Influence of different upper cervical positions on electromyography activity of the masticatory muscles

Musculoskeletal differences in the craniomandibular region of children and adolescents with and without bruxism: A comparative study

OBJECTIVE

To analyse the relationship between bruxism and musculoskeletal parameters of the cervical and mandibular regions in children and adolescents.

METHODS

A comparative cross-sectional study was performed with subjects from 6 to 16 years. Subjects were divided into bruxism (any type) and control groups. Descriptive data, jaw opening, upper cervical spine mobility, myofascial trigger points (MTPs) and muscular tension of the jaw and neck muscles, the activation pattern of neck flexors and activation of Deep Neck Flexors (DNF) were registered and compared between groups.

RESULTS

121 subjects participated in the study. Children and adolescents reporting bruxism showed a significant reduction in the contraction of DNF (p = .034) and the activation ratio (p = .035) compared to controls. Besides, MTPs of both masseters were significantly more frequent in subjects reporting bruxism (p = .001-0.002). No differences were found in other measurements.

CONCLUSION

Bruxism is related to a weaker contraction of DNF, a lower activation ratio, and a higher number of MTPs in masseters.

Pain-free bite force in a healthy population: Within-session test-retest reliability in different sitting positions

BACKGROUND

Pain-free bite force (PFBF) is a promising measure to evaluate bite function in temporomandibular disorders (TMDs), yet the reliability of the measure is unknown.

OBJECTIVES

Establish the (1) within-session test-retest reliability of PFBF in a healthy population for a single and mean of three trials in supported and unsupported sitting; (2) standard error of measurement (SEM) and minimal detectable change (MDC).

METHODS

Thirty healthy participants (n = 15 female, mean [SD] age = 34.4 [11.0] years) completed two sessions (30-60 min apart) comprising three PFBF trials on each side, in both supported and unsupported sitting, to provide data for 60 (30 participants × two sides) test-retest assessments. Test-retest reliability for the first trial and mean of three trials in each position were determined using intraclass correlation coefficients (ICCs), before calculating the corresponding SEM and MDC for males (M) and females (F) respectively.

RESULTS

Within-session reliability was considered excellent for a single trial in supported sitting (ICC = 0.85; SEM M/F = 99/84 N; MDC M/F = 275/232 N) and unsupported sitting (ICC = 0.91; SEM M/F = 72/59 N, MDC M/F = 200/163 N), and for a mean of three trials in supported sitting (ICC = 0.89; SEM M/F = 66/79 N, MDC M/F = 182/220 N) and unsupported sitting (ICC = 0.92; SEM M/F = 64/59 N, MDC M/F = 177/164 N).

CONCLUSION

Single and a mean of three trials in supported and unsupported sitting appear reliable methods to measure PFBF in a healthy population. Testing PFBF using a mean of three trials in unsupported sitting appears superior over other methods though due to higher test-retest reliability, and lower SEM and MDC. Future studies should examine the reliability of PFBF in TMD populations.

The linear intra-articular motions of the temporomandibular joint in individuals with severe forward head posture: A cross-sectional study

BACKGROUND

The cervical vertebrae and the temporomandibular joint (TMJ) may be linked through their common muscles.

OBJECTIVES

The aim of the present study was to compare the linear intra-articular motions of the TMJ between individuals with the normal craniocervical posture (CCP) and severe forward head posture (FHP).

DESIGN

Cross-sectional study.

METHODS

Volunteers (N = 38) were equally assigned to either the severe FHP group or the normal CCP group according to their craniovertebral angle (CVA). The CVA angles greater than 49° were considered as the normal CCP while angles between 44 and 40° were regarded as the severe FHP. The TMJ was imaged at the closed, median, and maximum open positions of the mouth using an ultrasound machine with a 7.5 MHz linear transducer in the sitting position. The best-fitting curve in the contour registration method was employed to measure displacement of the mandibular condyle on the transverse and vertical axes.

RESULTS

The forward displacement of the mandibular condyle in the severe FHP group was significantly (p-value = 0.037) reduced compared to the normal CCP group at maximum open position of the mouth, while no significant difference was revealed at closed (p-value = 0.937) or median open (p-value = 0.699) positions. The perpendicular displacement of the mandibular condyle exhibited no significant (p-value>0.107) difference between groups at any mouth position.

