Temporomandibular Disorders in Relation to Mandibular Advancement Devices for Treating Obstructive Sleep Apnea.

Mandibular advancement devices (MADs) keep the upper airways patent by holding the mandible and attached soft tissues forward via altered position of its condyles relative to the articulating surfaces of the temporal bones. During the first weeks of MAD therapy, pain may occur in the area of the temporomandibular joints, masticatory muscles, and/or teeth with a tendency of spontaneous resolution. In patients reporting temporomandibular disorder (TMD) symptoms prior to therapy, the MAD-related anterior condylar position during sleep may result in a reduction of TMD signs and symptoms.

Orofacial musculoskeletal pain: An evidence-based bio-psycho-social matrix model.

Pain is a multidimensional experience comprising sensory-discriminative, affective-motivational, and cognitive-evaluative dimensions. Clinical and research findings have demonstrated a complex interplay between social burdens, individual coping strategies, mood states, psychological disorders, sleep disturbances, masticatory muscle tone, and orofacial musculoskeletal pain. Accordingly, current classification systems for orofacial pain require psychosocial assessments to be an integral part of the multidimensional diagnostic process. Here, we review evidence on how psychosocial and biological factors may generate and perpetuate musculoskeletal orofacial pain. Specifically, we discuss studies investigating a putative causal relationship between stress, bruxism, and pain in the masticatory system. We present findings that attribute brain structures various roles in modulating pain perception and pain-related behavior. We also examine studies investigating how the nervous and immune system on cellular and molecular levels may account for orofacial nociceptive signaling. Furthermore, we review evidence pointing towards associations between orofacial musculoskeletal pain and neuroendocrine imbalances, sleep disturbances, and alterations of the circadian timing system. We conclude with several proposals that may help to alleviate orofacial pain in the future.

In-vivo kinematic assessment of alloplastic temporomandibular joint replacements by means of helical axis: A cohort study with historical control.

Alloplastic total temporomandibular joint replacement (TJR) is a surgical procedure used to restore normal mandibular function when conservative therapies fail. The instantaneous helical axis (HA), is a mathematical model used to visualize globally rigid body kinematics. It can be applied to mandibular motion for quantification of movement patterns and irregularities. Aim of this study was to analyze HA pathways in subjects with unilateral and bilateral TJR and compare them to a control group. An optoelectronic system was employed to track mouth opening/closing cycles (n = 3) of 15 patients (7 operated unilaterally, 8 bilaterally, 11 F, aged 24-72) and 12 controls (6 F, aged 23-40). HA position in space was determined for 30 equally-distributed steps of the observed movement. Total mandibular rotation around HA (Φtot) and total translation along HA (Ttot) were determined. Angles between HA and the anatomical coordinate system of the head (θx, θy, θz); global fluctuation of HA spatial orientation (θe), distance between condylar center (CP) and HA (dCP) and its projections on the axes (xdCP, ydCP, zdCP) were calculated. Overall, Φtot was larger in controls than in bilaterally operated subjects (p = 0.002, p = 0.003) and θz was larger in unilaterally operated subjects than in controls (p = 0.004) and bilaterally operated subjects (p = 0.002, p = 0.024). During opening, θe¯ was smaller in controls than in unilaterally operated subjects (p = 0.01). The distance dCP was smaller for alloplastic joints than for controls (p < 0.01 overall). In conclusion, mandibular HA pathways in patients with TJR differ significantly from controls in terms of spatial location and variability.

The Pain-to-Well-Being Relationship in Patients Experiencing Chronic Orofacial Pain.

