Comparative evaluation of the efficacy of occlusal splints fabricated in centric relation or maximum intercuspation in temporomandibular disorders patients

Fabrication of occlusal splints in centric relation for temporomandibular disorders (TMD) patients is arguable, since this position has been defined for asymptomatic stomatognathic system. Thus, maximum intercuspation might be employed in patients with occlusal stability, eliminating the need for interocclusal records. This study compared occlusal splints fabricated in centric relation and maximum intercuspation in muscle pain reduction of TMD patients. Twenty patients with TMD of myogenous origin and bruxism were divided into 2 groups treated with splints in maximum intercuspation (I) or centric relation (II). Clinical, electrognathographic and electromyographic examinations were performed before and 3 months after therapy. Data were analyzed by the Student's t test. Differences at 5% level of probability were considered statistically significant. There was a remarkable reduction in pain symptomatology, without statistically significant differences (p>0.05) between the groups. There was mandibular repositioning during therapy, as demonstrated by the change in occlusal contacts on the splints. Electrognathographic examination demonstrated a significant increase in maximum left lateral movement for group I and right lateral movement for group II (p<0.05). There were no significant differences (p>0.05) in the electromyographic activities at rest after utilization of both splints. In conclusion, both occlusal splints were effective for pain control and presented similar action. The results suggest that maximum intercuspation may be used for fabrication of occlusal splints in patients with occlusal stability without large discrepancies between centric relation and maximum intercuspation. Moreover, this technique is simpler and less expensive.

Treatment of posterior crossbite in mixed dentition with a removable appliance: Reports of cases

A posterior crossbite malocclusion is defined as an abnormal buccolingual relationship. One or more maxillary teeth improperly occludes with one or more mandibular teeth in centric relation. This alteration develops early and is seldom self-correcting. This study is a report of the benefits of treating posterior crossbite malocclusions in mixed dentitions using removable appliances.

Determinação da relação central. Estudo sobre as posições laterais da mandíbula, em relação à linha mediana facial, em função de dois métodos para esta determinação.

The authors studied the lateral positional desviations of the mandible, in relation to the facial median line in 30 (thirty) full edentulous patients, with the purpose to verify the influence of the unstrained guided (chinpoint guidance) and deglutition methods for the determination of centric relation. According the results obtained they conclude that the unstrained guided method produced a mandibular lateral desviation with a mean value of the 0.752 mm and in the deglutition method the mean value observed was 1.109 mm. The statistical analysis of the results revealed for the unstrained guided method a proportion of the points to the right and left of the median line not statistically significant, while for the deglutition method the difference was statistically significant at a level of 5%.

Ajuste oclusal na Ortodontia: Por que, quando e como?

Introduction: The knowledge of dental occlusion should be considered the basic foundation to an excellent orthodontic practice. The patient's diagnose without the centric relation assessment can take the orthodontist to an unpleasant surprises. The use of rectangular archwires requires occlusal contacts been checked to decide what kind of the dental movement will be necessary to achieve the dental equilibrium and mainly to investigate if the movement will be possible. Considering the occlusal surfaces complexity, the occlusal adjustment by selective grinding should be performed during the orthodontic treatment to allow vertical dental movements reducing treatment's time. Occlusal interferences are responsible not only for biomechanics adverse effects, producing undesirable dental movements, but also for potential side effects such as excessive forces (occlusal trauma), leading to roots reabsorption. The occlusal adjustment is a determinant point on dental balance after the end of orthodontics treatments, where each posterior occlusal tooth contacts A and B, or B and C on buccolingual aspect, as well as the stoppers and equalizers contacts on mesiodistal direction must be achieved and well established. The appropriate role of anterior teeth in mandibular movements must be determined, allowing immediate disclusion of posterior teeth, known as anterior guide, and promoting protecting muscle forces to the stomatognathic system. Selective grinding should not be used. in place of well planned and executed orthodontic movement. Aim: The aim of this article is to present the rationale use of occlusal adjustment in Orthodontics.

