Search

Objective: To develop a multidimensional facial surface electromyographic (EMG) analysis for assessing bulbar involvement in amyotrophic lateral sclerosis (ALS)., Methods: Fifty-four linear and nonlinear features were extracted from the surface EMG recordings for masseter, temporalis, and anterior belly of digastric in 13 patients with ALS and 10 healthy controls, each performed a speech task three times. The features were factor analyzed and then evaluated in terms of internal consistency, relation to functional speech outcomes, and efficacy for patient-control classification., Results: Five internally consistent, interpretable factors were derived, representing the functioning of masseter, temporalis, digastric, antagonists, and agonists, respectively. These factors explained 40-43% of the variance in the functional speech outcomes and were ≥90% accurate in patient-control classification. The jaw muscle performance of individuals with ALS was characterized by (1) reduced complexity and coherence of antagonist muscle activities, and (2) increased complexity and irregularity of temporalis activity., Conclusions: Two important bulbar muscular changes were identified in ALS, related to both upper and lower motor neuron pathologies. These changes reflected (1) decreased motor unit recruitment and synchronization for jaw antagonists, and (2) a potential neuromuscular adaptation for temporalis., Significance: The surface EMG-based framework shows promise as an objective bulbar assessment tool., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: This web-based survey, as a tool of teledentistry, is aimed at assessing the level of knowledge, attitudes, and awareness regarding MRONJ among dental professionals in Northern Cyprus., Methods: An online self-administered questionnaire about MRONJ was sent to all dentists in Northern Cyprus through Google Forms. The first part of the questionnaire consists of demographic and professional information, and the second part included questions about knowledge and awareness questions about MRONJ. The SPSS software was used for statistical data analysis. A Chi-square test was performed to compare between the groups. The significance level was set at p < 0.05., Results: A total of 112 dentists participated in this survey. The participants showed an insufficient level of knowledge regarding MRONJ, as only 56.6% of the participants stated that they had general knowledge about MRONJ. Regarding the practical questions of the survey, the participants showed poor knowledge about implant and tooth extraction procedures while a patient is using antiresorptive or antiangiogenic drugs, particularly the usage of oral antiresorptive or antiangiogenic drugs for less than 3 years. Participants showed adequate knowledge in terms of usage area of medications and administration of them., Conclusion: Teledentistry can be used as a supportive tool for dentists in diagnosing MRONJ. Similar to previous studies, the knowledge and awareness of MRONJ of dentists in Northern Cyprus were found to be inadequate. There is a significant need to provide more professional information as part of undergraduate programs so that the next generation of dentists can practice more confidently., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2021 Mujgan Firincioglulari and Kaan Orhan.)

Diabetes represents a challenge in implant therapy because hyperglycemia may negatively affect bone regeneration, directly compromising clinical outcomes and increasing clinical failures. The aim of this retrospective study is to analyse the prognostic significance of HbA1c levels in patients undergoing implant placement associated with horizontal guided bone regeneration. Thirty-four patients were divided into 3 groups according to their HbA1c levels: nondiabetic normoglycemic patients (HbA1c < 5.7%), nondiabetic hyperglycemic patients (HbA1c < 6.5%), and controlled diabetic patients (HbA1c < 7%). Primary outcomes were dimensional changes in height (VDH) and width (DW) of the peri-implant defect. Secondary outcomes were evaluations of periodontal parameters of adjacent tooth sites, wound healing, marginal bone loss (MBL), and survival and success rates. At T 1 (6 months), mean VDH values in groups 1, 2, and 3 were, respectively, 0.07, 0.5, and 0.25 mm. Mean DW values in those same groups were, respectively, 0.07, 0.38, and 0.33 mm. HbA1c levels were not statistically related to VDH and DW values at T 1 . No statistically significant differences were observed in MBL between groups ( p = 0.230). Implant survival and success rates were, respectively, 98% and 96%. Simultaneous guided bone regeneration is a feasible procedure for the treatment of horizontal bone deficiencies in controlled diabetic patients., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2021 Paolo De Angelis et al.)

BACKGROUND The aim of this study was to investigate the association of oral behaviors (OBs) with anxiety, depression, and jaw function in patients with temporomandibular disorders (TMDs) in China. MATERIAL AND METHODS A total of 537 patients diagnosed with TMD were included in this study (average age, 31.55±12.08 years; 86 men [16.0%] and 451 women [84.0%]). There were 31 cases of masticatory muscle pain, 459 cases of disc displacement, and 13 cases of arthralgia/arthrosis, and 34 cases were uncategorized. Patients were assessed using the Oral Behaviors Checklist (OBC), Jaw Functional Limitation Scale (JFLS), Generalized Anxiety Disorder-7 (GAD-7) scale, and Patient Health Questionnaire-9 (PHQ-9). The relationships between OBC scores and mouth opening, pain scores, JFLS, PHQ-9, and GAD-7 were evaluated with Spearman's correlation analysis. The median TMD symptom duration was 3 (0.5-154) months; men and women did not differ significantly in symptom duration or in the number of episodes of depression and anxiety. RESULTS The following OBs were common in patients with TMDs: "putting pressure on the jaw (52.9%)", "chewing food on 1 side (47.5%)", and "holding teeth together during activities other than eating (33.3%)". The OBC scores were significantly correlated with the JFLS, PHQ-9, and GAD-7 scores (P<0.01). CONCLUSIONS Patients with TMDs exhibit specific OBs, which are associated with depression, anxiety, and jaw function. It is necessary to further investigate the interaction of OBs with depression and anxiety in the development of TMDs.

Dental-tissue-derived stem cells have been used for tissue engineering owing to their ease of isolation and efficacy in in vitro and in vivo proliferation and differentiation. Nanohydroxyapatite/chitosan/gelatin (nHA/CG) three-dimensional porous scaffolds are promising for bone tissue engineering, especially jaw bone regeneration, because of their structural and functional similarity to natural bone. In our previous study, the efficiency of scaffolds with stem cell complexes in osteogenesis was confirmed in vivo in immunocompromised mice. However, studies on the bone regeneration efficiency of stem cell-seeded nHA/CG scaffolds using large animal jaw bone defect models have not been conducted. This study evaluated the bone regeneration potential of the nHA/CG scaffolds with transplanted human periodontal ligament stem cells (hPDLSCs) in critical-sized jaw bone defects in minipigs. The hPDLSCs isolated from periodontal ligaments of discarded teeth (postorthodontic purposes) were seeded onto the nHA/CG scaffolds. The scaffold was successfully synthesized according to our previous studies. Forty-eight critical-sized jaw bone defects were created in 12 minipigs. The defects were randomly assigned to one of three groups [scaffolds with seeded hPDLSCs (hPDLSCs/nHA/CG), only scaffold (nHA/CG), and a negative control group, ie, no cells and scaffolds implanted into defects] to investigate jaw bone regeneration. The bone regeneration capacities of the three groups were assessed for up to 12 weeks. The results showed that the hPDLSCs adhered well to the nHA/CG scaffold in vitro, and the cell-nHA/CG composites significantly increased new bone formation and generated large bones with normal architectures and vascularization in vivo compared to the nHA/CG and control groups. Immunohistochemistry staining showed that runt-related transcription factor 2 (Runx2) was highly expressed in the bone marrow formed in the hPDLSCs/nHA/CG group. This study provides strong evidence for future clinical applications of the nHA/CG scaffolds transplanted with hPDLSCs to regenerate the bone in large jaw bone defects.