Introduction: Orofacial pain features may negatively influence a person's well-being and vice versa. Some aspects of well-being can be measured with axis II instruments that assess patients' psychosocial and behavioral status. The aim of this study was to investigate associations between pain features and psychosocial variables as indicators of well-being. Materials and Methods: Seven hundred ninety-nine anonymized datasets collected using the Web-based Interdisciplinary Symptom Evaluation (WISE) of patients reporting to the Interdisciplinary Orofacial Pain Unit, University of Zurich, between March 19, 2017 and May 19, 2019, were analyzed. Pain features including intensity, number of locations, impact, and duration were evaluated. Psychometric measures assessed pain-related catastrophizing and disability, illness perception, distress, anxiety, depression, injustice experience, dysmorphic concerns, and insomnia. Results: Most patients were between 30 and 59 years old (58.3%), female (69.8%), working (66.0%), and experienced pain for more than 6 months (68.5%). Pain intensities were higher in women than men and higher in disabled than working patients. Scores indicating elevated stress and depression were also observed in disabled patients. The sample prevalence rates of clinically relevant axis II instrument scores were as follows: Graded Chronic Pain Scale for the Head (GCPS-H), 27%; Patient Health Questionnaire 4 (PHQ4), 21%; PHQ9, 21%; Pain Catastrophizing Scale (PCS), 20%; General Anxiety Disorder 7 (GAD7), 15%; Insomnia Severity Index (ISI), 15%; Injustice Experience Questionnaire (IEQ), 14%; GCPS for the Body (GCPS-B), 13%; PHQ for Stress (PHQstr), 6%; and Dysmorphic Concern Questionnaire (DCQ), 2%. Noteworthy results of correlation analysis of the clinically relevant axis II scores and pain measures were as follows: the PHQstr had moderate associations (0.34-0.43) with the sum of pain intensity at rest and during function, number of pain locations, and typical pain intensity. The IEQ scores were moderately associated with typical pain intensity at 0.39. The DCQ scores were moderately associated with pain extension at 0.41. Conclusions: Moderate correlations of certain pain and well-being measures were found in patients reporting clinically relevant stress, injustice experience, and dysmorphic concern, all of which reflect impaired well-being. PHQ4 is suitable for routine distress screening in the clinical setting.

Evaluating the Effects of Acupuncture Using a Dental Pain Model in Healthy Subjects - A Randomized, Cross-Over Trial.

Acupuncture is a complementary and nonpharmacological intervention that can be effective for the management of chronic pain in addition to or instead of medication. Various animal models for neuropathic pain, inflammatory pain, cancer-related pain, and visceral pain already exist in acupuncture research. We used a newly validated human pain model and examined whether acupuncture can influence experimentally induced dental pain. For this study, we compared the impact of manual acupuncture (real acupuncture), manual stimulation of a needle inserted at nonacupuncture points (sham acupuncture) and no acupuncture on experimentally induced dental pain in 35 healthy men who were randomized to different sequences of all 3 interventions in a within-subject design. BORG CR10 pain ratings and autonomic responses (electrodermal activity and heart rate variability) were investigated. An initial mixed model with repeated measures included preintervention pain ratings and the trial sequence as covariates. The results showed that acupuncture was effective in reducing pain intensity when compared to no acupuncture (ß = -.708, P = .002), corresponding to a medium Cohen's d effect size of .56. The comparison to the sham acupuncture revealed no statistically significant difference. No differences in autonomic responses between real and sham acupuncture were found during the intervention procedures. PERSPECTIVE: This study established a dental pain model for acupuncture research and provided evidence that experimentally induced dental pain can be influenced by either real acupuncture or manual stimulation of needles at nonacupuncture points. The data do not support that acupoint specificity is a significant factor in reducing experimental pain.

[Temporomandibular disorders - a biopsychosocial perspective]. / Kiefergelenkbeschwerden ­ eine biopsychosoziale Umschau.

Temporomandibular disorders - a biopsychosocial perspective Abstract. Clinicians encountering patients complaining of jaw joint symptoms need to see and understand the patients' somatic complaint in the context of possible biographic, psychological and social burdens and to select the appropriate therapeutic options accordingly.

Measuring anger in patients experiencing chronic pain - A systematic review.

