Orofacial pain and dysfunction

As one of the dental differentiations in The Netherlands, temporomandibular disorders (TMD) focuses on the diagnosis and treatment of pain and dysfunction of the masticatory system. Bruxism (i.e. tooth clenching and/or grinding) is thought to play an important aetiological role in TMD. Among others, bruxism may result in TMD pain and dental attrition. The close relationship between TMD, bruxism, and attrition necessitates an integrated approach to these clinical problems. This could be achieved through the multidisciplinary differentiation ‘oral kinesiology’, that covers not only the diagnosis and treatment of TMD and bruxism but also the restoration of worn dentitions. In addition, special attention is paid to the diagnosis and treatment of the obstructive sleep apnea syndrome due to its relation with the masticatory system. The Academic Centre for Dentistry Amsterdam offers dental practitioners a postgraduate training in oral kinesiology. This curriculum will ensure that specialized professionals (dentist–kinesiologists), who are able to approach the different aspects of oral kinesiology in an integrated manner, are available not only for the general dental practice but also for centres for special dental care and university departments. This will lead to improved care for patients, whose management is still frequently dispersed between various (dental) specialists.

Overloading of the constituent tissues of the masticatory system, notably cartilage, bone, muscle tissue, periodontal tissues, and hard dental tissues due to bruxism (i.e., tooth grinding and clenching) and adverse oral habits (e.g., nail biting and excessive gum chewing) may lead to pain and dysfunction of the chewing apparatus. In turn, such conditions may yield risks for the individual’s general health and cognitive abilities. Within the framework of ORM, the causes, consequences, and management of pain and dysfunction of the masticatory system are studied in multiple international and multidisciplinary settings. Chewing, laughing, smiling, talking, yawning etc. are important movement functions of the human masticatory system. Sometimes patients are confronted with problems in performing these functions, which are related to a malfunction of the jaw muscles and/or the temporomandibular joint. This sub-programme studies the normal and disturbed functions of the jaw muscles and the temporomandibular joint, the factors that influence these functions and the treatment modalities that preserve or restore these functions.

Some results obtained by the Department of Orofacial Pain and Dysfunction

  • Mechanical overloading of the masticatory system was studied in a series of trials concerning bruxism (tooth grinding and clenching). Our insight into the etiology of bruxism was deepened on the basis of multiple epidemiological studies, while the management of the condition was tested with a series of randomized clinical trials (RCTs) using oral splints, psychological counseling, and medication at treatment modalities. The dental management of obstructive sleep apnea with oral appliances also yields a possible overload of the masticatory system. Both the short-term and the long-term usage of such appliances were assessed with polysomnographic techniques in RCTs, with continuous positive airway pressure as the usual treatment option for comparison.
  • Overloading of the masticatory system may lead to temporomandibular disorders (TMD). Clinical tests for the diagnosis TMD were further developed and tested for their reliability and validity. Especially the important influence of asking for familiar pain on the diagnostic accuracy of TMD pain is noteworthy. Studies to the diagnosis of pain in the masticatory system in persons with a dementia are currently ongoing. The importance of chewing in maintaining a good cognition was already demonstrated in a systematic review. The role of several psychosocial factors in the onset and maintenance of TMD pain was assessed in multiple questionnaire studies. Functional disturbances of the temporomandibular joint were studied in a series of experiments, in which the important role of mechanical loading on joint disc reduction was found.