title: Evaluation of the relationship between bruxism and premature occlusal contacts.
abstract: OBJECTIVE
  This study evaluates the relationship between occlusal interferences and premature contacts and bruxism by determining the relationship between unassisted and assisted nonworking interferences.
  
  
  METHODS
  In this study, 60 subjects (14 males and 46 females) that consisted of 30 bruxers (7 males, 23 females) and 30 nonbruxers (7 males, 23 females) were selected after completion of a questionnaire based on the exclusion criteria. Occlusal interferences in the centric relation and eccentric movements in the two groups were evaluated and recorded. Data were analyzed by SPSS software (version 16) using the Chi-square and paired t-tests.
  
  
  RESULTS
  The results showed a statistically significant relationship between bruxism and nonworking interferences (p < 0.05). There was no statistically significant relationship in the centric relation and other eccentric movements (p > 0.05). The number of assisted nonworking occlusal contacts was more than unassisted nonworking occlusal contacts.
  
  
  CONCLUSIONS
  According to the results of this study, there is a relationship between certain types of occlusal interferences (nonworking interferences) and bruxism. Hence, it would be useful to examine occlusal contacts in bruxing patients to eliminate probable causative or contributing occlusal factors. Both assisted and unassisted nonworking occlusal contacts should be evaluated.
  
  
  CONCLUSIONS
  Bruxism is an oral habit that consists of involuntary rhythmic or spasmodic nonfunctional gnashing, grinding or teeth clenching, other than chewing movements by the mandible. Bruxism may lead to occlusal trauma, tooth wear, fracture of the teeth and fillings, and hypertrophy of the masticatory muscles. Treatment of bruxism needs a correct diagnosis. Therefore, it is useful to determine the relationship between occlusal interferences and bruxism in order to prevent its development by adjusting for these interferences.
authors.affiliation: Assistant Professor, Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Anahita
authors.initials: A
authors.lastname: Safari
authors.forename: Zahra
authors.initials: Z
authors.lastname: Jowkar
authors.forename: Mitra
authors.initials: M
authors.lastname: Farzin
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D016302:Centric Relation; D003430:Cross-Sectional Studies; D003766:Dental Occlusion; D003769:Dental Occlusion, Traumatic / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007574:Jaw Relation Record / Q000295:instrumentation; D008297:Male; D008334:Mandible / Q000503:physiopathology; D008410:Masticatory Muscles / Q000503:physiopathology; D012189:Retrospective Studies; D020186:Sleep Bruxism / Q000150:complications* / Q000503:physiopathology; D014070:Tooth / Q000473:pathology; D055815:Young Adult