title: Unilateral temporomandibular disorder and asymmetry of occlusal contacts.
abstract: BACKGROUND
  The relationship between temporomandibular disorders and occlusal tooth contacts is unclear and controversial.
  
  
  OBJECTIVE
  This study assessed whether unilateral temporomandibular disorders were associated with the absence of bilateral symmetry in the number of occlusal contacts.
  
  
  METHODS
  Fifteen university dental students who had complete natural dentition and normal occlusion and exhibited unilateral signs and symptoms of temporomandibular disorders were compared to 15 age- and sex-matched healthy control subjects. All participants met specific inclusion and exclusion criteria. Occlusal contacts were recorded in the intercuspal position with wax registrations. Dental impressions were made and poured in type I stone. Contacts were classified according to location and intensity. Four experienced dentists using an established protocol made all measurements. Assessment of the reliability of the occlusal registration procedure showed a small (<4%) within-subject variability. Statistical analysis was based on the binomial distribution and nonparametric tests (P < .05).
  
  
  RESULTS
  Subjects with unilateral temporomandibular disorders had greater bilateral difference in the number of contacts than controls. The median (95% confidence interval) difference was 3 (2 to 4) and 2 (1 to 2), respectively. In unilateral temporomandibular disorder subjects, the number of occlusal contacts was greater on the side with, rather than without, disorder (median number 20 vs. 16). The median (95% confidence interval) difference between sides with and without unilateral temporomandibular disorders was 3 (2 to 4) for all contacts and 2 (1 to 3) for contacts on the posterior teeth.
  
  
  CONCLUSIONS
  Within the population of this study, a weak association was found between unilateral temporomandibular disorders and asymmetry in the number of occlusal contacts.
authors.affiliation: Department of Biomedical Sciences and Technologies, LITA, San Paolo Hospital, University of Milan, and San Raffaele Hospital, Milan, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Ciancaglini
authors.forename: Enrico F
authors.initials: EF
authors.lastname: Gherlone
authors.forename: Giovanni
authors.initials: G
authors.lastname: Radaelli
mesh_terms: D000328:Adult; D016010:Binomial Distribution; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003769:Dental Occlusion, Traumatic / Q000150:complications*; D005260:Female; D006801:Humans; D007574:Jaw Relation Record; D008297:Male; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D013705:Temporomandibular Joint Disorders / Q000209:etiology*