This was a clinical observational study of primary incisor trauma, in children of under 4 years of age at the time of injury, with a 7-year follow up period. COHORT SELECTION: Children treated for intrusive injuries (as defined by World Health Organization guidelines) of primary incisors in a paediatric clinic. EXPOSURE MEASUREMENT: Patient's age, sex, cause of trauma, site and number of primary teeth involved, and nature of immediate treatment were recorded. Photographs and radiographs were taken. At 6-12-month intervals clinical and radiographical examinations recorded the process of re-eruption, and any post-traumatic changes to the intruded primary teeth: namely, pulpal necrosis, root resorption, ankylosis, or obliteration of the pulp canal. Developmental defects were recorded on the fully erupted successor teeth, namely enamel hypoplasia, malformation of tooth and/ or root, and site of eruption.