title: Relationship between Bruxism and Malocclusion among Preschool Children in Isfahan.
abstract: OBJECTIVE
  Bruxism is defined as a habitual nonfunctional forceful contact between occlusal tooth surfaces. In younger children bruxism may be a consequence of the masticatory neuromuscular system immaturity. The aim of this study was to assess the prevalence of bruxism and investigate the relationship between occlusal factors and bruxism among preschool children.
  
  
  METHODS
  In this cross-sectional survey, 400 3-6-year-old children were selected randomly from different preschools in Isfahan, Iran. The subjects were divided into two groups of bruxers and non-bruxers as determined by the clinical examination and their parents' reports. The examiner recorded the primary canines (Class I, Class II, and Class III) and molars (mesial step, distal step, flash terminal plane) relationship, existence of anterior and posterior crossbite, open and deep bite. Also, rotated teeth, food impaction, sharp tooth edges, high restorations, extensive tooth caries, and painful teeth (categorized as irritating tooth conditions) were evaluated. The relationship between bruxism and occlusal factors and irritating tooth conditions was evaluated with chi-square test.
  
  
  RESULTS
  Bruxism was seen in 12.75% of the subjects. Statistically significant relationships existed between bruxism and some occlusal factors, such as flash terminal plane (P = 0.023) and mesial step (P = 0.001) and also, between food impaction, extensive tooth caries, tooth pain, sharp tooth edge and bruxism.
  
  
  CONCLUSIONS
  The results showed significant relationship of bruxism with primary molar relationships and irritating tooth conditions among preschool children.
authors.affiliation: Assistant Professor, Department of Pediatric Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Ghafournia
authors.forename: Maryam
authors.initials: M
authors.lastname: Hajenourozali Tehrani
keywords: Bruxism; occlusal factors; preschool children