Epidemiology and associated factors of traumatic dental injuries presenting to emergency department: a retrospective study from Southern Taiwan

Background Traumatic dental injury (TDI) is a common dental emergency, yet prevalence data from Taiwan have relied mainly on questionnaire surveys. This study investigated TDI epidemiology in an emergency department setting and identified factors associated with combination injury, defined as the simultaneous presence of tooth hard tissue and periodontal injury. Methods This retrospective cohort study included all patients with TDI affecting permanent dentition who presented to the Emergency Department of National Cheng Kung University Hospital, Tainan, Taiwan, between January and December 2014. Injuries were classified per the WHO 1978 and Andreasen 1981 systems. Associations were tested by chi-square with Monte Carlo simulation and multivariable binary logistic regression. Results A total of 117 patients (72 males, 45 females; mean age 26.4 years) with 344 affected teeth were enrolled. Traffic accident was the leading cause (62.4%), predominantly motorcycle-related (63.0%). Upper central incisors were most frequently affected (45.3%). Crown fracture (23.0%) and subluxation (27.0%) were the most common injury types, and combination injury occurred in 18.0% of teeth. Multivariable logistic regression identified number of affected teeth (3–4 teeth: aOR 7.95, 95% CI 2.61–28.65; ≥5 teeth: aOR 11.99, 95% CI 2.97–56.57; both p < 0.001) and walk-in arrival (aOR 4.07, 95% CI 1.39–13.24, p = 0.013) as independent predictors, with good model discrimination (AUC 0.767, 95% CI 0.677–0.857). Conclusions Emergency department TDI in Taiwan is dominated by motorcycle-related traffic accidents. Number of affected teeth and walk-in mode of arrival are independent predictors of combination injury. These findings support targeted motorcycle safety measures and comprehensive clinical and radiographic assessment for patients presenting with multiple affected teeth.