful analysis of the patient's bite relationship is required. In particular, a treatment plan should be established considering the possibility of reproduction of the vertical dimension and centric relation, and appropriateness of the occlusal plane and anterior guidance. Also, the choice of prosthetic materials is an important consideration in patients with severe wear. In this case, patients with overall wear and erosion on tooth was established anterior guidance by orthodontic treatment and fully restored with monolithic zirconia, without increasing vertical dimension.

Complete denture treatment using lingualized occlusion scheme at the edentulous patient with severely absorbed flat residual ridges: a case report

Many factors should be considered for successful denture treatment at edentulous patients: support, retention, stability, occlusion, esthetics, etc. The patient who has severely absorbed residual ridges, however, treatments are challenging to satisfy those factors. The dentures that use anatomic artificial teeth show good mastication efficiency and esthetics but, can easily lose stability at absorbed ridges. On the contrary, the dentures that use non-anatomic artificial teeth perform better stability but, lower masticatory efficiency and esthetics at absorbed ridges. The lingualized occlusion, using both anatomic and non-anatomic teeth, introduced for compromise those of the pros and cons. At lingualized occlusion, buccal cusps of the teeth do not contact on centric relation. Therefore, direction of the occlusal force towards lingually, then stability of dentures increases. This case report shows the results of the treatment flat residual ridges using complete dentures with ligualized occlusion to increase dentures stability and satisfactory of the patient.

Complete denture rehabilitation of a fully edentulous patient with unilateral facial nerve palsy: A case report / 대한치과보철학회지

Bell's palsy is an acute-onset unilateral peripheral facial neuropathy. For patients with sequelae of facial paresis, the successful rehabilitation of fully edentulous arches is challenging. This case report described the treatment procedures and clinical considerations to fabricate complete dentures of a patient who showed unilateral displacement of mandible, unilateral chewing pattern and parafunctional jaw movement due to sequelae of Bell's palsy. Gothic arch tracing was used to record reproducible centric relation and lingualized occlusion was performed to provide freedom to move between centric relation and the patient's habitual functional area in fabricating satisfactory dentures in terms of function and esthetics.

The Effect of a Condylar Repositioning Plate on Condylar Position and Relapse in Two-Jaw Surgery

BACKGROUND: Numerous condylar repositioning methods have been reported. However, most of them are 2-dimensional or are complex procedures that require a longer operation time and a highly trained surgeon. This study aims to introduce a new technique using a condylar repositioning plate and a centric relation splint to achieve a centric relationship. METHODS: We evaluated 387 patients who had undergone surgery for skeletal jaw deformities. During the operation, a centric relation splint, intermediate splint, final centric occlusion splint, and condylar repositioning plate along with an L-type mini-plate for LeFort I osteotomy or a bicortical screw for bilateral sagittal split ramus osteotomy were utilized for rigid fixation. The evaluation included: a physical examination to detect preoperative and postoperative temporomandibular joint dysfunction, 3-dimensional computed tomography and oblique transcranial temporomandibular joint radiography to measure 3-dimensional condylar head movement, and posteroanterior and lateral cephalometric radiography to measure the preoperative and postoperative movement of the bony segment and relapse rate. RESULTS: A 0.3% relapse rate was observed in the coronal plane, and a 2.8% relapse rate in the sagittal plane, which is indistinguishable from the dental relapse rate in orthodontic treatment. The condylar repositioning plate could not fully prevent movement of the condylar head, but the relapse rate was minimal, implying that the movement of the condylar head was within tolerable limits. CONCLUSIONS: Our condylar repositioning method using a centric relation splint and mini-plate in orthognathic surgery was found to be simple and effective for patients suffering from skeletal jaw deformities.