Anger is prevalent in chronic pain and has been associated with pain perception, disability, behavior and treatment outcome. Objectives were (1) to survey in the context of chronic pain the application (and omission) of validated anger self-report instruments, (2) to discuss the instruments found in the context of emotion theories and (3) to identify a possible instrument preference. A systematic search of textbooks and review articles was first performed on validated instruments designed to measure the cognitive, the motivational and the subjective feeling component of anger. Thereafter, a systematic review aimed at finding chronic pain studies from 2005 to 2019 reporting on these instruments. Textbooks and reviews listed 16 validated self-report anger measurement instruments. 28 papers applying four of these were identified and two new instruments were additionally detected. The State-Trait Anger Expression (STAXI) and its precursors were most commonly used. Studies on chronic low back pain patients prevailed. In conclusion, anger in chronic pain patients is reliably measurable at low cost with self-report tools. The STAXI-II qualifies best for this purpose based on its extensive validation history. The majority of instruments lack sufficient theoretical and psychometric adequacy. A more detailed exploration of the cognitive anger component in chronic pain patients in future research is recommended.

Insomnia in Patients Seeking Care at an Orofacial Pain Unit.

Introduction: Orofacial pain and dysfunction include a broad range of disturbances among which pain and insomnia are some of the most common complaints. Sleep strengthens physiological and psychological resilience and is an absolute requirement for health. Insomnia is a common symptom or sleep disorder, yet data on its prevalence is sparse. Here we extracted data from the insomnia severity index which was part of the web-based interdisciplinary symptom evaluation (WISE) tool given to a large sample of patients seeking care at an orofacial pain unit for analyzing insomnia prevalence in this clinical population. Material and methods: Anonymized data were available from 952 patients who consulted the Orofacial Pain Unit at the Center of Dental Medicine, University of Zurich, Zurich, Switzerland between January 2017 and December 2018. Prevalence data for insomnia stratified by gender and 10 age groups (decades) were calculated. The distribution of four insomnia severity grades was determined, also stratified by age and gender. Results: 952 patients (290 men: 30.5%) with a mean age of 44.8 ± 17.4 years completed a WISE. Three hundred and fifty-two (37.0%) patients with a mean age of 45.8 ± 16.7 years positively responded to a screening question for insomnia and/or hypersomnia. Insomnia was severe in women from the 2nd to 8th decade, ranging from 4.3% (3rd decade) to 14.5% (6th decade), and moderately severe from the 2nd to 9th decade, ranging from 18.8% (6th decade) to 27.8% (2nd decade). In men, severe insomnia was present from the 3rd to 7th decade, ranging from 2.3% (7th decade) to 4.4% (4th decade) and moderately severe insomnia from the 3rd to 7th decade, ranging from 4.6% (7th decade) to 12.2% (5th decade). Conclusions: This is the first study reporting on insomnia in a large sample of patients seeking care at an orofacial pain unit. One in three patients reported some form of sleep disturbances, which for almost half of them was moderate to severe insomnia. The gender ratio was almost equal throughout adulthood, yet younger and older women were more frequently affected and experienced higher insomnia severity than men.

Dentin hypersensitivity monitored by cold air quantitative sensory testing.

BACKGROUND: Quantification of dentin hypersensitivity (DH) is challenging and requires standardised, graded stimulation by natural-like stimuli. OBJECTIVE: The present study aimed at identifying DH subjects and longitudinally monitoring their pain thresholds by cold air quantitative sensory testing (QST). METHODS: Subject recruitment started with an online DH questionnaire. Respondents were screened by dental air stimulation. Sensitising and habituating subjects were excluded. A recently developed stimulation device was employed for cold air QST. Single tooth DH was verified by applying an equi-intense stimulus to a control tooth. Descriptive statistics were applied for subject characteristics. Mean values were calculated for the stimulation parameters temperature and air flow. Reliability of temperatures for detecting pain and for evoking moderate pain over multiple time points within a 3-week period was analysed by two-way random single- and average-measure intra-class correlation coefficients. RESULTS: A total of 353 persons completed the online DH questionnaire of which 117 were screened. Forty-four passed the screening, yet 15 were excluded for various reasons. Twenty-nine subjects were monitored by QST across 3 weeks. Results revealed a high intra-individual stability of the temperature inducing moderate to strong pain intensity (MPI) (single-measure ICC of TMPI 0.83, P < 0.001). Mean TMPI was -13.69°C, yet it highly varied among the 29 subjects (SD ± 10.04°C). CONCLUSIONS: Using a novel approach, namely dental QST based on cold air stimuli, we present evidence for temporally stable DH perceptions over a 3-week period. The method fulfils international guideline requirements and is recommendable for obtaining valid results when testing various interventions for DH management.

