Effect of short-term increase in occlusal vertical dimension on masticatory muscle electrical activities and pressure-to-pain threshold: A crossover clinical study.

STATEMENT OF PROBLEM: Increasing the occlusal vertical dimension (OVD) is a common procedure in clinical practice. However, few studies have assessed the short-term influence of an increased OVD on the masticatory muscles. PURPOSE: The purpose of this crossover clinical study was to investigate the effect of increased OVD on the electrical activity of masticatory muscles and the pressure-to-pain threshold (PPT) in asymptomatic participants. MATERIAL AND METHODS: Twenty asymptomatic participants (22.7 ±2.39 years of age; 10 men, 10 women) were submitted to an increase in OVD by using interocclusal devices of different thicknesses (3- and 6-mm) for 24 hours. Masticatory muscle activity was assessed with electromyography (EMG), expressed in microvolts (µV), while the participants masticated 2 pieces of latex of different consistency (latex S and H) with and without the device. The PPT was measured with a digital algometer before and after the mastication. The results were assessed by using analysis of variance (ANOVA) and the Tukey honestly significant difference (HSD) test (α=.05). RESULTS: The change of OVD did not significantly affect the electrical activity of the muscles. The latex of hard consistency (latex H) showed higher electrical activity values than the soft texture (latex S). For the working side anterior temporal muscle, a change in the PPT was detected on the day the 6-mm-device was inserted, but for the other muscles, device thickness and latex mastication did not change the PPT. CONCLUSIONS: For a short time, an increase in occlusal vertical dimension did not affect the electrical activity in the masticatory muscles or pressure-to-pain threshold in asymptomatic participants.

Evaluation of silent period on masticatory cycles of different muscles in dentate oral contraceptives users and nonusers.

OBJECTIVE: The aim of this study was to evaluate the influence of oral contraceptive use on the silent period (SP) of anterior temporal and masseter muscles during the menstrual cycle. MATERIALS AND METHODS: Totally, 28 women on reproductive age were selected including 15 nonusers of any hormone and 13 contraceptive users. All patients were dentate without muscular temporomandibular disorders. Electromyography (SP test) of the anterior temporal and masseter muscles was conducted every week during three consecutive menstrual cycles at 1(st) day of menstruation (P1), 7(th) day (P2), 14(th) day (P3) and 21(st) day (P4). RESULTS: The SP values in the anterior temporal and masseter muscles were measured at both sides. The SP values of the right side (13.49 ms) at P2 were significantly different compared to the left side (12.28 ms). However, there was no significant difference on the interactions among the three factors. CONCLUSION: It can be concluded that the SP values in healthy women in reproductive age may not be influenced by the menstrual cycle with similar results for both muscles.

Variação da temperatura superficial dos músculos masseter e temporal anterior durante o apertamento dental voluntário com placas interoclusais maxilares de duas diferentes espessuras / Variation of surface temperature on superficial masseter and anterior temporal muscles during voluntary teeth clenching with maxillary splints of two different thicknesses

A atividade muscular tem sido estudada de maneira indireta pela análise da variação da temperatura superficial cutânea sobre os músculos mastigatórios. Essas mensurações podem representar uma ferramenta valiosa na avaliação clínica da atividade e do progresso das desordens temporomandibulares, bem como no acompanhamento do protocolo terapêutico adotado, justificando sua utilização para verificar alterações patológicas na circulação sanguínea e/ou atividade metabólica nos tecidos abaixo da pele, como os músculos mastigatórios. Em vista disso, o objetivo do presente estudo foi verificar o efeito da espessura da placa interoclusal sobre a variação da temperatura superficial dos músculos temporal anterior e masseter, durante o repouso e o apertamento dental, considerando-se a condição assintomática de 20 indivíduos (10 do gênero masculino e 10 do gênero feminino) selecionados através do questionário Research Diagnostic Criteria (RDC). A temperatura em graus Celsius (ºC) da superfície dos músculos masseter e temporal anterior foi medida com o auxílio de um termômetro digital, com um sistema de leitura por irradiação infravermelha. A temperatura superficial dos músculos temporal anterior e masseter apresentou redução significativa diante do apertamento dental em relação à posição de repouso mandibular. Entretanto, não houve diferenças significantes entre as condições com e sem placa interoclusal, bem como entre as distintas espessuras de placas interoclusais analisadas. Adicionalmente, os músculos mastigatórios apresentaram uma considerável semelhança entre os lados, sem haver também distinções significantes entre o gênero masculino e o feminino.

