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.

Is There "A Best" Centric Relation Record? Centric Relation Records, Condyle Positions, and Their Practical Significance.

PURPOSE: To investigate if and how the positions of condyles in centric relation (CR) varied from each other using different CR records. MATERIALS AND METHODS: Condylar positions in CR were repeatedly recorded by four licensed clinicians in 81 stomatognathically healthy, fully dentate subjects with six different types of CR records. The maxillary casts were mounted in articulators after individual facebow transfer, and the mandibular casts were mounted with a central bearing point (CBP) registration on the tip of the Gothic arch. Mean values from three registrations of the centric condylar positions with each of the six methods were calculated, and comparative calculations were made. RESULTS: The median spatial distances of the condylar positions between the CBP and all other CR records was 0.73 ± 0.24 mm (0 to 3.19 mm). The median spatial values between the condylar positions of the different CR records ranged from 0.48 to 0.79 mm. Statistically, the positions of almost all types of registration were slightly different from each other. CONCLUSION: Different CR records reproduce slightly different positions of the mandible, which is especially true for CBP registration, whereas reproducibilities and SDs between registrations are similar. Unrefined wax-wafer registrations using bimanual manipulation have proven particularly successful with regard to precision and time requirements, as has CBP registration with regard to condylar position.

Centric relation: A needed reference position.

PURPOSE: Centric relation (CR) is a universally recognized term and an acceptable reference position with a long history of success. The problem is that there is little consensus as to its definition or the method of recording it, and this has created an uprising to abolish it. METHODS: A review of pertinent literature related to its definition, method of recording, anatomic considerations, and long-standing principles was conducted. RESULTS: Centric relation is an established term but there are valid concerns over its definition and method of recording. There is consensus on using it as a restorative position in a patient in need of full-arch reconstruction, and there is no substantive clinical research to contradict this. If a clinician decides to use a different position, it should have a different name. CONCLUSIONS: Centric relation is a reproducible reference position that can be utilized for diagnostic and restorative dental procedures with substantial scientific evidence to support that premise. There are numerous well-documented techniques, all of which are intermaxillary, that can replicate the position. There is little scientific evidence to support a premise as to where the exact position of the condyle should be in relation to the fossa.

Centric relation: A matter of form and substance.

The recent review article by Zonnenberg, Türp and Greene 'Centric relation critically revisited - What are the clinical implications'? opens an important debate by addressing topics of central relevance in Dentistry, namely the relationship between occlusion and the condyle-to-glenoid-fossa position, and the need for diagnostic assessment and therapeutic alteration of the condylar position in orthodontic patients. Zonnenberg, Türp and Greene concluded that the mandibular condyle is correctly situated in most orthodontic patients. Thus, in their view, orthodontists can disregard this aspect during treatment, and rely on the plastic properties of the masticatory supporting structures, while aiming at finishing the cases in a good occlusal relationship. We think that this approach fails to consider that biological variation of the stomatognathic structures can also be pathological and that, as dental occlusion determines condylar relative position within the glenoid fossa, changes in the occlusion are likely to alter the original condylar-to-glenoid-fossa relation. Hence, we claim that whenever the occlusal relationship must be changed, the clinician should carefully monitor the condyle position and the mandibular function to prevent possible iatrogenic effects. To advance the discourse on the topic, we invite Zonnenberg, Türp and Greene to clarify their definition of 'average patient' and their interpretation of 'full-mouth orthodontic and orthognathic treatment', their understanding of 'biologically acceptable condylar relationship', their justification of maximum intercuspation as reference position, the extent to which they think it is safe to rely on the TMJ resilience, and finally their alternative to centric relation in the treatment of patients needing condylar repositioning.

ssEMG assessment of a new tool for the management of 3D vertical dimension of occlusion in prosthetic dental rehabilitations: A case report.

