Jaw Movements Research Articles

Investigating the effect of obsessive-compulsive disorder on clinical symptoms of temporomandibular joint disorders.

Temporomandibular disorders (TMD) are a group of clinical conditions involving muscles of mastication, temporomandibular joint (TMJ), and related structures or both. TMD is characterized by facial pain in TMJ and muscles of mastication, limitation or deviation of jaw movement, and TMJ sounds during jaw movement and function. The highest risk of TMD prevalence is between 18 and 24 years, and a relationship is between chronic TMD and psychological disorders such as stress and depression. The knowledge of the function of this joint and those with TMD symptoms when visiting the dentist will help to provide an ideal treatment plan for the patient. Therefore, if the therapist is familiar with the various etiological factors of this disorder, he will provide better treatment, especially if the simultaneous effect of psychological factors such as stress and obsessive-compulsive disorder (OCD) along with occlusal factors such as posterior cross-bite, overjet, and overbite is measured, it can be a valuable guide for clinicians. In this study, 385 patients were examined by DASS42 and Maudsley's test and classified into normal, with stress, and stress plus OCD groups. TMJ was examined for each of them by the TMD-RDC test. The presence or absence of TMD was noted in their file. The prevalence of TMD was 20.7% in the normal group, 30.70% in the stress group, and 44.68% in the stress and OCD group. After analyzing the data by SPSS 24 and performing analysis of variance and Duncan tests, no significant difference was found between the probability of TMD in normal and stressed groups, but the stress and OCD group has a higher chance of TMD. Although the co-occurrence of stress and OCD is associated with the prevalence of TMD, it cannot be considered a cause of TMD.

Anticipating food structure of meat products from mastication physics applying machine learning

Alternatives to animal-based products are becoming more relevant. Most of those products rely at some stage on a structuring process; hence researchers are developing techniques to measure the goodness of the structured material. Conventionally, a typical sensory study or texture analysis by measuring deformation forces would be applied to test the produced material for its texture. However, meat alternatives and meat differ in more points than just the texture, making it hard to extract the isolated texture impression. To objectively obtain qualitative and quantitative differences between different food structures, evaluation of oral processing features is an upcoming technology which qualifies as promising addon to existing technologies. The kinematic data of the jaw and exerted forces regarding muscle activities are recorded during mastication. Resulting datasets are high in dimensionality, covering thousands of individual chews described by often more than ten features. Evaluating such a dataset could benefit from applying computational evaluation strategies designed for large datasets, such as machine learning and neural networks. The aim of this work was to assess the performance of machine learning algorithms such as Support Vector Machines and Artificial Neural Networks or ensemble learning algorithms like Extra Trees Classifier or Extreme Gradient Boosting. We evaluated different pre-processing techniques and various machine algorithms for learning models with regard to their performance measured with established benchmark values (Accuracy, Area under Receiver-Operating Curve score, F1 score, precision-recall Curve, Matthews Correlation Coefficient (MCC)). Results show remarkable performance of classification of each single chew between isotropic and anisotropic material (MCC up to 0.966). According to the feature importance, the lateral jaw movement was the most important feature for classification; however, all features were necessary for an optimal learning process.

Chewing, dentition and tooth wear in Hippopotamidae (Hippopotamus amphibius and Choeropsis liberiensis).

