Risk factors associated with the occurrence of avulsion in the primary incisors: A case–control study

Background: Identifying factors associated with the occurrence of primary tooth avulsion is essential to promote prevention strategies. Aim: To investigate the risk factors associated with primary incisor avulsion and variables associated with post-avulsion sequelae in the permanent successor. Design: This case–control study comprised 407 children (cases) with primary incisor avulsion and 407 children (controls) with other traumatic dental injuries (TDI). The association between explanatory variables and avulsion was evaluated through logistic regression. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated. Poisson regression analyses between potential explanatory variables and sequelae were run, from which relative risks (RR) and corresponding 95% CI were estimated. Results: TDI caused by moderate falls (OR = 2.20; 95% CI = 1.47 to 3.27), affecting lateral incisors (OR = 10.10; 95% CI = 3.89 to 26.54) and the lower arch (OR = 9.54; 95% CI = 3.15 to 28.85), were associated with primary incisor avulsion. Moreover, children with previous severe TDI, anterior open bite, and anterior crossbite had higher odds of primary incisor avulsion. Children who suffered from any primary tooth avulsion (RR = 2.68; 95% CI = 1.82 to 3.95) had a higher risk of sequelae in the permanent successors. The risk for sequelae in the permanent teeth was significantly greater for younger children under age 2 years than for children ages 3 to 5 years. Conclusion: Risk factors for primary incisor avulsion are related to the severity of the fall, tooth position, history of previous TDI, and malocclusion. Furthermore, avulsion increases the risk of sequelae in the permanent successors.