Electromyographic Activity Of Masticatory Muscles Research Articles

Electromyographic Evaluation of Masticatory Muscle Activity in Individuals with and without Cleft Lip/Palate: A Systematic Review and Meta-analysis.

This study aims to systematically review and meta-analyze the electromyographic activity of masticatory muscles in cleft palate and non-cleft patients, and identify influencing factors. Systematic Review and Meta-analysis. Patients with cleft lip/ palate. Patients without CL/P. Electrical activity of masseter and temporalis muscles at rest and during peak activation. After a comprehensive search in MEDLINE, Web of Science, EMBASE, Scopus, and Cochrane's CENTRAL up to December 2022, without language or date restrictions. Eligible trials were selected based on the PECO question and assessed for bias using Cochrane's ROBINS-E tool. Eight clinical trials with 474 participants were included in the review. Then relevant data was extracted from included studies using customized forms. A random-effects meta-analysis was performed to combine the results of the studies, meta-analyses showed that CL/P patients have elevated electrical activity in the masseter (P = .01) and temporalis (P = <.01) muscles at rest compared to non-cleft control patients. During maximum bite force, cleft patients exhibited a statistically significant decrease in electrical activity in both the masseter (P = .03) and temporalis (P = <.01) muscles. According to our meta-analysis, cleft patients exhibited increased resting muscle activity but decreased activity during maximum bite force, indicating reduced efficiency of masticatory muscles compared to non-cleft patients. These differences can be attributed to anatomical variations, compensatory mechanisms, and previous treatments.

Occlusal function and electromyographic activity of masticatory muscles in skeletal Class III patients with different patterns of mandibular asymmetry.

Although jaw asymmetry is commonly seen in skeletal Class III patients, its correlation with occlusal function and masticatory muscle activity has not been fully elucidated. The purpose of this study was to investigate the occlusal function and masticatory muscle activity in skeletal Class III patients with various patterns of mandibular asymmetry. Forty-two patients and 10 normal participants were examined. The patients were categorised into three groups. Groups 1 and 2 exhibited menton and ramus deviation to the same side. Menton deviation was larger than ramus deviation in Group 1, whereas Group 2 showed the inverse relation. Group 3 patients showed menton and ramus deviation in opposite directions. Occlusal contact area (OCA), relative bite force (RBF), and temporalis anterior (TA) and masseter muscle (MM) activity at maximum clenching were measured using T-Scan Novus system and Bio-EMG-III. Statistical analysis was performed using the t-test, one-way analysis of variance with Bonferroni correction and Spearman correlation (α=.05). Compared with normal participants, the patients had smaller OCA and greater asymmetry in the distribution of masticatory muscle activity. Greater ramus deviation was associated with smaller OCA in Group 1 but with larger OCA in Group 3. In Group 1, greater menton deviation was related to stronger TA activity on the non-deviation side. In Group 2, greater ramus deviation was related to stronger MM activity on the deviation side. Deviation of the menton and ramus was individually related to OCA and masticatory muscle activity, and this relationship varied according to the pattern of mandibular asymmetry.

Electromyographic Activity of Masticatory Muscles in Asymptomatic Young Adults

Introduction: The masseter and the anterior part of the temporalis are the muscles mainly responsible for the clenching function. Clenching patterns and the activity of these muscles are not expected to differ between male and females, nor between different occlusal classes. Objective: The aim of this study was to determine whether the activity index of the masseter and temporalis muscles is related to occlusal class and gender. Methods: This study involved 145 eighteen-year-old Caucasian volunteers who underwent surface electromyography. The sEMG was analyzed at the moment of 100% occlusal contact. Occlusal classes were determined used plaster casts. Results: The Class I group contained 34 males and 63 females, while Class II had 11 males and 25 females. Comparison of the AcI data showed an insignificant relation between the genders in the activity indices of Classes I and II. Significant relation between male gender and predominance of the masseter muscles, as well as between female gender and an almost equal balance between the muscles, though with a tendency towards a predominance of the temporalis anterior. Conclusion: The activity of masseter muscles during clenching the teeth is bigger in the male than in the female group. Activity index is related to gender.

