Assessment of mandibular kinematics values and its relevance for the diagnosis of temporomandibular joint disorders

Assessment of Mandibular Kinematic Variables using a Motion Analysis System and a Regular Mobile Phone

Background

The development of a standard motion capture system is needed since the measurement of temporomandibular disorders is time-consuming and costly using laboratory tools.

Objective

The current study aimed to investigate the mandibular kinematic variables using a regular mobile phone and the motion analysis system.

Material and Methods

In this quasi-laboratory and comparative study, ten healthy individuals participated, and three mobile cameras, nine red markers, and Kinovea software were also used to investigate the mandibular kinematic variables. Nine light reflective markers were used to check the sensitivity, accuracy, and reliability of the proposed system. The motion was analyzed using seven motion analysis infrared cameras and Qualisys Track Manager (QTM) software. Two other raters analyzed the kinematic variables obtained from the mobile to measure intra- and inter-rater reliability.

Results

Pearson's correlation coefficient was obtained at 0.98, 0.75, 0.98, and 0.96, showing a high correlation. The accuracy and reliability validation tests showed an average error and an accuracy of 0.156 mm and 95%, respectively, with a mobile phone. The Intra Class Correlation coefficient showed a high internal correlation in the mentioned confidence interval (0.98 and 0.81, and 0.96 and 0.97). The intraclass correlation coefficient method also showed 97% inter-raster reliability.

Conclusion

Mobile phones as a new system can evaluate the kinematic variables of mandibular disorders with appropriate accuracy and reliability.

3-Dimensional quantitative analysis of mandibular motion in TMD and healthy subjects: Comparison with clinical observations

OBJECTIVES

To establish a quantitative method for objectively assessing 3-dimensional (3D) mandibular trajectories and comparing clinical evaluations with computational analyses.

METHODS

In total, 184 volunteers were recruited and grouped into control (n = 121) and temporomandibular disorder (TMD) groups (n = 63) according to the dual-axis DC/TMD checklist. 3D trajectories were generated by integrating mandibular motion and cone beam computed tomography (CBCT) records. Via digitalized data processing, the following 3 outcomes were assessed: (1) smoothness using the best-fitting polynomial curve, (2) open-closure separation by measuring the deviation between open-closure phases, and (3) condylar trajectory symmetry by comparing left and right movements. Intraclass Correlation Coefficients (ICC) were used to determine agreement between expert observations and quantitative results. Reference ranges for each parameter from the normal population were calculated. Mann‒Whitney test was used to analyze the features of the trajectories between the two groups.

RESULTS

ICC confirmed strong consistency between the parametric variations and expert observations (smoothness: 0.797; open-closure separation: 0.820; left-right symmetry: 0.920). Quantitative analyses revealed significant differences (P < 0.043 for smoothness, P < 0.01 for separation, and P = 0.012 for symmetry) in all comparisons between movement trajectories of normal participants and those with TMD, with the latter group exhibiting greater variation and irregularities. The normal range of smoothness was calculated for condylar trajectories between 0 and 0.25 and 0-0.10 for incisal point trajectories. Open-closure separation normal range was computed between 0 and 2.28 mm for incisal point trajectory, 0-1.90 mm for left condylar trajectory, and 0-1.76 mm for right condylar trajectory. The normal range of symmetry between condylar trajectories was calculated to be between 0 and 4.21 mm.

CONCLUSIONS

This quantitative analysis was confirmed to be reliable and consistent with expert observations. This allowed for the discovery of substantially quantified differences in smoothness, open-closure separation, and symmetry of the motion trajectories in TMD patients versus controls.