Muscle activity has been studied indirectly through analyses of temperature variation in skin surface temperature on the masticatory muscles. These procedure may be an important tool for clinical evaluation and assessment of the evolution of temporomandibular disorders, as well as monitoring the adopted protocol. Thus, its utilization for identified pathological alterations on blood circulation and/or on metabolic activity in subcutaneous tissues, such as the masticatory muscles, is justified. The aim of this study was to investigate the effect of occlusal splintsÆ thickness on the variation of surface temperature of the anterior temporal and masseter muscles during rest and clenching. It were analyzed 20 asymptomatic subjects (10 males and 10 females) selected through the Research Diagnostic Criteria (RDC) questionnaire. Temperature expressed in degrees Celsius (ºC) was measured on the surface of both muscles measured with the aid of a digital thermometer with an infrared radiation reading system. The surface temperature of the anterior temporal and masseter muscles presented significant reduction during teeth clenching in relation to the mandibular rest position. However, there were no significant differences between conditions with and without occlusal splint or between the different thicknesses of splints analyzed. Masticatory muscles showed a considerable similar behavior for both sides, and no significant distinctions were observed between male and female patients.

Effect of occlusal splint thickness on electrical masticatory muscle activity during rest and clenching.

The extent of separation between the maxillary and mandibular teeth in the fabrication of interocclusal splints designed to achieve efficiency and muscle relaxation is controversial and undefined in the literature. Based on this premise, the aim of this study was to evaluate the effect of interocclusal splint thicknesses of 3 and 6 millimeters on the electrical activity of the anterior temporal and masseter muscles during rest and dental clenching. Twenty asymptomatic individuals (10 males and 10 females) were selected using the Research Diagnostic Criteria (RDC). Electromyography (EMG) was performed both with and without the 3- and 6-mm splints using the Bio EMG software package, which recorded values given in microvolts (µV). The results, which were assessed using analysis of variance (ANOVA) to a 5% significance level (p < 0.05), showed increased electrical activity of the masticatory muscles during dental clenching compared with at rest, with greater activity in the masseter muscle. The electrical activity did not differ according to the thickness of the splints or between males and females. We can conclude that both splint thicknesses are effective in treating muscle hyperactivity given their similar clinical behavior for asymptomatic individuals.

Temporomandibular joint vibration before and after exercises and occlusal splints.

Temporomandibular joint (TMJ) sounds are frequent in patients. The aim of this study was to analyze patients with clicking at the end of opening and at the beginning of closing their mouths treated by muscular exercises through chewing and by occlusal splints. Fifteen patients with clinically verified clicking and TMJ and 15 patients without sounds were selected by the Research Diagnostic Criteria for Temporomandibular Disorders. They were submitted to electrovibratography at consultation and 60 and 120 days of treatment by occlusal splints and exercises. Patients demonstrated significant reduction of TMJ sounds after treatment, but vibration intensity was not similar with that of the control group after 120 days.

Effect of occlusal splint thickness on electrical masticatory muscle activity during rest and clenching

The extent of separation between the maxillary and mandibular teeth in the fabrication of interocclusal splints designed to achieve efficiency and muscle relaxation is controversial and undefined in the literature. Based on this premise, the aim of this study was to evaluate the effect of interocclusal splint thicknesses of 3 and 6 millimeters on the electrical activity of the anterior temporal and masseter muscles during rest and dental clenching. Twenty asymptomatic individuals (10 males and 10 females) were selected using the Research Diagnostic Criteria (RDC). Electromyography (EMG) was performed both with and without the 3- and 6-mm splints using the Bio EMG software package, which recorded values given in microvolts (µV). The results, which were assessed using analysis of variance (ANOVA) to a 5 percent significance level (p < 0.05), showed increased electrical activity of the masticatory muscles during dental clenching compared with at rest, with greater activity in the masseter muscle. The electrical activity did not differ according to the thickness of the splints or between males and females. We can conclude that both splint thicknesses are effective in treating muscle hyperactivity given their similar clinical behavior for asymptomatic individuals.

