Experience of using an integrated approach in the diagnosis of temporomandibular joint dysfunction

The article presents a clinical case of the diagnostics and treatment of the temporomandibular joint dysfunction (TMJ) in patient after orthodontic treatment. The hypertonia of masticatory muscles, limit of mouth opening and deviation of the jawbone to the right were observed during physical examination. Adhesion of the disk to the articular tubercle of the right temporal bone was detected on MRI. Hyperrotation of the articular head and the deviation of the jawbone to the right were observed on the charts during axiography. Disappearing of the feeling of heaviness in the right TMJ, free mouth opening, absence of deviation symptom, and the reduction of the rigidity of the masseter muscles were observed on the basis of diagnostic examinations after treatment. Presented clinical experience lets us make a conclusion that it is necessary to prescribe taking axiography and MRI during diagnosing and treating temporomandibular joint dysfunction.

The Effects of Wearing a Medical Mask on the Masticatory and Neck Muscle Activity in Healthy Young Women

The objective of this study was to analyze the influence of wearing a medical mask on masticatory and neck muscle activity in healthy young women. We recruited 66 healthy women aged from 18 to 30 years (mean 23.6 ± 2.3 years). The temporalis anterior (TA), the superficial part of the masseter muscle (MM), the anterior bellies of the digastric muscle (DA), and the middle part of the sternocleidomastoid muscle (SCM) potentials were recorded at rest and during functional activity using an eight-channel device for surface electromyography—BioEMG IIITM. There was a statistically significant decrease in mean TA activity during medical mask measurement compared to no mask examination at rest (2.16 µV vs. 2.58 µV; p = 0.05; ES = 0.2). Significant decreases in resting RMS values were also observed during the medical mask phase in comparison to no mask examination concerning the left MM (1.75 µV vs. 2.17 µV; p = 0.01; ES = 0.3), and mean bioelectrical activity of the MM (1.81 µV vs. 2.15 µV; p = 0.02; ES = 0.2). The differences between the two conditions did not reach the assumed significance level (p > 0.05) in terms of other indices. Wearing a medical mask has a small effect on decreasing the resting potentials of the temporalis anterior and masseter muscles without changing the parameters of activity and asymmetry within the stomatognathic system.

Masseter Muscle Activity in Orthodontically Treated Patients with a History of Temporomandibular Joint Disorder: An Electromyographic Study

The present study aimed to evaluate the surface electromyography (sEMG) activity of the masseter muscles in patients with a history of temporomandibular joint disorder (TMJD) who received orthodontic treatment. In total, 22 participants aged 18–35 years old were included in this study. They were divided into the control group (patients without a history of TMJD [n = 11]) and the test group (those with a history of TMJD [n = 11]). Each participant underwent sEMG of the right and left masseter muscles at 5-s maximum voluntary contraction (MVC). Results showed that the TMJD group had a lower sEMG activity of masseter muscles at MVC than the non-TMJD group. However, the differences were not statistically significant (p > 0.05, t-test). The Spearman’s correlation coefficient test revealed a weak negative correlation between muscle activity on sEMG and history of TMJD (p > 0.05). In conclusion, orthodontically treated patients in TMJD group have reduced masseter muscle activity during MVC, compare to the non-TMJD group.

Camel-related Major Vascular Injuries: A 20-years’ Experience

Background: Majority of animal-related injuries in United Arab Emirates are caused by camels. We aimed to study the anatomy, biomechanism and outcome of major camel-related human vascular injuries and correlate them to the camel anatomy and behavior.Methods: We retrospectively studied all patients who were admitted to Al-Ain Hospital with camel-related major vascular injury during January 2001 to January 2020. A special protocol was designed to collect the data. An adult 7-year-old male camel skull was prepared and web-based video clips of camel bites to humans were analysed to have an in-depth understanding of the biomechanism of injury.Results: Seven patients were studied, all were males having a median age of 26 years. Five out of six bite injuries (83%) occured during the camel rutting season. The injuries were severe and life threatening. Four involved the carotid artery, one the femoral artery and vein, one the external iliac vein and one the aorta which was due to a fall from a camel. Although the standard of surgical care was high, the outcome was poor. Six patients were admitted to the ICU for a median of 5 days. One patient died, one was vegetative, and one had arm paralysis. The elongated jaws of the camel having its biting component at the front, and the strong masseter muscles at the back increases the strength of its bite grip. Each bite causes four small elliptical wounds of the canine teeth which resembles two stab wounds of 8 cm long, penetrating deeply and injuring major vessels. Aggressive camels bite repeatedly to kill their victims.Conclusions: Camel-related vascular injuries have a poor clinical outcome. Although the basis of their surgical management is similar to other vascular injuries, their poor outcome is related to the aggressiveness of the attacking camel, the anatomy of its jaw, and its intention to kill. Neck wounds of camel bites can be closed primarily after debridement. Studying these unusual injuries gives an insight into the “one globe one health approach” in which humans interacts with the animals and the environment around them. It important to understand the camel behavior for injury prevention.