Kinematic classification of mandibular movements in patients with temporomandibular disorders based on PCA

This retrospective study aimed to kinematically classify mandibular movements collected during Temporomandibular Disorders (TMD) treatment, employing Fourier transformation (FT), Principal Component Analysis (PCA), and K-means clustering (k-means), and to investigate their correlation with symptoms of pain-related TMD. The study included five TMD participants diagnosed with myalgia (age: 39-86 years, with an SD of 18.96) and three healthy participants (age: 32-42 years, with an SD of 5.13) with no stomatognathic problems. TMD participants underwent tailored treatment for their symptoms, and their maximum unassisted mouth opening (MMO) was recorded randomly with a motion capture system (ARCUS digma II, Kavo, Biberach, Germany) at multiple time points. MMO for healthy participants served as a control. The dataset comprising 28 trials, was transferred to the AnyBody Modeling System (AnyBody Technology, Aalborg, Denmark) to extract joint angle time series, which were then transformed into Fourier series. Subsequently, PCA and k-means clustering were conducted. Two clusters were identified: Cluster 1, predominantly composed of symptomatic trials, and Cluster 2, mainly consisting of asymptomatic trials. Distinct transition pathways between the clusters were observed among participants, corresponding to the alleviation of pain-related symptoms during TMD treatment. These findings suggest that this approach has potential as an effective tool for diagnosing and assessing TMD by identifying symptomatic kinematic patterns and tracking temporal changes in mandibular movement. Despite the small dataset, these results suggest promise for a novel functional assessment method for TMD based on kinematic features.

Comparative analysis of myoelectric activity and mandibular movement in healthy and nonpainful articular temporomandibular disorder subjects

OBJECTIVES

Temporomandibular disorders (TMDs) are one of the leading causes of craniofacial pain, and a high incidence of TMDs in young adults has been reported. Previous studies have used surface electromyography (sEMG) and mandibular kinematic analysis for TMDs diagnosis. This study aimed to provide normal reference values of sEMG and mandibular kinematics in Han Chinese adults, compare the sex differences and assess their diagnosis value on pain-free articular TMDs.

MATERIALS AND METHODS

This observational study recruited healthy young adults with individual normal occlusion and nonpainful articular TMDs patients with disc displacement. The sEMG signals of the anterior temporalis (TA), masseter (MM), and sternocleidomastoid and digastric were recorded in the mandibular postural positions (MPP) and during maximal voluntary clenching (MVC) with K7 electromyograph. Mandibular kinematics, including maximum opening and opening/closing velocities, were assessed by K7 kinesiograph.

RESULTS

The sEMG reference values ranged from 3.0 to 4.3 µV in the MPP (n = 90) in healthy subjects. The sEMG values during MVC, maximum opening, and opening velocity were significantly higher in males than in females. Also, these indices showed good diagnostic efficiency for pain-free articular TMDs (n = 26).

CONCLUSIONS

Reference values and sex differences in sEMG and mandibular kinematics in healthy subjects were determined. Compared with them, articular TMDs patients showed significantly lower myoelectric activity during maximal biting and restricted mouth opening range and velocity, which may assist in TMDs diagnosis.

CLINICAL RELEVANCE

By analyzing sEMG of masticatory muscle and mandibular kinematics data from healthy Han Chinese young adults and TMDs patients with disc displacement, this study evaluated the sex difference and their diagnosis value on nonpainful TMDs with disc displacement.

CLINICAL TRIAL REGISTRATION ID

NCT06372769.

Hyaluronic Acid and Platelet-Rich Plasma Mixture Versus Hyaluronic Acid and Corticosteroid in the Treatment of Temporomandibular Joint Internal Derangement: A Comparative Randomized Study

Objectives

This study aimed to compare the effects of different intra-articular injections using a mixture of hyaluronic acid (HA) and platelet-rich plasma (PRP) versus hyaluronic acid and corticosteroid in the management of TMJ internal derangement with reduction.

Materials and Methods

Sixty patients were randomly divided into two equal groups. Group I was injected with hyaluronic acid and PRP, while group II was injected with hyaluronic acid and corticosteroid. Pain intensity according to the visual analogue scale, maximum inter-incisal opening (MIO), lateral movement, and joint sound were measured pre-operatively and at 1 week, 1 month, and 6 months post-operatively.

Results

MIO and lateral movements were improved in both groups, with a reduction in the number of patients suffering from clicking sounds along the follow-up periods with no significant difference between the studied groups. However, regarding pain, the group injected with HA and PRP achieved the best results after 6 months, while patients treated with HA and corticosteroids obtained the best results at the end of the 1st week.