Temporomandibular joint magnetic resonance imaging findings in adolescents with anterior disk displacement compared to those with juvenile idiopathic arthritis.

BACKGROUND: Deformation of the mandibular condyle can be associated with anterior disk displacement (ADD) or involvement of the temporomandibular joint (TMJ) by juvenile idiopathic arthritis (JIA). Diagnostic differentiation is critical for proper management. OBJECTIVES: To compare morphology and inflammation between TMJs with ADD and JIA. METHODS: Retrospective assessment of contrast-enhanced TMJ MRI in 18 adolescents (15 female, mean age 15.1 ± 1.9 years) with ADD and age- and gender-matched patients with JIA. Articular disk findings, inflammatory signs and osseous morphology were compared. RESULTS: In the ADD group, 31 of 36 disks were displaced. In total, 28 of 31 displaced disks showed thickening of the bilaminar zone. In JIA patients, the disks were mainly flattened (19/36), centrally perforated (12/36) and/or anteriorly displaced (2/36). In total, 19 of 31 TMJs with ADD showed various degrees of inflammation, with joint effusion, synovial thickening and joint enhancement not significantly different from JIA patients. Osseous deformity was present in 27 of 31 TMJs with ADD, with frequent erosions in both groups (ADD 25/31; JIA 32/36, P = 0.55) but lower grades of condylar and temporal bone flattening than in JIA (P ≤ 0.001). Glenoid fossa depth was preserved in 28 of 31 joints with ADD and decreased in 26 of 36 joints with JIA (P < 0.0001). Mandibular ramus height was decreased in both groups. CONCLUSION: In adolescents, inflammatory signs are common MRI findings in symptomatic TMJs with ADD and thus should not be considered diagnostic for JIA involvement. In this cohort, both entities had high rates of condylar deformity, while TMJs with ADD showed a better-preserved and often normal shape of the glenoid fossa.

Challenges recruiting to a proof-of-concept pharmaceutical trial for a rare disease: the trigeminal neuralgia experience.

BACKGROUND: This study aimed to describe recruitment challenges encountered during a phase IIa study of vixotrigine, a state and use-dependent Nav1.7 channel blocker, in individuals with trigeminal neuralgia. METHODS: This was an international, multicenter, placebo-controlled, randomized withdrawal study that included a 7-day run-in period, a 21-day open-label phase, and a 28-day double-blind phase in which patients (planned n = 30) were randomized to vixotrigine or placebo. Before recruitment, all antiepileptic drugs had to be stopped, except for gabapentin or pregabalin. After the trial, patients returned to their original medications. Patient recruitment was expanded beyond the original five planned (core) centers in order to meet target enrollment (total recruiting sites N = 25). Core sites contributed data related to patient identification for study participation (prescreening data). Data related to screening failures and study withdrawal were also analyzed using descriptive statistics. RESULTS: Approximately half (322/636; 50.6%) of the patients who were prescreened at core sites were considered eligible for the study and 56/322 (17.4%) were screened. Of those considered eligible, 26/322 (8.1%) enrolled in the study and 6/322 (1.9%) completed the study. In total, 125 patients were screened across all study sites and 67/125 (53.6%) were enrolled. At prescreening, reasons for noneligibility varied by site and were most commonly diagnosis change (78/314; 24.8%), age > 80 years (75/314; 23.9%), language/distance/mobility (61/314; 19.4%), and noncardiac medical problems (53/314; 16.9%). At screening, frequently cited reasons for noneligibility included failure based on electrocardiogram, insufficient pain, and diagnosis change. CONCLUSIONS: Factors contributing to recruitment challenges encountered in this study included diagnosis changes, anxiety over treatment changes, and issues relating to distance, language, and mobility. Wherever possible, future studies should be designed to address these challenges. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01540630 . EudraCT, 2010-023963-16. 07 Aug 2015.

