Analysis of TMJ vibration sounds before and after use of two types of occlusal splints

Temporomandibular joint (TMJ) sounds are important and common physical signs of temporomandibular disorders (TMD). The aim of this study was to evaluate the influence of the effect of the use of occlusal bite splints (stabilizing and repositioning) on the sounds produced in the TMJ, by means of the electrovibratography (EVG). Thirty-one patients with TMD from the Dental School of Ribeirão Preto, University of São Paulo, Brazil were selected for this study. Group 1 (n=23) wore stabilizing bite splints and Group 2 (n=8) used anterior repositioning splints. Before and after treatment with occlusal splints both groups were analyzed using the SonoPAK Q/S recording system (BioResearch System, Inc.). The treatments with stabilizing bite splints were satisfactory, since they reduced the total amount of the sound energies (p<0.05), but the use of anterior repositioning splints for no more than 4 weeks produced significantly better results (p<0.01). The total amount of vibration energy involved in the vibrating movements of the TMJ showed significant improvement using anterior repositioning splints.Os ruídos da articulação temporomandibular (ATM) são sinais físicos importantes e comuns da disfunção temporomandibular (DTM). O objetivo do presente estudo foi avaliar o efeito do uso da placa oclusal (estabilizadora e reposicionadora) nos sons produzidos na ATM, por meio da eletrovibratografia (EVG). Um total de 31 pacientes da Faculdade de Odontologia de Ribeirão Preto - USP foram selecionados para este estudo. O grupo 1 (n=23) foi selecionado para usar a placa estabilizadora e o grupo 2 (n=8) para usar a placa reposicionadora. Antes e depois do uso das placas os grupos foram analisados usando o SonoPAK Q/S (BioResearch System). Os tratamentos com placas estabilizadoras foram satisfatórios quando analisados estatisticamente uma vez que reduziram a quantidade total de energia dos sons (p<0,05). O tratamento com placa reposicionadora, por 4 semanas no máximo, produziu melhores resultados estatísticos (p<0,01). A quantidade total de energia de vibração nos movimentos vibratórios da ATM mostrou significante melhora usando a placa reposicionadora

Bite force in temporomandibular dysfunction (TMD) and healthy complete denture wearers

The signs and symptoms of temporomandibular dysfunction (TMD) may contribute to reduce bite force and muscular activity. The aims of this study were to compare bite force in complete denture wearers with TMD (TMD group) and without TMD (healthy group).The TMD group consisted of 9 individuals, who had worn a maxillary and a mandibular complete removable denture for more than 10 years. The healthy group consisted of 9 participants who wore dentures and had satisfactory interocclusal and maxillomandibular relationship. Helkimo Index was used to analyze the dysfunction level. Maximum bite force was measured using a digital dynamometer with capacity of 100 kgf and adapted to oral conditions.The TMD group presented smaller mean bite force values than the healthy group, though without statistical significance (p>0.05). This outcome suggests that the TMD signs and symptoms and the structural conditions of the dentures did not affect the maximal bite force of complete denture wearers.Os sinais e sintomas de DTM podem contribuir na redução da força de mordida e da atividade muscular. O objetivo deste trabalho foi comparar a força de mordida em indivíduos com prótese total com DTM (Grupo CDTM) e sem DTM (Grupo SDTM). O Grupo CDTM (n=9) era composto por indivíduos que utilizavam as mesmas próteses totais há mais de 10 anos. O Grupo SDTM (n=9) por indivíduos com próteses totais satisfatórias quanto aos requisitos estruturais e funcionais, observados pelo profissional e relatados pelo paciente. O índice de Helkimo foi utilizado para análise do índice de disfunção. A força de mordida máxima foi medida na região de molares com gnatodinamômetro. Os resultados mostraram que o Grupo CDTM apresentou valor numérico médio de força de mordida menor que o Grupo SDTM, porém sem diferença estatisticamente significante entre os grupos avaliados (p<0,05) sugerindo que os sinais e sintomas da DTM e as condições estruturais das próteses não afetaram os resultados da força de mordida

Measurements of jaw movements and TMJ pain intensity in patients treated with GaAlAs laser