DISCUSSION

The current study demonstrated, for the first time, that severe FHP may impact the intra-articular motion of the TMJ. This study presumed that individuals with severe FHP may encounter a force imbalance in the anterior-posterior direction.

Relationship of temporomandibular joint disorders with cervical posture and hyoid bone position

OBJECTIVE

To evaluate craniocervical posture and hyoid bone position in patients with and without temporomandibular joint disorder (TMD).

METHODS

A total of 113 people were included in the study, including 55 TMD patients and 58 healthy controls. Using lateral cephalograms, the craniofacial, craniocervical, and hyoid bone positions of the participants were evaluated in terms of 27 variables.

RESULTS

There was no significant difference in craniocervical angles between participants with or without TMD. While the Hy-B, Hy-NSL, Hy-NL measurements and FMA (°), AFH (mm) measurements of participants with TMD were lower than the control group, the hyoid angle was greater than the control group.

CONCLUSION

These study findings provide evidence that TMD is not related to craniocervical posture but to the position of the hyoid bone and craniofacial morphology.

The efficacy of orofacial myofunctional therapy in oral dysphagia accompanying temporomandibular dysfunction

OBJECTIVE

Patients with temporomandibular dysfunction (TMD) may develop oral-stage dysphagia (OD) in the chronic phase.

METHODS

This study investigated the effect of orofacial myofunctional therapy (OMT) in individuals with TMD-related OD. Fifty-one patients aged 18-65 years with TMD-related OD were separated into three groups using a simple randomization method: the control group (n = 12) underwent patient education and a home-exercise program; additionally, to an exercise program the manual therapy (MT) group (n = 19) received MT; and the OMT group (n = 20) received the OMT program. MT and OMT were applied in two sessions per week for 10 weeks. The patients were re-evaluated after treatment and at 3 months.

RESULTS

The OMT group showed the most improvement in jaw functionality, swallowing-related quality of life, pain, and dysphagia (p < .05).

DISCUSSION

OMT was superior to MT and exercises alone in reducing dysphagia and improving the swallowing-related quality of life.

Do intra-articular temporomandibular disorders show an association between physical bite function, self-perceived bite limitation and kinesiophobia? A case-control study

BACKGROUND

Little is known about the impact of intra-articular temporomandibular disorders (TMDs) on bite function, or how bite impairments in this subgroup relate to self-perceived bite limitation or kinesiophobia. This presents a challenge to practitioners involved in delivering care.

OBJECTIVES

To determine what bite impairments are associated with intra-articular TMDs, and explore how these impairments relate to self-perceived bite limitations and kinesiophobia.

DESIGN

Observational, case-control study.

METHOD

Sixty participants (n = 30 intra-articular TMDs, n = 30 healthy controls) were recruited via convenience sampling. Bite function was explored using pain-free bite force and bite endurance/steadiness (submaximal bite hold) measures. Self-perceived bite function and kinesiophobia were evaluated via the Patient specific functional scale (PSFS) and the Tampa Scale for kinesiophobia of Temporomandibular disorders (TSK-TMD) respectively. Between-group data were compared and associations between physical bite impairments, self-perceived bite limitation and kinesiophobia were explored in the intra-articular TMD group.

RESULTS

Pain-free bite force was significantly impaired in the intra-articular TMD group (-108N, p < 0.01, d = 0.9), and this impairment demonstrated moderate association with degree of kinesiophobia (p < 0.01, r = -0.4). No significant between-group difference was observed for bite endurance or force steadiness (p > 0.05). No association was observed between pain-free bite force and self-perceived bite limitation, or self-perceived bite limitation and kinesiophobia (p > 0.05).

CONCLUSIONS

Impaired pain-free bite force appears to be an important feature of intra-articular TMDs which should be considered within management. Kinesiophobia may be important to consider when assessing bite function in this subgroup. Future research is needed to guide optimal interventions and inform subsequent management guidelines.

