Dental luxation and avulsion injuries in Hong Kong primary school children.

OBJECTIVES: To identify the major causes and types of dental luxation and avulsion injuries, and their associated factors in primary school children in Hong Kong. DESIGN: Case series. SETTING: School dental clinic, New Territories, Hong Kong. PATIENTS: The dental records of children with a history of dental luxation and/or avulsion injury between November 2005 and October 2012 were reviewed. Objective clinical and radiographical findings at the time of injury and at follow-up examinations were recorded using a standardised form. Data analysis was carried out using the Chi squared test and multinomial logistic regression. RESULTS: A total of 220 children with 355 teeth of dental luxation or avulsion injury were recorded. Their age ranged from 6 to 14 years and the female-to-male ratio was 1:1.8. The peak occurrence was at the age of 9 years. Subluxation was the most common type of injury, followed by concussion. Maxillary central incisors were the most commonly affected teeth. The predominant cause was fall and most injuries occurred at school. Incisor relationship was registered in 199 cases: most of them were Class I. Comparison of the incisor relationship in study children and the general Chinese population in another study revealed a higher proportion of Class II and fewer Class III occlusions in the trauma group (P<0.0001). CONCLUSION: Most dental luxation and avulsion injuries in Hong Kong primary school children are caused by fall. Boys are more commonly affected than girls, and a Class II incisor relationship is a significant risk factor.