In oral rehabilitation the new dental morphology requires changes in the occlusal relations and in case of whole dental arch restoration also the mandibular position can undergo three-dimensional spatial modifications. Overloads and/or altered distributions of the stresses on the temporomandibular joint, teeth and bones may therefore result with not clearly understood consequences. In the present case report a new tool -Vertical Tester- designed to manage the 3D vertical occlusion during an implant retained full mouth rehabilitation was combined with standardized surface electromyographic (ssEMG) analysis in order to respect the masticatory muscle symmetry and coordination. The Authors conclude that the standardized surface electromyography of the masticatory muscles coupled with custom made centric relation registration device is an easy to use procedure to reduce torsional strains on the oral hard structures.

Centric relation critically revisited-What are the clinical implications?

PURPOSE OF THE ARTICLE: Centric relation is a dental term that has undergone many alterations over the years, which in turn have led to significant clinical controversies. These continuing changes in the meaning of the term CR have not only led to confusion, but they also have resulted in a variety of unnecessary diagnostic and therapeutic procedures. Analysis of the dental literature reveals ongoing misunderstanding and disagreement regarding that term among both clinicians and academic dentists. MATERIALS AND METHODS: A search of the PubMed database was performed with the following search terms: "centric relation", "masticatory muscles", "maxillomandibular relationship" and "condylar position." Relevant literature from the past 70 years until the present day was meticulously scrutinised. RESULTS: As expected, the literature review on the topic of CR revealed a problematic pattern of changing definitions and clinical disagreements, all of which have had a significant impact on the practice of dentistry. CONCLUSION: There are semantic, conceptual and practical reasons for concluding that the term 'centric relation' is flawed. Those flaws have a significant impact on dental practice. Based on our analysis, argumentation is provided to conclude that the term 'centric relation' should be abandoned. Instead, it appears that every individual has a unique temporomandibular joint relationship which cannot be described by any singular term. In healthy dentate patients, this relationship is determined by the maximum intercuspation of the teeth and should therefore be considered as biologically acceptable.

The Relationship Between Centric Occlusion and The Maximal Intercuspal Position and Their Use as Treatment Positions for Complete Mouth Rehabilitation: Best Evidence Consensus Statement.

PURPOSE: The purpose of this Best Evidence Consensus Statement was to evaluate the existing literature relative to two focus questions: How often does centric occlusion coincide with maximal intercuspal position in dentate and partially dentate populations?; and should centric occlusion or maximal intercuspal positions be equivalent for dentate and partially dentate patients undergoing complete mouth rehabilitation? MATERIALS AND METHODS: Keywords used in the initial search were: intercuspal position, centric occlusion, centric relation, maximal intercuspal position, prosthodontic rehabilitation, and occlusion. The search was then limited to Systematic Reviews, Randomized Controlled Studies, Meta-analyses and Clinical Trials. RESULTS: The initial search strategy related to the selected search terms resulted in more than 15,000 articles. When the subsequent search was limited to Systematic Reviews, Randomized Controlled Studies, and Meta-Analysis and Clinical Trials, 313 articles were selected for further analysis. CONCLUSIONS: Review of the literature reveals that most dentate and partially dentate patients do not have coincident centric occlusion and maximal intercuspal position. There is support for coincidence between centric occlusion and maximal intercuspal position as the preferred occlusal relationship in complete mouth rehabilitations. The literature does not report conclusive evidence of adverse prosthodontic outcomes with complete rehabilitations in centric occlusion or maximal intercuspal position in a healthy population. However, there is support for an association between centric occlusion-maximal intercuspal position discrepancies and occlusal instability as well as temporomandibular joint disorders. Hence, it is concluded that partially and completely dentate patients requiring complete mouth rehabilitation should be restored in centric occlusion.

Centric relation and increasing the occlusal vertical dimension: concepts and clinical techniques - part one.

This article explores the theoretical aspects and clinical procedures involved in recording centric relation. Established clinical techniques to record centric relation are considered and described in part one. The second article considers more recent concepts of centric relation and clinical techniques to record it. The basis of centric relation to increase the occlusal vertical dimension and clinical aspects of increasing the occlusal vertical dimension are considered.