Patient education is important in the treatment of temporomandibular disorder (TMD), but little is known about its effect on oral behaviors. We aimed to determine the dominant oral behaviours in patients with TMD and assess the impact of education on such behaviours. Between July 2018 and April 2019, 54 patients diagnosed with TMD according to DC/TMD were recruited. They received physical therapy and were provided education on TMD and offered a list of recommendations for improving their oral behaviours. The patient education process usually lasted for 10-20 min. Of these patients, 48 were reexamined at the outpatient clinic, 3-9 months posttreatment. We recorded the Oral Behaviour Checklist (OBC) score, maximum painless mouth opening (mm), visual analogue scale (VAS) score for pain, and Jaw Functional Limitation Scale (JFLS) score pre- and posttreatment. Wilcoxon signed rank test and paired sample t -test were used for statistical analysis. Results showed that the most dominant oral behaviours included "putting pressure on the jaw" (59.3%); "chewing food on one side" (46.3%); "pressing, touching, or holding teeth together at times other than eating" (33.3%); and "eating between meals" (33.3%). Posttreatment, the patients reported a decrease in "chewing gum" ( P = 0.002), "leaning with the hand on the jaw" ( P = 0.013), "chewing food on one side" ( P ≤ 0.001), and "eating between meals" ( P = 0.007), but this change was not significant in subgroups with a follow-up interval of 9 months. We also observed a significant improvement in the maximum painless mouth opening ( P ≤ 0.001), JFLS score ( P ≤ 0.001), and VAS score ( P ≤ 0.001) for pain, posttreatment. In conclusion, patient education can facilitate management of oral behaviours and should be targeted towards specific oral behaviours., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2021 Lili Xu et al.)

Motor- and pain-related processes separately induce a reduction in alpha and beta power. When movement and pain occur simultaneously but are independent of each other, the effects on alpha and beta power are additive. It is not clear whether this additive effect is evident during motor-evoked pain in individuals with chronic pain. We combined highdensity electroencephalography (EEG) with a paradigm in which motor-evoked pain was induced during a jaw force task. Participants with chronic jaw pain and pain-free controls produced jaw force at 2% and 15% of their maximum voluntary contraction. The chronic jaw pain group showed exacerbated motor-evoked pain as force amplitude increased and showed increased motor variability and motor error irrespective of force amplitude. The chronic jaw pain group had an attenuated decrease in power in alpha and lower-beta frequencies in the occipital cortex during the anticipation and experience of motor-evoked pain. Rather than being additive, motor-evoked pain attenuated the modulation of alpha and beta power, and this was most evident in occipital cortex. Our findings provide the first evidence of changes in neural oscillations in the cortex during motor-evoked jaw pain., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Jaw clonus is rhythmic, oscillatory contraction of jaw muscles induced by stretch and is caused by lesions of the descending motor neurons in the corticopontine tracts., Phenomenology Shown: We illustrate jaw clonus elicited with jaw activation and upon testing of the jaw jerk in a patient with amyotrophic lateral sclerosis., Educational Value: This video clearly demonstrates the uncommon sign of jaw clonus, a finding which needs to be distinguished from tremor and should direct the examiner to consider lesions of the corticopontine fibres, including amyotrophic lateral sclerosis., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2020 The Author(s).)

Objectives: We aimed to evaluate the clinical significance of the somatic modulation test in patients with tinnitus and analyze the treatment outcomes., Materials and Methods: Medical records of patients who visited the tinnitus clinic at a local university hospital between October 2018 and April 2019 were retrospectively reviewed., Results: The data of 81 patients were analyzed for this study, of which 61.7% (n=51) showed tinnitus modulation after one or more neck or jaw maneuvers. Patients with narrow-band noise tinnitus tended to show maneuver-induced modulation more frequently than those with pure-tone tinnitus (85.7% vs. 53.3%, p=0.010). Neck maneuvers reduced tinnitus loudness in 29.6% of the patients, while 27.2% of patients (n=22) reported worsening of tinnitus loudness, and 23.5% of patients (n=19) reported tinnitus suppression after jaw maneuvers. None of the patients with noise exposure history reported tinnitus modulation. Backward regression analysis revealed that age was an independent risk factor for improvement (Exp [B]=0.703, p=0.034, 95% CI=0.508-0.974). However, somatic modulation or medical treatments targeting somatic modulation were not related to improvement., Conclusion: Patients showing modulation after neck or jaw maneuvers have specific clinical characteristics. However, somatic modulation itself does not affect the final treatment outcome.

The extent to which load transfer in a diseased mandible with odontogenic tumour might influence the potential risk of pathological fracture has scarcely been investigated. The study sought to investigate the quantitative deviations in load transfer across healthy and cancer-affected (diseased) mandibles having odontogenic tumours. The effect of size of the tumours (small: 9 mm diameter, large: 19 mm diameter), and variation in bone mechanical (elastic) properties of the mandible on load transfer in cancer-affected mandibles during a mastication cycle have been investigated. Based on patient-specific computed tomography-scan datasets, detailed three-dimensional finite element models of healthy and diseased mandibles were developed. High stresses of 25-30 MPa and strains ∼700 µε were observed in the healthy mandible during the right molar bite. However, marginal deviations were observed in principal stress distributions in the diseased mandibles with small- and large-sized tumours, as compared to the healthy mandible. Maximum principal strains of ∼1474 µε were found in the body region adjacent to the symphysis region for small-sized tumour. Whereas for large-sized tumour, maximum strains of ∼2700 µε were observed in the right buccal regions. Reduction in Young's modulus due to different stages of odontogenic tumours had a localised effect on the principal stress distributions, but triggered an abrupt increase in the principal tensile strains. It appears that there is a potential risk of pathological fracture for large-sized odontogenic tumour, owing to high tensile stresses and strains.

One of the most important aspects of bone remodeling is the constant turnover mainly driven by the mechanical loading stimulus. The remodeling process produces changes not only in the bone microarchitecture but also in the density distribution of the mineralized matrix - i.e. in calcium concentrations- and in the osteocyte lacunar network. Synchrotron radiation-based X-ray microtomography (microCT) has proven to be an efficient technique, capable to achieve the analysis of 3D bone architecture and of local mineralization at different hierarchical length scales, including the imaging of the lacuno-canalicular network. In the present study, we used microCT within a conceptual study of jawbone remodeling, demonstratively focusing the investigation in two critical contexts, namely in the peri-dental and the peri-implant tissues. The microCT analysis showed that a relevant inhomogeneity was clearly present in both peri-dental and peri-implant biopsies, not only in terms of microarchitecture and mineralization degree, but also considering the lacunar network, i.e. size and numerical density of the osteocyte lacunae. The correlated histological results obtained on the same samples confirmed these observations, also adding information related to non-mineralized tissues. Despite its demonstrative nature, it was concluded that the proposed method was powerful in studying jawbone remodeling because it revealed a direct correlation of its rate with the lacunar density, as achieved by the analysis of the osteocyte lacunar network, and an inverse correlation with the local bone mineral density, as revealed with the Roschger approach.