Mind the Gap: A Systematic Review of Implementation of Screening for Psychological Comorbidity in Dental and Dental Hygiene Education.

The biopsychosocial model is advocated as part of a more comprehensive approach in both medicine and dentistry. However, dentists have not traditionally been taught psychosocial screening as part of their predoctoral education. The aim of this systematic review was to provide an overview of published studies on the implementation of screening for psychological comorbidity in dental and dental hygiene education. The term "psychological comorbidity" refers to the degree of coexisting anxiety, depression, or other mental health problems in a patient presenting with a physical condition. The review followed a protocol registered in PROSPERO (CRD42016054083) and was carried out in accordance with the PRISMA guidelines. The methodological quality of the included studies was assessed using a ten-item tool developed for medical education. The electronic search in PubMed, Scopus, and PsycINFO from the inception of each database until December 31, 2016, together with a hand search, identified 1,777 articles. After abstracts were screened, 52 articles were reviewed in full text applying inclusion and exclusion criteria; four articles remained for the qualitative synthesis. Generally, the reported data on specific methods or instruments used for psychological screening were limited. Only one of the included articles utilized a validated screening tool. The results of this systematic review show that published data on the implementation of psychological patient assessment in dental and dental hygiene education are limited. To address this gap, the authors recommend short screening tools such as the Graded Chronic Pain Scale and the Patient Health Questionnaire for Depression and Anxiety. Educating dental and dental hygiene students about easy-to-use, reliable, and validated screening tools for assessing psychological comorbidity warrants more research attention and greater implementation in educational curricula.

Neurochemical dynamics of acute orofacial pain in the human trigeminal brainstem nuclear complex.

The trigeminal brainstem sensory nuclear complex is the first central relay structure mediating orofacial somatosensory and nociceptive perception. Animal studies suggest a substantial involvement of neurochemical alterations at such basal CNS levels in acute and chronic pain processing. Translating this animal based knowledge to humans is challenging. Human related examining of brainstem functions are challenged by MR related peculiarities as well as applicability aspects of experimentally standardized paradigms. Based on our experience with an MR compatible human orofacial pain model, the aims of the present study were twofold: 1) from a technical perspective, the evaluation of proton magnetic resonance spectroscopy at 3 T regarding measurement accuracy of neurochemical profiles in this small brainstem nuclear complex and 2) the examination of possible neurochemical alterations induced by an experimental orofacial pain model. Data from 13 healthy volunteers aged 19-46 years were analyzed and revealed high quality spectra with significant reductions in total N-acetylaspartate (N-acetylaspartate + N-acetylaspartylglutamate) (-3.7%, p = 0.009) and GABA (-10.88%, p = 0.041) during the pain condition. These results might reflect contributions of N-acetylaspartate and N-acetylaspartylglutamate in neuronal activity-dependent physiologic processes and/or excitatory neurotransmission, whereas changes in GABA might indicate towards a reduction in tonic GABAergic functioning during nociceptive signaling. Summarized, the present study indicates the applicability of 1H-MRS to obtain neurochemical dynamics within the human trigeminal brainstem sensory nuclear complex. Further developments are needed to pave the way towards bridging important animal based knowledge with human research to understand the neurochemistry of orofacial nociception and pain.

Safety and efficacy of a Nav1.7 selective sodium channel blocker in patients with trigeminal neuralgia: a double-blind, placebo-controlled, randomised withdrawal phase 2a trial.

