title: Risk factors for injuries to maxillary permanent incisors and upper lip among schoolchildren in Dar es Salaam, Tanzania.
abstract: BACKGROUND
  Dental trauma is common among children, and the maxillary permanent central incisors are the most often affected teeth.
  
  
  OBJECTIVE
  This study aimed to investigate the risk factors for injury to maxillary permanent incisors and the upper lip among Tanzanian schoolchildren aged 8-14 years.
  
  
  METHODS
  A cross-sectional study involving 1119 children. The risk variables investigated included age, gender, lip competence, and overjet. The corresponding proportions of injuries and the relative risk (with 95% confidence interval) were calculated and tested by Fisher's exact test. Logistic regression was applied to ascertain the strength and direction of the association of the risk variables to injuries, and backward selection was used to test significant risk factors.
  
  
  RESULTS
  About 24% of the children had trauma to maxillary incisors, 45% had incompetent lip whereas 31% had increased overjet. Age, gender, overjet, and lip competence showed significant association with injuries to upper lip and maxillary incisors. Boys had sustained more injuries than girls, with a higher relative risk for luxation injuries. Enamel fracture was associated with overjet combined with lip competence, whereas enamel dentine fracture without pulp involvement was related to gender. Luxation injuries were associated with gender, tooth avulsion with overjet, and lip competence. Injury to the upper lip was associated with age.
  
  
  CONCLUSIONS
  Male gender, increased overjet, and lip incompetence were the main risk factors of getting trauma to maxillary incisors, whereas age was the risk factor for injury to the upper lip.
authors.affiliation: School of Dentistry, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania. fkahabuka@muhas.ac.tz
authors.forename: Febronia Kokulengya
authors.initials: FK
authors.lastname: Kahabuka
authors.forename: Emeria Abella
authors.initials: EA
authors.lastname: Mugonzibwa
mesh_terms: D000293:Adolescent; D002648:Child; D015897:Comorbidity; D003430:Cross-Sectional Studies; D019229:Dentition, Permanent; D005151:Facial Injuries / Q000453:epidemiology; D005260:Female; D006801:Humans; D007180:Incisor / Q000293:injuries*; D008046:Lip / Q000293:injuries* / Q000503:physiopathology; D008297:Male; D008310:Malocclusion / Q000145:classification / Q000453:epidemiology*; D008437:Maxilla; D012307:Risk Factors; D012737:Sex Factors; D013636:Tanzania / Q000453:epidemiology; D018677:Tooth Injuries / Q000453:epidemiology*