The association between forward head posture and masticatory muscle pressure pain thresholds in patients with temporomandibular joint dissorders: a cross-sectional observational study

OBJECTIVES

Forward head posture (FHP) is common in patients with temporomandibular joint disorders (TMDs); however, whether it contributes to TMD symptoms remains unclear. The aim of this study was to investigate the association between (1) FHP and masticatory muscle pressure pain thresholds (PPTs) and (2) neck muscle and masticatory muscle PPTs.

MATERIALS AND METHODS

A total of 145 patients diagnosed with TMD were recruited between December 2020 and April 2021. Data regarding FHP and neck and masticatory muscle PPTs were collected. FHP was characterized by the craniocervical angle (CVA) measured between the horizontal line through C7 and the line between the tragus of the ear and C7. Patients were divided into either the FHP group (CVA ≤ 51°) or the non-FHP group. Differences in the masseter and temporalis muscle PPTs between the two groups were analyzed using the Mann-Whitney U test. The correlation between the CVA, neck, and masticatory muscle PPTs in all patients was determined by Spearman's correlation analysis.

RESULTS

There were 70 patients in the FHP group and 75 patients in the non-FHP group. No significant difference in masseter and temporalis muscle PPTs was found between the two groups (p > 0.05). No correlation was found between FHP and masticatory muscle PPTs (p > 0.05). A significant association was found between the neck muscle and masticatory muscle PPTs (p < 0.05). The C5-C6 pillar and masticatory PPTs were either moderately (r = 0.435, masseter muscle) or strongly (r = 0.608, temporalis muscle) correlated, while the correlation between the trapezius and masticatory muscles was moderate (r = 0.378, masseter muscle and r = 0.461, temporalis muscle).

CONCLUSION

FHP was not directly associated with masticatory muscle PPTs. Masticatory muscle PPTs were strongly or moderately associated with neck muscle PPTs. Therefore, the presence of neck pain, not the degree of FHP, in patients with TMD is of significance.

CLINICAL RELEVANCE

In TMD treatment, we should pay attention to and actively relieve neck pain.

Effects of breathing reeducation on cervical and pulmonary outcomes in patients with non specific chronic neck pain: A double blind randomized controlled trial

OBJECTIVE

The purpose of this randomized controlled trial was to study effects of breathing reeducation in the treatment of patients with non specific chronic neck pain.

METHODS

A total of sixty eight eligible patients with chronic neck pain were randomly allocated to breathing reeducation (BR) group (n = 34) and routine physical therapy (RPT) group (n = 34). Clinical outcomes were neck pain measured through visual analogue score, cervical active range of motion through CROM device, strength of neck muscles through hand held dynamometer and endurance of neck muscles measured through craniocervical flexion test. The neck disability was measured through neck disability index (NDI) and pulmonary outcomes such as forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FEV1/FVC ratio were measured through Spirolab 4. The outcomes were assessed at baseline and at 4 and at 8 weeks from baseline.

RESULTS

There were significant improvements in the BR group compared with the RPT group (P = 0.002) for cervical flexion, extension (P = 0.029), endurance (P = 0.042), strength of neck flexors (P <0.001), neck extensors (P = 0.034). Likewise there was a significant change in NDI (P = 0.011), FEV1 (P = 0.045), FVC (P <0.001), and FEV1/FVC ratio (P <0.001) in the BR group compared with the RPT group. The cervical side flexion and rotation showed no significant difference in breathing reeducation group with p > 0.05.

CONCLUSION

Breathing reeducation combined with routine physical therapy is an effective treatment in patients with non specific chronic neck pain.

TRIAL REGISTRATION

IRCT 20200226046623N1, https://www.irct.ir/trial/46240.

