BACKGROUND/AIM: Traumatic dental injuries (TDIs) in the primary dentition occur frequently. Long term complications may potentially cause damage to the permanent successor. The aim of this study was to report the risk of pulp necrosis (PN), pulp canal obliteration (PCO), repair related resorption (RRR), infection-related resorption (IRR), ankylosis-related resorption (ARR) and premature tooth loss (PTL) in primary teeth following concussion and subluxation injuries, and to identify possible risk factors for PN, PCO and PTL following subluxation.

MATERIAL AND METHODS: The study was a retrospective analysis of a cohort comprising 31 patients (36 teeth) with concussion injury and 174 patients (241 teeth) with subluxation injury. No treatment was performed. The follow-up program included examination after 4 weeks, 8 weeks, 6 months, 1 year, and when the patients were 6 years of age. Minimum follow-up was 1 year or until the time of tooth loss.

STATISTICS: Kaplan Meier- and Aahlen Johansson methods and Cox regression analysis. Level of significance was set at 5%.

RESULTS: Risk estimated after one year. Concussion: PCO 8.6% (95% CI: 0 - 17.9), PN 5.7% (95% CI: 0 - 13.4), PTL 5.6% (95% CI: 0 - 13.4). Subluxation: PCO 23.2% (95% CI: 17.8 - 28.6), PN 8.3% (95% CI: 4.8 - 11.8), IRR 2.6% (95% CI: 0.5-4.6%), PTL 9.5% (95% CI: 5.0 -14.1). Most complications (95%) were diagnosed within the first year. Most cases of PN (65%) and PTL (85%) were seen in patients aged four years or more.

CONCLUSION: Primary teeth with concussion or subluxation injury carry a low risk of pulp necrosis and infection with periapical inflammation, root resorption and premature tooth loss. Nearly all complications were diagnosed within the first year after the injury. The risk of premature tooth loss was highest in patients more than 4 years of age at the time of injury. This article is protected by copyright. All rights reserved.