The aim of this study was to evaluate the effectiveness of low-level laser therapy (LLLT) on the improvement of the mandibular movements and painful symptoms in individuals with temporomandibular disorders (TMD). Forty patients were randomly divided into two groups (n=20): Group 1 received the effective dose (GaAlAs laser ? 830 nm, 40 mW, 5J/cm2) and Group 2 received the placebo application (0 J/cm2), in continuous mode on the affected condyle lateral pole: superior, anterior, posterior, and posterior-inferior, twice a week during 4 weeks. Four evaluations were performed: E1 (before laser application), E2 (right after the last application), E3 (one week after the last application) and E4 (30 days after the last application). The Kruskal-Wallis test showed significant more improvements (p<0.01) in painful symptoms in the treated group than in the placebo group. A significant improvement in the range of mandibular movements was observed when the results were compared between the groups at E4. Laser application can be a supportive therapy in the treatment of TMD, since it resulted in the immediate decrease of painful symptoms and increased range of mandibular movements in the treated group. The same results were not observed in the placebo group.O objetivo deste estudo foi avaliar a eficácia da terapia com laser de baixa intensidade na melhora dos movimentos mandibulares e dos sintomas dolorosos em pacientes com disfunção temporomandibular (DTM). Quarenta pacientes foram aleatoriamente divididos em dois grupos (n=20): Grupo 1 recebeu a dose efetiva (laser de AsGaAl 830 nm, 40 mW, 5 J/cm2) e Grupo 2 recebeu a aplicação placebo (0 J/cm2), no modo contínuo no pólo lateral do côndilo afetado: superior, anterior, e posterior-posterior e inferior, 2 vezes por semana, por 2 meses. Quatro avaliações foram feitas: A1 (antes da aplicação), A2 (imediatamente após a última aplicação), A3 (uma semana após a última aplicação) e A4 (um mes após a última aplicação). O teste estatístico de Kruskal-Wallis mostrou melhoras significativas (p<0,01) nos sintomas dolorosos no grupo 1, diferentemente do grupo 2. Uma melhora significativa na extensão dos movimentos mandibulares foi observada quando os resultados foram comparados entre os dois grupos na A4. A aplicação do laser é uma terapia de suporte no tratamento da DTM, uma vez que resultou em imediata redução dos sintomas dolorosos e aumento na extensão dos movimentos mandibulares no grupo experimental. Os mesmos resultados não foram observados no grupo placebo

Reestablishment of occlusion through overlay removable partial dentures: a case report

Loss of posterior teeth may cause an imbalance in the stomatognathic system. Overlay removable partial dentures (ORPD) are a reversible and relatively inexpensive treatment for patients with severely worn teeth. This paper presents a treatment with ORPD in a 55-year-old male patient who had severe attrition in the maxillary and mandibular teeth, temporomandibular joint pain and reduced vertical dimension of occlusion (VDO). The treatment consisted in the reestablishment of the VDO using Lucia&#8217;s jig, fabricating removable partial denture with reconstruction of the worn teeth without preparation. This therapy can be used as an alternative treatment to provide esthetic, function and stable occlusion in patients with severely worn teeth

Impact of chronic allergic rhinitis on bite force and electromyographic activity of masseter and temporalis muscles of adult women

The aim of this study was to analyse the stomatognathic system of adult women with chronic allergic rhinitis by means of molar bite force and electromyographic activity of the masseter and temporalis muscles. A total of 26 subjects were screened and divided into two distinct groups: chronic allergic rhinitis group (n = 13) and healthy control group (n = 13). Subjects were assessed by maximal molar bite force (right and left) and normalized electromyographic activity of mandibular tasks (rest, right and left laterality, protrusion and maximal voluntary contraction). Data were submitted to Student?s t test (p< .05). There was significant difference in right (p = .03) and left (p = .04) maximal molar bite force with force reduction in the chronic allergic rhinitis group. There was significant difference in normalized electromyographic activity in maximal voluntary contraction in the right (p =.01) and left (p = .01) temporalis muscles, with increased electromyographic activity in the masticatory muscles for the chronic allergic rhinitis group. The results suggest that chronic allergic rhinitis in adult women promoted negative changes in the electromyographic activity of temporalis muscles in maximal voluntary contraction and maximal molar bite force

Marginal adaptation of lithium disilicate crowns obtained by scanning techniques (CAD/CAM): in vitro confocal microscopy analysis