Electromyographic values of masticatory muscles in middle-aged dentate patients

Introduction. Surface electromyography has proven to be a useful instrument for the assessment of success rate for different dental treatments. However, due to numerous variables that may influence the data like age, gender, fat tissue thickness etc. it is necessary to adjust the obtained values to a reference group with the same parameters. Material and methods. A number of 33 patients were included in the study (21 women and 12 men) aged between 43-67 years old (mean 54± SD1.26). Surface electromyography of masticatory muscles was used in these patients to assess the average value in a time span and overlapping coefficients. Totally 10 parameters from each patient were recorded: TAL, TAR, MML, MMR, PocTA, PocMM, BAR, Asym, TORS, Impact. Data were stored in an Excel spreadsheet and then analyzed statistically using RStudio software. Results. Based on the results of our study, the main EMG activity indices in middle-aged Moldavian individuals had the following values: for the left temporalis (TAL) was 42 µV, median 18.8 with a minimum of 3.8 and a maximum of 190 µV. For the right temporalis (TAR) the mean was 51.4 µV, median – 32.9, a minimal value of 7.9 and a maximum of 248 µV. The left masseter had a mean of 48.7 µV, median 12.3, a minimal value of 1.5 and a maximum value of 439 µV. The right masseter had a mean of 42.1 µV, a median of 16.3, minimum value 11.4 and maximum 243 µV. The overlapping coefficients deviated with 20.5% from the normal range provided by the manufacturer. Conclusions. Electromyographic activity of masticatory muscles in healthy patients can be used for comparison with patients that had various dental treatment but have the same age, gender, ethnicity, etc. The overlapping coefficients did not perfectly match in the normal range provided by manufacturer even if these subjects had previously minimum dental procedures.

Electromyographic Activity of Masticatory Muscles in Subjects with Juvenile Idiopathic Arthritis: A Case—Control Study

The aim of this study was to evaluate the effect of juvenile idiopathic arthritis (JIA) on the activity of masticatory muscles using surface electromyography (sEMG). Forty-one JIA subjects (ten males, thirty-one females; average age 13 years ± 3) and thirty-two healthy control subjects (twenty-seven females, five males; average age 14 years ± 2) were recruited. sEMG of anterior temporalis (TA), masseter (MM), and sternocleidomastoid (SCM) muscles was performed by using the occlusal contact analyzer software called Teethan (BTS S.p.A., Garbagnate Milanese, Milan, Italy). Comparisons between groups were assessed with unpaired t-tests for non-normally distributed data and with Mann–Whitney U tests for normally distributed parameters. The JIA group showed a significant increased percentage overlapping coefficient of TA (POC TA) (p = 0.01) and impact index (IMP) (p = 0.003). No significant differences were observed for the POC MM, POC SCM, percentage overlapping coefficient between posterior and anterior teeth contact (BAR), the torsion index (TORS), and the asymmetry index (ASIM). Masticatory muscles seemed to be slightly affected by JIA. sEMG could be an effective aid in the early clinical detection of TMJ involvement in JIA. Further research is needed to confirm its validity.

Evaluation of Electromyographic Activity of Masticatory Muscles in Adults with Posterior Crossbite.

Introduction There is evidence that patients with posterior crossbite (PXB) have neuromuscular changes in the masticatory muscles. However, up to the present time, the relationship among these changes on the electromyographic activity of the masticatory muscles is still unclear. Objective To systematic review the available literature on the electromyographic activity of masticatory muscles in adults with PXB. Methods Between August 22 and September 9, 2020, we searched the following seven electronic databases: PubMed, EMBASE, Web of Science, Cochrane Library, SciELO, LILACS, and Scopus. No restrictions were applied regarding the language and year of publication. This systematic review was registered in the Prospective Register of Systematic Reviews (PROSPERO - CRD42020205057) database and conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. After data selection and extraction, the methodological quality of the selected studies was conducted independently by two reviewers, using two different evaluation tools. Results 6957 records were initially located after the search process. In the end, eight papers were selected. Most studies were classified as having average to low methodological quality and moderate to high risk of bias. Based on the available evidence, adult patients with PXB have electromyographic activity changes in the masticatory muscles when compared with individuals without PXB. Moreover, adult patients with unilateral posterior crossbite (UPXB) have asymmetrical electromyographic activity when the crossbite side is compared with the noncrossbite side. Conclusion Despite the lack of studies with high methodological quality, electromyographic evaluation of masticatory muscles should be considered in the diagnosis and in the orthodontic treatment plan of patients with PXB. Prospective studies with a higher sample size and follow-up time, conducted using a rigorous scientific methodology, are necessary to reach a more reliable conclusion.