Mandible protrusion and decrease of TMJ sounds: An electrovibratographic examination

This study quantified by, electrovibratography, the amount of mandible protrusion required to decrease significantly temporomandibular joint (TMJ) vibratory energy as an aid in the diagnosis of the recapture of anteriorly displaced disk. Eighteen patients diagnosed as having anterior disk displacement with reduction and TMJ clicking were submitted to electrovibratographic examination at the first appointment and treated with a stabilizing appliance and anterior positioning appliance with 1 to 5 mm protrusion. Vibratory energy was checked in each of these positions. Baseline data were used as control. At the first appointment, the patients had vibrations with more elevated intensities at the middle and late phases of the mouth opening cycle. At only one clinical step, mandible protrusion was obtained with the anterior repositioning appliance, ranging from 1 to 5 mm protusion. At each new position, a new electrovibratographic exam was made. After the 5-mm mandibular projection, only 2 patients presented vibration, with means between 0.6 and 2.8 Hz. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). The outcomes of this study indicate that 3 mm is the minimum amount of mandible protrusion to significantly decrease the TMJ vibratory energy and to recapture the displaced articular disk.

Analysis of mandibular position using different methods of location.

There has been much discussion regarding the ideal position of the condyle in the mandibular fossa. Although the centric relation position (CR) is used as a reference, some authors do not believe that it is physiologic. Thus, the aim of this study was to evaluate in a group of asymptomatic individuals the position of the condyle in the mandibular fossa at maximum intercuspation (MI), with a occlusal splint and with a Lucia jig between the teeth. It was analyzed by means of magnetic resonance imaging (MRI), transcranial radiography imaging and analysis of horizontal axis of rotation from casts mounted on an articulator. The results showed that even if patients had mandibular displacement in positions of CR, habitual maximum intercuspation and with the occlusal splint, confirmed by means of the analysis of the horizontal axis of rotation, the images showed no statistically significant differences among condylar positions. It can therefore be concluded that the positions analyzed were similar and that transcranial radiography seems to be a reliable method for analyzing condylar position.

Estudo cinesiográfico da deglutição em indivíduos com dentição natural e com próteses totais

Pós-graduação em Reabilitação Oral - FOAR

Análise da posição mandibular através de diferentes métodos de localização

Pós-graduação em Odontologia - FOA

Avaliação comparativa da efetividade das placas oclusais confeccionadas em relação central ou máxima intercuspidação em pacientes com DTM

Pós-graduação em Odontologia - FOA

Registros posicionais de protrusão e lateralidade em resinaacrílica à partir de diferentes posições iniciais

The lateral movement presents a combination of lateral condylar and protrusive displacement on the non-working side. The objective os this study was to check the differences in the adjustment of the semiadjustable articulator starting from two different initial positions, centric relation an intercuspal position using positional records of rotusion and lateral movements in acrylic resin for the adjustment of condylar guidance as for ennett Angle. Twenty pacients dentate and assintomatic were recruited and their adjustment were performed in the semiadjustable articulator checking the differences among the studied groups, not finding statistically significant differences. Concludes that, in semiadjustable articulator adjustment, starting the montage in centric relation or intercuspal position, the results obtained for the condylar guidande and Bennett Angle aren´t statistically diferents, as well there is no difference in condylar guidance adjustment using lateral or protrusive records.

Aspectos oclusais na etiologia das desordenstemporomandibulares

Since the occlusion area is presented in almost all specialties of Dentistry, its relationship with the health of the patient has been shown. The etiology of temporomandibular disorders is multifactorial and the occlusion is considered an etiologic factor. This study aimed to discuss the functional occlusion aspects and the presence of temporomandibular disorders. Literature Review: The loss of orthopedic balance can induce temporomandibular disorder. Therefore, both the physiological and functional occlusions have been analyzed as a dental relation. Several functional occlusal factors have been linked to the temporomandibular disorders such as deviations of centric relation to maximum intercuspation, occlusal interferences, absence of posterior teeth, changes on the occlusion vertical dimension, malocclusion, orthodontic treatment and parafunction. Conclusion: The most common occlusal factors related to temporomandibular disorders are quite frequent; however, the diagnosis and treatment of such disorders should be considered individually

Técnicas de obtenção da posição de relação central em pacientes edêntulos

Edentulism causes loss of horizontal intermaxillary relationship, which is defined by the condyle position in the joint cavities, called centric relation. The correct record of centric relation in edentulous pacients has a strong influence on the treatment final result and is considered one of the most difficult clinical steps to achieve success. The aim of this study was to describe the main centric relation recording methods for edentulous patients reported in the literature. The study described physiological methods such as swallowing and pull tongue back, manipulative and graphic methods. It is concluded that the combination of different methods facilitates the correct centric relation record. Dentists must have a good knowledge of those techniques to perform this procedure satisfactorily.