Among mammals, hippopotamids ('hippos') have been described as the species with the lowest chewing efficacy despite elaborate enamel folds on the occlusal surface or their cheek teeth, which was hypothesized to result from the lack of a grinding chewing motion. We investigated the chewing and dentition of the two extant hippo species, the common hippo (Hippopotamus amphibius) and the pygmy hippo (Choeropsis liberiensis), making (video) observations of live animals and gathering data on museum specimens (n = 86 H. amphibius and 26 C. liberiensis skulls). Hippos have a low degree of anisodonty (differences in width between maxillary and mandibular cheek teeth) and anisognathy (difference in width between the upper and the lower jaw), corresponding to a mainly orthal (up-and-down) chewing motion. The two hippo species differ slightly, but distinctively, in their anterior dental morphology and chewing mode. In both species, the canines do not completely prevent a lateral jaw movement but would, in theory, permit this movement until the mandibular canines get into contact with the maxillary protruding snout. This movement is only realized, to a small extent, in pygmy hippos, leaving distinct wear traces on their incisors and creating relatively wider wear facets on the maxillary canines. In common hippos, the interlocking upper and lower incisors prevent lateral jaw movement. Corresponding contact wear facets are evident on the medial aspect of the upper, and on the lateral aspect of the lower incisors-unless museal reconstructions mispositioned these teeth. If these facets are interpreted as an indication for a relic of a lateral jaw movement that was probably more prominent in hippo ancestors, i.e. if we assume that hippos evolved orthal chewing secondarily, several other characteristics of hippos can be explained, such as a low degree of hypsodonty (in the absence of distinct attrition due to a grinding chewing movement), a secondary loss of complexity in their enamel schmelzmuster, a secondary evolution of a wide mouth gape, a reduction in anisodonty compared to their ancestors, and the evolution of a bilaterally symmetrical ('trifoliate') enamel folding pattern on the molar occlusal surface from an ancestral bunoselenodont condition. As an underlying driving force, selection for intraspecific combat with canines and incisors, necessitating a wide gape and a rigid jaw, has been suggested.

Application of virtual technology to maximize esthetics and function in the restoration of anterior traumatic dental injuries

The restoration of multiple teeth with traumatic injury in the esthetic zone is complex. For the present patient, an intraoral scanner, a facial scanner, a jaw motion analyzer, and cone beam computed tomography were applied to collect patient data and establish a virtual dental patient. The virtual technology increased the accuracy of tooth- and implant-supported crowns in both appearance and occlusion.

Insights on mandibular jaw movements during polysomnography in obstructive sleep apnea.

Malhotra A, Martinot J-B, Pépin J-L. Insights on mandibular jaw movements during polysomnography in obstructive sleep apnea. J Clin Sleep Med. 2024;20(1):151-163.

Psychological Stress as a Determinant of Increased Maximum Voluntary Bite Force - A Clinical Observational Study.

Background Psychological stress is a known risk factor and modulator for several oral diseases. It is among the critical etiological factors of bruxism and several other disorders. The quantum of bite force is one of the prime determinants of wear resistance and the clinical performance of restorations. Thus, the present study aims to investigate the relationship between the maximum voluntary bite force (MVBF) and the amount of perceived stress experienced by an individual. Materials and methods Patients (n=111) fulfilling the exclusion and inclusion criteria were divided into high, medium, and low-stress groups based on their stress scores deduced from the Perceived Stress Scale questionnaire (PSS). Bite force measurement was recorded in Newtons (N) for each subject using a portable customized bite recording FlexiForce sensor (B 201). The data were analyzed using Kruskal-Wallis and independent samples t-test. Results Among the females, the bite force in the medium and high-stress groups was greater compared to the low-stress level group. On the other hand, there was no difference in bite force between any of the stress level groups among male participants. Conclusion The results show that higher MVBF is associated with higher perceived stress scores in adult females. Practical Implications Psychological counseling can be included in the dental treatment plan of individuals with a high-stress score to counteract their stress-related higher occlusal forces, parafunctional jaw movements, and risky oral health behaviors, thereby potentially reducing the incidence of adverse outcomes such as temporomandibular joint dysfunction and restoration failure by careful choice of restorative materials.

Dosimetric investigation of radiation-induced trigeminal nerve toxicity in parotid tumor patients.

We aimed to describe the association between trigeminal nerve (TN) dose and toxicity and determine a threshold value that leads to TN toxicity in patients with parotid tumors treated with adjuvant conventional fractionated radiation therapy. Eighteen patients who underwent adjuvant radiotherapy (RT) between 2013 and 2018 were included in this retrospective study. TN and its branches were outlined subsequently on the planning CT scans. The doses received by TN were obtained based on the dose-volume histogram. The dose and toxicity relationship was investigated over the total prescribed dose. RT-related toxicity was graded according to Common Terminology Criteria for Adverse Events V4.0 (CTCAEv4.0). The median follow-up was 29.5 months. After RT, 61% of patients had Grade I-II late TN toxicity divided into Grade I in 4 (22%) and Grade II in 7 (39%) patients. TN injury symptoms were as follows: loss of sensation in the chin area in 3, difficulty in jaw movements in 3, and paresthesia in 5 patients. The total RT dose (p = 0.001), Dmax (p = 0.001), PTV-TN Dmax (p = 0.001), D1cc (p = 0.004), D0.5cc (p = 0.001), and D0.1cc (p = 0.01) had a significant effect on TN toxicity. Cut-off values leading to toxicity were determined as 66, 65.5, 65.25, 63.6, and 62.7 Gy for Dmax, PTV-TN Dmax, D0.1cc, D 0.5cc, and D1cc, respectively. Radiation-induced TN injury in head and neck cancer patients may further be investigated in clinically prospective trials by virtue of high toxicity rates with current RT doses in our retrospectively designed dosimetric study in parotid tumors.

