Enamel defects in permanent incisors after trauma to primary predecessors: inter-observer agreement based on photographs.

UNLABELLED Trauma to primary teeth may cause mineralization disturbances in the permanent successors. OBJECTIVE To study the distribution and type of enamel defects in permanent incisors after trauma to primary teeth and to examine inter-observer agreement when registrations were based on photographs. MATERIAL AND METHODS Of 266 children who suffered an oral injury to primary teeth in one county of Norway in 2003, 193 were included in a follow-up study to record enamel defects in the permanent successors 7 years later (age, 8-15 years). Clinical examination and intraoral photographs were undertaken by the principal investigator. The photographs were evaluated twice for enamel defects by three paediatric dentists. Evaluation 1: age at the time of injury, traumatized teeth and diagnoses were kept unknown to the examiners. Evaluation 2: age and trauma diagnoses were known to the examiners. Inter-observer agreement was calculated using Cohen's kappa and chi-square test. RESULTS Of 338 successor teeth, 42% exhibited enamel defects. In neighbouring teeth (339) with non-injured predecessors, 30% were registered with defects. The most common enamel disturbance in successors was demarcated opacities, recorded in 18% of the teeth. Enamel defects owing to a previous trauma were registered in 37% of the children in Evaluation 1, kappa 0.88-0.93 and in 21% in Evaluation 2, kappa 0.63-0.84. The examiners disagreed on a higher proportion of the children when all information on the injury was available (P < 0.001). CONCLUSION Demarcated enamel opacities were the most common defects in permanent successors. Although the inter-examiner agreement was good, the results indicated that recordings of enamel disturbances following trauma is associated with uncertainty.