Object-centric process models and the design of flexible processes

Mainstream business process modelling techniques promote a design paradigm wherein the activities to be performed within a case, together with their usual execution order, form the backbone of a process model, on top of which other aspects are anchored. This paradigm, while eective in standardised and production-oriented domains, shows some limitations when confronted with processes where case-by-case variations and exceptions are the norm. In this thesis we develop the idea that the eective design of exible process models calls for an alternative modelling paradigm, one in which process models are modularised along key business objects, rather than along activity decompositions. The research follows a design science method, starting from the formulation of a research problem expressed in terms of requirements, and culminating in a set of artifacts that have been devised to satisfy these requirements. The main contributions of the thesis are: (i) a meta-model for object-centric process modelling incorporating constructs for capturing exible processes; (ii) a transformation from this meta-model to an existing activity-centric process modelling language, namely YAWL, showing the relation between object-centric and activity-centric process modelling approaches; and (iii) a Coloured Petri Net that captures the semantics of the proposed meta-model. The meta-model has been evaluated using a framework consisting of a set of work ow patterns. Moreover, the meta-model has been embodied in a modelling tool that has been used to capture two industrial scenarios.

A review of radio channel models for body centric communications

The human body is an extremely challenging environment for the operation of wireless communications systems, not least because of the complex antenna-body electromagnetic interaction effects which can occur. This is further compounded by the impact of movement and the propagation characteristics of the local environment which all have an effect upon body centric communications channels. As the successful design of body area networks (BANs) and other types of body centric system is inextricably linked to a thorough understanding of these factors, the aim of this paper is to conduct a survey of the current state of the art in relation to propagation and channel models primarily for BANs but also considering other types of body centric communications. We initially discuss some of the standardization efforts performed by the Institute of Electrical and Electronics Engineers 802.15.6 task group before focusing on the two most popular types of technologies currently being considered for BANs, namely narrowband and Ultrawideband (UWB) communications. For narrowband communications the applicability of a generic path loss model is contended, before presenting some of the scenario specific models which have proven successful. The impacts of human body shadowing and small-scale fading are also presented alongside some of the most recent research into the Doppler and time dependencies of BANs. For UWB BAN communications, we again consider the path loss as well as empirical tap delay line models developed from a number of extensive channel measurement campaigns conducted by research institutions around the world. Ongoing efforts within collaborative projects such as Committee on Science and Technology Action IC1004 are also described. Finally, recent years have also seen significant developments in other areas of body centric communications such as off-body and body-to-body communications. We highlight some of the newest relevant research in these areas as well as discussing some of the advanced topics which are currently being addressed in the field of body centric communications. Key Points Channel models for body centric comms ©2014. The Authors.

Human-Centric Chronographics:Making Historical Time Memorable

A series of experiments is described, evaluating user recall of visualisations of historical chronology. Such visualisations are widely created but have not hitherto been evaluated. Users were tested on their ability to learn a sequence of historical events presented in a virtual environment (VE) fly-through visualisation, compared with the learning of equivalent material in other formats that are sequential but lack the 3D spatial aspect. Memorability is a particularly important function of visualisation in education. The measures used during evaluation are enumerated and discussed. The majority of the experiments reported compared three conditions, one using a virtual environment visualisation with a significant spatial element, one using a serial on-screen presentation in PowerPoint, and one using serial presentation on paper. Some aspects were trialled with groups having contrasting prior experience of computers, in the UK and Ukraine. Evidence suggests that a more complex environment including animations and sounds or music, intended to engage users and reinforce memorability, were in fact distracting. Findings are reported in relation to the age of the participants, suggesting that children at 11–14 years benefit less from, or are even disadvantaged by, VE visualisations when compared with 7–9 year olds or undergraduates. Finally, results suggest that VE visualisations offering a ‘landscape’ of information are more memorable than those based on a linear model. Keywords: timeline, chronographics