Purpose: To analyze the presence of a floppy epiglottis (FE) during drug-induced sleep endoscopy in non-apneic snoring patients, non-positional obstructive sleep apnea (OSA) patients (NPP), and position-dependent OSA patients (PP) and to evaluate the impact of maneuvers and body position during drug-induced sleep endoscopy, including jaw thrust and supine and lateral head (and trunk) position., Methods: Retrospective cohort study., Results: In total, 324 patients were included. In 60 patients (18.5%), a FE was found in supine position: seven non-apneic snoring patients and 53 OSA patients. When performing lateral head rotation only, a FE was present in four patients (NPP, N = 0; PP, N = 4). When patients were tilted to both lateral head and trunk position, a FE was found in only one subject. After applying jaw thrust, a FE was still present in 10 patients. The prevalence of a FE did not differ between NPP and PP. When comparing baseline characteristics between patients with and without a FE in supine position, no significant differences were found., Conclusion: A FE appears almost exclusively in supine position. In patients with a FE, positional therapy can be a promising alternative as a standalone treatment, but also as part of combination therapy with for example mandibular advancement devices or less invasive forms of upper airway surgery.

Purpose The current study tested jaw movement characteristics and their impact on tongue movement for speech production in individuals with amyotrophic lateral sclerosis (ALS). Specifically, the study examined tongue and jaw movement in multiple directions during jaw opening and closing strokes in individuals with ALS and controls. Method Twenty-two individuals with ALS and 22 controls participated in the current study. Tongue and jaw movements during the production of the words "Iowa" and "Ohio" (produced in a carrier phrase) were recorded using electromagnetic articulography. Tongue and jaw distances were measured for jaw opening and closing strokes. Distance was measured in the anterior-posterior and superior-inferior dimensions (retraction, advancement, lowering, and raising). Results Findings revealed that individuals with ALS exaggerated their jaw opening movements, but not their jaw closing movements, compared to controls. Between the groups, a comparable tongue lowering distance was observed during jaw opening movements. In contrast, reduced tongue raising was observed during the jaw closing movements in individuals with ALS compared to controls. Conclusion The findings suggest that individuals with ALS produce excessive jaw opening movements in the absence of excessive jaw closing movements. The lack of excessive jaw closing movements results in reduced tongue raising in these individuals. Excessive jaw opening movements alone suggest a direction-specific jaw dysfunction. Future studies should examine whether excessive jaw raising can be facilitated and if it enhances tongue raising movement for speech production in individuals with dysarthria secondary to ALS.

Background: The effort to improve tracheal intubation process is clinically valuable. We hypothesized that a preoperative brief exercise therapy would increase mouth opening and neck extension, enhancing intubation conditions during general anesthesia., Methods: Patients undergoing general anesthesia were randomized into two groups. The exercise group performed the exercise regimen including masseter muscle massage and stretching of jaw and neck joints before anesthetic induction, while the control did not. Before (baseline) and after the intervention, we evaluated Mallampati score, mouth aperture size, and sternomental distance. After tracheal intubation, intubation difficulty scale with direct laryngoscope and oropharyngeal soft tissue injury were also evaluated., Results: A total of 138 patients completed the analysis (control = 68, exercise = 70). Baseline characteristics did not differ between groups. At anesthetic induction, there was a significant difference in Mallampati score between the two groups (P = 0.039) and the incidence of Mallampati scores of 1 was higher in the exercise group (odds ratio [95% CI]: 2.1 [1.0-4.3], P = 0.043). Mouth opening after the intervention was greater in the exercise group than in the control group (estimated difference [95% CI]: - 2.4 [- 4.8 - -0.1], P = 0.042) and sternomental distance was similar between the two groups (estimated difference [95% CI]: - 3.7 [- 9.0-1.7, P = 0.175). The exercise group showed less soft tissue injuries (odds ratio [95% CI]: 0.2 [0.1-0.8], P = 0.009), however, intubation difficulty scale did not differ between the study groups (P = 0.112)., Conclusions: The brief pre-anesthetic exercise improved intubation conditions and enabled faster tracheal intubation with less injury to oropharyngeal soft tissue., Trial Registration: Clinical Research Information Service (registration number: KCT0002618), registered at December 28, 2017.

Purpose : To compare two different tasks and kinematic measures in terms of their ability to detect Amyotrophic lateral sclerosis (ALS) and differences in ALS severity in order to establish potential candidate markers of bulbar decline. Method : We tracked jaw kinematics during speech and chewing to determine which is more affected by bulbar motor deterioration, based on measures of maximum speed and articulatory working space. Data were collected from 31 individuals diagnosed with ALS and 17 neurologically intact controls. Result : (1) Both sentence and chewing tasks were effective in distinguishing between the groups of individuals with ALS and controls, (2) jaw maximum speed for both chewing and speech was a more sensitive marker for bulbar dysfunction than articulatory working space, (3) the sentence task distinguished between ALS subgroups stratified by severity and (4) distinct jaw kinematic differences existed between chewing and sentence tasks. More specifically, movement speed for speech decreased with severity while movement speed for chewing increased with disease severity. Conclusion : The findings from the current investigation suggest that measures of jaw movement speed during chewing and sentence tasks are affected by bulbar deterioration, and jaw speed during a sentence task may serve as a candidate marker of bulbar disease onset and severity.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which motor neurons degenerate, resulting in muscle atrophy, paralysis, and fatality. Studies using mouse models of ALS indicate a protracted period of disease development with progressive motor neuron pathology, evident as early as embryonic and postnatal stages. Key missing information includes concomitant alterations in the sensorimotor circuit essential for normal development and function of the neuromuscular system. Leveraging unique brainstem circuitry, we show in vitro evidence for reflex circuit-specific postnatal abnormalities in the jaw proprioceptive sensory neurons in the well-studied SOD1 G93A mouse. These include impaired and arrhythmic action potential burst discharge associated with a deficit in Nav1.6 Na + channels. However, the mechanoreceptive and nociceptive trigeminal ganglion neurons and the visual sensory retinal ganglion neurons were resistant to excitability changes in age-matched SOD1 G93A mice. Computational modeling of the observed disruption in sensory patterns predicted asynchronous self-sustained motor neuron discharge suggestive of imminent reflexive defects, such as muscle fasciculations in ALS. These results demonstrate a novel reflex circuit-specific proprioceptive sensory abnormality in ALS. SIGNIFICANCE STATEMENT Neurodegenerative diseases have prolonged periods of disease development and progression. Identifying early markers of vulnerability can therefore help devise better diagnostic and treatment strategies. In this study, we examined postnatal abnormalities in the electrical excitability of muscle spindle afferent proprioceptive neurons in the well-studied SOD1 G93A mouse model for neurodegenerative motor neuron disease, amyotrophic lateral sclerosis. Our findings suggest that these proprioceptive sensory neurons are exclusively afflicted early in the disease process relative to sensory neurons of other modalities. Moreover, they presented Nav1.6 Na + channel deficiency, which contributed to arrhythmic burst discharge. Such sensory arrhythmia could initiate reflexive defects, such as muscle fasciculations in amyotrophic lateral sclerosis, as suggested by our computational model., (Copyright © 2019 the authors.)

Rhythmic jaw muscle activities frequently occur during non-rapid eye movement sleep in patients with sleep bruxism. The present study aimed to investigate the response characteristics of the masticatory rhythm generation during non-rapid eye movement sleep in animals. Eleven guinea pigs were surgically prepared for polygraphic recordings by electromyography, electrooculography, electroencephalography and electrocardiography with the implantation of a stimulating electrode. Repetitive electrical microstimulations at three intensities were applied to the corticobulbar tract under freely moving conditions. The rhythmic electro-myographic responses of the digastric and masseter muscles were scored and analysed. Changes in cortical electro-encephalographic power and heart rate in association with these stimulations were quantified. Microstimulations to the corticobulbar tract induced rhythmic jaw muscle activities in digastric muscles, occasionally with masseter activities during wakefulness and non-rapid eye movement sleep. The response rate of rhythmic jaw muscle activities was significantly lower (p < 0.01) and the response latency was significantly longer (p < 0.01) during non-rapid eye movement sleep than during wakefulness. At higher stimulus intensities, the response rate increased and response latency decreased. The mean burst intervals of the digastric and masseter muscles were similar regardless of vigilance states and stimulus intensities. Induced rhythmic jaw muscle activities during non-rapid eye movement sleep were followed by a transient decrease in delta power and increases in beta power and heart rate. During non-rapid eye movement sleep, the masticatory motor system is able to generate rhythmic outputs to the jaw muscles in response to facilitatory inputs although the responsiveness was decreased from wakefulness., (© 2019 European Sleep Research Society.)

