Masticatory muscle activity evaluation by electromyography in subjects with zygomatic implants

BACKGROUND: Zygomatic implants are an alternative treatment in the rehabilitation of atrophic maxilla to promote stability in the stomatognathic system. The aim of this study was to compare the electromyographic (EMG) activity of masseter and temporalis muscles in controls and in individuals with complete implant-supported dentures anchored in the zygomatic bone. MATERIAL AND METHODS: Fifty-four volunteers of both genders (mean age 52.5 years) were selected and distributed into two groups: Individuals with zygomatic implant (ZIG; n=27) and fully dentate patients (CG; n=27). MyoSystem-BR1 was used to assess masseter and temporalis muscles EMG activity in different mandibular movements: protrusion, clenching, maximal voluntary contraction (MVC) with Parafilm M(R), right and left laterality and chewing (peanuts and raisins). Data was processed, normalized (MVC) and analyzed using the SPSS 21.0. Student t-test (P ≤ 0.05) was used for group comparison. RESULTS: The results were statistically significant (P ≤ 0.05) for protrusion, clenching, right and left laterality and raisin chewing. For the mandibular posture conditions, the ZIG obtained higher EMG activity patterns when compared to CG. For the masticatory performance during chewing of peanuts and raisins, the ZIG showed higher EMG mean values when compared to CG. CONCLUSIONS: The zygomatic implant promoted an active response of the muscle fibers (hyperactivity) during both mandibular posture and chewing conditions, probably due to the absence of periodontal receptors, which play a significant role for preparing a bolus for swallowing

All on Four® fixed implant support rehabilitation: a masticatory function study.

BACKGROUND: Fixed implant-supported prostheses according to All-on-Four® (Nobel Biocare, Goteborg, Sweden) principles have become an accepted treatment modality in totally edentulous patients, whereas the functional effect of this therapy is limited. PURPOSE: The purpose of this study was to evaluate the muscular function of patients totally rehabilitated with All-on-Four. MATERIALS AND METHODS: This study evaluated 63 patients. Twenty-one patients were successfully rehabilitated with maxillary and mandibular All-on-Four (no dropout implants, satisfactory aesthetic and function demands prosthesis), 21 patients were dentate, and 21 were rehabilitated with double complete dentures. Electromyography was carried out during clenching, nonhabitual and habitual chewing, and rest. All values were standardized as percentage of a maximum voluntary contraction. Data were analyzed by ANOVA to compare groups and paired t-test was used for comparison between sides within each group. RESULTS: All groups presented symmetric muscular activity. The All-on-Four and dentate groups had a similar muscles surface electromyography (sEMG) contraction pattern, that is, a higher sEMG activity of masseter than temporalis muscles, differing (p ≤ .05) from those of denture group. Not one statistical difference was found between All-on-Four and dentate groups. CONCLUSION: The muscular function similarity of All-on-Four and dentate patients shows that this treatment concept may be considered as a good option for oral rehabilitation in edentulous patients.

Pilar sobre implante em zircônia: relato de caso clínico / Zirconia implant abutment: a case report

A Odontologia Estética trouxe para a realidade do consultório odontológico atual a mimetização das nuances de cor, texturas e características ópticas para reabilitações realizadas em porcelana. Para que este fato ocorra, é necessário que uma boa parte das características estruturais de um dente natural seja reproduzida. O esmalte dental é reproduzido com sucesso satisfatório através da utilização de técnicas inovadoras e porcelanas de qualidade avançada. A dentina também deve ser reproduzida, e para que isso seja possível em reabilitações sobre implantes surgiu a possibilidade de serem confeccionados pilares em porcelana pura do tipo zircônia. São pilares instituídos com a proposta de oferecer resistência mecânica satisfatória à sustentação de coroas sobre implantes, além da condição estética. Desta forma, descreveu-se o caso clínico que visou a utilização de um implante imediato ativado imediatamente com a utilização de um provisório sobre o implante posicionado na região do dente 22 de uma paciente de 33 anos. Como o objetivo principal do caso foi atingir excelência em estética, optou-se pela utilização de um pilar de zircônia (CONEXÃO@) sobre o implante colocado. Verificou-se, além de benefícios estéticos, saúde gengival na área implantada, pois a zircônia possui biocompatibilidade e filia aos tecidos vivos quando comparada a pilares sobre implantes confeccionados em metal. O caso clínico vem sendo acompanhado com proservação de 7 anos. Conclui-se que a opção da utilização dos novos pilares em zircônia traz para os casos de reabilitação sobre implantes uma resolução mais interessante para os anseios estéticos e funcionais dos pacientes da atualidade.