Cervical Myofascial Pain Is Associated with an Imbalance of Masticatory Muscle Activity

This study aimed to assess the relationship between the occurrence of cervical myofascial pain with active myofascial trigger points (MTrPs) within the upper trapezius muscle and the electromyographic asymmetry index (AsI) of masticatory muscles: temporalis anterior (TA), superficial part of the masseter muscle (MM), and anterior belly of the digastric muscle (DA). The study group comprised 100 subjects (80 women and 20 men) aged 18 to 30 years (mean 23 ± 2.6 years) reporting pain in the neck muscles, diagnosed with myofascial pain with active MTrPs only within the upper trapezius muscle. The control group comprised 60 healthy, pain-free subjects (42 women and 18 men) aged 20 to 30 years (mean 22.8 ± 2.6 years) without MTrPs in the upper trapezius muscle. The palpation measurement, based on the diagnostic criteria of Travell and Simons, was used to diagnose active MTrPs. The masticatory muscle activity was recorded using an 8-channel device for surface electromyography—BioEMG III^TM. Significant differences in electromyographic patterns between the group with MTrPs in the right side of upper trapezius muscle and the control group were observed within resting activity for the AsI TA (MTrPs: 8.64 vs. controls: −3.22; p = 0.001) and AsI MM (MTrPs: 7.05 vs. controls: −2.09; p = 0.018). Controls presented different electromyographic patterns during maximum voluntary clenching with cotton rolls between teeth within masseter muscle compared to the MTrPs group (MTrPs: 9.27 vs. controls: −0.43 vs. p = 0.041). Participants with MTrPs in the left side of upper trapezius muscle presented predomination of left-sided electromyographic patterns at rest within temporalis anterior in comparison to controls (MTrPs: −19.22 vs. controls: −3.22; p = 0.001). MTrPs within the trapezius muscle may be related to asymmetry within the masticatory muscle activity, suggesting that the presence of myofascial pain within the cervical muscles plays a role in the imbalance of the stomatognathic system. A unilateral active MTrPs within the trapezius muscle may increase the sEMG activity on the same side of the temporalis anterior and masseter muscles.

Body postural realignment in the first 2 months after orthognathic surgery

INTRODUCTION

This study aimed to assess the static posture in patients with Angle Class II and III malocclusions in the first 2 months after orthognathic surgery.

METHODS

This was a longitudinal observational study. Eligible participants were adult patients who had an indication of orthognathic surgery (bilateral sagittal split osteotomy of the maxilla and/or mandible, can be associated or not with genioplasty). Thirty-five patients were evaluated from the orthognathic surgery group (OSG) and control group (CG). Measurements in OSG were performed at 3 time points: preoperative orthognathic surgery (P0), first postoperative month (P1), and second postoperative month (P2). Static posture was evaluated using the PostureScreen Mobile (PostureCo Inc, Trinity, Fla) application in 4 views.

RESULTS

Patients with Angle Class II malocclusion in the OSG evidenced a tendency to a left hip translation at P1 with a significant difference at P2 in the anterior view (P = 0.052). In the right lateral view, patients with Angle Class II malocclusion in the OSG at P1 presented an accentuated anterior shoulder translation when compared with CG (P <0.001). At P1, patients with Angle Class II malocclusion in the OSG showed a significant anterior knee translation compared with the CG and OSG at P0 and P2 (P <0.001 for all). Patients in the OSG with Angle Class III malocclusion presented an average posterior head translation in the right lateral view at P1 when compared with those in the CG and OSG at P0, who presented an anterior translation (P = 0.0008).

CONCLUSIONS

These findings suggest a realignment of static posture in the first 2 months after orthognathic surgery.

Is jaw muscle activity impaired in adults with persistent temporomandibular disorders? A systematic review and meta-analysis