BACKGROUND: Current standard of care for trigeminal neuralgia is treatment with the sodium channel blockers carbamazepine and oxcarbazepine, which although effective are associated with poor tolerability and the need for titration. BIIB074, a Nav1.7-selective, state-dependent sodium-channel blocker, can be administered at therapeutic doses without titration, and has shown good tolerability in healthy individuals in phase 1 studies. We therefore assessed the safety and efficacy of BIIB074 in patients with trigeminal neuralgia in a phase 2a study. METHODS: We did a double-blind, multicentre, placebo-controlled, randomised withdrawal phase 2a trial in 25 secondary care centres in Denmark, Estonia, France, Germany, Italy, Latvia, Lithuania, Romania, South Africa, Spain, Switzerland, and the UK. After a 7-day run-in phase, eligible patients aged 18-80 years with confirmed trigeminal neuralgia received open-label, BIIB074 150 mg three times per day, orally, for 21 days. Patients who met at least one response criteria were then randomly assigned (1:1) to BIIB074 or placebo for up to 28 days in a double-blind phase. We used an interactive web response system to assign patients with a computer-generated schedule, with stratification (presence or absence of existing pain medication). Patients, clinicians, and assessors were masked to treatment allocation. The primary endpoint was the difference between groups in the number of patients classified as treatment failure during the double blind phase assessed in the modified intention-to-treat population. We assessed safety in all patients who received one or more doses of BIIB074. This study is registered with ClinicalTrials.gov (NCT01540630) and EudraCT (2010-023963-16). FINDINGS: The first patient was enrolled on April 23, 2012, and the last patient completed the study on February 26, 2014. We enrolled 67 patients into the open-label phase; 44 completed open-label treatment, and 29 were randomly assigned to double-blind treatment (15 to BIIB074 and 14 to placebo). During the double-blind phase, five (33%) patients assigned to BIIB074 versus nine (64%) assigned to placebo were classified as treatment failures (p=0·0974). BIIB074 was well tolerated, with similar adverse events in the double-blind phase to placebo. Headache was the most common adverse event with BIIB074 in the open-label phase (in 13 [19%] of 67 patients), followed by dizziness (in six [9%] patients). In the double-blind phase, headache, pyrexia, nasopharyngitis, sleep disorder, and tremor were the most frequent adverse events in patients assigned to BIIB074 (in one [7%] of 15 patients for each event), and headache, dizziness, diarrhoea, and vomiting were the most frequent adverse events in patients assigned to placebo (in one [7%] of 14 patients for each event). No severe or serious adverse events were reported in the BIIB074 group during the double-blind phase. One patient assigned to placebo reported intestinal adhesions with obstruction as a severe and serious adverse event, which was considered as unrelated to study medication. INTERPRETATION: The primary endpoint of treatment failure was not significantly lower in the BIIB074 group than in the placebo group. However, our findings provide a basis for continued investigation of BIIB074 in patients with trigeminal neuralgia in future clinical trials. FUNDING: Convergence Pharmaceuticals.

Simultaneous multislice readout-segmented echo planar imaging for accelerated diffusion tensor imaging of the mandibular nerve: A feasibility study.

