title: Vertical jaw separation and masseter muscle electromyographic activity: a comparative study between asymptomatic controls & patients with temporomandibular pain & dysfunction.
abstract: The aims of the present study were to assess the relationship pattern between bilateral masseter muscle electromyographic (MEMG) activity recordings and vertical jaw separation (VJS). Asymptomatic subjects (n = 15) were compared with age and gender-matched patients (n = 18) with temporomandibular pain and dysfunction (TMPD); before and after undergoing interocclusal appliance (IOA) therapy for 4 months. In asymptomatic subjects a bilateral minimum MEMG activity was found in a 'resting zone' at approximately a quarter of maximum mandibular opening (mean, 15.4 mm of VJS; range, 5.5-22.5 mm including overbite). No overall relationship between MEMG and VJS was shown for patients with TMPD. After successful IOA therapy, the majority of TMPD patients (14 of 18) showed normalization of the relationship between MEMG and VJS, but electromyographic assessment was not found to be of value as a single objective assessment parameter in evaluating the resolution of TMPD or the effectiveness of IOA therapy.
authors.affiliation: Department of Stomatognathic Physiology and Prosthetic Dentistry, Institute of Dentistry, University of Helsinki, Finland.
authors.forename: T I
authors.initials: TI
authors.lastname: Suvinen
authors.forename: P C
authors.initials: PC
authors.lastname: Reade
authors.forename: M
authors.initials: M
authors.lastname: Könönen
authors.forename: P
authors.initials: P
authors.lastname: Kemppainen
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology*; D020247:Myofunctional Therapy / Q000295:instrumentation; D017090:Occlusal Splints; D015203:Reproducibility of Results; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000503:physiopathology* / Q000628:therapy; D016896:Treatment Outcome; D014716:Vertical Dimension