Background: "Temporomandibular disorders" (TMD) is an umbrella term for symptoms in the area of the temporomandibular joints and muscles of mastication. TMD constitute one of the more common types of musculoskeletal pain. Previous estimates of the prevalence of TMD suffered from methodological limitations. The NAKO Health Study enables, for the first time, an examination-based estimate of the prevalence of painful TMD in a large population sample. Methods: The baseline survey (2014-2019) was carried out in a partial population sample and involved standardized examinations of jaw mobility and palpation of the muscles of mastication. Painful TMD was recorded when a positive pain history was combined with pain that could be localized and induced on examination. Crude and adjusted prevalences were calculated, and associations with putative etiological and associated factors were analyzed by logistic regression. Results: Of the 20 603 participants, 10.9% reported jaw or facial pain in the preceding month. The point prevalence of painful TMD was 3.7% overall and 6% among persons aged 20-29. TMD was more common in women, with an odds ratio of 2.72 (95% confidence interval: [2.28; 3.25]), as well as in smokers (1.42 [1.16; 1.74]) and in participants reporting sleep disturbances (1.96 [1.6; 2.4]), childhood trauma (1.11 [1.08; 1.14] per scale point), anxiety (1.12 [1.09; 1.14] per scale point), or depression (1.11 [1.09; 1.13] per scale point). Orthodontic treatment before the age of 19 did not increase or decrease the likelihood of painful TMD. Abnormal tooth and jaw positions were associated with a lower prevalence. Conclusion: Painful TMD is a common health problem that is not associated with dental morphological abnormalities, but rather with various biopsychosocial factors. These findings underscore the need for interdisciplinary diagnosis and treatment.

This retrospective, monocentric, questionnaire-based cross-sectional study investigated self-reported symptoms of temporomandibular disorders (TMDs) and oral splint use among elite German athletes. Elite athletes (all sports except disability sports, 18–35 years old) who completed a questionnaire on oral health in sports between May 2020 and April 2021 were included. The assessed parameters included anamnestic TMD symptoms (3Q/TMD), oral splint use (presence, reason, wearing habits), current stress levels (scale 1–10), current training load (hours/week), and oral health-related quality of life (OHRQoL; OHIP-G5). Data from 337 elite athletes (23 ± 4 years, 50

OBJECTIVES:Reconstruction of a three-dimensional jaw position determined by a bite recording is an important aspect of prosthetic therapy. Different materials are used for this purpose. In the dental technical workflow, recordings are used to mount a lower jaw cast in a patient-like spatial position relative to the upper jaw cast. We evaluated the accuracy of positioning under the influence of different jaw positions and materials.MATERIALS AND METHODS:In an experimental setup, comprising an articulator, a pair of metal casts, and an optoelectronic measurement system, the spatial position of the incisal point and two condylar points were measured. To evaluate the accuracy of repeated repositioning of casts in the technical workflow, 324 measurements were taken from 108 recordings, consisting of silicone bite-stops made of addition curing silicone with 95 shore hardness, acrylic wafers, and wax recordings. The recordings were obtained in four jaw relations differing in vertical and protrusive components.RESULTS:Of the three materials/material combinations examined, silicone showed the most consistent results across all measurements, followed by the acrylic wafer system, and then wax recordings. Generally, recordings with smaller gaps between the jaws and no protrusive components showed greater deviations compared to jaw positions with greater protrusion and higher vertical dimensions.CONCLUSIONS AND CLINICAL RELEVANCE:To achieve reliable model mounting with high accuracy, recordings should include the use of a frontal jig and four small recording platelets made of silicone, especially if only a slight elevation of the vertical dimension is needed.

