Method: Sixty-two children, with a history of trauma to the primary dentition, were recalled for examination. Thirty-two children, with sixty-seven traumatized primary teeth, were available for examination. Any developmental disturbances of the corresponding permanent teeth were recorded. A control group was also set up.
Results: Analysis of the results showed that 52.2% of the permanent successor teeth exhibited developmental disturbances following trauma to their primary predecessors. The incidence of disturbances in the control group was 10%. The highest frequency of malformations in the permanent dentition was found following subluxation of the primary incisors. Enamel discoloration was the commonest disturbance seen in the permanent successor teeth. Clinically detectable defects in the enamel surface were mainly seen following intrusion injuries to primary incisors. Intrusion injuries were also associated with the most severe malformations in the permanent dentition. The age of the child at the time of traumatic injury to the primary dentition was a principal factor in the risk of developing malformations in the permanent successor teeth. Trauma to the primary incisors between 1 and 2 years of age had a more deleterious effect on the permanent successors than in the older age groups.
Conclusions: The study concluded that the extent of malformation of the developing tooth germ was highly related to its developmental stage and to the severity and type of trauma sustained by the primary incisor.