Silent period of masticatory cycles in dentate subjects and complete denture wearers.

PURPOSE: The purpose of this study was to assess, through electromyographic activity (EMG), the silent period (SP) of masseter and anterior temporal muscles in dentate subjects (DS) and complete denture wearers (CDW). MATERIALS AND METHODS: The evaluations were performed at the initial and final period of the mastication for the DS group. For the CDW group, the evaluations were performed at the initial period of mastication, with old complete dentures worn for more than 10 years (OCDW) and at the final period of the mastication with new complete dentures (NCDW), 5 months after rehabilitation. Twenty-four asymptomatic subjects (12 DS, 12 CDW) answered a questionnaire based on the Research Diagnostic Criteria for temporomandibular disorders. The CDW group answered the questionnaire before and after new denture insertion and after 5 months of rehabilitation. The SP of the muscles was recorded through EMG at the initial and final periods of mastication using artificial food (Optocal). The operator monitored 35 chewing cycles performed to grind the artificial food and selected eight open-close-clench-chewing cycles for the record. RESULTS: The SP of the muscles analyzed with new complete dentures showed no statistical difference in comparison to the old dentures. There was a statistically significant difference in the SP between the CDW and DS groups for initial and final chewing. CONCLUSION: Lowered muscular capacity and ability reduced the SP of muscles after rehabilitation with NCDWs.

Relationship between anxiety and chronic orofacial pain of temporomandibular disorder in a group of university students.

PURPOSE: This study evaluated the relationship between anxiety levels and severity degrees of chronic orofacial pain of temporomandibular disorder in brazilian university students. METHODS: 150 volunteers (117 men and 33 women), with age ranging from 17 to 30 years, were subjects to this study. Spielberger's trait-state anxiety inventory was used to evaluate trait and state anxiety of the students, while examination for chronic orofacial pain was performed in accordance with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Association between anxiety levels and severity degrees of chronic orofacial pain was tested using the Chi-square test. The significance level was set at p<.05. RESULTS: The results showed that 32.7% (n=49) of the subjects exhibited TMD, and the intensity of chronic orofacial pain was classified as degree 1 in 85.7% (n=42) and as degree 2 in 14.3% (n=7) of them. Based on the results of the Spielberger's trait-state anxiety inventory, the majority of the students had moderate anxiety (48.6% and 48.1%, respectively). The correlation between trait-anxiety levels and chronic orofacial pain degrees was significant and positive (p<.05). However, no significant correlation was found to state-anxiety levels and chronic orofacial pain degrees (p>.05). CONCLUSION: It was concluded that chronic orofacial pain of TMD could be present in university students and anxiety may be related.

Effect of occlusal splint treatment on the temperature of different muscles in patients with TMD.

PURPOSE: The aim of this study was to evaluate the effect of occlusal splint treatment on the temperature of masseter (inferior, intermediate and superior), anterior temporal, digastric and trapezius muscles in patients with temporomandibular disorder (TMD). MATERIALS AND METHODS: Thirty patients (6 male and 24 female) aged from 16 to 57 years (mean 37.8±11.4 years) were selected. The patients were diagnosed with muscular TMD by clinical examination (application of Research Diagnostic Criteria questionnaire and physical examination). Occlusal splints in acrylic resin were inserted in all patients with a weekly follow-up. The superficial thermography (°C) on the both sides of the muscles was performed using a digital thermometer in a controlled temperature room. This procedure was performed before occlusal splint insertion (patient with pain) and after the completion of the treatment (patient without pain). The data were analyzed by 2-way repeated-measures ANOVA and means were compared by Tukey HSD test (P<.05). RESULTS: After occlusal splint treatment a significant increase in temperature was observed in each muscle, both in the right and left sides. When the muscles were compared in the same period (before or after therapy) there was no significant difference among them. CONCLUSION: It can be concluded that the use of occlusal splint promoted a significant increase on the muscles temperature. There was symmetry in the temperature of muscles on the right and left sides both before and after the treatment.

