TDI in Beijing, China not only shows epidemiologic characteristics in common with many other studies in the world, but also shows different characteristics that should be further studied and taken into consideration when planning for preventive programs and emergency resources.

Background/Aims Decoronation offers one of the best and most predictable clinical outcomes for dentoalveolar ankylosis. The aim of this study was to determine the factors associated with the efficacy and psychological impact of decoronation for bone preservation. Materials and Methods The study included 42 paediatric patients with 42 infrapositioned replanted permanent teeth. Twelve of these teeth were decoronated. Variables such as the time of injury, stage of root development and the extent of infraposition were analysed. The vertical changes in the alveolar bone level of the decoronated teeth were assessed on radiographs using a three‐point scoring system. Parents of 30 patients with teeth that were not decoronated completed a questionnaire addressing their considerations and concerns regarding the treatment of infraposition. Results Teeth with root development in stages 2 and 3 showed a significantly higher rate of severe infraposition during the follow‐up visits. Decoronation was performed on 12 teeth within 1.5–5 years (mean 3.8 ± 1.3 years) after replantation and 11 of these cases developed a considerable alveolar bone level. The alveolar bone levels of boys and girls showed improvements of 2.2 and 3.2 mm, respectively. The optimal age for decoronation to have a considerable increase in bone level was 12.12 ± 0.83 years for boys and 11.25 ± 1.77 years for girls. Complicated treatments, followed by parents’ lack knowledge regarding decoronation, children's fear, follow‐up times, and cost were the major concerns regarding decoronation. Conclusion The optimal time for decoronation should be decided after considering the age, gender, skeletal growth pattern, and the degree of infraposition at the time of decoronation.

This retrospective study evaluated the clinical outcomes of surgical crown reattachment in the treatment of complicated crown-root fractures in permanent teeth in 35 patients. Treatments were defined as follows: surgical crown reattachment combined with internal fixation with a fiberreinforced core post, ostectomy, and reattachment of the original crown fragment. Patients were examined to record the periodontal pocket depth (PD), marginal bone loss, tooth migration, and coronal fragment looseness or loss. In most cases, the fracture lines on the palatal aspect were located below the alveolar crest. About 20% to 30% of teeth had periodontal pockets ≥ 3 mm present at least 1 year after surgery. Significant PD differences were observed between the traumatized teeth and adjacent untraumatized teeth at 6 months. The available evidence suggests that surgical crown reattachment is a feasible and effective technique for managing complicated crown-root fractures in permanent teeth.