Electromyography-Guided Adjustment of an Occlusal Appliance: Effect on Pain Perceptions Related with Temporomandibular Disorders. A Controlled Clinical Study.

Background: The purpose of this study is to evaluate the effect of an electromyography-guided adjustment of an occlusal appliance on the management of Temporomandibular disorder-related pain. Methods: Data from 40 adult patients (20 males and 20 females), who underwent treatment with occlusal appliances, were recorded. A total of 20 appliances were adjusted according to electromyographic data (group 1), while the others were adjusted by a clinical conventional procedure (group 2). Muscle pain to palpation, pain during articular movements and headache were recorded by a VAS score (from 0 to 100) before the beginning of treatment (T0), at T1 (4 weeks) and T2 (8 weeks). Results: Results showed a reduction of pain in both groups, with a better trend for group 1, where better results were achieved at T1 and maintained stability at T2, with an improved mean value regarding all parameters studied. After 8 weeks, only small recurrences started to occur in muscle pain to palpation in group 2. Conclusions: An occlusal appliance seems to be able to achieve a clinical improvement of Temporomandibular disorder (TMD)-related pain and headache, independently from the adjustment procedure adopted. However, the use of a surface electromyographic activity of masticatory muscles (sEMG) device as an aid in the calibration procedure seems to allow a better trend because the improvement of symptoms was obtained before, after the first four weeks, with an improvement in percentages of all the variables investigated. While the conventional procedure obtained later the improvement.

Comparison of Simultaneously Recorded Computerized Occlusal Analysis and Surface Electromyographic Activity of Masticatory Muscles Between Patients with Unilateral TMD.

To investigate the relationships among occlusion time, disclusion time, occlusal load distributions, and simultaneous electromyographic (EMG) recordings of the anterior temporalis (TA) and masseter (MM) muscles during centric and lateral movements in patients with unilateral temporomandibular disorder (TMD) pain and in asymptomatic control subjects. Twelve healthy and 13 unilateral TMD subjects participated in the present study. The diagnosis of unilateral TMD was verified with vibrational analysis of the temporomandibular joints (TMJs) using the BioJVA (BioResearch Associates). Simultaneous computerized digital occlusal analysis using T-Scan III (Tekscan) and EMG activity of the MM and TA muscles using BioEMG III (BioResearch Associates) were performed in the intercuspal position and in right and left excursive movements. In intercuspal and lateral movement records, EMG activity of the masticatory muscles, occlusion time, disclusion time, and bite force distribution ratios were evaluated. No statistically significant differences were observed in occlusion time, disclusion time, or EMG activity of the MM and TA muscles between controls and patients with unilateral TMD in the intercuspal position. In unilateral TMD patients, disclusion time of the painful side was significantly higher than in the control group and compared to the nonpainful side (P < .05). Bite force distribution of the balancing side in TMD patients was shown to be statistically significantly higher values than in control subjects. EMG activity of the working-side TA muscle was higher than the nonworking side TA in controls and in the nonpainful side of TMD patients (P < .05). However, EMG activity of both the MM and TA muscles did not show a difference between the working side and nonworking side in unilateral TMD patients. In the intercuspal position, there was no difference in occlusion time, distribution of force, or EMG activity of the masticatory muscles observed between the control group and unilateral TMD pain patients. However, in lateral movements, the painful side of the unilateral TMD patients revealed increased balancing side TA activity, with higher disclusion time and balancing side force distribution.

