Birth order--a risk factor for dental trauma?

Abstract

Background: Many character traits are influenced by birth order with greatest differences between first and lastborns.

Aim: To investigate the influence of birth order on the risk of dental trauma.

Methods: Five hundred mothers in Switzerland were interviewed personally regarding dental trauma in their children. Inclusion criteria were a family size of at least two children. Data of 1282 children were collected.

Results: Thirty-two percent of the children had sustained one or more dental trauma before the age of 16 (57% male, 43% female). In children who had sustained dental trauma twice, the gender ratio moved to 68% male and 32% female (P = 0.003). Regarding birth order, lastborns sustained more second dental traumas. Relative risk of second dental trauma was 2.1 times higher in lastborns than in firstborns (P = 0.02). Moreover, certain character traits in children are influenced by birth order. According to their mothers, lastborns were more curious, less calm and less deliberate than firstborns (P < 0.001). Second born without younger siblings were more athletic/active than firstborns (P = 0.011). Athletic/active children as well as not calm/deliberate children sustained second dental trauma more often than not athletic/active (P = 0.038) and calm/deliberate children (P < 0.001).

Conclusion: Birth order is a risk factor for sustaining dental trauma twice. Character traits of lastborns (curious, not calm/deliberate and aggressive) could be reasons for higher risk of dental trauma.

Keywords: birth order; characteristics; dental trauma; firstborn; lastborn.