The effects of jaw clenching on balance has been shown under static steady-state conditions but the effects on dynamic steady-state balance have not yet been investigated. On this basis, the research questions were: 1) if jaw clenching improves dynamic steady-state balance; 2) if the effects persist when the jaw clenching task loses its novelty and the increased attention associated with it; 3) if the improved dynamic steady-state balance performance is associated with decreased muscle activity. A total of 48 physically active healthy adults were assigned to three groups differing in intervention (Jaw clenching and balance training (JBT), only balance training (OBT) or the no-training control group (CON)) and attending two measurement points separated by two weeks. A stabilometer was used to assess the dynamic steady-state balance performance in a jaw clenching and non-clenching condition. Dynamic steady-state balance performance was measured by the time at equilibrium (TAE). The activities of tibialis anterior (TA), gastrocnemius medialis (GM), rectus femoris (RF), biceps femoris (BF) and masseter (MA) muscles were recorded by a wireless EMG system. Integrated EMG (iEMG) was calculated to quantify the muscle activities. All groups had better dynamic steady-state balance performance in the jaw clenching condition than non-clenching at T1, and the positive effects persisted at T2 even though the jaw clenching task lost its novelty and attention associated with it after balance training with simultaneous jaw clenching. Independent of the intervention, all groups had better dynamic steady-state balance performances at T2. Moreover, reductions in muscle activities were observed at T2 parallel to the dynamic steady-state balance performance improvement. Previous studies showed that jaw clenching alters balance during upright standing, predictable perturbations when standing on the ground and unpredictable perturbations when standing on an oscillating platform. This study complemented the previous findings by showing positive effects of jaw clenching on dynamic steady-state balance performance.

In 1976, Marbach first described in the literature a clinical entity that he called “the phantom bite,” now known as “occlusal dysesthesia” (OD). Most patients suffering from OD are going through an unusually stressful period in their lives and have undergone dental therapy at the same time, resulting in a mental fixation on their teeth. They perceive clinically unremarkable occlusal contacts as bothersome or uncomfortable and TMD is a common comorbidity. Although there is no apparent relationship between the clinical findings and the nature and severity of the reported occlusal complaints, patients search for their “ideal” occlusion or to regain their “lost bite.” As a result, they suffer from persistent and severe emotional distress. The co-occurrence of depression, anxiety and/or personality disorders is common. The primary therapeutic goal is to improve oral health-related quality of life. Occlusal adjustments are contraindicated. Instead, professional counseling and education as information therapy, psychological therapy, oral splints as a form of occlusal therapy with the goal of defocusing effects and medication are recommended forms of therapy. Unfortunately, the acceptance of the diagnosis of OD and the therapeutic recommendations is usually low among these patients and a large proportion reject therapeutic efforts out of conviction and continue their journey in search of “healing” invasive therapy.

BACKGROUND:Jaw clenching improves dynamic reactive balance on an oscillating platform during forward acceleration and is associated with decreased mean sway speed of different body regions.OBJECTIVE:It is suggested that jaw clenching as a concurrent muscle activity facilitates human motor excitability, increasing the neural drive to distal muscles. The underlying mechanism behind this phenomenon was studied based on leg and trunk muscle activity (iEMG) and co-contraction ratio (CCR).METHODS:Forty-eight physically active and healthy adults were assigned to three groups, performing three oral motor tasks (jaw clenching, tongue pressing against the palate or habitual lower jaw position) during a dynamic one-legged stance reactive balance task on an oscillating platform. The iEMG and CCR of posture-relevant muscles and muscle pairs were analysed during platform forward acceleration.RESULTS:Tongue pressing caused an adjustment of co-contraction patterns of distal muscle groups based on changes in biomechanical coupling between the head and trunk during static balancing at the beginning of the experiment. Neither iEMG nor CCR measurement helped detect a general neuromuscular effect of jaw clenching on the dynamic reactive balance.CONCLUSION:The findings might indicate the existence of robust fixed patterns of rapid postural responses during the important initial phases of balance recovery.

In orthodontics, accurate registration of jaw relationships is essential for correct diagnosis and treatment planning. Therefore, accuracy of the digital spatial registration of maxillary and mandibular models and – for the first time—the influence of dentition stage and malocclusion type on this procedure were investigated under controlled conditions. Eight pairs of jaw models, representing different occlusal and developmental statuses (m1–m8), were scanned using two IOS types (PS: Primescan; TR: Trios4). Buccal scans for registering maxillary and mandibular models were repeated (n = 3). Reference scans were obtained using a desktop scanner (RDS; Ceramill Map 600). Arch-specific 3D coordinate systems were used to calculate the linear and angular deviations among different registrations. Trueness of registration by PS and TR was calculated using a statistical mixed-effect model (random-effect: model-type). Precision values of IOS registrations across m1–m8 were characterized as standard deviations (SDs). As maximum deviations compared to RDS, PS showed caudal translation (0.11 ± 0.02 mm), while TR showed ventral translation (0.08 ± 0.06 mm), of the maxillary relative to the mandibular model. Maximum rotational values were calculated for tilting around the transverse axis (PS: anteinclination (0.25 ± 0.16°), TR: retroinclination (0.27 ± 0.16°)). These deviations varied with the malocclusion type. The lowest IOS precision was recorded for sagittal translation (PS: 0.013 ± 0.005 mm, TR: 0.021 ± 0.010 mm) and rotation around the transverse axis (PS: 0.051 ± 0.013°, TR: 0.076 ± 0.031°). Registrations using buccal IOS scans showed quantifiable but clinically negligible 3D deviations from reference scan registrations, whereby the type of tooth and jaw misalignment did not appear to have a clinically relevant influence. Therefore, the examined IOSs appear to be suitable for digital jaw relation determination in everyday clinical orthodontic practice.

