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.

[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.

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.

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.

Tracking local anesthetic effects using a novel perceptual reference approach.

Drug effects of loco-regional anesthetics are commonly measured by unidimensional pain rating scales. These scales require subjects to transform their perceptual correlates of stimulus intensities onto a visual, verbal, or numerical construct that uses a unitless cognitive reference frame. The conceptual understanding and execution of this magnitude estimation task may vary among individuals and populations. To circumvent inherent shortcomings of conventional experimental pain scales, this study used a novel perceptual reference approach to track subjective sensory perceptions during onset of an analgesic nerve block. In 34 male subjects, nociceptive electric stimuli of 1-ms duration were repetitively applied to left (target) and right (reference) mandibular canines every 5 s for 600 s, with a side latency of 1 ms. Stimulus strength to the target canine was programmed to evoke a tolerable pain intensity perception and remained constant at this level throughout the experiment. A dose of 0.6 ml of articaine 4% was submucosally injected at the left mental foramen. Subjects then reported drug effects by adjusting the stimulus strength (in milliamperes) to the reference tooth, so that the perceived intensity in the reference tooth was equi-intense to the target tooth. Pain and stimulus perception offsets were indicated by subjects. Thus, the current approach for matching the sensory experience in one anatomic location after regional anesthesia allows detailed tracking of evolving perceptual changes in another location. This novel perceptual reference approach facilitates direct and accurate quantification of analgesic effects with high temporal resolution. We propose using this method for future experimental investigations of analgesic/anesthetic drug efficacy.

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.

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.

Brain activation induced by dentine hypersensitivity pain--an fMRI study.

AIM: Dentine hypersensitivity (DH) is characterized by a short, sharp pain arising from exposed dentin. Most published literature reports on peripheral neural aspects of this pain condition. The current investigation focused on differential cerebral activity elicited by stimulation of sensitive and insensitive teeth by means of natural air stimuli. MATERIALS AND METHODS: Five graded stimulus strengths were randomly applied by means of a multi-injector air jet delivery system, each followed by an individual rating of perceived stimulus intensity. Brain activity was analysed by functional magnetic resonance imaging (fMRI). RESULTS: Stimulation of sensitive teeth induced significant activation in the thalamus, somatosensory cortices (SI & SII), anterior, middle and posterior insular cortices, anterior mid cingulate cortex, perigenual anterior cingulate cortex and frontal regions (BA10 and BA46). Differential responses to DH and painless perceptions were observed in the anterior insula and anterior midcingulate cortex. CONCLUSION: For the first time, this fMRI study demonstrates the feasibility of investigating cerebral processes related to DH evoked by natural (air) stimuli. Our neuroimaging data additionally provide evidence that differential activity in the anterior Insula (aIC) and anterior midcingulate cortex (aMCC) may represent clinically relevant pain experienced by DH patients.

Impact of a collagen matrix on early healing, aesthetics and patient morbidity in oral mucosal wounds - a randomized study in humans.

AIM: To test whether a collagen matrix (CM) can improve early wound healing and aesthetics, and decrease wound sensitivity compared with spontaneous healing. METHODS: In 15 volunteers, 6-mm punch biopsies were harvested at both palatal sites. A CM was sutured in one site; the other one was left untreated (control). Measurements included the remaining defect area, the colour match to surrounding tissue and somatosensory parameters at various time-points (pre-operative, post-operative, 4, 8, 15, 29 days). RESULTS: The defect area decreased over time for both treatments. Re-epithelization was completed in all subjects by day 15. The defect area was significantly smaller for CM (mean ± SD: 19.3 ± 3.4 mm(2)) compared with control (21.3 ± 3.3 mm(2)) at day 4 (p < 0.05), and at day 8 (CM: 11.7 ± 2.5 mm(2) ; control: 13.6 ± 2.9 mm(2) ; p < 0.01). The colour match was more favourable for CM at day 4, 8 and 29 (p > 0.05). Somatosensory measurements revealed slightly lower wound sensitivity at day 4 for CM compared with control. CONCLUSIONS: The use of CM can enhance wound healing compared with spontaneous healing during the first week. This was mainly documented by a faster re-epithelization. Colour match and wound sensitivity measurements did not reach statistical significance between CM and control sites.

Placebo-mediated, Naloxone-sensitive suggestibility of short-term memory performance.

Physiological studies of placebo-mediated suggestion have been recently performed beyond their traditional clinical context of pain and analgesia. Various neurotransmitter systems and immunological modulators have been used in successful placebo suggestions, including Dopamine, Cholecystokinin and, most extensively, opioids. We adhered to an established conceptual framework of placebo research and used the µ-opioid-antagonist Naloxone to test the applicability of this framework within a cognitive domain (e.g. memory) in healthy volunteers. Healthy men (n=62, age 29, SD=9) were required to perform a task-battery, including standardized and custom-designed memory tasks, to test short-term recall and delayed recognition. Tasks were performed twice, before and after intravenous injection of either NaCl (0.9%) or Naloxone (both 0.15 mg/kg), in a double-blind setting. While one group was given neutral information (S-), the other was told that it might receive a drug with suspected memory-boosting properties (S+). Objective and subjective indexes of memory performance and salivary cortisol (as a stress marker) were recorded during both runs and differences between groups were assessed. Short-term memory recall, but not delayed recognition, was objectively increased after placebo-mediated suggestion in the NaCl-group. Naloxone specifically blocked the suggestion effect without interfering with memory performance. These results were not affected when changes in salivary cortisol levels were considered. No reaction time changes, recorded to uncover unspecific attentional impairment, were seen. Placebo-mediated suggestion produced a training-independent, objective and Naloxone-sensitive increase in memory performance. These results indicate an opioid-mediated placebo effect within a circumscribed cognitive domain in healthy volunteers.

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.

Familial occipital and nervus intermedius neuralgia in a Swiss family.

Familial trigeminal neuralgia has been reported in 1-2% of cases consistent with an autosomal dominant inheritance. We present a Swiss family with several members suffering from occipital and nervus intermedius neuralgia alone or in combination. We suggest that peripheral sensory anastomoses or central convergence of afferent pathways could explain neuralgia affecting two cranial nerves. The pedigree has two main characteristics: (1) affected individuals in two generations and (2) in the first generation the father is affected, in the second generation all women are affected, and none of the men. This is suggestive of an X-linked dominant or an autosomal dominant mode of inheritance.

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.

[Treatment of localized gingival erythema]. / Behandlung des lokalisierten gingivalen Erythems.

Forms of a localized erythema can be observed occasionally as an expression of inflamed gingiva. It is characterized by a localized sharply demarcated and painless swelling of the gingiva with considerable redness. The differential diagnosis is not unequivocal and appropriate diagnosis and therapy are a challenge. In the present case presentation we report on three cases, which showed good disease remission after simple antiseptic prophylactic measures. Based on the available literature possible etiologic factors are reviewed and a pragmatic treatment strategy is discussed.

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.

Design and construction of a magnetic resonance compatible multi-injector gas jet delivery system.

We present the design, construction, and performance of a novel multi-injector gas jet delivery capable of operating in a magnetic resonance imaging environment. This apparatus is computer controlled and built with two separate pneumatic circuits enabling gas jet applications at variable sites through four independently activated injectors. Gas jet delivery is fully controllable in terms of pressure, flow rate, gas temperature, application time, and duration of interstimulus interval. We characterized these parameters, considering effects such as pressure drop by flow transport, transient effects, and delays in activation. The system offers new possibilities for use in various biomedical contexts such as, e.g., quantitative sensory testing or dental hypersensitivity assessment.