title: Local kinematic and anthropometric factors related to the maximum mouth opening in healthy individuals.
abstract: The aim of the present study was to investigate the influence of local anthropometric (mandibular length and width) and kinematic (forward and downward condylar translation and angle of rotation) variables upon the maximum mouth opening (MMO). Thirty-five healthy individuals, 17 men and 18 women, mean age 23 years with a range from 18 to 31 years, performed six to eight maximal, symmetrical and pain-free open-close movements during a 20-s recording. Mandibular movements were recorded by means of the OKAS-3D jaw movement recording system. A stepwise regression analysis showed that differences in MMO are mainly explained by differences in the angle of rotation and in mandibular length (R2adj=91.5%). Including the downward and forward component of condylar translation into the regression model increased the explained variance with only 4.7%. A second stepwise analysis showed that the angle of rotation is positively related to the forward component of the condylar translation and negatively related to its downward component (R2adj=52.7%). In conclusion, differences in MMO between healthy individuals are, to a large extent, explained by differences in the angle of rotation and in mandibular length. In its turn, differences in the angle of rotation are related to differences in condylar translation.
authors.affiliation: Department Oral Function, Section Craniomandibular Disorders, Academic Centre Dentistry Amsterdam, The Netherlands. m.naeije@acta.nl
authors.forename: M
authors.initials: M
authors.lastname: Naeije
mesh_terms: D000293:Adolescent; D000328:Adult; D003799:Dental Stress Analysis; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation; D007574:Jaw Relation Record / Q000295:instrumentation; D008297:Male; D008334:Mandible / Q000033:anatomy & histology* / Q000502:physiology; D008335:Mandibular Condyle / Q000502:physiology*; D009068:Movement; D016059:Range of Motion, Articular; D012044:Regression Analysis; D013704:Temporomandibular Joint / Q000502:physiology*; D019415:Torque