Purpose The aim of this study was to determine the relation of tongue-jaw coupling to phonetic distinctiveness of vowels in persons at different stages (i.e., early, middle, late) of bulbar motor involvement in amyotrophic lateral sclerosis (ALS) and healthy controls. Method The pattern of spatial tongue-jaw coupling was derived from 11 individuals with ALS and 11 healthy controls using the parallel factor analysis. Two articulatory components, which correspond to tongue displacement independent of the jaw (iTongue) and jaw contribution to tongue displacement (cJaw), were extracted from the composite tongue-jaw displacement. These articulatory components were correlated with F1 (i.e., height) and F2-F1 (i.e., advancement) of 4 vowels (/i/, /u/, /æ/, and /ɔ/) across all participants in each group. In addition, a comprehensive index of functional tongue-jaw coupling was derived as the ratio of cJaw/(iTongue + cJaw), and an acoustic index of vowel distortion (VowelDis) was derived to quantify the overall disease-related changes in phonetic distinctiveness of vowels. Based on these indices, disease-related changes in tongue-jaw coupling and phonetic distinctiveness of vowels were examined in individuals at the early, middle, and late stages of the disease. Results For healthy controls, both iTongue and cJaw contributed to F2-F1, while only cJaw contributed to F1. For individuals with ALS, both iTongue and cJaw contributed to F1, whereas only cJaw contributed to F2-F1. Disease-related changes in tongue-jaw coupling included (a) an overall decrease of the percent contribution of the tongue to the composite tongue-jaw displacement accompanied by an increase of percent contribution of the jaw and (b) several changes in the direction of tongue and jaw displacements occurred at different stages of the disease. These disease-related changes in tongue-jaw coupling had various impacts on phonetic distinctiveness of vowels, resulting in (a) a backward shift of front vowels and reduced front-back vowel contrasts, which occurred early and throughout the disease stages; (b) raising of all vowels during the middle stage of the disease; and (c) reduced high-low vowel contrasts during the late stage of the disease. Overall, phonetic distinctiveness of vowels deteriorated progressively throughout the disease course. Conclusions Different from healthy controls who established optimal functional coupling between the tongue and the jaw during vowel productions, individuals at the early-to-middle stages of bulbar ALS showed various adaptive changes in tongue-jaw coupling in response to the disease-related biomechanical and muscular changes in the articulators (particularly in the tongue). These adaptive changes in tongue-jaw coupling were found to be partially effective in mitigating the negative effect of articulatory involvement on phonetic distinctiveness of vowels. As the disease progressed to the late stage, such adaptations appeared to be no longer evident, resulting in a substantial overall reduction of vowel contrasts.

Purpose Motor neuron diseases, such as amyotrophic lateral sclerosis (ALS), have a devastating effect on speech muscle function that often results in severe communication deficits. Over the course of bulbar disease, tongue and jaw movements are modified, but their impact on speech is poorly understood. The aim of this study was to determine the effect of disease-related changes in tongue-jaw movement coupling on speech intelligibility in persons at different stages of bulbar ALS. Method Parallel factor analysis was used to quantify the pattern of spatial coupling between 4 semi-independent regions of the tongue and the jaw in various vowels and consonants in 10 individuals with ALS and 10 healthy individuals, respectively, from the X-Ray Microbeam database (Westbury, 1994). The relation of spatial tongue-jaw coupling to speech intelligibility was examined in individuals at the early and late stages of bulbar ALS and healthy individuals. Results Tongue movement, independent of the jaw, decreased early and progressively, which negatively impacted speech intelligibility. Jaw contribution to tongue movement was increased during the early stages of bulbar ALS compared to that of the healthy subjects, which was followed by a decrease during the late stages of bulbar ALS. The early-stage increase of jaw contribution significantly improved speech intelligibility and is thus most likely to be an adaptive strategy to mitigate the negative impact of tongue movement reductions on speech intelligibility. This adaptive strategy became unavailable during the late stages of bulbar ALS, which might accelerate intelligibility decline. Conclusions The loss of functional tongue-jaw coupling may be the critical physiological factor leading to the eventual loss of functional speech in ALS. Monitoring changes in tongue-jaw coupling may improve the prediction about the timing of speech loss and guide clinical management of dysarthria in ALS.

We report the osteogenic potential of silver (Ag), gold (Au), or silver-gold doped hydroxyapatite nanoparticles (Ag-Au-HA) in zebrafish (ZF) jawbone regeneration (JBR) model. The hydroxyapatite (HA, Ca 10 (PO 4 ) 6 (OH) 2 ), Ag-HA, Au-HA, and Ag-Au-HA nanomaterials were synthesized by the co-precipitation procedure. The surface structures of Ag-HA, Au-HA, HA, and Ag-Au-HA were analysed by scanning electron microscopy, transmission-electron microscopy (TEM), x-ray diffraction, Fourier transform infrared (FTIR), UV-vis, energy dispersive x-ray spectroscopy (EDS), elemental mapping, and laser fluorescent spectroscopy. The TEM and EDS analysis confirmed that the Ag and Au are associated with the surface of HA nanoparticle. The chemical structure of HA, Ag-HA, Au-HA, and Ag-Au-HA nanoparticles was validated by FTIR and EDS analysis. We observed that Ag and Au are associated with HA nanoparticles by electrostatic, wander wall, and electrostatic and H-bonding interaction. The effect of Ag-HA, Au-HA, and Ag-Au-HA nanoparticles on bone regeneration was confirmed by ZF JBR model. The significant growth of ZF bone regeneration was observed in Ag-Au-HA nanoparticles as compared with HA, Ag-HA, and Au-HA nanoparticles. These results indicating a therapeutic potential of Ag-Au-HA compositions suggest these nanomaterials would be excellent for bone regeneration and fracture healing.

Neurodegenerative pathologies as Parkinson's Disease (PD) show important distortions in speech, affecting fluency, prosody, articulation and phonation. Classically, measurements based on articulation gestures altering formant positions, as the Vocal Space Area (VSA) or the Formant Centralization Ratio (FCR) have been proposed to measure speech distortion, but these markers are based mainly on static positions of sustained vowels. The present study introduces a measurement based on the mutual information distance among probability density functions of kinematic correlates derived from formant dynamics. An absolute kinematic velocity associated to the position of the jaw and tongue articulation gestures is estimated and modeled statistically. The distribution of this feature may differentiate PD patients from normative speakers during sustained vowel emission. The study is based on a limited database of 53 male PD patients, contrasted to a very selected and stable set of eight normative speakers. In this sense, distances based on Kullback-Leibler divergence seem to be sensitive to PD articulation instability. Correlation studies show statistically relevant relationship between information contents based on articulation instability to certain motor and nonmotor clinical scores, such as freezing of gait, or sleep disorders. Remarkably, one of the statistically relevant correlations point out to the time interval passed since the first diagnostic. These results stress the need of defining scoring scales specifically designed for speech disability estimation and monitoring methodologies in degenerative diseases of neuromotor origin.