Understanding jaw muscle activity changes in temporomandibular disorders (TMD) is crucial to guide clinical management. The nature of these changes is currently unclear. Explore changes in jaw muscle activity in TMD. Electronic databases (PubMed, EMBASE, CINAHL, Scopus, Web of Science, Cochrane) and bibliographies were searched from inception to 9 July 2020 for eligible studies, including grey literature. Case-control and interventional studies reporting time-domain and frequency-domain electromyographic measures of jaw muscle activity in TMD and control groups were included. SIGN checklist for case-control studies was used to evaluate risk of bias. Results were pooled for meta-analysis using random-effects model. Confidence in cumulative evidence was established using American Academy of Neurology guidelines. Forty-five studies were included. Most were rated moderate risk of bias. Activity of four muscles (masseter, temporalis, lateral pterygoid, suprahyoids) was assessed across six domains (resting, clenching, chewing, swallowing, concentrating, resisted mandibular movements), with partial meta-analysis scope. Masseter and temporalis activity were significantly higher at rest (P = .05, P < .0001), but lower during brief maximal clenching (P = .005, P = .04) in TMD vs controls. Insufficient data precluded meta-analysis of remaining outcomes and subgroup analysis. Confidence in cumulative evidence ranged from moderate to very low. Changes in jaw muscle activity exist in TMD, which are both task-specific and muscle-specific. It remains unclear whether jaw muscle activity changes vary between TMD subgroups. Muscle function should be considered in clinical management of TMD. Insufficient subgroup data highlight future direction for research.

Standing Up from a Chair with an Asymmetrical Initial Foot Position Decreases Trunk and Masticatory Muscle Activities in Healthy Young Men

This study aimed to identify the activation of lower extremity, trunk, and masticatory muscle and trunk kinematics of the initial foot position during the sit-to-stand (STS) movement. Sixteen young men participated in this cross-sectional pilot study and performed STS using both symmetrical and asymmetrical foot positions. Activation of the tibialis anterior (TA), gastrocnemius lateral head (GA), rectus femoris (RF), biceps femoris (BF), rectus abdominis, erector spinae (ES), sternocleidomastoid (SCM), upper trapezius (UT), temporalis (TE), and masseter muscles in the dominant side was determined. For trunk kinematics, head and trunk velocities, front-back (For-Back) and mediolateral (Med-Lat) weight translation rates, and trunk inclination were measured. GA, TA, BF, and RF activation significantly increased, whereas ES, SCM, UT, and TE activation significantly decreased when using the asymmetrical foot position. Head velocity, For-Back, Med-Lat, and trunk inclination were also significantly decreased. In conclusion, the asymmetrical foot position increases muscle activation in the lower extremities and decreases trunk inclination. In addition, ES, UT, and TE muscle activity decreases at the initial asymmetrical foot position.

Craniocervical and Cervical Spine Features of Patients with Temporomandibular Disorders: A Systematic Review and Meta-Analysis of Observational Studies

To assess neck disability with respect to jaw disability, craniocervical position, cervical alignment, and sensorimotor impairments in patients with temporomandibular disorders (TMD), a systematic review and meta-analysis of observational studies trials were conducted. The meta-analysis showed statistically significant differences in the association between neck disability and jaw disability (standardized mean difference (SMD), 0.72 (0.56-0.82)). However, results showed no significant differences for cervical alignment (SMD, 0.02 (-0.31-0.36)) or for the craniocervical position (SMD, -0.09 (-0.27-0.09)). There was moderate evidence for lower pressure pain thresholds (PPT) and for limited cervical range of motion (ROM). There was limited evidence for equal values for maximal strength between the patients with TMD and controls. There was also limited evidence for reduced cervical endurance and conflicting evidence for abnormal electromyographic (EMG) activity and motor control in TMD patients. Results showed a clinically relevant association between cervical and mandibular disability in patients with TMD. Regarding sensory-motor alterations, the most conclusive findings were observed in the reduction of PPT and cervical ROM, with moderate evidence of their presence in the patients with TMD. Lastly, the evidence on impaired motor control and cervical EMG activity in patients with TMD was conflicting.

Comparison of Ultrasonic Thickness of Masseter Muscle Between Individuals With and Without Severe Forward Head Posture: A Cross-Sectional Study

OBJECTIVE

In this cross-sectional descriptive-analytical study, we sought to compare the ultrasonic thickness of the masseter muscle in people with severe forward head posture vs people without forward head posture, and to determine sex differences in muscle thickness.

METHODS

Thirty-eight volunteers (19 with normal head postures and 19 with severe forward head postures), aged 18 to 35 years, entered the study. The severity of the forward head posture was measured by a plumb line and the craniovertebral angle drawn on the recorded images. Based on the recorded images, the masseter muscle thickness was also measured by a 7.5-MHz linear transducer using an ultrasound device in the seated position with 3 mouth positions (closed, half open, and fully open).

