title: Risk factors for anterior disc displacement with reduction and intermittent locking in adolescents.
abstract: OBJECTIVE
  To test the hypothesis that oral parafunctions and symptomatic temporomandibulair joint (TMJ) hypermobility are risk factors in adolescents for both anterior disc displacement with reduction (ADDR) and intermittent locking.
  
  
  METHODS
  Participants were two hundred sixty 12- to 16-year-old adolescents (52.3% female) visiting a university clinic for regular dental care. ADDR and symptomatic TMJ hypermobility were diagnosed using a structured clinical examination. During the anamnesis, reports of intermittent locking and of several parafunctions were noted, eg, nocturnal tooth grinding, diurnal jaw clenching, gum chewing, nail biting, lip and/or cheek biting, and biting on objects. The adolescents' dentitions were examined for opposing matching tooth-wear facets as signs of tooth grinding. Risk factors for ADDR and intermittent locking were first assessed using univariate logistic regression and then entered into a stepwise backward multiple model.
  
  
  RESULTS
  While in the multiple model, ADDR was weakly associated only with increasing age (P = .02, explained variance 8.1%), intermittent locking was weakly correlated to diurnal jaw clenching (P = .05, explained variance 27.3%).
  
  
  CONCLUSIONS
  In adolescence, diurnal clenching may be a risk factor for intermittent locking while age may be a risk factor for ADDR. Symptomatic TMJ hypermobility seems to be unrelated to either ADDR or to intermittent locking.
authors.affiliation: Department of Oral Kinesiology, Academic Center for Dentistry, Amsterdam, The Netherlands. s.kalaykova@acta.nl
authors.forename: Stanimira I
authors.initials: SI
authors.lastname: Kalaykova
authors.forename: Frank
authors.initials: F
authors.lastname: Lobbezoo
authors.forename: Machiel
authors.initials: M
authors.lastname: Naeije
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001734:Bites, Human / Q000150:complications; D005260:Female; D005386:Fingersucking / Q000009:adverse effects; D006184:Habits; D006801:Humans; D004204:Joint Dislocations / Q000453:epidemiology / Q000209:etiology; D007593:Joint Instability / Q000150:complications / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D009119:Muscle Contraction; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D012737:Sex Factors; D020186:Sleep Bruxism / Q000150:complications; D013705:Temporomandibular Joint Disorders / Q000453:epidemiology* / Q000209:etiology