Registros posicionais de protrusão e lateralidade em resina acrílica à partir de diferentes posições iniciais / Positional records of protrusion and lateral movements in acrylic resin starting from differents initials positions

O movimento de lateralidade apresenta uma combinação de deslocamento condilar lateral e protrusivo no lado de não trabalho. O objetivo deste estudo foi verificar as diferenças do ajuste do articulador semi ajustável à partir de duas posições iniciais diferentes, relação cêntrica e máxima intercuspidação, a partir da utilização de registros posicionais de protrusão e lateralidade em resina acrílica, tanto para o ajuste do guia condilar quanto para o ângulo de Bennett. Foram empregados 20 pacientes dentados assintomáticos para os quais realizou-se o ajuste do articulador verificando-se as diferenças entre os grupos estudados, não se encontrando diferenças estatisticamente significantes. Conclui-se que, no ajuste do articulador, seja a partir de uma montagem inicial em Relação Central ou Máxima Intercuspidação, os resultados obtidos para guia condilar e ângulo de Bennett, não são estatisticamente diferentes; bem como não há diferença em ajustar o guia condilar empregando-se o registro de lateralidade ou protrusivo

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

Silent period-dentate, edentulous, and patients with craniomandibular dysfunction.

BACKGROUND: The record of electrical activity of elevator muscles in mandible is important for the evaluation of muscular potency and diagnosis of neuromuscular pathologies, which allows prevention and treatment. The aim of this study was to define silent periods (SPs) and the importance in dentistry and compare the SPs in masticatory muscles of dentate and edentulous patients wearing prosthesis considering the presence or absence of craniomandibular dysfunction (CMD). MATERIALS AND METHODS: Literature review in PubMed database. DISCUSSION: Silent periods are isolated pulses of transcranial magnetic stimulation in the primary motor cortex during voluntary muscular activity that generates an interruption of muscular activity for hundredths of milliseconds. The SP duration depends on the patient (dentate or edentulous), type of stimulus, and presence of CMD. CONCLUSIONS: The SP is higher in complete edentulous patients and in individuals with occlusal disharmonies than in dentate patients without CMDs. The treatment of CMDs through occlusal therapy decreases SP duration.

TMJ vibrations in asymptomatic patients using old and new complete dentures.

PURPOSE: The aim of this study was to assess the presence of temporomandibular joint (TMJ) noises in subjects with severe bone resorption, who have worn the same complete dentures for over 10 years, and 5 months after treatment with increments of acrylic resin on the occlusal surface after having new dentures in place. METHODS: After applying the research diagnostic criteria (RDC)/temporomandibular disorder (TMD) questionnaire, 20 asymptomatic subjects were assessed before and 5 months after the new dentures were put in place. Joint vibrations were assessed by the Sono Pak program by selecting the vibrations that occurred during the opening and closing cycle. RESULTS: The means of the results revealed a nonnormal distribution and were submitted to Kruskal-Wallis statistical analysis (p < 0.05). The vibration means were of low intensity (< or =9.96 Hz). After rehabilitation, there was a reduction in the vibrations (< or =5.2 Hz) statistically significant only at the end of mouth opening with the old dentures when compared with the other cycles. CONCLUSION: The intensity and number of occurrences of joint vibrations were reduced after 5 months of wearing new dentures.