PURPOSE: To assess the feasibility of diffusion tensor imaging (DTI) using simultaneous multislice (SMS) acquisition with blipped controlled aliasing in parallel imaging (CAIPI) for accelerated readout-segmented echo planar imaging (rs-EPI) of the mandibular nerves. DTI of the mandibular nerves using EPI is challenging due to susceptibility artifacts. Rs-EPI is less prone to artifacts but associated with longer scan durations. MATERIALS AND METHODS: Eight asymptomatic volunteers were imaged at 3T using a 64-channel head/neck coil. Conventional, 2-fold (2xSMS) and 3-fold (3xSMS) slice-accelerated rs-EPI sequences were acquired. Tractography of the mandibular nerves was performed. Signal-to-noise ratio (SNR), fractional anisotropy (FA), mean diffusivity (MD), and number of tracts were calculated. Artifacts were evaluated qualitatively on Likert scales. Parameters were compared statistically. Clinical feasibility of 2xSMS rs-EPI was tested in four patients. RESULTS: SNR was similar for conventional (mean ± SD; 8.55 ± 3.90) and 2xSMS rs-EPI (7.83 ± 3.15) but lower for 3xSMS rs-EPI (5.42 ± 2.93; analysis of variance, P = 0.004). FA was similar for all sequences (rs-EPI, 0.42 ± 0.08; 2xSMS rs-EPI, 0.43 ± 0.08; 3xSMS rs-EPI, 0.44 ± 0.06), while 3xSMS rs-EPI showed lower MD (rs-EPI, 0.0015 ± 0.0003; 2xSMS rs-EPI, 0.0014 ± 0.0001; 3xSMS rs-EPI, 0.0013 ± 0.0003) and lower number of tracts (rs-EPI, 66.56 ± 51.31; 2xSMS rs-EPI, 65.75 ± 55.40; 3xSMS rs-EPI, 37.93 ± 52.42) compared to rs-EPI and 2xSMS rs-EPI. Additionally, 2xSMS rs-EPI was feasible in four clinical patients and provided robust imaging results. CONCLUSION: 2xSMS rs-EPI yielded similar SNR, FA, and MD values compared to conventional rs-EPI at reduced scan time and is feasible in clinical patients. These findings suggest the potential clinical applicability of rs-EPI for DTI of the mandibular nerve. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:663-677.

MR imaging of the temporomandibular joint: comparison between acquisitions at 7.0 T using dielectric pads and 3.0 T.

OBJECTIVES: To qualitatively and quantitatively compare MRI of the temporomandibular joint (TMJ) at 7.0 T using high-permittivity dielectric pads and 3.0 T using a clinical high-resolution protocol. METHODS: Institutional review board-approved study with written informed consent. 12 asymptomatic volunteers were imaged at 7.0 and 3.0 T using 32-channel head coils. High-permittivity dielectric pads consisting of barium titanate in deuterated suspension were used for imaging at 7.0 T. Imaging protocol consisted of oblique sagittal proton density weighted turbo spin echo sequences. For quantitative analysis, pixelwise signal-to-noise ratio maps of the TMJ were calculated. For qualitative analysis, images were evaluated by two independent readers using 5-point Likert scales. Quantitative and qualitative results were compared using t-tests and Wilcoxon signed-rank tests, respectively. RESULTS: TMJ imaging at 7.0 T using high-permittivity dielectric pads was feasible in all volunteers. Quantitative analysis showed similar signal-to-noise ratio for both field strengths (mean ± SD; 7.0 T, 13.02 ± 3.92; 3.0 T, 14.02 ± 3.41; two-sample t-tests, p = 0.188). At 7.0 T, qualitative analysis yielded better visibility of all anatomical subregions of the temporomandibular disc (anterior band, intermediate zone and posterior band) than 3.0 T (Wilcoxon signed-rank tests, p < 0.05, corrected for multiple comparisons). CONCLUSIONS: MRI of the TMJ at 7.0 T using high-permittivity dielectric pads yields superior visibility of the temporomandibular disc compared with 3.0 T.

Design, construction, and technical implementation of a web-based interdisciplinary symptom evaluation (WISE) - a heuristic proposal for orofacial pain and temporomandibular disorders.