Objective: In this study, we examined if 6-9 Hz jaw tremor, an indirect indicator of Periodontal Mechanoreceptor (PMR) activity, is different in bruxists compared to healthy participants during production of a low-level constant bite force., Methods: Bite force and surface EMG from the masseter muscle were recorded simultaneously as participants (13 patients, 15 controls) held a force transducer between the upper and lower incisors very gently., Results: Tremor in 6-9 Hz band for bruxists was greater on average compared to controls, but the difference was not significant, both for force recordings and EMG activity., Conclusions: The low effect sizes measured with the current protocol contrast highly with those of our previous study, where larger, dynamic bite forces were used, and where jaw tremor was markedly different in bruxists compared with controls., Significance: We have now gained important insight into the conditions under which abnormal jaw tremor can be elicited in bruxism. From a scientific standpoint, this is critical for understanding the 'abnormality' of PMR feedback in bruxism. From a clinical perspective, our results represent progress towards the development of an optimal protocol in which jaw tremor can serve as a biological marker of bruxism., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Multiple sclerosis can affect the speech motor system and result in dysarthria., Objectives: This pilot study sought to identify tongue, lip, and jaw motor deficits in persons with dysarthria due to multiple sclerosis (PwDMS) to better understand the speech motor mechanisms that underlie their aberrant speech., Methods: Tongue and jaw movements during "ai" and lower lip and jaw movements during "bob"were examined in eleven PwDMS and fourteen age- and sex-matched controls using three-dimensional electromagnetic articulography. Movement duration, maximum displacement, peak speed, stiffness (i.e., peak speed/displacement ratio), and jaw contribution to lower lip and tongue displacements were of particular interest., Results: Whereas most kinematic measures yielded significant between-group differences for tongue and jaw motor performance during "ai", lower lip and jaw motor performance during "bob" were mostly comparable between groups., Conclusion: Findings suggest that speech movements of the tongue are differentially more impaired than those of the lower lip in PwDMS. Particularly the ability to move the tongue with adequate speed during speech was significantly impaired in PwDMS, which may explain, in part, their slowed speech rate. Aberrant jaw kinematics during "ai" may be a compensatory strategy to maximize speech clarity in the presence of the impaired tongue motor performance., (Copyright © 2018. Published by Elsevier B.V.)

Background/aims: Specific language impairment (SLI) is characterized by deficits in language ability. However, studies have also reported motor impairments in SLI. It has been proposed that the language and motor impairments in SLI share common origins. This exploratory study compared the gross, fine, oral, and speech motor skills of children with SLI and children with typical development (TD) to determine whether children with SLI would exhibit difficulties on particular motor tasks and to inform us about the underlying cognitive deficits in SLI., Methods: A total of 13 children with SLI (aged 8-12 years) and 14 age-matched children with TD were administered the Movement Assessment Battery for Children - Second Edition and the Verbal Motor Production Assessment for Children to examine gross and fine motor skills and oral and speech motor skills, respectively., Results: Children with SLI scored significantly lower on gross, fine, and speech motor tasks relative to children with TD. In particular, children with SLI found movements organized into sequences and movement modifications challenging. On oral motor tasks, however, children with SLI were comparable to children with TD., Conclusion: Impairment of the motor sequencing and adaptation processes may explain the performance of children with SLI on these tasks, which may be suggestive of a procedural memory deficit in SLI., (© 2018 S. Karger AG, Basel.)

Early identification of bulbar involvement in persons with ALS is critical for improving diagnosis and prognosis; however, efficacious diagnostic markers have not yet been identified. The purpose of this study was to determine whether kinematic changes of the tongue and jaw during swallowing, measured using 3D electromagnetic articulography (EMA), predate clinically identifiable symptoms of speech and swallowing impairment in persons diagnosed with ALS. Data were collected from 16 adults diagnosed with ALS and 18 neurotypical controls. Groups were aged matched. Eligible participants with ALS were tolerating an unrestricted diet (FOIS = 7), produced intelligible speech (> 97%), and had a speaking rate greater than 150 words per minute. Participants completed a 3-mL water swallow task, during which EMA recorded kinematic measures of the anterior and posterior regions of tongue including lingual speed, range of motion, duration, coordination, and efficiency. Jaw speed and range of motion were also recorded. Persons diagnosed with ALS demonstrated reduced posterior lingual range of motion (11.40 mm ± 4.01 vs. 16.07 mm ± 5.27), slower posterior lingual speeds (83.67 mm/s ± 47.96 vs. 141.35 mm/s ± 66.54), increased lingual movement duration (13.46 s ± 6.75 vs. 9.21 s ± 3.28), and reduced lingual coordination (0.04 s ± 0.11 vs. 17 s ± 0.19) during the 3-oz water swallow task compared to controls. Persons diagnosed with ALS demonstrated increased range of motion (9.86 mm ± 5.38 vs. 6 mm ± 3.78) and increased jaw speed (68.62 mm/s ± 50.13 vs. 34.72 mm/s ± 17.75) during swallowing compared to controls. The current findings suggest that changes in lingual and jaw motor performance during a simple water swallow task are present in persons with ALS who are pre-symptomatic of clinically detectable bulbar impairment.

Purpose: The current study examined overall articulatory range of movement (ROM) in individuals with amyotrophic lateral sclerosis (ALS). Differential involvement of articulators was also tested using articulatory working space in individuals with varying degrees of dysarthria severity and in typically aging individuals. A strong association between overall articulatory ROM and severity measures among individuals with ALS was hypothesized. In addition, it was hypothesized that differential involvement of articulators would be detected using overall articulatory ROM measures., Method: Twenty-two speakers with dysarthria secondary to ALS and 22 typically aging speakers participated. Speech intelligibility and speaking rate were used as indices of severity. Movement range and overall articulatory working space area (convex hull) of the tongue, lower lip, and jaw were each measured by electromagnetic articulography while the speakers produced the Rainbow Passage., Results: Tongue convex hull size was significantly correlated with both indices of severity. A significant interaction between articulators and groups was observed. Individuals with severe dysarthria had reduced tongue convex hull size and exaggerated lower lip convex hull size. ROM in the anterior-posterior dimension showed a more notable differential involvement pattern than ROM in the superior-inferior dimension. Results in the area under a receiver operating characteristic curve analysis revealed group-specific ROM sensitivity., Conclusions: The findings indicate that tongue ROM is reduced in individuals with more severe dysarthria when estimated using a standardized paragraph containing all American English phonemes. The articulatory working space measure could be useful for estimating speech dysfunction in ALS. ROM of the tongue decreases, but ROM of the lower lip and jaw each increase in individuals with severe dysarthria. Differential involvement of the articulators in the anterior-posterior dimension needs to be further investigated.