Effect of manual therapy on pain and electromyographic activity of masticatory muscles in patients with temporomandibular disorders

Background: Temporomandibular disorders (TMD) are disorders of multifactorial origin that affect the temporomandibular joint and/or masticatory muscles. The TMD can generate compensations where physical therapy acts through myofascial releases and joint mobilizations to restore functionality. Objective: To verify the effects of manual therapy techniques on pain and electromyographic activity (EMG) of masticatory muscles in TMD patients. Methods: This is a quasi-experimental study composed of 10 subjects with TMD and 10 healthy subjects who underwent a session of myofascial release, joint mobilization and digit-pressure on the masticatory and cervical muscles. Pain levels and electromyographic activities of the temporal and masseter muscles were bilaterally assessed during the following situations: (1) Maximum Occlusion and (2) Chewing in the right and the left side with chewing gum. Data analysis was performed using BIOMEC-SAS software, in which the data were filtered with a 4th order Butterworth bandpass filter with 20-400hz and normalized as a percentage of maximum occlusion. Data were divided into homolateral and contralateral muscles alongside chewing. EMG variables were compared by factorial ANOVA, and pain by dependent t-test. Results: TMD patients had pain level reduction during maximum occlusion (Pre:4.55±2.2; Post:2.55±1.6; p=&lt;0.001), right chewing (Pre:2.3±2.16; Post:0.4±0.69; p = 0.02) and left chewing (Pre: 1.0±1.15; Post:0.10±0.31; p = 0.05). There was no effect of manual therapy techniques on the EMG activity bilaterally of the temporal (p = 0.617) and masseter (p = 0.926) muscles during chewing. Patients with TMD had higher EMG activities during chewing on the homolateral temporal (p = 0.001) and masseter (0.004) muscles compared to subjects without injury. Conclusion: Manual therapy techniques reduced pain level in TMD patients. No changes in EMG activity were observed after manual therapy techniques. Finally, the study provides evidence of the influence of manual therapy techniques on short-term pain.

Are occlusal contact area asymmetry and masticatory muscle activity asymmetry related in adults with normal dentition?

ABSTRACTObjective: To examine whether asymmetry in the area of occlusal contact and near contact (ACNC) and asymmetrical masticatory muscle electromyographic activity are correlated in healthy dentate adults.Methods: Ninety-one healthy subjects with full dentition were included. Seven levels of ACNC were registered, and the asymmetry indexes (AsI) for each level of ACNC (AsI-ACNC) were determined. Surface EMG was used to record bilateral anterior temporalis activity and masseter muscle activity. The AsI for the anterior temporalis, masseter, and the combination of both muscles were calculated.Results: Pearson’s correlation analysis revealed all levels of AsI-ACNC were significantly, negatively correlated with the AsI of the anterior temporalis and the combination of both muscles (p < 0.05), but not the AsI of the masseter muscle (p > 0.05).Conclusion: The side with greater ACNC has significantly lower anterior temporalis activity and combined anterior temporalis and masseter muscle activity on the ipsilateral side.

Understanding the role of osteoarthrosis on electromyographic activity of masticatory muscles and quality of life.

BackgroundOsteoarthrosis is a severe, evolutionary, chronic, and limiting disease that influences on quality of life, as it affects synovial joints and promoted degradation of hyaline articular cartilage. We sought to determine if electromyographic activity of the masticatory muscles and quality of life are negatively impacted by osteoarthrosis. Material and MethodsA sample of 72 participants between 40 and 70 years old diagnosed with osteoarthrosis were selected. Forty-eight participants met the inclusion criteria of this study and were divided into two distinct groups: with osteoarthrosis (n=24) and without osteoarthrosis (n=24). Electromyographic activity of the masseter and temporalis muscles (mandibular rest, right laterality, left laterality, protrusion, and dental clenching in maximal voluntary contraction) and quality of life measurements were used. Electromyographic activity was used to analyze muscle activation patterns. OHIP-14Br and SF-36 questionnaires determined the quality of life. ResultsThe participants with osteoarthrosis presented significant greater electromyographic activity (p≤0.05) at rest for the right temporal muscle (p=0.04), maximum voluntary contraction for the left masseter muscle (P=0.04), repercussions of oral conditions on quality of life by the sum of OHIP-14 (p=0.002), and a statistically significant difference was found in all subgroups of the SF-36 scale between the subjects with and without osteoarthrosis (p≤0.001). ConclusionsPeople with osteoarthrosis have changes in electromyographic activity of the masticatory muscles and quality of life compared to healthy participants. Key words:Electromyography, quality of life, bone diseases.

