Parafunctional Clenching Research Articles

Adjunctive treatment of chronic migraine using an oral dental device: overview and results of a randomized placebo-controlled crossover study

ObjectiveTo assess the nocioceptive input of habitual nocturnal jaw clenching that acts as a contributing factor in migraine pathogenesis.BackgroundHabitual nocturnal jaw clenching has been implicated as a trigger, particularly in those whose headaches are present upon waking or shortly thereafter. Nocturnal EMG studies of patients diagnosed with migraine show nearly twice the temporalis clenching EMG levels and double the bite force as matched asymptomatic controls, leading to the speculation that parafunctional clenching activity may have some role in headache pathogenesis. The NTI (Nociceptive Trigeminal Inhibition) oral device is a dental splint designed to reduce nocturnal jaw clenching intensity and is FDA approved for the prevention of medically diagnosed migraine pain based on open label studies. There are no prior placebo-controlled trials to assess the migraine prevention efficacy of the NTI splint. This is the first placebo-controlled cross-over study to assess the efficacy of the NTI splint in patients with Chronic Migraine.MethodA placebo controlled, single-blinded cross-over study was done with IRB oversight assessing the efficacy of the NTI splint compared to placebo using the change in the HIT-6 score as the outcome measure.Results68% of refractory chronic migraine sufferers using the NTI as measured by sequential HIT 6 scores had at least a one-category improvement (severe to substantial, or substantial to some, or some to none) compared to 12% when using a placebo device. 36% of subjects using the NTI device reported a two-category improvement in their HIT-6 score, compared to 0% when using placebo.ConclusionThe improvement in HIT-6 scores produced by the NTI device, suggests that patients with Chronic Migraine may have intense nocturnal jaw clenching as a contributing factor to their headache related disability. An NTI device is one method of assessing whether jaw-clenching is a contributing factor to ongoing migraine.Trial registrationCurrent Controlled Trials NCT04871581. 04/05/2021. Retrospectively registered.

The Temporomandibular Joint: A Critical Review of Life-Support Functions, Development, Articular Surfaces, Biomechanics and Degeneration.

The temporomandibular joint is a highly conserved articulation because it promotes survival and propagation via the essential functions of mastication, communication, and routine mating success (dentofacial esthetics). The temporomandibular joint is a unique secondary joint formed between the endochondral temporal bone and the mandibular secondary condylar cartilage via Indian hedgehog and bone morphogenetic protein signaling that is closely related to ear development. A dynamic epigenetic environment is provided by Spry1 and Spry2 genetic induction of the lateral pterygoid and temporalis muscles. Mechanical loading of the condylar periosteum during fetal development produces a superficial layer of fibrocartilage that separates from the condyle to form the interposed temporomandibular joint disc. The articular surfaces of the condyle and fossa are dynamically modified periosteum that has healing and regenerative capability. This unique tissue is composed of a superficial fibrous layer (synovial surface) with an underlying proliferative (cambium) layer that produces a cushioning layer of fibrocartilage which subsequently forms bone. Prior to occlusion of the first primary (deciduous) molars at about 16 months, facial development is dominated by primary genetic mechanisms. After achieving posterior functional occlusion, biomechanics enhances temporomandibular joint maturation, and assumes control of facial growth, development and adaptation. Concurrently, hypothalamus control of musculoskeletal physiology shifts from insulin-like growth factor IGF2 to IGF1, which affects bone via muscular loading (biomechanics). Three layers of temporomandibular joint fibrocartilage are resistant to heavy functional loading, but parafunctional clenching may result in degeneration that is first manifest as trabecular sclerosis of the mandibular condyle.