Objetivo. El objetivo de este estudio fue evaluar la adaptación marginal de coronas de disilicato de litio obtenidas mediante técnicas de escaneo (CAD/CAM), antes y después de la cristalización, a través de análisis in vitro con microscopía confocal (MC). Métodos. Fueron confeccionadas 16 réplicas en poliuretano a partir de la pieza 1.4, de modelo typodont, tallada para corona total. Las réplicas fueron divididas en dos grupos, de acuerdo a la técnica de escaneo: Técnica Indirecta (Grupo IND, n=08), donde modelos de yeso fueron escaneados con escáner de laboratorio (inEos X5, Sirona Dental Systems) y Técnica Directa (Grupo DIR, n=08), donde modelos typodont fueron escaneados con escáner intraoral (CEREC BlueCam, Sirona Dental Systems). A seguir, se fresaron (inLab MC XL, Sirona Dental Systems) coronas en disilicato de litio (IPS e.max CAD, Ivoclar Vivadent) y se adaptaron a las réplicas. Se evaluó la adaptación marginal con análisis de MC en dos momentos, antes y después de la cristalización del disilicato de litio. Los datos fueron analizados con la prueba de Mann-Whitney, t de Student y Wilcoxon (α= 0,05). Resultados. Hubo una diferencia estadísticamente significativa en la adaptación marginal horizontal entre los grupos IND y DIR después de la cristalización (p=0,05). En el grupo IND, la comparación de la adaptación marginal vertical antes y después de la cristalización mostró una diferencia estadísticamente significativa (p=0,038). Conclusiones. Las coronas de disilicato de litio obtenidas mediante escaneo directo (CAD/CAM) presentaron menor desajuste marginal vertical. La etapa de cristalización afectó la adaptación marginal de las coronas.Objective. This study aimed to evaluate lithium disilicate marginal adaption on crowns by scanning techniques (CAD/CAM), before and after crystallization, through confocal microscopy (CM) in vitro analysis. Methods. Sixteen polyurethane replicas were performed from tooth 1.4, of a typodont model, prepared for a full crown. The replicas were divided into two groups, according to the scanning technique: Indirect Technique (Group IND, n=08), where dental stone models were scanned with a laboratory scanner (inEos X5, Sirona Dental Systems) and Direct Technique (Group DIR, n=08), where typodont models were scanned with an intraoral scanner (CEREC BlueCam, Sirona Dental Systems). Then, the lithium disilicate crowns (IPS e.max CAD, Ivoclar Vivadent) were milled (inLab MC XL, Sirona Dental Systems) and adapted to the replicas. Marginal adaptation was evaluated with CM analysis before and after lithium disilicate crystallization. Data were analyzed with the Mann-Whitney, t test, and Wilconxon test (α=0.05). Results. There was a statistically significant difference in horizontal marginal adaptation between IND and DIR groups after crystallization (p=0.05). In IND group, the comparison of vertical marginal adaptation before and after crystallization showed a statistically significant difference (p=0.038). Conclusions. Lithium disilicate crowns obtained by direct scanning technique (CAD/CAD) showed less vertical marginal maladjustment. The crystallization stage affected the crown’s marginal adaptation

Severity of Sleep Bruxism and its Implications for the Stomatognathic System in Healthy Subjects

BACKGROUND: Sleep bruxism (SB) changes the functionality patterns of the stomatognathic system. However, its severity can be an aggravating factor in the function of this complex system. AIM: The purpose of the study was to investigate the stomatognathic system of healthy subjects with different severity of SB, as determined by BiteStrip. METHODS: Thirty-four subjects were divided into two groups: Mild SB (n = 15) and severe SB (n = 19). Electromyograph was used to evaluate the electromyographic activity of the right masseter (RM), left masseter (LM), right temporal (RT), and left temporal (LT) muscles at mandibular rest, right and left laterality, protrusion, and maximum voluntary contraction. Molar bite force was measured by the dynamometer. The data were tabulated and submitted for statistical analysis (p &lt; 0.05). RESULTS: Molar bite force was significantly lower in the severe SB group. There was a significant increase in electromyographic activity in the severe SB group for the mandibular rest tasks (RM, RT, and LT), protrusion (RM, LM, RT, and LT), and right and left laterality in the temporalis muscles. There was a significant decrease in electromyographic activity in the severe SB group in maximum voluntary contraction for the masseter and temporalis muscles. CONCLUSION: Subjects with severe SB demonstrated greater functional impairment of the stomatognathic system, mainly affecting the electromyographic activity and molar bite force