Autologous Hematopoietic Stem Cell Therapy of the Subjects with Systemic Sclerosis: Electromyographic Results of the Masticatory Muscles.

Musculoskeletal system impairment is a major cause of functional alterations in subjects with systemic sclerosis. Autologous hematopoietic stem cell therapy (AHSCT) may have an important role in the treatment functional of systemic sclerosis patients. The aim of this pilot study was to assess whether AHSCT interferes with the electromyographic activity of the masseter and temporalis muscles of subjects with systemic sclerosis. Before transplantation, seven subjects with systemic sclerosis (mean age [± SD], 40.1 ± 9.6 years) underwent electromyographic analysis of the masseter and temporalis muscles in mandibular tasks at rest, right and left laterality, protrusion and maximum voluntary contraction. Two months after AHSCT, the subjects re-evaluated using the same methods. Data were analyzed using the repeated-measure test, with p&lt;0.05 considered to be statistically significant. Two months after AHSCT, there was reduction in normalized electromyographic activity in the dental clenching in maximal voluntary contraction, with significant differences, for the left temporal muscle (p=0.04). AHSCT in subjects with systemic sclerosis promotes alterations in stomatognathic system function, especially those related to electromyographic activity of masticatory muscles.

Cervical spine range of motion, posture and electromyographic activity of masticatory muscles in temporomandibular disorders

Abstract Introduction: Temporomandibular joint disorders (TMD or TMJD) involve clinical problems and symptoms affecting the temporomandibular joint (TMJ) and associated structures. The temporomandibular joints are anatomically connected to the cervical region, where cervical spine movements occur simultaneously to masticatory muscle activation and jaw movements. Objective: Our study sought to assess the relationship between the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), surface electromyography (sEMG) of the masticatory muscles, posture and cervical flexibility in women with TMD. Method: Fifty women with an average age of 27.0 ± 6.37 years, diagnosed with TMD according to RDC/TMD, were assessed for craniocervical posture, cervical flexibility and sEMG of the masticatory muscles. Results: There were no differences in jaw function limitations, depression, pain level and its interference in work ability and daily activities, posture and sEMG between TMD diagnoses or between muscle classification (p &gt; 0.05). Depression scores were higher among participants with biarticular dysfunction (p = 0.023). The group with bruxism exhibited a higher pain level at assessment (p = 0.001) and a greater reduction in work ability (p = 0.039). Subjects with muscular and mixed TMD showed less cervical rotation to the right when compared with those with articular TMD. Conclusion: There was no difference in posture or sEMG values for TMD diagnoses, joint and muscle dysfunctions and the presence of bruxism. Muscle dysfunction is associated with reduced cervical rotation to the right. Jaw function limitations did not interfere in posture or sEMG and depression was associated with pain.

Effect of osteoporosis on the electromyographic activity of masticatory muscles (masseter and temporalis) in edentulous patients after rehabilitation with complete dentures

Effect of osteoporosis on the electromyographic activity of masticatory muscles (masseter and temporalis) in edentulous patients after rehabilitation with complete dentures