Prevalence and quality of temporomandibular disorders, chronic pain and psychological distress in patients with classical and hypermobile Ehlers-Danlos syndrome: an exploratory study

BackgroundThe Ehlers-Danlos syndromes are a group of clinically and genetically heterogeneous hereditary diseases affecting the connective tissue. They are characterized by hypermobility of the joints, hyperextensible skin and friable tissue. According to current classification, 13 subtypes can be distinguished, of which the hypermobile and the classical subtype are the most prevalent. This study aimed to evaluate patients with classical (cEDS) and hypermobile (hEDS) Ehlers-Danlos syndrome regarding temporomandibular disorder (TMD), chronic pain, and psychological distress.MethodsSupport groups from Germany, Austria, and Switzerland were contacted, and social media were used to recruit participants. Free text questions, the German version of the Depression Anxiety and Stress Scale (DASS), and the German version of the Graded Chronic Pain Status (GCPS) were used.Results259 participants were included (230 hEDS/29 cEDS). At least 49.2% of the participants had painful or restricted jaw movements, and at least 84.9% had pain in the masticatory muscles, with 46.3% already having a diagnosed TMD. Multivariate analysis showed a significant correlation between TMJ involvement and chronic pain with a 2.5-fold higher risk of chronic pain with a diagnosed TMD. 22.8% of participants had a critical score for depression, 53.3% had a critical score for anxiety, and 34.0% had a critical score for stress.ConclusionThere is a high prevalence of TMD problems and chronic pain in patients with cEDS and hEDS. The lack of knowledge about these problems can create psychological distress. More research is needed to provide adequate treatment for patients with EDS.

Oral processing, rheology, and mechanical response: Relations in a two-phase food model with anisotropic compounds.

Food-material poses a challenging matrix for objective material scientific description that matches the consumers' perception. With eyes on the emerging structured food materials from alternative protein sources, objectively describing perceived texture characteristics became a topic of interest to the food industry. This work made use of the well-known methodologies of jaw tracking and electromyography from the field of "food oral processing" and compared outcomes with mechanical responses to the deformation of model food systems to meat alternatives. To enable transferability to meat alternative products, an anisotropic structuring ingredient for alternative products, high-moisture texturized vegetable protein (HM-TVP), was embedded in an isotropic hydrocolloid gel. Data of the jaw movement and muscle activities exerted during mastication were modeled in a linear mixed model and set in relation to characteristic values obtained from small- and large-strain deformation. For improvement of the model fit, this work makes use of two new data-processing strategies in the field of oral processing: (i) Muscle activity data were set in relation to true forces and (ii) measured data were standardized and subjected to dimensional reduction. Based on that, model terms showed decreased p-values on various oral processing features. As a key outcome, it could be shown that an anisotropic structured phase induces more lateral jaw movement than isotropic samples, as was shown in meat model systems.

Strategi produksi bunyi vokal oleh ventrilokuis Indonesia

Ventriloquism or voice magic illusion involves the ability of speakers to control lip and jaw movements to create the impression that sound or speech comes from a puppet being played. This study aims to analyze the strategies used by ventriloquists in producing vowel sounds in Indonesian using the acoustic analysis method (spectrography). Our research data was obtained from three Indonesian ventriloquists who appeared in a video entitled "Moveless Lips Ventriloquism Tutorial (Indonesian Ventriloquist)" on Tenggo Wicaksono's Youtube channel. The data was analyzed using Praat software version 6.2.10 and adopting Instituut voor Perceptie Onderzoek (IPO) design stages. From the analysis of formant 1 and formant 2 on the spectrogram, the three ventriloquists in this study used the same strategy in producing vowel sounds, namely by lowering the tongue position compared to when speaking normally, except for the [a] sound, which requires a higher tongue position. However, regarding horizontal tongue movement, each respondent has a different strategy. Some change the tongue's position forward, while others do it the other way around.

