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Not talking about coffee grinding here. Bruxism...

Interesting facts about grinding.

Bruxism or “teeth grinding” is a complicated phenomena which has a prevalence or 8-31.4% in the general population (Manfredini et al.2013). In the last 5 years the classification and definition of bruxism has quickly adapted and changed. An international consensus of dentistry experts (International Network for Orofacial Pain an related Disorders Methodology; INfORM) and the German associations Deutsche Gesellschaft für Funktionsdiagnostik und -Therapie in der Zahn-, Mund- und Kieferheilkunde (DGFDT)Deutsche Gesellschaft für Zahn-, Mund- und Kieferheilkunde (DGZMK)) (2019) worked to create a strong international consensus about the ethology, assessments and management of bruxism.

Bruxism is not a disease but a collective term for abnormal mouth habitual activity together with increased jaw-muscle activity (Lobbezoo et al. 2018). The complexity of the neurophysiological mechanism has been poorly understood until now. Risk factors (anatomical, psychosocial, and/or neuromuscular) are complex and the interference of the different risk factors are controversial (Manfredini et al 2013).

TMD, such as difficulty closing and opening the mouth, jaw locking, temporomandibular joint sounds, and a feeling of stiffness or jaw fatigue, can be a possible risk factor for bruxism (Ciancaglini et al., 2001). Feeling of stiffness or jaw fatigue is more frequently seen in sleep bruxism; whereas, awake bruxism is more associated with joint sounds and depressive mood (Selms et al., 2004; Manfredini et al., 2013). A recent study confirmed that when there is an increase severity of TMD with increased neck disability and pain the prevalence of bruxism is increased (von Piekartz 2019). Palpation of masticatory muscles, especially the masseter and temporal muscle may be significantly sensitive in bruxers but is it fair to hypothesize that there is a causal relationship between hypersensitivity, increased muscle tone and the bruxers complaints? In patients with bruxism these signs are mainly centrally mediated, not peripherally. There is convincing evidence, however, that (sleep-related) bruxism is part of an arousal response. Disturbances in the central dopaminergic system have been implicated in the etiology of bruxism as well. Further, there is a role for factors like smoking, alcohol, diseases, trauma and heredity, while the proposed role of stress and other psychological factors is probably smaller than previously assumed (Lobbezoo e and Naeije et al 2001, Lobbezoo et al 2018 ). Patients and therapist are often influenced by the media or not scientific, commercial publications that a splint may help to get rid of (the complaints caused by) bruxism. Based on several reviews, it should be concluded that there is no evidence what-so ever for a causal relationship between bruxism and the bite (Lobbezoo et al 2012). Definitive occlusal adjustment measures therefore should not be used for the causal treatment of bruxism. Splints are nowadays commonly used to protect the teeth because they reliably prevent excessive attrition-type tooth wear by interrupting tooth-to-tooth contact. Therefore, they may be worn on the maxilla as well as the mandible. Only in children should short-term splint therapy can be considered. After the completion of tooth development, splints can be used in children in basically the same manner as in adults. (A3 German Guideline Bruxism) Bruxism behavior does not directly lead to orofacial pain, headache or restrictions in daily life. According an overview study the prevalence of bruxism in orofacial and or headaches varying between 6% and 91% but 60% of all bruxers seems to have no complaints (Lobbezoo et al 2009, Paesani 2010). It is the potential risk factors of bruxism which interfere and leads to complex pathophysiological changes like increase of trigeminal sensitivity and therefore pain experiences (Molina e t al 1997). Bruxism does not restrict a person’s daily life but polysomnograph studies have found that sleep bruxism is associated with sleep changes during the night which may influence concentration and fitness (Lavigne et al 2007,Bader et al 2000).

  1. Neck disability and pain in Bruxers is mostly related to cervical impairments In daily practice bruxers often seem to have neck pain. During assessment (muscle and joint palpation, physiological and accessory movements) the neck tests may be painful and mobility may be changed. Neck impairments are present in people with TMD and may be one of the risk factors of bruxism (Lobbezoo et al 2012), but is there a clear relation between cervical dysfunctions/impairments and bruxism? In a recent study it was noted that severity of bruxism is independently associated with cervical impairments. Pain associated with cervical movement tests without clear cervical impairments was found to be correlated with bruxism. The coordination is probably related to an increased trigeminal sensitivity which causes false positive neuromusculoskeletal tests (von Piekartz et al 2019).

Reflecting on this information it may be concluded that bruxism in a complicated phenomenon which facilitates an interesting debate with many questions which can (still) not be answered. Bruxism seems to be the domain of the dentist because it has (also) to do with teeth. All credits on research, debates and consensus go to the dentist which is clearly fair but is it not also the domain of the psychology, somnology and physical therapy? There is the challenge for physical therapy. If physical therapy organizations and researcher execute studies specially on awake bruxism and also integrate and update knowledge in education for specialized physical therapy, for example the education CRAFTA provides, can we step on the exiting wave dentistry is on? The future will give us the answer.

  • Lobbezoo, F., Ahlberg, J., Raphael, K. G., Wetselaar, P., Glaros, A. G., Kato, T., ... & Koyano, K.(2018) International consensus on the assessment of bruxism: Report of a work in progress. Journal of oral rehabilitation, 45(11),837-844.