Introduction Good balance is essential for human daily life as it may help to improve the quality of life and reduce the risk of falls and associated injuries. The influence of jaw clenching on balance control has been shown under static and dynamic conditions. Nevertheless, it has not yet been investigated whether the effects are mainly associated with the dual-task situation or are caused by jaw clenching itself. Therefore, this study investigated the effects of jaw clenching on dynamic reactive balance task performance prior to and after 1 week of jaw clenching training. It was hypothesized that jaw clenching has stabilizing effects resulting in a better dynamic reactive balance performance, and these effects are not related to dual-task benefits. Methods A total of 48 physically active and healthy adults (20 women and 28 men) were distributed into three groups, one habitual control group (HAB) and two jaw clenching groups (JAW and INT) that had to clench their jaws during the balance tasks at T1 and T2. One of those two groups, the INT group, additionally practiced the jaw clenching task for 1 week, making it familiar and implicit at T2. The HAB group did not receive any instruction regarding jaw clenching condition. Dynamic reactive balance was assessed using an oscillating platform perturbed in one of four directions in a randomized order. Kinematic and electromyographic (EMG) data were collected using a 3D motion capture system and a wireless EMG system, respectively. Dynamic reactive balance was operationalized by the damping ratio. Furthermore, the range of motion of the center of mass (CoM) in perturbation direction (RoMCoM_AP or RoMCoM_ML), as well as the velocity of CoM (VCoM) in 3D, were analyzed. The mean activity of the muscles relevant to the perturbation direction was calculated to investigate reflex activities. Results The results revealed that jaw clenching had no significant effects on dynamic reactive balance performance or CoM kinematics in any of these three groups, and the automation of jaw clenching in the INT group did not result in a significant change either. However, high learning effects, as revealed by the higher damping ratio values and lower VCoM at T2, were detected for the dynamic reactive balance task even without any deliberate balance training in the intervention phase. In the case of backward perturbation of the platform, the soleus activity in a short latency response phase increased for the JAW group, whereas it decreased for HAB and INT after the intervention. In the case of forward acceleration of the platform, JAW and INT showed a higher tibialis anterior muscle activity level in the medium latency response phase compared to HAB at T1. Discussion Based on these findings, it can be suggested that jaw clenching may lead to some changes in reflex activities. However, the effects are limited to anterior–posterior perturbations of the platform. Nevertheless, high learning effects may have overall overweighed the effects related to jaw clenching. Further studies with balance tasks leading to less learning effects are needed to understand the altered adaptations to a dynamic reactive balance task related to simultaneous jaw clenching. Analysis of muscle coordination (e.g., muscle synergies), instead of individual muscles, as well as other experimental designs in which the information from other sources are reduced (e.g., closed eyes), may also help to reveal jaw clenching effects.

Nachhaltigkeit in die zahnärztliche Praxis zu integrieren, ist heute wichtiger denn je. Sowohl für Patienten als auch für Behandelnde ist es wichtig, sich auf eine nachhaltige, „resiliente“ Zahnmedizin verlassen zu können, die qualitativ hochwertig und zugänglich zugleich ist. Zudem sollte sie den Bedürfnissen unserer Umwelt gerecht werden. Die Zahnmedizin verursacht eine nicht unerhebliche Menge an „CO2-Äquivalenten“, die es in Zukunft zu verringern gilt. Der Beitrag rahmt das Thema in einem größeren Kontext, unterstreicht die Bedeutung für die Zahnärzteschaft und skizziert beiläufig den aktuellen Stand.