A 3D printed electronic wearable device to generate vertical, horizontal and phono-articulatory jaw movement parameters: A concept implementation.

The current research aimed to develop a concept open-source 3D printable, electronic wearable head gear to record jaw movement parameters. A 3D printed wearable device was designed and manufactured then fitted with open-source sensors to record vertical, horizontal and phono-articulatory jaw motions. Mean deviation and relative error were measured invitro. The device was implemented on two volunteers for the parameters of maximum anterior protrusion (MAP), maximum lateral excursion (MLE), normal (NMO), and maximum (MMO) mouth opening and fricative phono-articulation. Raw data was normalized using z-score and root mean squared error (RMSE) values were used to evaluate relative differences in readings across the two participants. RMSE differences across the left and right piezoresistive sensors demonstrated near similar bilateral movements during normal (0.12) and maximal mouth (0.09) opening for participant 1, while varying greatly for participant 2 (0.25 and 0.14, respectively). There were larger differences in RMSE during accelerometric motion in different axes for MAP, MLE and Fricatives. The current implementation demonstrated that a 3D printed electronic wearable device with open-source sensor technology can record horizontal, vertical, and phono-articulatory maxillomandibular movements in two participants. However, future efforts must be made to overcome the limitations documented within the current experiment.

Determinants of apnea-hypopnea index variability during home sleep testing

BackgroundA single-night attended in-laboratory polysomnography or home sleep testing are common approaches for obstructive sleep apnea (OSA) diagnosis. However, internight variability in apnea-hypopnea index value is common, and may result in misclassification of OSA severity and inapropriate treatment decisions. ObjectiveTo investigate factors determining short-term apnea-hypopnea index variability using multi-night automated home sleep testing, and to determine how this variability impacts clinical decisions. Patients/methodsAdults with suspected OSA who successfully performed three home sleep tests using measurements of mandibular jaw movements (Sunrise, Namur, Belgium) combined with automated machine learning analysis were enrolled. Data analysis included principal component analysis, generalized estimating equation regression and qualitative agreement analysis. Results160 individuals who performed three sleep tests over a mean of 8.78 ± 8.48 days were included. The apnea-hypopnea index varied by −0.88 events/h (5th-95th percentile range: −14.33 to 9.72 events/h). Based on a single-night recording, rates of overtreatment and undertreatment would have been of 13.5% and 6.0%, respectively. Regression analysis adjusted for age, sex, body mass index, total sleep time, and time between home sleep tests showed that time spent in deep non-rapid eye movement sleep and with head in supine position were independent significant predictors of the apnea-hypopnea index variability. ConclusionsAt the individual level, short-term internight variability in the apnea-hypopnea index was significantly associated with time spent in deep non-rapid eye movement sleep and head in supine position. Clinical decisions based on a single-night testing may lead to errors in OSA severity classification and incorrect therapeutic decisions.

Classifying Chewing and Rumination in Dairy Cows Using Sound Signals and Machine Learning.

This research paper introduces a novel methodology for classifying jaw movements in dairy cattle into four distinct categories: bites, exclusive chews, chew-bite combinations, and exclusive sorting, under conditions of tall and short particle sizes in wheat straw and Alfalfa hay feeding. Sound signals were recorded and transformed into images using a short-time Fourier transform. A total of 31 texture features were extracted using the gray level co-occurrence matrix, spatial gray level dependence method, gray level run length method, and gray level difference method. Genetic Algorithm (GA) was applied to the data to select the most important features. Six distinct classifiers were employed to classify the jaw movements. The total precision found was 91.62%, 94.48%, 95.9%, 92.8%, 94.18%, and 89.62% for Naive Bayes, k-nearest neighbor, support vector machine, decision tree, multi-layer perceptron, and k-means clustering, respectively. The results of this study provide valuable insights into the nutritional behavior and dietary patterns of dairy cattle. The understanding of how cows consume different types of feed and the identification of any potential health issues or deficiencies in their diets are enhanced by the accurate classification of jaw movements. This information can be used to improve feeding practices, reduce waste, and ensure the well-being and productivity of the cows. The methodology introduced in this study can serve as a valuable tool for livestock managers to evaluate the nutrition of their dairy cattle and make informed decisions about their feeding practices.