RESULTS

The results showed that the head posture affects masseter thickness significantly (P = .01), with masseter thickness significantly lower in the participants without severe forward head postures compared to those with severe forward head postures in the closed, half-open, and fully open mouth positions (P < .05). Comparing the mean masseter thickness across sexes showed that the masseter muscle is significantly thicker in men compared to women (P = .01).

CONCLUSION

Head posture and thickness of the masseter muscle are linked, as the masseter muscle was thicker in all 3 positions in the participants with severe forward head postures.

Influence of the Craniocervical Posture on Tongue Strength and Endurance

Tongue strength has an important role in the swallowing process, and previous research has suggested that tongue position, concerning the craniomandibular region, could affect the oral function. This study aimed to evaluate the strength and endurance of three areas of the tongue in three experimentally induced craniocervical postures. A cross-sectional study with a nonprobabilistic sample of 37 participants (mean age: 3.85 ± 3.64 years; 20 men, 17 women) was performed. Tongue strength and endurance were assessed using a pressure device entitled Iowa Oral Performance Instrument (IOPI), in three different craniocervical positions: neutral head position (NHP), anterior head translation-or forward head position (FHP), and posterior head translation-or retracted head position (RHP). Measurements taken using the IOPI system showed significant differences in tongue strength for the anterior (p = 0.015) and middle areas of the tongue (p = 0.01). Significant differences were observed in analysis of variance (ANOVA) in the FHP (p = 0.02) and NHP (p = 0.009). The results of tongue endurance measurements showed statistically significant differences for FHP (p = 0.001), NHP (p = 0.00), and RHP (p = 0.007). The craniocervical position influences tongue strength, especially in the anterior and middle tongue areas, concerning the posterior, and, in the anterior and neutral head posture, regarding the retracted position. No differences were found in tongue resistance between the various craniocervical positions, but differences were found in resistance between the different tongue areas.

Electromyography of the masticatory muscles during chewing in different head and neck postures - A pilot study

Objectives

The objectives of this pilot study were to analyze the electromyography (EMG) activity of masseter and anterior temporalis muscles during chewing in 2 different posture conditions: natural head posture (NHP) and maximum yet comfortable forward head posture (FHP) in healthy individuals; and to compare EMG activity between subjects based on their NHP during chewing.

Methods

Fifteen subjects participated. Sagittal head posture in sitting position was clinically assessed using a plumb line. Participants were classified as having FHP or upright head posture (UP). Surface EMG was used to evaluate superficial masseter and anterior temporalis bilaterally during chewing in NHP and FHP. Three trials with five chewing cycles were recorded. EMG data were normalized using a maximum voluntary contraction. An independent t-test was used to calculate differences between sides. If no differences were found, both sides were analyzed together. To analyze differences between the 2 conditions, a paired t-test was used. Independent t-test was used to calculate difference between subjects with UP and FHP.

Results

A significant increase in muscle activity was found for masseter muscle in the FHP condition. No differences were found in muscle activity in natural head position by posture classification. A trend of increased activity was observed for masseter and temporalis muscles during chewing in FHP.

Conclusion

Head and neck posture was found to influence masticatory muscle activity during the function of chewing. The results of this study may help clinicians to better understand the association between head and neck posture alterations with masticatory muscles related disorders.

Does altered mandibular position and dental occlusion influence upper cervical movement: A cross-sectional study in asymptomatic people

OBJECTIVE

Gross mandibular position and masticatory muscle activity have been shown to influence cervical muscles electromyographic activity. The purpose of this study was to investigate the influence of three different mandible positions including conscious occlusion, tongue tip against the anterior hard palate (Palate tongue position) and natural resting position (Rest), on sagittal plane cervical spine range of motion (ROM) as well as the flexion-rotation test (FRT) in asymptomatic subjects.

MATERIALS AND METHODS

An experienced single blinded examiner evaluated ROM using an Iphone in 22 subjects (7 females; mean age of 29.91years, SD 5.44).