The Relationship between Eccentric Occlusion with Temporomandibular Disorders (TMD) and Para-functional Habits among Dentistry Students of Tabriz University of Medical Sciences in 2017

Aim: The aim of this study is to investigate the relationship between side occlusion with temporomandibular joint problems (TMD) and parafunctional habits among Dentistry Students of Tabriz University of Medical Sciences. Materials and Methods: In this cross - sectional study, 98 students from the School of Dentistry of Tabriz University of Medical Sciences were randomly selected, and the occlusion was also examined. Data from the study were analyzed using descriptive statistics and chi-square test software SPSS 17. Results: In this study, 16.33 % of population had Group function occlusion, 13.23 % had Anterior Group function occlusion and 70.4 % had canine raise occlusion. 3.1% of people had functional Paralympic symptoms of Bruxism and 6.1 % were marked with Parafunctional clenching. The study population consisted, all patients with Group function occlusion that had para-functional habits. However, in patients with canine raised occlusion, 63.3 % para-functional habit parameters, 2 % has Bruxism and 1.5 % had clenching. Conclusions: a significant relationship was not observed between side occlusion with parafunctional habits and TMD problems among students of Tabriz University of Medical Sciences.

Bruxisme induit par les psychotropes : mise au point

ObjectiveBruxism is the parafunctional clenching or grinding of teeth, which can occur during sleep or during wakefulness. Psychiatric patients have been shown to suffer from bruxism more than healthy controls. Updating knowledge on bruxism and psychopharmacology, and the elucidation of the induction-effect of psychotropic drugs on this temporo-mandibular joint disorder is important in order to manage it in psychiatric patients. MethodsA review of the published literature in English or in French was made via Medline. The terms used for the search were “bruxism” or “temporo-mandibular joint disorder” in association with one of the following: antipsychotic, neuroleptic, antidepressant, mood stabilizers, anticonvulsant, antiepileptic, antiparkinsonian, anxiolytic, benzodiazepines, stimulants, alpha-blockers, beta-blockers, anticholinergic, or antihistaminergic. Thirty-two articles were found to be related to our subject since 1993. ResultsPsychotropic drugs are directly incriminated in the induction or exacerbation of bruxism. Antipsychotic drugs are involved in the induction of bruxism as a part of their induced movement disorders due to their dopamine receptor blockade. Bruxism could be related to acute dystonia making it respondent to propranolol treatment, or to tardive dyskinesia making it respondent to dose augmentation or switching to atypical drugs such as clozapine. Tricyclic antidepressants do not seem to induce or exacerbate bruxism. Other antidepressants, especially SSRIs, are involved in bruxism induction or aggravation since their serotonergic effect mimics dopaminergic antagonism. This effect could be reversed with the administration of beta-blockers such as propranolol or partial serotonin agonists such as buspirone or tandospirone. Data concerning the influence of dopaminergic agonists such as antiparkinsonian drugs or amphetamines is controversial and needs to be evaluated in randomized controlled studies. Other psychotropic drugs were not found to induce or exacerbate bruxism. ConclusionAlthough psychiatric patients present frequently with temporo-mandibular joint disorders such as bruxism, treatment of their psychiatric symptoms should take into consideration the effect of psychotropic drugs. Typical antipsychotic drugs and SSRIs are the psychotropic drugs that are clearly involved in the induction or aggravation of bruxism.

Bruxism – a function of the masticatory organ to cope with stress

Bruxism is generally defined as a parafunctional clenching and grinding action between the upper and lower teeth. During this activity, extremely strong forces can be applied for time periods exceeding those of functional mastication. These biomechanical loads create many dental problems, such as abfractions, hypersensitivity, periodontal distraction, and temporo-mandibular dysfunction. Researchers studying Bruxism have long discussed psychic stress and emotional tension. It has also been indicated that an aggressive biting is associated with a significant attenuation of the stress-induced increase of nor-adrenalin turnover in the brain, of the striatal DOPAC contents and with the prevention of stomach ulcer formation in experimental animals. The concept of stress management based on the psychological background of Bruxism and the benefits attributable to masticatory muscle activity in attenuating stress-related symptoms such as stomach ulcer. The clenching and bruxing function of the masticatory organ is an emergency exit during periods of psychic overloading. Therefore, occlusion of the masticatory organ contributes significantly to an individual's ability to manage stress. Bruxism in proper dentition can be recognized as a valid system prophylaxis for all stress related diseases.