Esthetic Dentistry has brought the reality of current dental mimicking the nuances of color,texture and optical properties for renovations carried out in porcelain. So that this does occur, it is necessary for a good part of the structural characteristics of a natural tooth to be played. The enamel is successfully reproduced satisfactorily by the use of innovative techniques and advanced quality porcelain. Dentin also be reproduced, and for this to be possible in rehabilitation on implants arose the possibility of pillars made of porcelain-type pure zirconia. Pillars are set up with the proposal to provide satisfactory mechanical strength to the support of crowns on implants in addition to the aesthetic condition. Thus, described the case history which endorsed the use of an implant immediately activated immediately by using a duty on the implant positioned in the region of tooth 22, a patient of 33 years. As the main objective of the case was achieved excellence in aesthetics, it was decided to use a pillar of zirconia (CONEXÃO SISTEMA DE PRÓTESE@) on the implant placed. It was found, and aesthetic benefits, gingival health in the area because the implanted zirconia has biocompatibility and affiliated to the living tissue quite satisfactory when compared to pillars on implants ma de of metal, and it was proved with preservation of 7 years. We conclude that the option of using new pillars in zirconia brings to the cases of rehabilitation on implants a resolution much more interesting for the aesthetic and functional desires of patients.

Using overdenture on implants and complete dentures: effects on postural maintenance of masticatory musculature

Aims: Thanks to advances in osseointegration, oral rehabilitation specialists have had the option of using implants to improve retention and stability in treatments with complete dentures. This study compared the masticatory muscle electromyographic activity in implant-supported overdenture wearers, complete denture wearers and dentate individuals. The electromyographic activity of the right and left masseter muscles, and the right and left anterior temporalis muscles was analyzed in 10 implant-supported overdenture wearers (Group 1), 10 conventional complete denture wearers (Group 2), and 10 dentate individuals (Group 3), with mean age of 65 years, at rest and during postural position maintenance. The analysis was performed using the MyoSystem-Br1 electromyographer with differential active electrodes. Analysis of variance tests were carried out to compare the groups and muscles and revealed different electromyographic values that were statistically significant at 1% significance level. Duncan’s pos-hoc test showed that Group 3 presented the smallest values (pd”0.01). The electromyographic contraction pattern was similar between Groups 1 and 3 (p>0.01), and hyperactivity of anterior temporalis muscles was observed in Group 2 (pd”0.01). Conclusions: dentate individuals had smaller electromyographic values of masticatory muscles and the overdenture use caused electromyographic contraction patterns similar to those of dentate individuals in both positions.

Evaluation of molar and incisor bite force in indigenous compared with white population in Brazil.

The purpose of this study was to determine maximum bite force in molar and incisor regions in young Brazilian indigenous individuals, who have had a natural diet since birth, and compare the sample with white Brazilian individuals. To do this, individuals were paired one-to-one (same weight, height, and Class I facial pattern). A secondary purpose was to elucidate the relation between bite force and gender in both populations. Eighty-two Brazilians took part in this study. Participants were aged between 18 and 28 years and were divided into two groups: 41 Xingu indigenous individuals and 41 white Brazilian individuals, with 28 men and 13 women in each group. The inclusion criteria were: having complete dentition; normal occlusion; no neurological, psychiatric or movement disorders; no reports of toothaches; having satisfactory periodontal health; absence of large facial skeletal alterations (typical Class II and Class III individuals); and no previous treatments using occlusal splints. To measure maximum bite force, a digital dynamometer model IDDK (Kratos-Equipamentos Industriais Ltda, Cotia, São Paulo, Brazil) was used, with a capacity of 1000N, adapted for oral conditions. Assessments were made in the first molar (right and left) and central incisive regions. Results reveal that mean maximum bite forces in indigenous individuals of the right molar is 421N, left molar 429N and incisor region is 194N and for white individuals of the right molar is 410N, left molar 422N and incisor region is 117N. Comparing indigenous with white individuals, maximal bite force showed a tendency of being greater in the indigenous group. It was observed that the incisor region showed statistical significance (p<0.0005) but no significance was observed in the molar region. Moreover, indigenous men showed the highest bite force values.

The effect of age on the function of the masticatory system--an electromyographical analysis.

BACKGROUND: Old age is the last stage of human life and, unfortunately, the ageing rhythm of the oral cavity and masticatory system seems to be rather accelerated. Hence, there is a reduction in the amount of food ingested, establishing the imbalance of nutritional phenomena. OBJECTIVE: To assure a better quality of life for the elderly, it is necessary to understand their masticatory system. MATERIALS AND METHODS: An electromyographical analysis of the masticatory system in 10 individuals aged between 60-75 years (group 1) and 10 between 23-30 years old (group 2) was carried out. The analysis was performed using a MyoSystem-Br1 electromyographer with differential active electrodes. The test was registered during positioning and functional conditions, such as chewing, and the muscles assessed were the temporalis and masseter. Data were normalised by maximum voluntary contraction (MVC), and the results were analysed statistically using independent t-test during the comparison between groups. RESULTS: Statistical significance (p < or = 0.05) was found in the analysis of various activities, in which the elderly showed greater electromyographical activity values relative to their MVC during the different mandibular positions, such as left laterality. While the elderly subjects revealed values of 30% relative to their MVC, the young revealed 10%. However, during masticatory activities, the elderly revealed values of up to 79%, and the young of 108%, relative to their MVC, such as when they are chewing peanuts. CONCLUSION: It could be concluded that the elderly show hyperactivity of masticatory musculature during posture maintenance and a slight hypoactivity of this musculature during chewing when analysed side by side with young individuals.