BACKGROUND: Medical symptoms independent of body location burden individuals to varying degrees and may require care by more than one expert. Various paper and computer-based tools exist that aim to comprehensively capture data for optimal clinical management and research. METHODS: A web-based interdisciplinary symptom evaluation (WISE) was newly designed, constructed, and technically implemented. For worldwide applicability and to avoid copyright infringements, open source software tools and free validated questionnaires available in multiple languages were used. Highly secure data storage limits access strictly to those who use the tool for collecting, storing, and evaluating their data. Concept and implementation is illustrated by a WISE sample tailored for the requirements of a single center in Switzerland providing interdisciplinary care to orofacial pain and temporomandibular disorder patients. RESULTS: By combining a symptom- burden checklist with in-depth questionnaires serving as case-finding instruments, an algorithm was developed that assists in clarifying case complexity and need for targeted expert evaluation. This novel modular approach provides a personalized, response-tailored instrument for the time- and cost-effective collection of symptom-burden focused quantitative data. The tool includes body drawing options and instructional videos. It is applicable for biopsychosocial evaluation in a variety of clinical settings and offers direct feedback by a case report summary. CONCLUSIONS: In clinical practice, the new instrument assists in clarifying case complexity and referral need, based on symptom burden and response -tailored case finding. It provides single-case summary reports from a biopsychosocial perspective and includes graphical symptom maps. Secure, centrally stored data collection of anonymous data is possible. The tool enables personalized medicine, facilitates interprofessional education and collaboration, and allows for multicenter patient-reported outcomes research.

Reproducibility of Neurochemical Profile Quantification in Pregenual Cingulate, Anterior Midcingulate, and Bilateral Posterior Insular Subdivisions Measured at 3 Tesla.

The current report assessed measurement reproducibility of proton magnetic resonance spectroscopy at 3 Tesla in the left and right posterior insular, pregenual anterior cingulate, and anterior midcingulate cortices. Ten healthy male volunteers aged 21-30 years were tested at four different days, of which nine were included in the data analysis. Intra- and inter-subject variability of myo-inositol, creatine, glutamate, total-choline, total-N-acetylaspartate, and combined glutamine-glutamate were calculated considering the influence of movement parameters, age, daytime of measurements, and tissue composition. Overall mean intra-/inter-subject variability for all neurochemicals combined revealed small mean coefficients of variation across the four regions: 5.3/9.05% in anterior midcingulate, 6.6/8.84% in pregenual anterior cingulate, 7.3/10.00% in left posterior and 8.2/10.55% in right posterior insula. Head movement, tissue composition and day time revealed no significant explanatory variance contribution suggesting a negligible influence on the data. A strong correlation between Cramer-Rao Lower Bounds (a measure of fitting errors) and the mean intra-subject coefficients of variation (r = 0.799, p < 0.001) outlined the importance of low fitting errors in order to obtain robust and finally meaningful measurements. The present findings confirm proton magnetic resonance spectroscopy as a reliable tool to measure brain neurochemistry in small subregions of the human brain.

Novel Air Stimulation MR-Device for Intraoral Quantitative Sensory Cold Testing.

The advent of neuroimaging in dental research provides exciting opportunities for relating excitation of trigeminal neurons to human somatosensory perceptions. Cold air sensitivity is one of the most frequent causes of dental discomfort or pain. Up to date, devices capable of delivering controlled cold air in an MR-environment are unavailable for quantitative sensory testing. This study therefore aimed at constructing and evaluating a novel MR-compatible, computer-controlled cold air stimulation apparatus (CASA) that produces graded air puffs. CASA consisted of a multi-injector air jet delivery system (AJS), a cold exchanger, a cooling agent, and a stimulus application construction. Its feasibility was tested by performing an fMRI stimulation experiment on a single subject experiencing dentine cold sensitivity. The novel device delivered repetitive, stable air stimuli ranging from room temperature (24.5°C ± 2°C) to -35°C, at flow rates between 5 and 17 liters per minute (l/min). These cold air puffs evoked perceptions similar to natural stimuli. Single-subject fMRI-analysis yielded brain activations typically associated with acute pain processing including thalamus, insular and cingulate cortices, somatosensory, cerebellar, and frontal brain regions. Thus, the novel CASA allowed for controlled, repetitive quantitative sensory testing by using air stimuli at graded temperatures (room temperature down to -35°C) while simultaneously recording brain responses. No MR-compatible stimulation device currently exists that is capable of providing non-contact natural-like stimuli at a wide temperature range to tissues in spatially restricted areas such as the mouth. The physical characteristics of this novel device thus holds promise for advancing the field of trigeminal and spinal somatosensory research, namely with respect to comparing therapeutic interventions for dentine hypersensitivity.