After a stroke, patients frequently show compromised swallowing, mastication, and speech, as well as unfavorable motion and deviation of the tongue and mandible. The dentist can improve the oral rehabilitation of a patient with deteriorated facial and oral muscles after a stroke by incorporating orofacial myofunctional therapy. This report describes a method for tongue exercises and correction of mandible deviation in an edentulous patient after a stroke by using a pearl on a wire in the anteriomedian palatal part of the maxillary denture., (Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The effectiveness of photobiomodulation (PBM) and manual therapy (MT), alone or combined (CT), were evaluated in pain intensity, mandibular movements, psychosocial aspects, and anxiety symptoms of temporomandibular disorder (TMD) patients. Fifty-one TMD patients were randomly assigned to three groups: the PBM group (n = 18), which received PBM with 808 nm, 100 mW, 13.3 J/cm2, and 4 J per point; the MT group (n=16) for 21 minutes each session on masticatory muscles and temporomandibular joint TMJ; and the CT group (n = 17), applied during twelve sessions. Seven evaluations were performed in different moments using visual analogue scale (VAS), Research Diagnosis Criteria for Temporomandibular Disorders (RDC/TMD) Axis I and II, and Beck anxiety inventory (BAI). All groups demonstrated reductions in pain and improvement in jaw movements during treatment and at follow-up (< 0.001). The assessment of psychosocial aspects of TMD, comparing baseline and follow-up in all treatment groups, revealed that treatment did not promote modification in the intensity of chronic pain (p > 0.05). However, depression symptoms showed a reduction in PBM and CT groups (p≤0.05). All treatments promoted reduction in physical symptoms with and without pain and enhancement of jaw disabilities (p ≤ 0.05). MT promotes improvement in 5 functions, PBM in 2, and CT in 1 (p < 0.001). BAI analysis revealed that all treatments lead to a reduction in anxiety symptoms (p≤0.05). All protocols tested were able to promote pain relief, improve mandibular function, and reduce the negative psychosocial aspects and levels of anxiety in TMD patients. However, the combination of PBM and MT did not promote an increase in the effectiveness of both therapies alone.

Musculoskeletal pain changes how people move. Although experimental pain is associated with increases in the variability of motor output, it is not clear whether motor-evoked pain in clinical conditions is also associated with increases in variability. In the current study, we measured jaw force production during a visually guided force paradigm in which individuals with chronic jaw pain and control subjects produced force at 2% of their maximum voluntary contraction (low target force level) and at 15% of their maximum voluntary contraction (high target force level). State measures of pain were collected before and after each trial. Trait measures of pain intensity and pain interference, self-report measures of jaw function, and measures of depression, anxiety, and fatigue were also collected. We showed that the chronic jaw pain group exhibited greater force variability compared with controls irrespective of the force level, whereas the accuracy of force production did not differ between groups. Furthermore, predictors of force variability shifted from trait measures of pain intensity and pain interference at the low force level to state measures of pain intensity at the high force level. Our observations show that motor-evoked jaw pain is associated with increases in force variability that are predicted by a combination of trait measures and state measures of pain intensity and pain interference., Perspective: Chronic jaw pain is characterized by increases in variability during force production, which can be predicted by pain intensity and pain interference. This report could help clinicians better understand the long-term consequences of chronic jaw pain on the motor system., (Copyright © 2018 The American Pain Society. Published by Elsevier Inc. All rights reserved.)

Purpose: The goals of this study were to (a) classify speech movements of patients with amyotrophic lateral sclerosis (ALS) in presymptomatic and symptomatic phases of bulbar function decline relying solely on kinematic features of lips and jaw and (b) identify the most important measures that detect the transition between early and late bulbar changes., Method: One hundred ninety-two recordings obtained from 64 patients with ALS were considered for the analysis. Feature selection and classification algorithms were used to analyze lip and jaw movements recorded with Optotrak Certus (Northern Digital Inc.) during a sentence task. A feature set, which included 35 measures of movement range, velocity, acceleration, jerk, and area measures of lips and jaw, was used to classify sessions according to the speaking rate into presymptomatic (> 160 words per minute) and symptomatic (< 160 words per minute) groups., Results: Presymptomatic and symptomatic phases of bulbar decline were distinguished with high accuracy (87%), relying only on lip and jaw movements. The best features that allowed detecting the differences between early and later bulbar stages included cumulative path of lower lip and jaw, peak values of velocity, acceleration, and jerk of lower lip and jaw., Conclusion: The results established a relationship between facial kinematics and bulbar function decline in ALS. Considering that facial movements can be recorded by means of novel inexpensive and easy-to-use, video-based methods, this work supports the development of an automatic system for facial movement analysis to help clinicians in tracking the disease progression in ALS.

Objective: This study determines the effect of temporomandibular disorders (TMD) on the reliability of mandibular movement assessments., Methods: The vertical and horizontal jaw movements, as well as overjet and overbite, were measured twice in 56 consecutively recruited adult subjects with TMD according to the RDC/TMD and 29 controls without TMD diagnosis by experienced dentists utilizing a millimeter ruler. The reliability was determined by intraclass correlation coefficient (ICC)., Results: Neither statistically nor clinically relevant differences in the repeatability between both subgroups could be detected (all p ≥ 0.077). The mouth opening and overjet proved an excellent reliability (ICC 0.85-0.92). Overbite and laterotrusion showed good to excellent reliable results (ICC 0.74-0.82). The second measurement of the vertical jaw movement resulted in systematically higher values (p < 0.003)., Discussion: The assessment of the mandibular movement with a millimeter ruler is a reliable procedure irrespective of TMD. To decrease the variances in the mouth opening measurements, the patient should be asked beforehand to practice this movement.

Unlike other antiresorptive medications, bisphosphonate molecules accumulate in the bone matrix. Previous studies of side-effects of anti-resorptive treatment focused mainly on systemic effects. We hypothesize that matrix-bound bisphosphonate molecules contribute to the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ). In this study, we examined the effect of matrix-bound bisphosphonates on osteoclast differentiation in vitro using TRAP staining and resorption assay, with and without pretreatment with EDTA. We also tested the effect of zoledronate chelation on the healing of post-extraction defect in rats. Our results confirmed that bisphosphonates bind to, and can be chelated from, mineralized matrix in vitro in a dose-dependent manner. Matrix-bound bisphosphonates impaired the differentiation of osteoclasts, evidenced by TRAP activity and resorption assay. Zoledronate-treated rats that underwent bilateral dental extraction with unilateral EDTA treatment showed significant improvement in mucosal healing and micro-CT analysis on the chelated sides. The results suggest that matrix-bound bisphosphonates are accessible to osteoclasts and chelating agents and contribute to the pathogenesis of BRONJ. The use of topical chelating agents is a promising strategy for the prevention of BRONJ following dental procedures in bisphosphonate-treated patients., (Copyright © 2018 Elsevier Inc. All rights reserved.)