Exploring the interaction of viscosity and nipple design on feeding performance in an infant pig model.

Infant feeding behaviors are modulated via sensorimotor feedback, such that sensory perturbations can significantly impact performance. Properties of the nipple and milk (e.g., nipple hole size and viscosity) are critical sources of sensory information. However, the direct effects of varying milk and nipple properties on infant motor output and the subsequent changes in feeding performance are poorly understood. In this study, we use an infant pig model to explore the interaction between nipple hole size and milk viscosity. Using high-speed videofluoroscopy and electromyography, we measured key performance metrics including sucks per swallow and suck duration, then synchronized these data with the onset and offset of activity of jaw opening and closing muscles. The combination of a small nipple hole and thick milk resulted in negative effects on both suck and swallow performance, with reduced feeding efficiency compared to the other treatments. It also appears that this combination of viscosity and hole size disrupts the coordination between correlates of tongue and jaw movements. We did not see a difference in feeding efficiency between viscosities when infants fed on the large-hole nipple, which may be the result of non-Newtonian fluid mechanics. Our results emphasize the importance of considering both fluid and nipple properties when considering alterations to an infant's feeding system.

Reliability of 3D kinematic recording of jaw and head movements

Reliability of 3D kinematic recording of jaw and head movements

The effect of motor resource suppression on speech perception in noise in younger and older listeners: An online study.

Speech motor resources may be recruited to assist challenging speech perception in younger normally hearing listeners, but the extent to which this occurs for older adult listeners is unclear. We investigated if speech motor resources are also recruited in older adults during speech perception. Specifically, we investigated if suppression of speech motor resources via sub-vocal rehearsal affects speech perception compared to non-speech motor suppression (jaw movement) and passive listening. Participants identified words in speech-shaped noise at signal-to-noise ratios (SNRs) from -16 to +16 dB in three listening conditions during which participants: (1) opened and closed their jaw (non-speech movement); (2) sub-vocally mimed 'the' (articulatory suppression); (3) produced no concurrent movement (passive listening). Data from 46 younger adults (M age = 20.17 years, SD = 1.61, 36 female) and 41 older adults (M age = 69 years, SD = 5.82, 21 female) were analysed. Linear mixed effects modelling investigated the impact of age, listening condition, and self-reported hearing ability on speech perception (d' prime). Results indicated that speech perception ability was significantly worse in older adults relative to younger adults across all listening conditions. A significant interaction between age group and listening condition indicated that younger adults showed poorer performance during articulatory suppression compared to passive listening, but older adults performed equivalently across conditions. This finding suggests that speech motor resources are less available to support speech perception in older adults, providing important insights for auditory-motor integration for speech understanding and communication in ageing.

Assessment of Trismus among Patients with Head and Neck Cancer

Background: Trismus means the inability to open the mouth more than 35 mm, it is also called restriction of the mouth opening, and negatively affects eating, drinking, and speech, as well as the difficulty of the mouth cleaning. In addition, the Trismus in patients with head and neck cancer may be caused by an increase in the size of the tumor that affects the chewing muscles or tissue fibrosis as a result of surgery or radiation. Study Aim: The present study aims to determine the incidence of trismus among patients with head and neck cancer. Methods: A descriptive, cross-sectional study design was conducted national teaching hospital of oncology in Al-Najaf Al-Ashraf City. Anon-probability (purpose sampling technique was used to select 91 patients with head and neck carcinoma. Descriptive statistics like frequency, mean, standard deviation, percentage and inferential statistics, were used to analyze the study data. Results: The study found the patient-related trismus suffering from mild to severe trismus (16.5 %, vs. 11.0 %). Conclusion: Our study results showed that the most of participant patients had been jaw movement problems that can have affected by location, duration, and treatment of cancer.

