Introduction

Over the last two decades the classification and definition of bruxism has been adapted and changed because of the complexity and the minor evidence of the mechanism behind bruxism. In 2013 an international consensus of dentistry experts (International Network for Orofacial Pain and Related Disorders Methodology (INfORM) of the International Association Dental Research (IADR)) met and a grading system was proposed.

It was refined in 2018 together with an assessment proposal (Lobbezoo et al 2018). In 2019 The German associations Deutsche Gesellschaft für Funktionsdiagnostik und -Therapie in der Zahn-, Mund- und Kieferheilkunde (DGFDT) and Deutsche Gesellschaft für Zahn-, Mund- und Kieferheilkunde (DGZMK), performed a literature review and published a guideline about the management of bruxism which is a deepening of the review of Lobezoo et al 2008. The actual definitions from the INfORM are:

Bruxism is repetitive masticatory muscle activity characterized by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible and specified as either sleep bruxism or awake bruxism. (Lobbezoo et al 2013)

• Sleep bruxism (SB) is a masticatory muscle activity during sleep that is characterized as rhythmic(phasic) or non-rhytmic (tonic) and is NOT a movement or sleep disorder in otherwise healthy individuals.
• Awake bruxism (AB) is a masticatory muscle activity during wakefulness that is characterized by repetitive or sustained tooth contact and/or by bracing or thrusting of the mandible and is NOT a movement disorder in otherwise healthy individuals.

(Lobbezoo et al International Consensusgroup 2018)

The consensus group concluded that bruxism is a disorder and not a disease with a high level of masticatory muscle activity which may increase the risk of negative oral health consequences, severe masticatory muscle and or temporomandibular joint pain, extreme mechanical tooth wear and prosthodontic complications (Abe et al 2009, Manfredini et al. 2008, 2014). Risk factors for bruxism may be classified in occlusion factors or clinical factors e.g Temporal Mandibular Disorder (TMD) and psychological factors (Lobbezoo et al 2018)