title: Jaw clenching effects in relation to two extreme occlusal features: patterns of diagnoses in a TMD patient population.
abstract: OBJECTIVE
  The aim of this investigation was to compare the pattern of temporomandibular disorder (TMD) diagnoses in clenching patients with different occlusal features, the null hypothesis being that no between-group differences exist.
  
  
  METHODS
  Two groups of subjects receiving a jaw clenching diagnosis and having large overjet or anterior open bite (Group A; N=45, 75.5% females, mean age: 38.1 +/- 15.9 years) or normal occlusion (Group B; N=69, 71% females, mean age: 34.6 +/- 13.8 years) were recruited among a TMD patient population and were given Research Diagnostic Criteria for TMD (RDC/TMD) axis I diagnoses, namely, group I muscle disorders, group II disc displacements, and group III arthralgia/osteoarthritis/osteoarthrosis.
  
  
  RESULTS
  The distribution of RDC/TMD single and combined group diagnoses was significantly different between the two groups (P<0.05), with Group A subjects showing a higher prevalence of multiple diagnoses (60% versus 43.3%), as well as a higher prevalence of combined RDC/TMD axis I group II and III diagnoses (37.8% versus 20.2%). All TMD signs and symptoms were more frequent in the patients with large overjet or anterior open bite with respect to the patients with normal occlusion.
  
  
  CONCLUSIONS
  In a TMD patient population, jaw clenching may have different consequences in subjects with large overjet or anterior open bite with respect to subjects featuring normal occlusion.
authors.forename: Daniele
authors.initials: D
authors.lastname: Manfredini
authors.forename: Michele
authors.initials: M
authors.lastname: Vano
authors.forename: Redento
authors.initials: R
authors.lastname: Peretta
authors.forename: Luca
authors.initials: L
authors.lastname: Guarda-Nardini
mesh_terms: D000328:Adult; D018771:Arthralgia / Q000209:etiology; D002012:Bruxism / Q000150:complications*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D004198:Disease Susceptibility; D005157:Facial Pain / Q000209:etiology; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000175:diagnosis*; D008297:Male; D008410:Masticatory Muscles / Q000503:physiopathology*; D008875:Middle Aged; D009119:Muscle Contraction; D024343:Open Bite / Q000503:physiopathology; D010003:Osteoarthritis / Q000150:complications / Q000175:diagnosis; D057887:Overbite / Q000503:physiopathology; D012189:Retrospective Studies; D013016:Sound; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis* / Q000209:etiology*