Quantitative analysis of the mouth opening movement of temporomandibular joint disorder patients according to disc position using computer vision: a pilot study

BACKGROUND

Temporomandibular joint disorder (TMD), which is a broad category encompassing disc displacement, is a common condition with an increasing prevalence. This study aimed to develop an automated movement tracing algorithm for mouth opening and closing videos, and to quantitatively analyze the relationship between the results obtained using this developed system and disc position on magnetic resonance imaging (MRI).

METHODS

Mouth opening and closing videos were obtained with a digital camera from 91 subjects, who underwent MRI. Before video acquisition, an 8.0-mm-diameter circular sticker was attached to the center of the subject's upper and lower lips. The automated mouth opening tracing system based on computer vision was developed in two parts: (I) automated landmark detection of the upper and lower lips in acquired videos, and (II) graphical presentation of the tracing results for detected landmarks and an automatically calculated graph height (mouth opening length) and width (sideways values). The graph paths were divided into three types: straight, sideways-skewed, and limited-straight line graphs. All traced results were evaluated according to disc position groups determined using MRI. Graph height and width were compared between groups using analysis of variance (SPSS version 25.0; IBM Corp., Armonk, NY, USA).

RESULTS

Subjects with a normal disc position predominantly (85.72%) showed straight line graphs. The other two types (sideways-skewed or limited-straight line graphs) were found in 85.0% and 89.47% in the anterior disc displacement with reduction group and in the anterior disc displacement without reduction group, respectively, reflecting a statistically significant correlation (χ2=38.113, P<0.001). A statistically significant difference in graph height was found between the normal group and the anterior disc displacement without reduction group, 44.90±9.61 and 35.78±10.24 mm, respectively (P<0.05).

CONCLUSIONS

The developed mouth opening tracing system was reliable. It presented objective and quantitative information about different trajectories from those associated with a normal disc position in mouth opening and closing movements. This system will be helpful to clinicians when it is difficult to obtain information through MRI.

Quantitative Sensory Testing Across Chronic Pain Conditions and Use in Special Populations

Chronic pain imposes a significant burden to the healthcare system and adversely affects patients' quality of life. Traditional subjective assessments, however, do not adequately capture the complex phenomenon of pain, which is influenced by a multitude of factors including environmental, developmental, genetic, and psychological. Quantitative sensory testing (QST), established as a protocol to examine thermal and mechanical sensory function, offers insight on potential mechanisms contributing to an individual's experience of pain, by assessing their perceived response to standardized delivery of stimuli. Although the use of QST as a research methodology has been described in the literature in reference to specific pain populations, this manuscript details application of QST across a variety of chronic pain conditions. Specific conditions include lower extremity chronic pain, knee osteoarthritis, chronic low back pain, temporomandibular joint disorder, and irritable bowel syndrome. Furthermore, we describe the use of QST in placebo/nocebo research, and discuss the use of QST in vulnerable populations such as those with dementia. We illustrate how the evaluation of peripheral sensory nerve function holds clinical promise in targeting interventions, and how using QST can enhance patient education regarding prognostic outcomes with particular treatments. Incorporation of QST methodology in research investigations may facilitate the identification of common mechanisms underlying chronic pain conditions, guide the development of non-pharmacological behavioral interventions to reduce pain and pain-related morbidity, and enhance our efforts toward reducing the burden of chronic pain.

Low-Intensity Pulsed Ultrasound Alleviates Hypoxia-Induced Chondrocyte Damage in Temporomandibular Disorders by Modulating the Hypoxia-Inducible Factor Pathway