RESULTS

Intra-rater reliability for range recorded was good for the FRT with ICC (intraclass correlation) 0.95 (95% CI: 0.88-0.98) and good for sagittal plane cervical ROM with ICC 0.90 (95% CI: 0.77-0.96). A repeated measures ANOVA determined that mean ROM recorded during the FRT differed significantly between assessment points (F(1.99, 41.83) = 19.88, P < 0.001). Bonferroni Post hoc tests revealed that both conscious Occlusion and Palate tongue position elicited a significant large reduction in ROM recorded during the FRT from baseline (p < 0.01). Despite this, one activation strategy did not influence ROM more than the other. An additional repeated measures ANOVA determined that mean sagittal cervical ROM did not significantly vary between assessment points (F(2, 42) = 8.18, P = 0.08).

CONCLUSION

This current study provided further evidence for the influence of the temporomandibular region on upper cervical ROM. Results suggest that clinicians should focus on the natural mandible rest position when evaluating upper cervical mobility.

Influence of the mandibular position on the active cervical range of motion of healthy subjects analyzed using an accelerometer

OBJECTIVE

The aim of this study is to analyze the influence of the mandibular positions (habitual rest position, habitual maximum intercuspation, habitual maximum intercuspation with clenching, and mandibular position with cotton rolls) on the active cervical range of motion (ROM) (flexion-extension, lateroflexions, rotations) using an accelerometer in a sample of healthy subjects.

METHODS

A total of 21 (14 M, 7 F) healthy volunteers aged from 18 to 27 years (mean age 23.88 ± 2.34 years; mean weight 67.86 ± 11.38 kg; mean height 172.52 ± 9.00 cm) underwent a cervical range of movement examination using a 9-axis accelerometer. A one-way ANOVA analysis was performed in order to statistically evaluate the effective influence of the mandibular position on the recorded parameters.

RESULTS

The analysis showed no statistically significant differences (all p-values > 0.1) with variations smaller than three degrees among the different mandibular positions.

DISCUSSION

The mandibular position seems to have no influence on the active cervical ROM in healthy subjects. Further studies are needed to assess the usefulness of the accelerometer in the cervical analysis of temporomandibular disorder subjects.

Do subjects with acute/subacute temporomandibular disorder have associated cervical impairments: A cross-sectional study

BACKGROUND

There is preliminary evidence of cervical musculoskeletal impairment in some temporomandibular disorder (TMD) pain states.

OBJECTIVES

To determine whether people with TMD, classified as either mild or moderate/severe TMD, have more cervical signs of dysfunction than healthy subjects.

DESIGN

Cross-sectional survey.

METHOD

Based on the Conti Amnestic Questionnaire and examination of the temporomandibular joint (Axis I classification of the Research Diagnostic Criteria for TMD), of 144 people examined 59 were classified to a mild TMD group, 40 to a moderate/severe TMD group and 45 to an asymptomatic control group without TMD. Subjects were evaluated for signs of cervical musculoskeletal impairment and disability including the Neck Disability Index, active cervical range of motion, the Flexion-Rotation Test, mechanical pain threshold of the upper trapezius and obliquus capitis inferior muscles, Cranio-Cervical Flexion test and passive accessory movements of the upper 3 cervical vertebrae.

RESULTS

According to cervical musculoskeletal dysfunction, the control group without TMD were consistently the least impaired and the group with moderate/severe TMD were the most impaired. These results suggest, that the more dysfunction and pain is identified in the temporomandibular region, the greater levels of dysfunction is observable on a number of cervical musculoskeletal function tests. The pattern of cervical musculoskeletal dysfunction is distinct to other cervical referred pain phenomenon such as cervicogenic headache.

CONCLUSION

These findings provide evidence that TMD in an acute/subacute pain state is strongly related with certain cervical spine musculoskeletal impairments which suggests the cervical spine should be examined in patients with TMD as a potential contributing factor.

