Title:  Developmental disturbances in permanent successors after intrusion injuries to maxillary primary incisors

Abstract:  Aim The aim of the present study was to report the frequency of developmental disturbances in permanent teeth as a result of intrusive injuries to the primary predecessors and relate this to the degree of intrusion, the age of the child, the developmental stage of permanent germ and the treatment given. Methods Seventy children with previous intrusive trauma of their maxillary primary incisors were recalled for a follow-up examination of the erupted permanent successors. The children had a total of 118 intruded teeth. The severity of intrusion was recorded as well as the developmental stage of the permanent successor and the treatment given at the time of trauma. The permanent successors were examined for different levels of developmental disturbances. Results Seventy per cent of the succeeding incisors had some complications in development. White or yellow-brown hypomineralisation was the most common finding representing 60% of all complications. The more serious complications such as circular hypoplasia, crown dilaceration, odontoma-like malformation, root developmental disturbances, sequestration of the tooth germ, and eruption disturbances were few and the majority (90%) related to trauma before the age of 3 years combined with severe intrusion. When the intruded primary incisor was extracted, 80% of the permanent successors developed complications. Conclusions Traumatic injuries to primary incisors are common. Because of the close relationship between the apices of the primary incisors and developing permanent teeth, disturbances in development occur. Intrusion of a primary incisor often occurs before the age of 3 years and the risks of damage occurring to the permanent germ are high.