Sintomas auditivos e desordens temporomandibulares / Hearing symptoms and temporomandibular disorders

Introdução: Uma variedade de hipóteses tem sido propostas para esclarecer a associação entre desordens temporomandibulares e sintomas auditivos, entre elas as múltiplas possibilidades anatômicas e/ou neurológicas que, a partir de uma disfunção muscular ou articular, podem acarretar tais sintomas. Objetivo: O propósito do presente estudo é discutir, através de uma revisão sistemática de literatura, a inter-relação entre os sintomas auditivos e as desordens temporomandibulares. Material e Método: Foram consultados os indexadores Medline/PubMed, ISI e Scielo, no período de 1918 a 2008. Os termos relacionados para a pesquisa foram: “temporomandibular disorders”, “signs and symptoms of temporomandibular disorders”, “otologic symptoms” e “aural symptoms”, onde 19 artigos foram incluídos através dos critérios pré-selecionados para a confecção de uma metaanálise. Resultados: Segundo os dados encontrados, os sintomas auditivos mais frequentemente relacionados com desordens temporomandibulares foram otalgia e zumbido, seguido de vertigem e perda auditiva, respectivamente. Conclusões: Torna-se evidente a correlação entre os sintomas auditivos e as desordens temporomandibulares, entretanto há a necessidade de pesquisas clínico-científicas mais complexas para comprovarem as específicas relações causa-efeito entre ambos

Introduction: A variety of hypotheses have been proposed to explain the association between temporomandibular disorders and hearing symptoms, including the many anatomical and/or neurological ways, as of a muscle or joint dysfunction, can cause such symptoms. Objective: The purpose of this study is to discuss, through a systematic review of literature, the interrelation between hearing symptoms and temporomandibular disorders. Material and Methods: We consulted the Medline/PubMed, ISI and Scielo in the period 1918 to 2008. The terms related to the research were: “temporomandibular disorders”, “signs and symptoms of temporomandibular disorders”, “otologic symptoms” and “aural symptoms”, where 19 papers were included using the pre-selected criteria for the manufacture of a meta-analysis. Results: According to the findings, the hearing symptoms most often associated with temporomandibular disorders were otalgia and tinnitus, followed by vertigo and hearing loss, respectively. Conclusions: It’s clear the correlation between hearing symptoms and temporomandibular disorders, however there is a need clinical and scientific research more complex to prove the specific cause-effect relationships between them

Stress levels and quality of sleep in subjects with temporomandibular joint dysfunction / Níveis de estresse e distúrbios do sono em indivíduos com disfunção temporomandibular

Purpose: The aim of this study was to test the association between quality of sleep and stress in individuals with temporomandibular disorder (TMD). Methods: The study sample consisted of 354 adult subjects (males and females) from the municipality of Piacatu, São Paulo state, in the Southeast region of Brazil. Data were collected using the Fonseca Questionnaire to record the level of TMD, the Pittsburgh Sleep Quality Index (PSQI) to assess quality of sleep and the Social Readjustment Rating Scale (SRRS) to record stress level. The data were analyzed by the software Epi Info 2000 version 3.2 using a chi-square test at the 0.05 level of significance. Results: One hundred and eighty (50.8%) subjects had some level of TMD. The statistical analysis showed a significant relationship between the three stress scores and the presence or absence of sleep disorders, considering an overall PSQI score > 5 as an indicator of a subject with sleep problems (P<0.01). Conclusion: Both quality of sleep and stress levels were associated with TMD in this sample.

Objetivo: O objetivo deste trabalho foi comparar níveis de estresse e qualidade do sono em indivíduos com DTM. Metodologia: O universo desta pesquisa constituiu-se por 354 indivíduos de ambos os sexos do município de Piacatu, SP, Brasil. Os dados foram coletados através do uso de: Questionário de Fonseca para verificar o grau de DTM, Índice da Qualidade do Sono de Pittsburgh (PSQI) para a qualidade do sono e a Escala de Reajustamento Social (SRRS) para o grau de estresse. Os dados foram tabulados por meio do programa Epi Info 2000, versão 3.2, e analisados estatisticamente por meio do Teste Qui-Quadrado, ao nível de significância de 5%. Resultados: Do total, 180 (50,8%) apresentavam algum grau de disfunção temporomandibular, sendo que destes, 96 (53,3%) tinham distúrbios do sono e 107 (59,4%) graus mais elevados de estresse. O teste estatístico mostrou relação entre os fatores analisados (P<0,01). Conclusão: Há associação estatisticamente significativa entre qualidade do sono e estresse em indivíduos com DTM.