AIMS : Sjӧgren Syndrome is a disorder involving oral tissues, with xerostomia, dysgeusia, dysphagia, tooth decay, gingivitis, angular cheilitis and glossitis. Temporomandibular disorders are a generic term referred to clinical conditions involving the jaw muscles and temporomandibular joint. The aim of this study was to investigate the prevalence of oral manifestations and temporomandibular disorders (TMD) in Sjӧgren Syndrome (SS) patients compared with healthy people. METHODS : The study group included 72 SS patients (2 men, 70 women) diagnosed according to the American-European Consensus Group (AECG) Criteria. A randomly selected group of 72 patients, matched by sex and age, served as control group. The examination for TMD signs and symptoms was based on the standardized Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) through a questionnaire and clinical examination. RESULTS : SS patients complained more frequently (95.8%) of oral symptoms (xerostomia, dysgeusia, dysphagia) than controls (22.2%) (χ 2 = 80.66 p < 0.001). TMD symptoms (muscle pain on chewing, difficulty in mouth opening, arthralgia, headaches, tinnitus) were complained by 91.7% of SS patients and by 84.7% of controls (χ 2 = 1,667 p = 0,196). At the clinical examination, 91,7% of SS had at least one oral sign respect to 75 % of controls. The salivary flow measurements showed high statistical significance between the two groups (Unpaired test, p< 0,0001). Myofascial pain ( caused by muscular contracture) was significantly higher in the study group than in the control one ( p ≤ 0,05). Furthermore 18,05% of SS patients showed deflection versus 5,5% of controls (χ 2 =5,402 p =0,020). CONCLUSIONS : Sjӧgren's Syndrome seems to play a role in temporomandibular joint disorders., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Purpose: The current study investigated whether articulatory kinematic patterns can be extrapolated across the spectrum of dysarthria severity in individuals with amyotrophic lateral sclerosis (ALS)., Method: Temporal and spatial articulatory kinematic data were collected using electromagnetic articulography from 14 individuals with dysarthria secondary to ALS and 6 typically aging speakers. Speech intelligibility and speaking rate were used as indices of severity., Results: Temporal measures (duration, speed of articulators) were significantly correlated with both indices of severity. In speakers with dysarthria, spatial measures were not correlated with severity except in 3 measures: tongue movement displacement was more reduced in the anterior-posterior dimension; jaw movement distance was greater in the inferior-superior dimension; jaw convex hull area was larger in speakers with slower speaking rates. Visual inspection of movement trajectories revealed that overall spatial kinematic characteristics in speakers with severe dysarthria differed qualitatively from those in speakers with mild or moderate dysarthria. Unlike speakers with dysarthria, typically aging speakers displayed variable tongue movement and minimal jaw movement., Conclusions: The current study revealed that spatial articulatory characteristics, unlike temporal characteristics, showed a complicated pattern across the severity spectrum. The findings suggest that articulatory characteristics in speakers with severe dysarthria cannot simply be extrapolated from those in speakers with mild-to-moderate dysarthria secondary to ALS.

Aims: To determine the effect of amyotrophic lateral sclerosis (ALS) on aspects of masticatory function and to assess the relationship between ALS and the prevalence of traumatic mucosal lesions caused by oral self-injury., Methods: A total of 153 ALS patients and 23 control subjects participated in this cross-sectional study. Clinical characteristics including site of onset, medication, type of feeding, and use of noninvasive mechanical ventilation were recorded. The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocol and a specific questionnaire to assess aspects of masticatory dysfunction and frequency of self-injury of the oral mucosa were applied to all participants. Maximum mandibular range of motion, maximum bite force, and maximum finger-thumb grip force were determined and tested with Mann Whitney, Kruskal-Wallis, or chi-square tests. P < .05 was considered significant., Results: Maximum unassisted and assisted mouth opening, protrusion, left laterotrusion, and finger-thumb grip force were significantly reduced in both spinal- (n = 102) and bulbar-onset (n = 40) patients compared to the control group; however, bite force was reduced only in bulbar-onset patients. ALS patients with tube feeding (n = 16) had the greatest reduction in maximum bite force and mandibular opening. There was no relationship between TMD and ALS. Oral self-injury due to biting was more frequent in the ALS group (29.9%) than in the control group (8.7%) and in the bulbar-onset group (55.0%) compared to the spinal- (20.8%) and respiratory-onset (18.2%) groups. Of the ALS patients in the study, 10% sought dental treatment related to the condition., Conclusion: The ALS patients in this study had a reduction in finger-thumb grip force that was twice as great as the reduction in bite force. The maximum range of mandibular movement was also reduced, especially in bulbar-onset patients. ALS patients did not have a higher prevalence of TMD but did have more traumatic mucosal injury than controls. The dentist should be an integral part of the multidisciplinary team to manage ALS patients.

Desmognathine salamanders possess unusual morphological features for lungless salamanders that have been proposed to aid in burrowing and biting, including well-ossified jaws and skull and a pair of robust ligaments connecting the atlas to the mandible. We evaluated the function of these and other peculiar desmognathine cranial features in biting by examining the morphology, mechanics and in vivo biting performance of the large Desmognathus quadramaculatus We estimated theoretical biting force using a novel geometric method that we describe. Results provide quantitative evidence to bolster earlier conclusions that the unusual atlanto-mandibular ligaments couple ventral head flexion, a unique desmognathine behavior, with biting performance. Our analysis also reveals that the ligaments not only transmit, but also amplify the force of head flexion when acting together with the unusual stalked occipital condyles, enlarged atlas and massive quadratopectoralis muscles. The geometric model predicts that this mechanism contributes five times the biting force of the three jaw levator muscles combined and predicts that maximum biting force in D. quadramaculatus matches or exceeds forces reported for similarly sized lizards. The i n vivo biting performance we measured was several times greater in D. quadramaculatus than another plethodontid salamander, Pseudotriton ruber , which lacks the unusual morphology and mechanism of desmognathines. The effective biting mechanism of D. quadramaculatus we describe is an emergent property of many of the distinguishing morphological features of desmognathine salamanders and likely plays an important role in their natural history given that desmognathines use biting in feeding, defense and even courtship., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2017. Published by The Company of Biologists Ltd.)

The impairment of orofacial motor function during orthodontic treatment needs to be addressed, because most orthodontic patients experience pain and motor excitability would be affected by pain. In the present study, the temporal alteration of the jaw-opening reflex excitability was investigated to determine if orthodontic treatment affects orofacial motor function. The excitability of jaw-opening reflex evoked by electrical stimulation on the gingiva and recorded bilaterally in the anterior digastric muscles was evaluated at 1 (D1), 3 (D3), and 7 days (D7) after orthodontic force application to the teeth of right side; morphological features (e.g., osteoclast genesis and tooth movement) were also evaluated. To clarify the underlying mechanism of orthodontic treatment-induced alteration of orofacial motor excitability, analgesics were administrated for 1 day. At D1 and D3, orthodontic treatment significantly decreased the threshold for inducing the jaw-opening reflex but significantly increased the threshold at D7. Other parameters of the jaw-opening reflex were also evaluated (e.g., latency, duration and area under the curve of anterior digastric muscles activity), and only the latency of the D1 group was significantly different from that of the other groups. Temporal alteration of the jaw-opening reflex excitability was significantly correlated with changes in morphological features. Aspirin (300 mg·kg -1 ·day -1 ) significantly increased the threshold for inducing the jaw-opening reflex, whereas a lower dose (75-150 mg·kg -1 ·day -1 ) of aspirin or acetaminophen (300 mg·kg -1 ·day -1 ) failed to alter the jaw-opening reflex excitability. These results suggest that an increase of the jaw-opening reflex excitability can be induced acutely by orthodontic treatment, possibly through the cyclooxygenase activation. NEW & NOTEWORTHY It is well known that motor function is affected by pain, but the effect of orthodontic treatment-related pain on the trigeminal motor excitability has not been fully understood. We found that, during orthodontic treatment, trigeminal motor excitability is acutely increased and then decreased in a week. Because alteration of trigeminal motor function can be evaluated quantitatively by jaw-opening reflex excitability, the present animal model may be useful to search for alternative approaches to attenuate orthodontic pain., (Copyright © 2017 the American Physiological Society.)