Electromyographic analysis of the orbicularis oris muscle in oralized deaf individuals

A eletromiografia, como método de estudo, tem sido bastante utilizada e vem contribuindo para elucidar o desempenho da musculatura peribucal em vários processos fisiológicos como a mastigação, deglutição e fala, e é um instrumento importante na análise das bases fisiopatológicas das mudanças que ocorrem nesta musculatura. Muitos trabalhos têm sido conduzidos em pacientes com deficiência auditiva e de fala, mas nenhum deles avaliou a musculatura responsável pela fala. Este estudo comparou medidas eletromiográficas dos fascículos superior e inferior do músculo orbicular da boca em indivíduos portadores de deficiência auditiva neurossensorial profunda (surdos) com indivíduos clinicamente normais (ouvintes). A análise eletromiográfica foi realizada em 20 indivíduos, de ambos os sexos, com idade média de 18,5 anos, divididos em dois grupos: o primeiro grupo constituído por 10 indivíduos portadores de deficiência auditiva neurossensorial profunda bilateral e o segundo por indivíduos clinicamente normais. Cinco condições clínicas foram avaliadas: sucção, sopro, projeção e compressão labial e emissão da sílaba "Pa". Verificou-se que os pacientes surdos apresentaram hiperatividade muscular em todas as condições clínicas analisadas, e que o fascículo inferior do músculo orbicular da boca apresentou os níveis mais altos de atividade eletromiográfica, sugerindo a necessidade de um tratamento fonoaudiológico, com enfoque em motricidade oral.

Effect of denture quality on perioral muscle activity during speech / Efeito da qualidade da dentadura no músculo peribucal durante a atividade da fala

This study aimed to evaluate the electromyographic activity of the orbicularis oris muscle in patients using clinically inadequate conventional dentures before and after the insertion of clinically acceptable new convencional denture. Six patients, using inadequatedentures, were asked to pronounce the syllables PAH, BAH, MAH, SAH, FAH, VAH, MEE and the word MISSISSIPI. During this activity, we analyzed the Electromyographic activity of the orbicularis oris muscle. This was done before and after changing the inadequate denture for a acceptable new denture. A K6-I EMG Light Channel SurfaceElectromyograph was used (Myo-tronics Co). Results were analyzed by repeated measures ANOVA, with 3 sources of variation (Syllables, Muscles, and Clinical Conditions). ANOVA revealed higher electromyographic readings in the mandibular fascicle of the orbicular oris muscle, as compared to those of the maxillary fascicle (F = 79.02;P<0.01). The comparison regarding clinical conditions indicated higher electromyographic values after insertion of acceptable new denture (F= 32.64; P<0.01). Clinical condition after the implantation of a new well-adapted complete denture revealed higher electromyographicactivity levels than those measured with the use of maladapted complete dentures

Electromyographic analysis of the orbicularis oris muscle in oralized deaf individuals.

Electromyography has been used to evaluate the performance of the peribuccal musculature in mastication, swallowing and speech, and is an important tool for analysis of physiopathological changes affecting this musculature. Many investigations have been conducted in patients with auditory and speech deficiencies, but none has evaluated the musculature responsible for the speech. This study compared the electromyographic measurements of the superior and inferior fascicles of the orbicularis oris muscle in patients with profound bilateral neurosensorial hearing deficiency (deafness) and healthy volunteers. Electromyographic analysis was performed on recordings from 20 volunteers (mean age of 18.5 years) matched for gender and age. Subjects were assigned to two groups, as follows: a group formed by 10 individuals with profound bilateral neurosensorial hearing deficiency (deaf individuals) and a second group formed by 10 healthy individuals (hearers). Five clinical conditions were evaluated: suction, blowing, lip projection and compression, and production of the syllable "Pa". It was found that the deaf patients presented muscle hyperactivity in all clinical conditions, and that the inferior fascicle of the orbicularis oris muscle showed higher electromyographic activity rates, suggesting the need for a hearing-speech treatment with emphasis on oral motricity.

Autogenous tooth fragment reattachment--association of periodontal surgery and endodontic and restorative procedures: a case report.

The occurrence of dental traumas in adult patients is on the rise, according to the literature, and require correct and adequate treatment specific to each fracture in order to preserve the remaining tooth. In this article, two different fracture cases are reported. Based upon these cases, it may be concluded that there are situations that require the clinician to have a multidisciplinary vision of the different dental specializations in order to effectively treat the patient.