Abstract: PURPOSE: To study the clinical prognosis of laterally luxated primary teeth after 6-month follow-up without treatment. METHODS: Patients with laterally luxated primary teeth, visiting Department of Pediatric Dentistry, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from March 2018 to March 2019, were selected for the study. Based on the inclusion and exclusion criteria, totally 45 patients with 57 primary teeth were included. The reposition outcomes and pulp prognosis were reviewed at the end of follow-up. The data were analyzed using SPSS 23.0 software package. RESULTS: During a 6-month follow-up, 92.98% of the luxated teeth showed spontaneous reposition while only 31.58% of the traumatic teeth were back to the original position. Regarding the pulp healing complications, 54.39% of the luxated teeth exhibited no clinical symptoms, and 14.04% of the evaluated teeth displayed pulp canal obliteration, and pulp necrosis happened in 31.58% of the injured teeth. There was significant difference in the reposition outcome between labial-palatal luxation and mesial-distal luxation(P<0.05), but no significant difference was found in pulp prognosis between the two luxation types(P>0.05). Spontaneous reposition and crown discoloration observed in most of the evaluated cases, were the earliest signs after one-month follow-up. Periapical translucent image and root resorption due to periapical inflammation showed within the first three months after injury, pulp canal obliteration appeared after 6 months. CONCLUSIONS: In general, most of the laterally luxated teeth left without treatment can reposition spontaneously and show lower incidence of pulp necrosis compared with mature permanent teeth in half a year after injury. The direction of luxation does not affect pulp prognosis but has an influence on teeth reposition procedure.

Key words: Traumatic dental injury, Primary teeth, Lateral luxation, Without treatment