The Application of Manual Techniques in Masticatory Muscles Relaxation as Adjunctive Therapy in the Treatment of Temporomandibular Joint Disorders

Temporomandibular disorders (TMD) are primarily characterized by pain as well as disorders concerning the proper functioning of individual elements of the stomatognathic system (SS). The aim of the study was to compare the degree of relaxation of the anterior part of the temporal muscles and the masseter muscles, achieved through the use of post-isometric relaxation and myofascial release methods in patients requiring prosthetic treatment due to temporomandibular joint disorders with a dominant muscular component. Sixty patients who met the inclusion criteria were alternately assigned to one of the two study groups, either group I—patients received post-isometric relaxation treatment (PIR), or group II—patients received myofascial release treatment (MR). The series of ten treatments were performed in both groups. The comparative assessment was based on physiotherapeutic examination, a surface electromyography (sEMG) of the anterior temporal and masseter muscles and the intensity of spontaneous masticatory muscle pain, assessed using the Visual Analogue Scale (VAS). We observed a significant decrease in the electrical activity of examined muscles and a significant drop in the intensity of spontaneous pain in the masticatory muscles both in group I and II. There were no significant differences between groups. Both therapeutic methods may be used as successful forms of adjunctive therapy in the prosthetic treatment of TMD. The trial was registered with an international clinical trials register.

Electromyographic activity of the masseter muscle in individuals with group function and canine guidance

Background. There is no general consensus in restorative dentistry about which lateral guidance should be established. Some studies have shown that canine guidance decreases the tension of masticatory muscles. Others have reported that group function might achieve a better physiologic distribution of occlusal forces. Also, some reports have shown that both guidances are equally acceptable. Despite all discussions, clinical evidence of one guidance being superior to another is limited. Thus, this study aimed to analyze the electromyographic (EMG) activity of masseter muscles in individuals with group function and canine guidance. Methods. Twenty volunteers of both genders, aged 20-25, were divided into two groups: GF (group function guidance, n=10) and CA (canine guidance, n=10). EMG activity of masseters was captured using surface electrodes during habitual maximum intercuspation (HMI) and right and left lateral jaw movements and recorded using EMG amplitude values (RMS – root means square). Student’s t-test was used to compare mean RMS values between the groups and lateral movements in each group. Results. During HMI, there was no difference in masseter EMG activity between the groups. Both masseters showed higher activity in group GF only on the right side during lateral movements, while the left masseter exhibited higher activity on the nonworking side in both groups. The activity of both masseters distributed by tooth was higher in group CA. Conclusion. During tooth restorative procedures, any guidance is acceptable considering HMI. However, group function guidance is more favorable during lateral movements due to greater dissipation of occlusal pressures.

Incidence and Effects of Posterior Cranial Vault Deformation in Adult Females With Skeletal Class III Malocclusion

BackgroundThe precise characteristics of posterior cranial vault deformation are difficult to identify using a two-dimensional analysis. Recently, three-dimensional analysis using computed tomography (CT) data and software analysis has enabled us to examine the craniofacial structure precisely. To identify the deformation in the cranial vaults by a three-dimensional analysis and examine its effects on other structures, CT data of skeletal mandibular protrusion cases without lateral deviation of pogonion (Pog) were examined.MethodsThirty-two adult female patients with skeletal mandibular protrusion who visited Meikai University Hospital were included in this study. CT images were taken before orthognathic surgeries, and the craniofacial structures were examined threedimensionally.The lateral deviation of Pog was less than 3 mm in all cases.Genetic/congenital anomaly cases, endocrine disorders, or cases with severe trauma or temporomandibular disorder were excluded.ResultsMany cases had three-dimensional deformations in the cranial vaults. The cranial vaults with unilateral posterior deformation had posteriorly positioned mandibular fossae on the same sides. Mandibular body lengths were related to the position of the mandibular fossae, and the posterior mandibular fossae tended to have longer mandibular body lengths on the same sides. Masseter muscles with larger volumes were related to longer mandibular body lengths.ConclusionsMandibular body lengths can compensate for the bilateral difference in the position of the mandibular fossae to avoid lateral deviation of the Pog. The masseter muscles are likely one of the factors related to the bilateral differences in the mandibular body length.

Stiffness of the Masseter Muscle in Children—Establishing the Reference Values in the Pediatric Population Using Shear-Wave Elastography

In children, the quality and muscle function are altered in many pathologic conditions, including temporomandibular disorders. Although several methods have been used to evaluate muscle tonus, none became a golden standard. Moreover, the masseter muscle characteristics in children have not been investigated to date. This study aimed to measure the stiffness of the masseter muscle using shear-wave elastography in healthy children. We enrolled 30 healthy children (mean age 10.87 ± 3.38 years). The stiffness of masseter muscles was measured with shear wave elastography. Stiffness for the total sample was 6.37 ± 0.77 kPa. A comparison of the measurements did not show significant differences between the right and the left masseter muscles (left—6.47 ± 0.78 kPa; right—6.24 ± 0.76 kPa; p = 0.3546). A significant difference was seen between boys and girls (boys—5.94 ± 0.50 kPa; girls—6.63 ± 0.80; p = 0.0006). Shear-wave elastography is a promising diagnostic tool. It may help to detect changes in the stiffness of the masseter muscle and draw attention to pathological processes within the jaw muscles. Directions for further research shall include determining stiffness values in pathological conditions and the impact of biological and functional factors on the stiffness of the masseter muscle.