Centric relation and increasing the occlusal vertical dimension: concepts and clinical techniques - part two.

Part one of this article considered the theoretical and clinical aspects of recording centric relation using established techniques, and presented a range of methods available all with advantages and limitations. This second article will consider more recent concepts in recording centric relation and practical aspects of increasing the occlusal vertical dimension.

[Comparison of the accuracy of three methods for determining maxillomandibular horizontal relationship of the complete denture].

OBJECTIVE: To observe the changes of forward displacement of maxillary complete denture during centric occlusion, three different methods were used to record the changes of vertical overlap and the comfort level of patients before and after the selective grinding of the three dentures made according to maxillo-mandibular horizontal relationship record. METHODS: Twelve edentulous patients with normal stomatognathic system were recruited in this study. Three types of complete dentures for these 12 edentulous patients were made according to their different maxilla-mandibular horizontal relationship record methods. The amount of displacement of the maxillary complete denture, the vertical overlap of the anterior teeth as well as patient comfort level were recorded before and after selective grinding. Statistical analysis was performed using the SPSS 17.0 software package. RESULTS: Before selective grinding, the amount of displacement of denture A was significantly larger than those of dentures B and C (P<0.05). After selective grinding, there was no statistical difference among the three dentures (P>0.05). During selective grinding, the vertical overlap variation of denture A was significantly greater than those of dentures B and C (P<0.05). Before selective grinding, the comfort level of the denture A was the lowest (P<0.05), and no statistical difference was found between dentures B and C (P>0.05). After selective grinding, no statistical difference was found among the three dentures (P>0.05). CONCLUSIONS: Among the complete dentures with anatomical teeth, the dentures whose horizontal relationship was recorded at 1 mm before the apex of the Gothic arch apex and with checkbite are more in line with clinical repair requirements. Complete dentures whose horizontal relationship was recorded at the apex of Gothic arch need to be adjusted with selective grinding to meet the clinical restoration requirements.

How a Discrepancy Between Centric Relation and Maximum Intercuspation Alters Cephalometric and Condylar Measurements.

OBJECTIVE: The authors' objective was to determine, by means of cone-beam computed tomography (CBCT), if there is a significant difference between the cephalometric and condylar measurements obtained in maximum intercuspation (MIP) and those obtained in centric relation (CR), which would interfere in orthodontic diagnosis and planning. METHODS: The sample consisted of 30 randomly selected patients (15 men and 15 women, mean age 14 years, CR ≠ MIP between 1 mm and 2 mm) who had undergone orthodontic treatment. This retrospective study used CBCT scans, one in MIP and the other in CR. Cephalometric measurements and sagittal, axial, and vertical condylar variations between the CR and MIP positions were analyzed in a tridimensional (3D) imaging software. RESULTS: Patients with a small CR-MIP discrepancy (<2 mm) presented significant differences in the cephalometric analysis carried out in CR and MIP, although these differences might be of low clinical significance. The condyle-fossa relationships in sagittal, coronal, and axial planes did not seem to be relevant, because only one measurement presented significant change between CR and MIP positions. CONCLUSIONS: Class II malocclusion in patients with a large CR-MIP discrepancy may be exacerbated in the CR position, which may in turn increase treatment difficulty. In these cases, not only must cephalometrics be registered in CR, but dental casts and photographs of the patient are needed to permit orthodontists to plan an appropriate treatment.

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)

Two-dimensional versus three-dimensional Frӓnkel Manoeuvre: a reproducibility study.