Analysis of masticatory cycle efficiency in complete denture wearers.

PURPOSE: This study assessed masticatory efficiency and duration of the masticatory cycle in 14 asymptomatic patients with severe bone resorption. All patients had worn complete dentures for over 10 years. Recall visits were scheduled at 5 months and 1 year after receiving new dentures. MATERIALS AND METHODS: Fourteen patients were evaluated in this study. The Research Diagnostic Criteria questionnaire and tests of the efficiency and duration of the masticatory cycle were performed with artificial food before, 5 months after, and 1 year after new dentures were delivered. Masticatory efficiency was assessed using a sieve system; artificial food was ground for 35 masticatory cycles and monitored by the operator. RESULTS: Masticatory efficiency at 5 months was significantly improved for the 0.42-mm mesh. An improvement in masticatory efficiency and a reduction in mastication time were observed with the new dentures after 1 year. CONCLUSION: The results of this study indicated that 5 months did not allow enough time to demonstrate improved muscular capacity and ability after receiving new dentures. After 1 year, the duration of the masticatory cycle was reduced, and masticatory efficiency was significantly improved.

Reestablishment of occlusion with prosthesis and composite resin restorations.

Here, we present a case report on prosthetic reconstruction of posterior teeth and composite resin restoration of anterior teeth yielding considerable esthetic improvement, reestablishment of disocclusion guides and function.

Fatores associados à ocorrência de vibrações articulares / Factors associated to the occurrence of joint sounds

Objetivou-se neste trabalho verificar a associação do sexo, classe econômica, qualidade do sono e estresse com a ocorrência de vibrações articulares. A população deste estudo constituiu-se inicialmente por 160 indivíduos de ambos os sexos do município de Piacatu, São Paulo, Brasil, nos quais aplicou-se o Questionário de Fonseca, para verificar o grau de DTM. Posteriormente, os indivíduos com disfunção moderada e severa foram classificados economicamente por meio do Critério de Classificação Econômica Brasil (CCEB), responderam à tradução do Questionário de Avaliação do Sono de Toronto (SAQ) e a Escala de Reajustamento Social (SRRS), para verificar o grau de estresse. Realizou-se também exame eletrovibratográfico. Do total, 37 (23,1%) indivíduos apresentavam disfunção moderada ou severa, sendo que destes, 20 (54,1%) eram do sexo feminino, 21 (56,8%) pertenciam a “Classe D”, 29 (78,4%) apresentavam distúrbios do sono, 24 (64,8%) graus mais elevados de estresse e 19 (51,4%) vibração articular. Há associação estatisticamente significativa da qualidade do sono e classe econômica na ocorrência de vibrações articulares.

This study aimed to verify the association of gender, economic class, quality of sleep and stress with the occurrence of joint vibration. The population of this study was made up initially by 160 individuals of both sexes in the city of Piacatu, São Paulo, Brazil, which applied the Fonseca’s Questionnaire, to check the degree of temporomandibular joint dysfunction (TMD). Later, individuals with moderate and severe dysfunction were classified economically through the Criterion of Economic Classification Brazil (CCEB), aswered to the translation of the Sleep Assessment Questionnaire of Toronto (SAQ) and the Social Readjustment Rating Scale (SRRS), to verify the degree of stress. There was also an examining of electrovibratographic. From the total, 37 (23.1%) subjects had moderate or severe dysfunction, of which 20 (54.1%) were female, 21 (56.8%) belonged to “D Class”, 29 (78.4%) had sleep disorders, 24 (64.8%) higher degrees of stress and 19 (51.4%) joint vibration. There is a statistically significant association between quality of sleep and economic class in the occurrence of joint vibration.

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 percent 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.

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.

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.