Mechanical force regulates Sox9 expression at the developing enthesis.

Entheses transmit force from tendons and ligaments to the skeleton. Regional organization of enthesis extracellular matrix (ECM) generates differences in stiffness required for force transmission. Two key transcription factors co-expressed in entheseal tenocytes, scleraxis (Scx) and Sox9, directly control production of enthesis ECM components. Formation of embryonic craniofacial entheses in zebrafish coincides with onset of jaw movements, possibly in response to the force of muscle contraction. We show dynamic changes in scxa and sox9a mRNA levels in subsets of entheseal tenocytes that correlate with their roles in force transmission. We also show that transcription of a direct target of Scxa, Col1a, in enthesis ECM is regulated by the ratio of scxa to sox9a expression. Eliminating muscle contraction by paralyzing embryos during early stages of musculoskeletal differentiation alters relative levels of scxa and sox9a in entheses, primarily owing to increased sox9a expression. Force-dependent TGF-β (TGFβ) signaling is required to maintain this balance of scxa and sox9a expression. Thus, force from muscle contraction helps establish a balance of transcription factor expression that controls specialized ECM organization at the tendon enthesis and its ability to transmit force.

Bennett Angle, Condylar and Jaw Movements in Asymptomatic Athletes with a History of a Blow to One Side of the Mandibula.

Sports activities may induce long-lasting changes in mandibular trajectories. The aim was to compare condylar and mandibular movements in athletes with orofacial injuries with values measured in non-injured athletes. The group of 132 athletes without mandibular injury included asymptomatic athletes with a history of a blow to the right side (N = 43) and the group included asymptomatic athletes with a history of a blow to the left side (N = 41) of the mandible. The injured athletes suffered from stiffness/pain and/or limitation of jaw movements. The symptoms disappeared shortly after the injury. Athletes with a history of injury have smaller mean values of Bennett angle on the side of impact, and Bennett angle on the opposite side is greater than the mean found in non-injured athletes. Significantly smaller Bennett angle values in athletes with a history of a blow to one side of the mandible are due to the adaptability of the orofacial system. The larger Bennett angle on the opposite side of the injury is also due to the adaptive mechanism of the TMJ. Clinical Relevance: An individualized approach to TMJ values is mandatory in restorative procedures in every patient, especially in patients with a history of trauma to the orofacial system.

Kinematics of lateral tongue-pushing movement in coordination with masticatory jaw movement: An anteroposterior projection videofluorographic study

ObjectiveDuring the mastication of solid food, the tongue pushes the bolus laterally to place it onto occlusal surfaces as the jaw is opened. This movement is referred to as tongue-pushing (TP). TP has an important role in efficient chewing, but its kinematic mechanisms remain unclear. The present study quantified the kinematics of TP and its coordination with masticatory jaw movements. MethodsVideofluorography (VFG) in anteroposterior projection was recorded while 14 healthy young adults ate 6 g each of cookies and meat. Small lead markers were glued to the tongue surface (left, right, and anterior) and buccal tooth surfaces (upper molars and lower canines). The position of the tongue and lower canine markers relative to the upper occlusal plane was quantified with Cartesian coordinates, using the right upper molar as the origin. Jaw motion during chewing was divided into TP and Non-TP cycles, based on the lateral movement of the food and tongue markers. The side of the jaw that compressed food particles was defined as the working side, while the other side was termed the balancing side. Horizontal and vertical displacements of tongue and jaw markers were compared between TP and Non-TP cycles, as well as between food types. ResultsThe mediolateral displacement of all tongue markers was significantly larger in TP than in Non-TP cycles. Vertical displacement was also significantly greater in TP than in Non-TP cycles for the anterior and working side tongue markers. TP cycles occurred more frequently with meat-chewing than with cookie-chewing. ConclusionTP is accomplished by rotation and lateral movements of the tongue surface on the working side and the anterior tongue blade, along with medial movement on the balancing side. These movements produce lateral shift and rotation of the tongue surface toward the working side in concert with jaw opening. Designing exercises to improve the strength of the lateral motion and rotation of the tongue body may be useful for individuals with impaired tongue function for eating and swallowing.