EMG COMPARISON BETWEEN MASTICATORY MUSCLES WHEN USING NARROW DIAMETER IMPLANT ASSISTED MANDIBULAR OVERDENTUES

INTRODUCTION: One of the primary objectives of complete dentures is to restore masticatory function in people who have lost their natural teeth. Patients wearing conventional complete denture (CD) often complain of instability of the mandibular denture leading to a feeling of insecurity, inefficient mastication, and overall dissatisfaction with the prosthesis. Implant mandibular overdentures (IOD) constitute a secure therapeutic alternative, affording a great patient’s satisfaction and masticatory efficiency. The most common problem in implant dentistry is the presence of insufficient bone volume to receive the conventional size of dental implants. The 2-pieces narrow diameter implants were introduced into the market combining the undisturbed healing period required for proper osseointegration and the avoidance of time, cost and morbidity of extensive surgeries for bone augmentation. OBJECTIVES: The aim of the current work was to evaluate and compare the electromyographic (EMG) activity of masseter and anterior temporalis muscles when using three different treatment protocols i.e. (conventional CDs, two and four IODs). MATERIALS AND METHODS: Eight completely edentulous patients were selected from the prosthetic department, Faculty of dentistry, Alexandria University. Implant mandibular assisted overdentures were constructed for each patient using narrow diameter implants and delayed loading protocol. EMG activity of masseter and anterior temporalis muscles during habitual chewing and maximal voluntary clenching were recorded for each of the studied patients in the three different treatment protocols. RESULTS: EMG activity of masseter and anterior temporalis muscles of IOD was significantly lower with conventional CD than with IOD. Patients with four IOD showed higher EMG activity of masticatory muscles and better function compared to two IOD. Masticatory muscles activity during clenching was significantly higher than during chewing. CONCLUSIONS: It was concluded that IODs have great masticatory efficiency when compared to CD. Implants number affect masticatory efficiency and muscle activity in cases of severely resorbed mandibular ridge.

Revisited relationships between probable sleep bruxism and clinical muscle symptoms

ObjectivesSleep bruxism (SB), characterized by repetitive jaw-muscle activity during sleep, is often suggested as a cause of temporomandibular disorders (TMD), orofacial pain, and headache. This study aimed to challenge the relationship between jaw-muscle electromyographic (EMG) activity during sleep and jaw muscle symptoms including pain by modulation of the levels of EMG activity. Contingent electrical stimulation (CES) using a portable single-channel EMG device was applied at different stimulus intensities to inhibit jaw muscle activity. Materials and methodsSixty probable sleep-bruxers, screened and confirmed by a 2-week use of a portable EMG device, were randomly allocated into one of 3 groups (High/Low/Placebo CES). At baseline and after 2 weeks CES intervention, the participants were asked to score pain intensity, as well as unpleasantness, fatigue, tension, soreness and stiffness in their jaw muscles, on 0–10 numerical rating scales (NRS). ResultsOnly in the High CES group, the number of EMG events/hour was significantly decreased (P = 0.024). Although the NRS scores of pain did not change, interestingly the NRS scores of unpleasantness (P = 0.037), tension (P < 0.001) and soreness (P = 0.004) in the High CES group and tiredness (P = 0.002) and soreness (P = 0.006) in the Low CES group were significantly decreased after the CES intervention compared to baseline. ConclusionHigh intensity CES demonstrated inhibitory effect on masticatory muscle EMG activity during sleep and was associated with significant decreases in jaw muscle symptoms (unpleasantness/tiredness/soreness) but not pain responses. These findings challenge the traditional concept that probable sleep bruxism is directly related to pain but appears related to more unspecific muscle symptoms.

Chewing efficiency and electromyographic activity of masticatory muscles with two different system attachments with lower overdentures

Chewing efficiency and electromyographic activity of masticatory muscles with two different system attachments with lower overdentures

Electromyographic activity of masticatory muscles in elderly women - a pilot study.

