Impact of avulsion of the primary incisors on the occurrence of sequelae in the permanent teeth: A retrospective cohort study

Objectives: The purpose of this retrospective cohort study was to investigate the occurrence of sequelae in the permanent teeth after avulsion of their primary antecessors and to evaluate the factors associated with this occurrence. Methods: We screened 2922 records of patients with photographic and radiographic images who attended a reference centre for dental trauma in the primary teeth from 1998 to 2019. Among them, 240 were eligible records of children who had suffered avulsion of the primary incisors and were followed up until complete eruption of the permanent successors. Multilevel Poisson regression analyses were conducted between the explanatory variables related to children and avulsed teeth; outcome variables were occurrences of any type of sequelae in the permanent teeth, opacities, hypoplasia and malformation. Relative risks (RRs) and respective 95% confidence intervals (95% CIs) were calculated. Results: Among the 240 children's records, 194 fulfilled the inclusion criteria. Finally, we found 266 primary avulsed teeth and 115 (43.2%) permanent teeth presenting with sequelae. Avulsion occurring when children were older than 4 years (RR = 0.48; 95% CI = 0.24-0.95) had lower risks for developing sequelae than children aged 0-2 years of age. Additionally, when avulsion occurred in the lower dental arch (RR = 1.45; 95% CI = 1.06-1.99) and when three or more teeth were affected (RR = 1.57; 95% CI = 1.02-2.41), the occurrence of sequelae in the permanent teeth was more probable than if avulsion occurred in the upper arch and affected only a single tooth. Age older than 3 years was a protective factor for the occurrence of hypoplasia and age older than 4 years protective for the occurrence of opacities. Conclusions: The risk of sequelae in the permanent teeth after avulsion of their antecessor is higher when the trauma occurs in young children (<2 years) and in patients with avulsions of greater magnitude, such as when it affects the lower jaw, and more teeth are involved.