Background The digital panoramic radiograph (orthopantomogram, OPG) is the standard radiographic technique for basic diagnostics in dental practice. A correctly taken image provides a good overview of teeth and jaw, whereas radiopaque foreign materials, e. g. metal, can obscure relevant findings. Methods A literature review on unexpected metallic foreign bodies in OPG was performed to determine the spectrum of metallic foreign bodies that may cause radiopaque areas on panoramic radiographs in routine clinical use. Results and Conclusion A total of 37 different unexpected metallic foreign bodies were found. They can be categorized as jewelry, clothing, personal protective equipment, medical devices, iatrogenic foreign bodies, and rare incidental findings. Radiopaque foreign materials in the OPG are often relatively easy to recognize as artifacts because of their location, and they are avoidable in most cases. If unclear, a three-dimensional radiograph was helpful for determining the location. Radiopaque areas caused by foreign bodies can lead to misinterpretation or partial or complete non-evaluability and should therefore be avoided.

BACKGROUND:The influence of the stomatognatic system on human posture control has been investigated under static conditions, but the effects on dynamic balance have not yet been considered.OBJECTIVE:Investigating the influence of different functional stomatognatic activities (jaw clenching (JAW), tongue pressing (TON) and habitual jaw position (HAB)) on postural performance during a dynamic reactive balance task.METHODS:Forty-eight physically active and healthy adults were assigned to three groups differing in oral-motor tasks (JAW, TON or HAB). Dynamic reactive balance was assessed by an oscillating platform which was externally perturbed in four directions. Performance was quantified by means of Lehr's damping ratio. Mean speeds of the selected anatomical regions (head, trunk, pelvis, knee and foot) were analysed to determine significant performance differences.RESULTS:The groups differed significantly in balance performance in direction F (i.e., forwards acceleration of the platform). Post hoc tests revealed that the JAW group had significantly better performance compared with both the HAB and TON groups. Better performance was associated with a decreased mean speed of the analysed anatomical regions.CONCLUSION:JAW can improve dynamic reactive balance but the occurrence of positive effects seems to be task-specific and not general. TON seems not to have any observable effects on dynamic reactive balance performance, at least when evaluating it with an oscillating platform. JAW might be a valuable strategy which could possibly reduce the risk of falls in elderly people; however, further investigations are still needed.

Multiple sensory signals from visual, somatosensory and vestibular systems are used for human postural control. To maintain postural stability, the central nervous system keeps the center of mass (CoM) within the base of support. The influence of the stomatognathic motor system on postural control has been established under static conditions, but it has not yet been investigated during dynamic steady-state balance. The purpose of the study was to investigate the effects of controlled stomatognathic motor activity on the control and stability of the CoM during dynamic steady-state balance. A total of 48 physically active and healthy adults were assigned to three groups with different stomatognathic motor conditions: jaw clenching, tongue pressing and habitual stomatognathic behavior. Dynamic steady-state balance was assessed using an oscillating platform and the kinematic data were collected with a 3D motion capturing system. The path length (PL) of the 3D CoM trajectory was used for quantifying CoM sway. Temporal dynamics of the CoM movement was assessed with a detrended fluctuation analysis (DFA). An uncontrolled manifold (UCM) analysis was applied to assess the stability and control of the CoM with a subject-specific anthropometric 3D model. The statistical analysis revealed that the groups did not differ significantly in PL, DFA scaling exponents or UCM parameters. The results indicated that deliberate jaw clenching or tongue pressing did not seem to affect the sway, control or stability of the CoM on an oscillating platform significantly. Because of the task-specificity of balance, further research investigating the effects of stomatognathic motor activities on dynamic steady-state balance with different movement tasks are needed. Additionally, further analysis by use of muscle synergies or co-contractions may reveal effects on the level of muscles, which were not visible on the level of kinematics. This study can contribute to the understanding of postural control mechanisms, particularly in relation to stomatognathic motor activities and under dynamic conditions.

Hinweis Die Beiträge in der Rubrik „SOP/Arbeitsablauf“ sind als Anregung und Orientierungshilfe zu verstehen. Es bleibt jeder/jedem Kollegin/Kollegen überlassen, von diesem Schema abzuweichen, sofern man sich mit der Indikationsfrage befasst hat und sachliche Gründe für ein alternatives Vorgehen sprechen.