Symptoms of craniomandibular disorder amongelderly people

This study investigated the subjective symptoms of craniomandibular disorder and the restriction in maximal mandibular opening of 891 elderly Singaporean citizens. A distribution of 22% of subjects (20% of the women and 26% of the men) reported subjective symptoms of craniomandibular disorders. The most common single symptom reported was occasional to frequent clicking sounds from the temporomandibular joints (in 15% of subjects). The other single symptoms were reported only occasionally in 2-6% of subjects. Nineteen per cent of the subjects had some restriction in maximal interincisal opening (30-39 mm) and about 1% of subjects were severely restricted in maximal opening (less than 30 mm). Subjectively evaluated limitation of wide mandibular opening was recorded for only 2% of the subjects. Background factors included general musculo-skeletal problems (54%), perceived fair to poor general health (29%), headaches (33%), work-related stress (24%), oral parafunctional clenching (4%) and grinding activity (4%). This paper confirms earlier reports that the subjective signs and symptoms of craniomandibular disorder tend to diminish in elderly people.

実験的平衡側こう頭干渉が顎機能に及ぼす影響

The influences of experimental balancing-side interference on the jaw function were investigated on 6 subjects. A specially designed onlay was fabricated for the lower second molar, which acted as an artificial balancing-side interference in the lateral mandibular position. The subjects were asked to do maximum clenching, lateral gliding and gum chewing with and without the device. Electromyographic activity of the masseter and the anterior and posterior temporal muscles were measured and the related mandibular movement was simultaneously recorded during these tasks. Introduction of the experimental interference caused alteration in the muscle activity as follows: 1. When the subjects exerted maximum clenching efforts in the lateral mandibular position, the ratio of the temporal muscle activity on the working-side to the balancing-side decreased, while that of the masseter muscle remained unchanged. 2. There was a tendency for the activity in the working-side posterior temporal muscle to increase during gliding from intercuspation. The ratio of the temporal muscle activity on the working-side to the balancing-side decreased during gliding into intercuspation. 3. Prolongation of the occlusal phase associated with the increase of the muscle activity was observed during gum chewing on the side opposite to the interference. It was suggested that the balancing-side interference might provoke a specific muscle activity in the temporal muscles during parafunctional clenching or grinding.

The influence of altered working-side occlusal guidance on masticatory muscles and related jaw movement

The effect of four different occlusal situations (group function, canine guidance, working side occlusal interference, and hyperbalancing occlusal interference) on EMG activity in jaw elevator muscles and related mandibular movement was investigated on 12 subjects. With a computer-based system, EMG and displacement signals were collected simultaneously during specific functional (unilateral chewing) and parafunctional tasks (mandibular gliding movements and various tooth clenching efforts) and analyzed quantitatively. When a naturally acquired group function was temporarily and artificially changed into a dominant canine guidance, a significant general reduction of elevator muscle activity was observed when subjects exerted full isometric tooth-clenching efforts in a lateral mandibular position. The original muscular coordination pattern (relative contraction from muscle to muscle) remained unaltered during this test. With respect to unilateral chewing, no significant alterations in the activity or coordination of the muscles occurred when an artificial canine guidance was introduced. Introduction of a hyperbalancing occlusal contact caused significant alterations in muscle activity and coordination during maximal tooth clenching in a lateral mandibular position. A marked shift of temporal muscle EMG activity toward the side of the interference and unchanged bilateral activity of the two masseter muscles were observed. The results suggest that canine-protected occlusions do not significantly alter muscle activity during mastication but significantly reduce muscle activity during parafunctional clenching. They also suggest that non-working side contacts dramatically alter the distribution of muscle activity during parafunctional clenching, and that this redistribution may affect the nature of reaction forces at the temporomandibular joints.