Cervical-scapular muscles strength and severity of temporomandibular disorder in women with mechanical neck pain

Abstract Introduction: Changes in cervical muscle function have been observed in patients with neck pain (NP) and TMD. However, the relationship between TMD severity and neck muscle strength in the presence/absence of NP is unknown. Objective: To determine the prevalence of TMD in women with and without mechanical NP and assess the cervical-scapular muscle strength and its association with TMD severity. Methods: Fifteen volunteers without neck pain (CG) and 14 women with mechanical neck pain (NPG) took part and were selected by the Neck Disability Index. The diagnosis and severity of TMD were determined by the Research Diagnostic Criteria for TMD and Temporomandibular Index (TI), respectively. The strength of the upper trapezius muscle, and cervical flexor and extensor muscles was measured by digital hand dynamometer. Results: 64.5% of women with NP and 33.3% without NP were diagnosed with TMD (p = 0.095). The NPG showed lower strength of the cervical flexor (p = 0.044) and extensor (p=0.006) muscles, and higher TI (p = 0.038) than in the CG. It was also verified moderate negative correlation between TI and the strength of dominant (p = 0.046, r = -0.547) and non-dominant (p = 0.007, r = -0.695) upper trapezius, and cervical flexors (p = 0.023, r = -0.606) in the NPG. Conclusion: There was no difference in the prevalence of TMD in women with and without NP. However, women with NP have lower cervical muscle strength - compared to those without NP - which was associated with greater severity of TMD. Thus, in women with NP associated with TMD, it is advisable to assess and address the severity of this dysfunction and identify the cervical-scapular muscles compromise.

Dry needling for management of pain in the upper quarter and craniofacial region

Dry needling is a therapeutic intervention that has been growing in popularity. It is primarily used with patients that have pain of myofascial origin. This review provides background about dry needling, myofascial pain, and craniofacial pain. We summarize the evidence regarding the effectiveness of dry needling. For patients with upper quarter myofascial pain, a 2013 systematic review and meta-analysis of 12 randomized controlled studies reported that dry needling is effective in reducing pain (especially immediately after treatment) in patients with upper quarter pain. There have been fewer studies of patients with craniofacial pain and myofascial pain in other regions, but most of these studies report findings to suggest the dry needling may be helpful in reducing pain and improving other pain related variables such as the pain pressure threshold. More rigorous randomized controlled trials are clearly needed to more fully elucidate the effectiveness of dry needling.

Relação da atividade elétrica dos músculos supra e infra-hióideos durante a deglutição e cefalometria

OBJETIVO: investigar a influência da postura habitual da cabeça, da posição mandibular e do osso hióide na atividade dos músculos supra e infra-hióideos durante deglutição de diferentes consistências de alimentos. MÉTODO: estudo observacional, transversal, com mulheres entre 19 e 35 anos, sem alterações miofuncionais de deglutição. A postura craniocervical, posição da mandíbula e osso hióide foram avaliados pela cefalometria. A atividade eletromiográfica dos músculos supra e infra-hióideos foi coletada durante a deglutição de água, gelatina e biscoito. RESULTADOS: amostra com 16 mulheres, média de idade 24,19±2,66 anos. No repouso, observaram-se correlações negativas/moderadas entre a atividade elétrica dos músculos supra-hióideos com as variáveis posturais NSL/CVT (posição da cabeça em relação às vértebras cervicais) e NSL/OPT (posição da cabeça em relação à coluna cervical) e positiva/moderada com o ângulo CVA (posição de flexão/extensão da cabeça). Durante a deglutição do biscoito, a atividade dos músculos infra-hióideos apresentou correlação negativa/moderada com o ângulo NSL/OPT. Constatou-se maior atividade elétrica dos músculos supra-hióideos durante a deglutição de todos os alimentos testados e, dos músculos infra-hióideos, no repouso. Os supra-hióideos foram mais ativos que os infra-hióideos durante a deglutição, entretanto, houve aumento da atividade eletromiográfica em ambos os grupos musculares durante a deglutição do biscoito, comparado com a deglutição de água e gelatina. CONCLUSÃO: a hiperextensão da cabeça repercutiu na menor atividade dos músculos supra-hióideos no repouso e, dos músculos infra-hióideos, na deglutição. A consistência do alimento influenciou na atividade elétrica dos músculos supra e infra-hióideos, havendo maior recrutamento muscular na deglutição de alimento sólido.