Background Passive mandibular advancement with functional appliances is commonly used to treat juvenile patients with mandibular retrognathism. Objective The aim of this study was to investigate whether active repetitive training of the mandible into an anterior position would result in a shift of the habitual mandibular position (HMP). Methods Twenty adult healthy subjects were randomly assigned to one of two groups: a training group receiving six supervised functional training sessions of 10 min each and a control group without training. Bonded lateral biteplates disengaged occlusion among both groups throughout the 15-day experiment. Customised registration-training appliances consisted of a maxillary component with an anterior plane and a mandibular component with an attached metal sphere. Training sessions consisted of repeated mouth-opening/closing cycles (frequency: 30/min) to hit an anteriorly positioned hemispherical target notch with this metal sphere. The HMP was registered at defined times during the experiment. Results The HMP in the training group showed a statistically significant anterior shift of 1.6 mm (interquartile range [IQR]: 1.2 mm), compared with a significant posterior shift of -0.8 mm (IQR: 2.8 mm) in the control group (p < .05). Although the anterior shift among the training group showed a partial relapse 4 days after the first training block, it then advanced slightly in the 4-day interval after the second training block, which might indicate neuroplasticity of the masticatory motor system. Conclusions Motor learning by repetitive training of the mandible into an anterior position might help to improve the results of functional appliance therapy among patients with mandibular retrognathism.

ABSTRACT Background Closing movements are among the jaw’s basic physiological motor actions. During functional movements, the jaw changes position continually, which requires appropriate proprioception. However, the significance of the various proprioceptive receptors involved and how they interact is not yet fully clear. Objectives This study’s main objective was to test whether preventing intercuspation (IC) for 1 week would affect the precision of jaw‐closing movements into IC and the functional space of habitual chewing movements (HCM). A secondary objective was to compare precision of jaw‐closing movements into IC with the precision of movements into a target position (TP) far from IC. Methods Fourteen participants’ HCM and jaw‐closing movements into IC were recorded on two sessions (T1 and T2) 1 week apart. Between sessions, participants wore posterior bite plates to prevent IC. They also received a 10‐minute training session at T1 to guide their jaw‐closing movements into TP. The precision of the closing movements into IC and TP was analysed. For HCM, the vertical amplitude, lateral width and area of chewing cycles were evaluated. Results The precision of jaw movements into IC increased as the jaw gap decreased, but precision did not differ significantly between T1 and T2. For HCM, the vertical amplitude and area of chewing cycles increased significantly between T1 and T2. The precision of the closing trajectory into TP increased significantly during the training session. Conclusion Our results confirm the excellent adaptability of the craniomandibular system, controlled by stringent motor programmes that are supported by continuous peripheral sensory input.

The Ochsentour describes the slow, hard road to the top of political positions and is colloquially negatively associated . But despite this negative image, it remains unclear what actually constitutes this process of intra-party proving and how to interpret the metaphor of the arduous journey of the ox dragging the plough . A descriptive analysis based on the IParl survey shows that an aspirant’s nomination success depends on much more than the symptomatical duration of his or her party membership . These findings instead indicate that the development of a trusted relationship between candidate and party base is the key component of intra-party promotion . Overall the data suggests that aspirants are mostly flexible, show high levels of engagement and have proved themselves to their party base . Thus, the Ochsentour metaphor does not fit to the actual performance of candidature applicants.

Intraorale Schienen sind in Deutschland unter den zur Verfügung stehenden Optionen die am häufigsten eingesetzten Therapiemittel bei der Behandlung der schmerzhaften kraniomandibulären Dysfunktion (sCMD). Okklusionsschienen werden mehr und mehr im CAD/CAM-Verfahren hergestellt. Jedoch gelten die grundlegenden Gesetzmäßigkeiten aus der „analogen Welt“ in Bezug auf die Gestaltung und Wirkung. Unter der Therapie mit Okklusionsschienen kommt es zu einer langanhaltenden Neuorganisation inter- und intramuskulärer Funktionsmuster in der Kaumuskulatur und zu einer Reorganisation der Belastungsverteilung in den Kiefergelenken. Die sog. Michigan-Schiene ist die wohl bekannteste und in Deutschland am häufigsten verwendete Schienenart bei der Behandlung der sCMD. Ihre Produktion mithilfe des digitalen Workflows hat sich dabei aufgrund der hohen Präzision bei der Fertigung und des sofort durch den Patienten empfundenen Tragekomforts im klinischen Alltag bewährt.