The aim of this study was to investigate the association between patterns of jaw motor activity during sleep and clinical signs and symptoms of sleep bruxism. A total of 35 university students and staff members participated in this study after providing informed consent. All participants were divided into either a sleep bruxism group (n = 21) or a control group (n = 14), based on the following clinical diagnostic criteria: (1) reports of tooth-grinding sounds for at least two nights a week during the preceding 6 months by their sleep partner; (2) presence of tooth attrition with exposed dentin; (3) reports of morning masticatory muscle fatigue or tenderness; and (4) presence of masseter muscle hypertrophy. Video-polysomnography was performed in the sleep laboratory for two nights. Sleep bruxism episodes were measured using masseter electromyography, visually inspected and then categorized into phasic or tonic episodes. Phasic episodes were categorized further into episodes with or without grinding sounds as evaluated by audio signals. Sleep bruxism subjects with reported grinding sounds had a significantly higher total number of phasic episodes with grinding sounds than subjects without reported grinding sounds or controls (Kruskal-Wallis/Steel-Dwass tests; P < 0.05). Similarly, sleep bruxism subjects with tooth attrition exhibited significantly longer phasic burst durations than those without or controls (Kruskal-Wallis/Steel-Dwass tests; P < 0.05). Furthermore, sleep bruxism subjects with morning masticatory muscle fatigue or tenderness exhibited significantly longer tonic burst durations than those without or controls (Kruskal-Wallis/Steel-Dwass tests; P < 0.05). These results suggest that each clinical sign and symptom of sleep bruxism represents different aspects of jaw motor activity during sleep., (© 2016 European Sleep Research Society.)

Temporal summation of nociceptive inputs may be an important pathophysiological mechanism in temporomandibular disorders (TMD) pain; however, it remains unknown how natural jaw function relates to underlying pain mechanisms. This study evaluated changes in pain and movement patterns during repeated jaw movements in patients with painful temporomandibular joints (TMJ) compared with healthy controls. Twenty patients with TMD with TMJ pain, and an anterior disk displacement without reduction and 20 age- and gender-matched healthy volunteers were included. Participants performed 20 trials (4 × 5 sessions) of standardized and repeated mandibular movements, and scored the movement-associated pain intensity on 0 to 10 numeric rating scale in addition to measurements of jaw movements. Patients with TMJ pain reported higher baseline pain compared to the control group for all types of jaw movements (P = 0.001) and significant increases in numeric rating scale pain scores by repetition of jaw movements (P < 0.001), which was not observed in the control group (P > 0.05). Jaw total opening distance (P = 0.030), maximum opening velocity (P = 0.043) and average closing velocity (P = 0.044) in the TMJ pain group were significantly reduced during the repeated movements. In the control group, however, total opening distance (P = 0.499), maximum opening velocity (P = 0.064), and average closing velocity (P = 0.261) remained unchanged, whereas average opening velocity (P = 0.040) and maximum closing velocity (P = 0.039) increased. The study demonstrates that repeated jaw movements constitute a sufficient and adequate stimulation for triggering temporal summation effects associated with significant inhibition of motor function in painful TMJs. These findings have practical implications for diagnosis of TMD pain and for more mechanism-driven management protocols in the future.

Purpose: This preliminary study compared the speech motor control of the tongue and jaw between children with cerebral palsy (CP) and their typically developing (TD) peers., Method: Tongue tip and jaw movements of 4 boys with spastic CP and 4 age- and sex-matched TD peers were recorded using an electromagnetic articulograph during 10 repetitions of "Dad told stories today." The duration, path distance, average speed, and speech movement stability of the movements were calculated for each repetition., Results: The children with CP had longer durations than their TD peers. Children with CP had longer path distances and faster average speed as compared with their TD peers for both articulators. The TD group but not the CP group had longer path distances and faster average speeds for the tongue than the jaw. The CP group had reduced speech movement stability for the tongue as compared with their TD peers, but both groups had similar speech movement stability for the jaw., Conclusions: Children with CP had impaired speech motor control of the tongue and jaw as compared with their TD peers, and these speech motor control deficits were more pronounced in the tongue tip than the jaw.

Purpose: This study evaluated a novel method for characterizing jaw rotation using orientation data from a single electromagnetic articulography sensor. This method was optimized for clinical application, and a preliminary examination of clinical feasibility and value was undertaken., Method: The computational adequacy of the single-sensor orientation method was evaluated through comparisons of jaw-rotation histories calculated from dual-sensor positional data for 16 typical talkers. The clinical feasibility and potential value of single-sensor jaw rotation were assessed through comparisons of 7 talkers with dysarthria and 19 typical talkers in connected speech., Results: The single-sensor orientation method allowed faster and safer participant preparation, required lower data-acquisition costs, and generated less high-frequency artifact than the dual-sensor positional approach. All talkers with dysarthria, regardless of severity, demonstrated jaw-rotation histories with more numerous changes in movement direction and reduced smoothness compared with typical talkers., Conclusions: Results suggest that the single-sensor orientation method for calculating jaw rotation during speech is clinically feasible. Given the preliminary nature of this study and the small participant pool, the clinical value of such measures remains an open question. Further work must address the potential confound of reduced speaking rate on movement smoothness.

Background: Vocal tremor may be associated with cyclic oscillations in the pulmonary, laryngeal, velopharyngeal, or oral regions., Objectives: This study aimed to correlate the overall severity of vocal tremor with the distribution and severity of tremor in structures involved., Methods: Endoscopic and clinical examinations were completed on 20 adults with vocal tremor and two age-matched controls during sustained phonation. Two judges rated the severity of vocal tremor and the severity of tremor affecting each of 13 structures., Results: Participants with mild vocal tremor typically presented with tremor in three laryngeal structures, moderate vocal tremor in five structures (laryngeal and another region), and severe vocal tremor in eight structures affecting all regions. The severity of tremor was lowest (mean = 1.2 out of 3) in persons with mild vocal tremor and greater in persons with moderate (mean = 1.5) and severe vocal tremor (mean = 1.4). Laryngeal structures were most frequently (95%) and severely (1.7 out of 3) affected, followed by velopharynx (40% occurrence, 1.3 severity), pulmonary (40% occurrence, 1.1 severity), and oral (40% occurrence, 1.0 severity) regions. Regression analyses indicated tremor severity of the supraglottic structures, and vertical laryngeal movement contributed most to vocal tremor severity during sustained phonation (r = 0.77, F = 16.17, P < 0.0001). A strong positive correlation (r = 0.72) was found between the Tremor Index and the severity of the vocal tremor during sustained phonation., Conclusion: It is useful to obtain a wide endoscopic view of the larynx to visualize tremor, which is rarely isolated to the true vocal folds alone., (Published by Elsevier Inc.)

Purpose: Although it is frequently presumed that bulbar muscle degeneration in Amyotrophic Lateral Sclerosis (ALS) is associated with progressive loss of speech motor control, empirical evidence is limited. Furthermore, because speaking rate slows with disease progression and rate manipulations are used to improve intelligibility in ALS, this study sought to (i) determine between and within-group differences in articulatory motor control as a result of speaking rate changes and (ii) identify the strength of association between articulatory motor control and speech impairment severity., Method: Ten talkers with ALS and 11 healthy controls repeated the target sentence at habitual, fast, and slow rates. The spatiotemporal variability index (STI) was calculated to determine tongue, lower lip, and jaw movement variability., Results: During habitual speech, talkers with mild-moderate dysarthria displayed significantly lower tongue and lip movement variability whereas those with severe dysarthria showed greater variability compared to controls. Within-group rate effects were significant only for talkers with ALS. Specifically, lip and tongue movement variability significantly increased during slow speech relative to habitual and fast speech. Finally, preliminary associations between speech impairment severity and movement variability were moderate to strong in talkers with ALS., Conclusion: Between-group differences for habitual speech and within-group effects for slow speech replicated previous findings for lower lip and jaw movements. Preliminary findings of moderate to strong associations between speech impairment severity and STI suggest that articulatory variability may vary from pathologically low (possibly indicating articulatory compensation) to pathologically high variability (possibly indicating loss of control) with dysarthria progression in ALS., (Copyright © 2017 Elsevier Inc. All rights reserved.)