  • German Society of Craniomandibular Function and Disorders (DGFDT),German Society of Dental, Oral and Craniomandibular Sciences (DGZMK) S3 Guideline (ect version) Bruxismus Diagnosis and Treatment, J. of Craniomand. Function (2019)11(3):225–i385(download (Leitlinie Bruxismus) German and english

Harry von Piekartz


  1. Bader, G., & Lavigne, G. (2000). Sleep bruxism; an overview of an oromandibular sleep movement disorder. Sleep medicine reviews, 4(1), 27-43.

  2. Cesar, G. M., Tosato, P. J., & Biasotto-Gonzalez, D. A. (2006). Correlation between occlusion and cervical posture in patients with bruxism. Compendium of continuing education in dentistry (Jamesburg, NJ: 1995), 27(8), 463-6.

  3. Ciancaglini, R., & Radaelli, G. (2001). The relationship between headache and symptoms of temporomandibular disorder in the general population. Journal of dentistry, 29(2), 93-98.

  4. German Society of Craniomandibular Function and Disorders (DGFDT),German Society of Dental, Oral and Craniomandibular Sciences (DGZMK) S3 Guideline (ect version) Bruxismus Diagnosis and Treatment, J. of Craniomand. Function (2019)11(3):225–i385

  5. Kritsineli, M., & Shim, Y. S. (1992). Malocclusion, body posture, and temporomandibular disorder in children with primary and mixed dentition. The Journal of clinical pediatric dentistry, 16(2), 86-93.

  6. Lavigne, G. J., Huynh, N., Kato, T., Okura, K., Adachi, K., Yao, D., & Sessle, B. (2007). Genesis of sleep bruxism: motor and autonomic-cardiac interactions. Archives of oral biology, 52(4), 381-384.

  7. Lobbezoo, F., & Naeije, M. (2001). Bruxism is mainly regulated centrally, not peripherally. Journal of oral rehabilitation, 28(12), 1085-1091.

  8. Lobbezoo F, Aarab G, Zaag J van der. Definitions, epidemiology, and etiology of sleep bruxism(2009) In: Lavigne GJ, Cistulli P, Smith M, eds. Sleep medicine for dentists: a practical overview. Chicago: Quintessence Publishing Co, Inc:95–100.

  9. Lobbezoo, F., van Selms, M., & Naeije, M. (2012)Bruxism and associated risk indicators in Dutch adolescents: a cross-sectional study: O18. Journal of Oral Rehabilitation,39(1).

  10. Lobbezoo, F., Ahlberg, J., Raphael, K. G., Wetselaar, P., Glaros, A. G., Kato, T., ... & Koyano, K.(2018) International consensus on the assessment of bruxism: Report of a work in progress. Journal of oral rehabilitation, 45(11),837-844.

  11. Manfredini, D., Castroflorio, T., Perinetti, G., & Guarda‐Nardini, L. (2012). Dental occlusion, body posture and temporomandibular disorders: where we are now and where we are heading for. Journal of oral rehabilitation, 39(6), 463-471.

  12. Manfredini, D., Winocur, E., Guarda-Nardini, L., Paesani, D., & Lobbezoo, F. (2013). Epidemiology of bruxism in adults: a systematic review of the literature. J Orofac Pain, 27(2), 99-110.

  13. Motta, L. J., Martins, M. D., Fernandes, K. P. S., Mesquita‐Ferrari, R. A., Biasotto‐Gonzalez, D. A., & Bussadori, S. K. (2011). Craniocervical posture and bruxism in children. Physiotherapy Research International, 16(1), 57-61.

  14. Molina, O. F., dos Santos Jr, J., Nelson, S. J., & Grossman, E. (1997). Prevalence of modalities of headaches and bruxism among patients with craniomandibular disorder. CRANIO®, 15(4), 314-325.

  15. Muzalev K, Lobbezoo F, Janal MN, Raphael KG.(2017) Inter-episode sleep bruxism intervals and myofascial face pain. Sleep.;40

  16. Van Selms, M., Lobbezoo, F., Wicks, D. J., Hamburger, H. L., & Naeije, M. (2004). Craniomandibular pain, oral parafunctions, and psychological stress in a longitudinal case study. Journal of oral rehabilitation, 31(8), 738-745.

  17. von Piekartz, H., Rösner, C., Batz, A., Hall, T., & Ballenberger.(2019)Bruxism, temporomandibular dysfunction and cervical impairments in females–Results from an observational study. Musculoskeletal Science and Practice,45, 102073.

  18. Paesani DA. Bruxism theory and practice. Chicago: Quintessence Publishing Co, Inc; 2010

  19. Raphael KG, Janal MN, Sirois DA, et al. (2013)Masticatory muscle sleep background electromyographic activity is elevated in myofascial temporomandibular disorder patients. J Oral Rehabil.;40:883-891.

  20. Vázquez Delgado, E., Cascos-Romero, J., & Gay Escoda, C. (2010). Myofascial pain associated to trigger points: a literature review. Part 2: differential diagnosis and treatment. Medicina Oral, Patología Oral y Cirugia Bucal, 2010, vol. 15, num. 4, p. 639-643.

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