ObjectivesTo evaluate the effect of age and chosen factors related to aging such as dentition, muscle strength, and nutrition on masticatory muscles electromyographic activity during chewing in healthy elderly women.BackgroundWith longer lifespan there is a need for maintaining optimal quality of life and health in older age. Skeletal muscle strength deteriorates in older age. This deterioration is also observed within masticatory muscles.MethodsA total of 30 women, aged 68–92 years, were included in the study: 10 individuals had natural functional dentition, 10 were missing posterior teeth in the upper and lower jaw reconstructed with removable partial dentures, and 10 were edontoulous, using complete removable dentures. Surface electromyography was performed to evaluate masticatory muscles activity. Afterwards, measurement of masseter thickness with ultrasound imaging was performed, body mass index and body cell mass index were calculated, and isometric handgrip strength was measured.ResultsIsometric maximal voluntary contraction decreased in active masseters with increasing age and in active and passive temporalis muscles with increasing age and increasing body mass index. In active masseter, mean electromyographic activity during the sequence (time from the start of chewing till the end when the test food became ready to swallow) decreased with increasing age and during the cycle (single bite time) decreased with increasing age and increasing body mass index. In active and passive temporalis muscles, mean electromyographic activity during the sequence and the cycle decreased with increasing age, increasing body mass index, and loss of natural dentition. Individuals with natural dentition had significantly higher mean muscle activity during sequence and cycle in active temporalis muscles than those wearing full dentures and higher maximal activity during cycle in individuals with active and passive temporalis muscles than in complete denture wearers.ConclusionDecrease in electromyographic activity of masticatory muscles in elderly women is related to age, deterioration of dental status, and body mass index.

Variation of Occlusal Contacts and Activity of Masticatory Muscles, In Relation to Increasing the Capacity of Movement of the Cervical Spine after Thrust Maneuver

The present study was carried out, to verify the immediate influence, not in the long term, on a sample of 90 asymptomatic (28 men 62 women), of the increased movement of the cervical spine on dental contacts. With an analogic inclinometer the breadth of the excursions of the cervical rachid was measured, it was ran a test hasassessing digital dental contacts and the electromyographic activity of masticatory muscles (Teethan), the subjects were manipulated at the neck, with low amplitude high speed technique (HVLA). After handling the unblock, the movement of the cervical spine was measured again as well as the dental contact. All subjects have had an increase of the excursions of the cervical spine and a variation of occlusal contacts after the manipulation. The work documents, how the unlocking of the cervical spine not always brings to advantages on the dental occlusion. In fact, it creates, as an overall concept, a variation and a consequent mandibular and contacts repositioning reaction. It modifies the occlusal adaptation of the subject, in some cases improving it, in others in a pejorative sense, confirming the close relationship between the two systems. There is a direct relationship between the mandibular barycenter and flax/extension, the asymmetry and the inclination between the torsion and the rotation of the column. To the decrease or increase of a specific cervical movement there is a specific occlusal orientation. The state of function of the column appears to influence the occlusion and vice versa. After the trust of the cervical spine the 55.5% of the cases got worse, 8.8% did not have variations, 35.5% had improved. In light of these results, the dentist who is facing rehabilitation procedures of the occlusion (orthodontic and / or prosthetic in particular), should take account of this intimate relation and consider a preventive control and treatment of the cervical spine before these therapies, to avoid that the variation of the cervical neuromotor ability, alter the stability and the occlusal references programmed or already obtained.

Порівняльний аналіз електроміографічної активності жувальних м’язів у осіб з ортодонтичною патологією та осіб з ортогнатичним прикусом

The analysis of bioelectric activity of masticatory muscles, as well as such characteristics as their symmetry and synergy is recommended to determine the degree of functional disorders of these muscles. The objective: to conduct a comparative analysis of electromyographic activity of masticatory muscles in patients with orthodontic disorders and those with orthognatic bite. The materials and methods: a total superficial electromyography of m. Masseter and the front part of the m. Temporalis in 87 people with the presence of orthodontic pathology and 22 persons with orthognatic bite at compression on teeth and cotton rolls. The results: it is determined the reduction of the average amplitude parameter of the same name muscles and ratio indexes of the average amplitude of the muscles of the right and left side at compression on rolls compared to the compression on teeth in both observed groups. Statistically significant differences form. Masseter were not found when comparing the coefficient of the same name muscles coordination between the groups, as opposed to the following measures for m. Temporalis (p&lt;0,05). Conclusion: The condition of occlusion appears on the EMG results, which have been confirmed by us in this study. At orthodontic pathology the EMG results should be evaluated together with the results of other studies (the diagnostics of TMD, clinical functional analysis, TMJ study). It is necessary to conduct further research in this area in order to highlight and explain some causes of the appearance of masticatory muscles asymmetry, its connection with orthodontic pathology, its impact on the course of the disease and the results of orthodontic treatment.