Conclusion

Hyaluronic acid and platelet-rich plasma mixture performed better than hyaluronic acid and corticosteroid in the treatment of TMJ internal derangement with reduction at the long-term follow-up regarding pain intensity.

Evaluation of Mandibular Movements in Patients with Bell's Palsy Using Kinematic Variables

Background

Since the function of muscles, and subsequently the mandibular joint, is affected in patients with Bell's palsy, therefore, the evaluation of facial muscles and mandibular function in these patients can be effective in diagnosis, prevention, and treatment planning. The present study aimed to evaluate the degree of displacement and range of motion (ROM) of the mandible and the ability of the facial symmetrical muscles of patients with Bell's palsy.

Methods

This was a quasi-experimental comparative study. The variables evaluated were mandibular movement in a vertical direction and side-to-side displacement. Ten patients with Bell's palsy and 10 healthy eligible volunteers participated in the present study. Three mobile video cameras (to record jaw movements), 9 color markers, Kinovea software, House-Brackmann index, Toledo protocol, and a specialized patient questionnaire were used. Descriptive and inferential statistics were used for data analysis, the Kolmogorov-Smirnov test was used to investigate the normality of data distribution, and independent samples the t test and paired samples t test were used to compare means.

Results

The maximum lateral on the sound side was 12.40 and 4.49 mm during lateral movements of the patients' mandible, while this value was between 12.30 and 3 mm on the involved side. There is a difference between the affected side and the nonaffected side in terms of the mean lateral movements of the patients' mandible. However, this difference in the mean ROM on both sides is not statistically significant. The maximum mouth opening in healthy individuals during mandibular movements was between 40 and 60 mm, while this value was between 25 and 50 mm in the patients with Bell's palsy. This study shows a significant difference (P = 0.007) between patients and healthy individuals in terms of the mean of maximum mouth opening ( P < 0.05).

Conclusion

The results of this study showed that the ROM of temporomandibular joint (TMJ) of the patient is the same as that of normal subjects, but the side-to-side motion is more than normal which should be considered in rehabilitation treatments. The present study emphasizes the need to implement a mandibular kinematic evaluation protocol in patients with bell's palsy to prevent damage to the TMJ in the long term.

Methods improvement for diagnostics and treatment of inflammatory diseases in the temporomandibular joint

Purpose

The article subject relevance is conditioned by poor knowledge of the aetiology and pathogenesis of inflammatory diseases in this area. The purpose of this study was to identify the most rational approach to solving the issues of improving methods for treating arthritis and arthrosis.

Methods

The leading approach was the combination of the analysis results concerning the clinical examination of dental patients of various age groups with the logical construction of conclusions drawn from the research results. The paper presented the clinical examination data of patients with TMJ pathologies of various age groups and described the methods of their treatment.

Results

The results include the main effective methods identification for the diagnostics and treatment of inflammatory diseases in the temporomandibular joint and the main prospects for improving these methods in the future, with the aim of a general expansion of ideas regarding the possibilities of diagnostics and treatment of such diseases.

Conclusion

The study value lies in the possibility of using its results in practical dentistry to bring practical improvements to the currently available methods for diagnostics and treatment of inflammatory TMJ diseases.

Clinical Manifestations, Imaging Features, and Pathogenic/Prognostic Risk Factors for Temporomandibular Disorders (TMD): A Case-Control Study Based on Psychogenic Factors of Patients