BACKGROUND/OBJECTIVES: To assess intra- and inter-observer reproducibility of the evaluation of the Frӓnkel Manoeuvre (FM) on three-dimensional (3D) scans and to compare it to the assessment on two-dimensional (2D) pictures. MATERIALS/METHODS: This study included 44 individuals with a skeletal Class II malocclusion [9-16-years old mean age ± standard deviation: 13.5 ± 2.01 years]. All patients had a full Class II molar relationship, overjet ≥6 mm and point A, Nasion, point B angle (ANB) ≥5 degrees. During the FM, each patient was invited to bite in centric occlusion and then to posture the mandible forward to reach a Class I molar relationship. The FM was recorded both by a normal camera and a 3D scanner (3dMD system). Six examiners divided into two groups according to their orthodontic clinical experience (<5 and >10 years), and one gold standard in the evaluation of FM, commented twice (every 15 days) on both 2D photographs (T0 and T2) and 3D scans (T1 and T3). The intra-observer agreement and the inter-observer agreement compared to the gold standard were evaluated by computing the Cohen's K. RESULTS: The agreement between observations for each examiner ranged from 0.36 to 1 on 2D pictures (T0 versus T2), and from 0.22 to 0.69 on 3D scans (T1 versus T3). The overall agreement was 0.63 (95 per cent CI = 0.35-0.91) in 2D analysis and 0.5 (95 per cent CI = 0.35-0.64) in 3D analysis. CONCLUSIONS/IMPLICATIONS: The FM was less reproducible when performed on 3D records than on 2D pictures.

Comparison of the accuracy of three methods for determining maxillomandibular horizontal relationship of the complete denture / 华西口腔医学杂志

OBJECTIVE@#To observe the changes of forward displacement of maxillary complete denture during centric occlusion, three different methods were used to record the changes of vertical overlap and the comfort level of patients before and after the selective grinding of the three dentures made according to maxillo-mandibular horizontal relationship record.@*METHODS@#Twelve edentulous patients with normal stomatognathic system were recruited in this study. Three types of complete dentures for these 12 edentulous patients were made according to their different maxilla-mandibular horizontal relationship record methods. The amount of displacement of the maxillary complete denture, the vertical overlap of the anterior teeth as well as patient comfort level were recorded before and after selective grinding. Statistical analysis was performed using the SPSS 17.0 software package.@*RESULTS@#Before selective grinding, the amount of displacement of denture A was significantly larger than those of dentures B and C (P0.05). During selective grinding, the vertical overlap variation of denture A was significantly greater than those of dentures B and C (P0.05). After selective grinding, no statistical difference was found among the three dentures (P>0.05).@*CONCLUSIONS@#Among the complete dentures with anatomical teeth, the dentures whose horizontal relationship was recorded at 1 mm before the apex of the Gothic arch apex and with checkbite are more in line with clinical repair requirements. Complete dentures whose horizontal relationship was recorded at the apex of Gothic arch need to be adjusted with selective grinding to meet the clinical restoration requirements.

[Research progress on the relationship between centric relation and orthodontic treatment].

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.

Terapia combinada de láser diódico y plano desprogramador neuromuscular en pacientes con disfunción temporomandibular / Combined therapy of diode laser and neuromuscular deprogrammer splint in patients with temporomandibular disorder

La desprogramación neuromuscular juega un papel importante en el tratamiento de la disfunción temporomandibular, uno de los principales inconvenientes es el periodo prolongado del tratamiento, lo cual influye en la aceptación del paciente o el abandono del tratamiento. El diagnóstico es crucial para planificar el tratamiento ya que cubre una amplia gama de variables para tratarlo, por lo que en este caso es un paciente dolicofacial, con problemas de disfunción temporomandibular de origen muscular, por lo cual se optó por utilizar laserterapia de bajo nivel como coadyuvante de tratamiento, dando como resultado una mejor aceptación y colaboración de la desprogramación del paciente en un periodo de tiempo más corto (AU)

Neuromuscular deprogramming plays an important role in the treatment of temporomandibular dysfunction, one of the main drawbacks is the prolonged period of treatment, which influences the acceptance of the patient or the abandonment of treatment. The diagnosis is crucial to plan the treatment since it covers a wide range of variables to treat it, so in this case it is a dolichofacial patient, with problems of temporomandibular dysfunction of muscular origin, which is why we chose to use low-level laser therapy, level as a coadjutant of treatment, resulting in a better acceptance and collaboration of the deprogramming of the patient in a shorter period of time (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.