Temporomandibular disorders are a common cause of chronic pain in the orofacial region and have a complex and multi-factorial pathophysiology. Mechanical loading or inflammatory conditions have been shown to decrease oxygen tension within the joint cartilage and activate the hypoxia-inducible factor (HIF) pathway, which in turn aggravates the pathological processes underlying temporomandibular joint (TMJ) disorders. We previously showed that low-intensity pulsed ultrasound (LIPUS) treatment effectively repairs TMJ injury induced by chronic sleep deprivation (CSD). Here, we explored the effects of LIPUS treatment on hypoxia-induced chondrocyte injury. We found that it effectively restored the proliferation capacity of mandibular chondrocytes under hypoxic conditions and lowered their rate of apoptosis. Chondrogenic capacity, as assessed by type II collagen levels, and mucin-positive areas were also significantly increased after LIPUS treatment. Levels of matrix metalloprotein-3 and interleukin-6 decreased in mandibular chondrocytes following this treatment, whereas the expression of tissue inhibitor of metalloproteinase-1 increased. We also found that HIF-1α expression was upregulated in mandibular chondrocytes under hypoxic conditions and was further enhanced by LIPUS treatment. Similarly, HIF-2α levels increased in mandibular chondrocytes under hypoxic conditions but decreased following LIPUS treatment. Subsequently, we established a CSD-induced TMJ injury model and found that LIPUS increased mucin-positive areas as well as HIF-1α expression and decreased HIF-2 level in the chondrocyte layer. Together, our results indicate that the protective effect of LIPUS on chondrocyte is partly associated with the HIF pathway.

Progressive muscle relaxation according to Jacobson in treatment of the patients with temporomandibular joint disorders

Significant impact factor and psycho-emotional stress in the etiology of dysfunction indicate the need of the routine approach in the treatment of patients with temporomandibular joint disorders to be changed. The aim of the study was to obtain data, documented test results as to the effciency of progressive muscle relaxation in the treatment of pain caused by temporomandibular joint disorders, as a supplement to previous methods using occlusal splint and other physical therapies. The study included 100 patients of both sexes, aged from 20 to 35 years who were diagnosed with pain due to temporomandibular joint disorders accompanied with high muscle tension of musticatory muscles which were treatment by relaxation therapy. All patients underwent physical examination, specialized functional examination of the masticatory system in accordance with the Polish version of the study RDC/TMD (The Research Diagnostic Criteria of Temporomandibular Disorders, Axis I - physical assessment, Axis II - assessment of psychosocial status and pain - related disability) and assessment of psycho emotional factor and stress, based on the survey developed for their own purpose. The results of the research were obtained using specialized statistical package "R" i386 3.2.3. The results of examinations a er relaxation therapy showed a significant reduction in the intensity of myofascial pain in all patients. Progressive muscle relaxation can be successfully used as an supportive therapy treatment of patient with dysfunction.

The value of MRI in patients with temporomandibular joint dysfunction: Correlation of MRI and clinical findings

AIM

To estimate the correlation between the MRI findings and clinical outcomes in patients with temporomandibular joint dysfunction (TMD).

METHODS AND MATERIALS

We included 546 female and 248 male patients who were clinically diagnosed with TMD (mean age 38.7 years) and examined by MRI (T1 and T2 weighted images, parasagittal and paracoronal slices). A questionnaire, radiological, and clinical findings were analysed for statistically significant correlations. The analysed parameters included gender, age, disk position, joint degeneration, arthralgia, mouth opening, condyle position and clinical progress.

RESULTS

Of all TMJ's 62% showed physiological disc position, 35% anterior and 3% posterior disc position. Modification of therapy occurred in 20% and alteration of diagnosis was found in 32% of all cases. Anterior disc displacement with reduction showed a specificity of 88% and a sensitivity of 78%, whereas anterior disc displacement without reduction showed a specificity of 84% and a sensitivity of 73%. A significant correlation between disc length, condyle morphology and disc displacement was found. With the increase of intra-articular liquid as seen on MRI the level of arthralgia significantly rose as opposed to mouth opening.

CONCLUSION

Specificity and sensitivity, for anterior disc displacement and osseous changes in TMJ were highly acceptable. Results had confirmed the diagnostic capability of MRI in diagnostic imaging of TMJ. Additionally MRI should be used primarily in severe, therapy-resistant cases and for surgical planning purposes.