Objective. To survey the clinical manifestations and imaging features of temporomandibular disorders (TMD) and analyze the risk factors for pathogenesis/prognosis through a case-control study based on psychogenic factors of patients. Methods. According to the inclusion criteria, 200 adult patients were randomly enrolled from the maxillofacial department of our hospital from January 2020 to May 2021, including 100 patients with TMD as the study group and 100 healthy patients as the control group. The study group can be assigned into four subgroups according to their clinical manifestations: (1) articular area or/and masticatory muscle pain group, (2) mandibular movement abnormality group, (3) joint murmur group, and (4) two or more symptom groups. Based on the study of psychogenic factors of patients, the clinical manifestations and imaging features of TMD were determined, and the risk factors for pathogenesis/prognosis were analyzed. Results. The distribution of psychological status in the TMD group was higher than that in the control group ( $P<0.05$ ). The distribution of anxiety, depression, and somatic symptoms in the TMD group was significantly different from that in the control group ( $P<0.05$ ). Anxiety, depression, and somatic symptoms were the risk factors for TMD. Compared with the control group, the incidence of abnormal MRI images in patients with temporomandibular disorders was significantly different ( $P<0.05$ ). There were significant differences in psychological status (anxiety, depression, and somatic symptoms) among the three groups ( $P<0.05$ ). Anxiety, depression, and somatic symptoms were the risk factors for abnormal mandibular movement and joint tremor and murmur ( $P<0.05$ ). Somatic symptoms were the risk factors for various clinical symptoms of TMD ( $P<0.05$ ). Depression was the risk factor for pain ( $P<0.05$ ). Conclusion. In patients with TMD, MRI can early identify disc abnormalities and other related imaging features, which is helpful for more comprehensive clinical evaluation and treatment of TMD patients. There exhibits no significant difference in psychological status (anxiety, depression, and somatic symptoms) of patients with different clinical symptoms, and abnormal psychological status may be one of the risk factors leading to different clinical symptoms and development of different types of TMD patients.

Efficacy of Kinematic Parameters for Assessment of Temporomandibular Joint Function and Disfunction: A Systematic Review and Meta-Analysis

The aim of this review was to answer the following PICO question: "Do TMJ kinematic parameters (intervention and comparison) show efficacy for assessment of mandibular function (Outcome) both in asymptomatic and TMD subjects? (Population)". PubMed, Scopus, Web of Science, Embase, Central databases were searched. The inclusion criteria were (1) performed on human, (2) English only, (3) on healthy, symptomatic or surgically altered TMJ, (4) measured dynamic kinematics of mandible or TMJ (5) with six degrees of freedom. To assess the Risk of Bias, the Joanna Briggs Institute tool for non-randomised clinical studies was employed. A pairwise meta-analysis was carried out using STATA v.17.0 (Stata). The heterogeneity was estimated using the Q value and the inconsistency index. Ninety-two articles were included in qualitative synthesis, nine studies in quantitative synthesis. The condylar inclination was significantly increased in female (effect size 0.03°, 95% CI: -0.06, 0.12, p = 0.00). Maximum mouth opening (MMO) was increased significantly in female population in comparison with males (effect size 0.65 millimetres (0.36, 1.66). Incisor displacement at MMO showed higher values for control groups compared with TMD subjects (overall effect size 0.16 millimetres (-0.37, 0.69). Evidence is still needed, considering the great variety of devices and parameters used for arthrokinematics. The present study suggests standardising outcomes, design, and population of the future studies in order to obtain more reliable and repeatable values.

In Vitro and In Vivo Assessment of a New Workflow for the Acquisition of Mandibular Kinematics Based on Portable Tracking System with Passive Optical Reflective Markers

Clinical use of portable optical tracking system in dentistry could improve the analysis of mandibular movements for diagnostic and therapeutic purposes. A new workflow for the acquisition of mandibular kinematics was developed. Reproducibility of measurements was tested in vitro and intra- and inter-rater repeatability were assessed in vivo in healthy volunteers. Prescribed repeated movements (n = 10) in three perpendicular directions of the tracking-device coordinate system were performed. Measurement error and coefficient of variation (CV) among repetitions were determined. Mandibular kinematics of maximum opening, left and right laterality, protrusion and retrusion of five healthy subjects were recorded in separate sessions by three different operators. Obtained records were blindly examined by three observers. Intraclass correlation coefficient (ICC) was calculated to estimate inter-rater and intra-rater reliability. Maximum in vitro measurement error was 0.54 mm and CV = 0.02. Overall, excellent intra-rater reliability (ICC > 0.90) for each variable, general excellent intra-rater reliability (ICC = 1.00) for all variables, and good reliability (ICC > 0.75) for inter-rater tests were obtained. A lower score was obtained for retrusion with “moderate reliability” (ICC = 0.557) in the inter-rater tests. Excellent repeatability and reliability in optical tracking of primary movements were observed using the tested portable tracking device and the developed workflow.