A recent study showed that approximately 180 million children worldwide have expe­rienced at least 1 traumatic dental injury in the primary teeth. For nearly 50 years, articles appearing in the den­tal literature have noted a correlation between these traumatic injuries and sequelae in successor permanent teeth, perhaps due to the closeness between the apices of primary teeth and the germ of permanent teeth, ranging from minor (a slight disturbance in the mineralization of enamel) to major (sequestration of the entire tooth germ). Reported prevalence of these subsequent problems ranges from 20% to >40%.

The most recent guidelines for trau­matic injury treatment in the primary dentition issued by the International Association of Dental Traumatology recommend a continuation of follow-up to diagnose possible prob­lems in the permanent successor tooth. Such issues may not manifest themselves until later, when they may have a negative impact on a patient’s quality of life. A recent systematic review found that children with trauma, who are younger, and who suffer intrusion and avulsion inju­ries in the permanent incisors, may be at greater risk for sequelae in the permanent teeth. However, very few studies in this area have included a control group, making it difficult to determine whether a cause-and-effect relationship exists.

Lenzi et al from the Federal University of Rio de Janeiro, Brazil, reviewed the dental records of 1500 children who suffered dental trauma to the primary teeth over a 10-year period, from 2005 to 2015. From this group, the authors selected 214 injured teeth in 124 chil­dren who had a history of trauma to primary incisors and/or canines and who subsequently had full eruption of their permanent dentition. As a con­trol, the authors included from the same children 247 anterior teeth that had not undergone dental trauma. The study compared the erupted per­manent teeth whose antecedent pri­mary teeth had suffered trauma with those whose antecedent primary teeth had not suffered trauma.

Collected data included patient’s age and sex, type of tooth and type of injury. Sequelae in the permanent denti­tion, such as discoloration, enamel hypoplasia, dilacerations, malforma­tions, arrest of root formation, seques­tration of permanent tooth germ and eruption disturbances, were recorded.

Successor permanent teeth to traumat­ically injured primary teeth were >5× more likely to demonstrate sequelae than were the successors to uninjured primary teeth. More than a quarter of the injured primary teeth were suc­ceeded by permanent teeth showing sequelae; the most common sequelae were enamel discoloration, enamel hypoplasia and eruption disturbance (Table 2). The most serious damage resulted following intrusion to the primary teeth; more than half of these successor permanent teeth demon­strated sequelae. Younger age at the time of trauma appeared to be associ­ated with a higher rate of sequelae.


Trauma to the primary teeth is a risk factor for the development of sequelae in succeeding permanent teeth. The risk appears to be greater in children who suffer injury at younger ages, with disturbances of enamel development the most common manifestation. These children should be given radio­graphic examinations during follow-up of their traumatic injuries to detect any sequelae in the permanent successors.

Lenzi MM, da Silva Fidalgo TK, Luiz RR, Maia LC. Trauma in primary teeth and its effect on the development of permanent suc­cessors: a controlled study. Acta Odontol Scand 2018;doi:10.1080/00016357.2018. 1508741.