Root fractures often occur in immature maxillary permanent central incisors and can be combined with other injuries, making treating more difficult and prognosis uncertain. A 10-year-old girl sustaining a second dental trauma came to our hospital. Teeth 11 and 21 experienced root fracture following the first injury 15 months earlier. The second injury resulted in lateral luxation of the coronal fragment of Tooth 11 from the original fracture site and subluxation of Tooth 21. Tooth 11 was repositioned, and both Teeth 11 and 21 were splinted for 3 months. An apical plug was applied to Tooth 21 at 52 months. After 8 years of follow-up, complete resorption was observed in the apical fragment of Tooth 11, and both teeth exhibited a favourable prognosis. It illustrates that complex root fractures sustaining two separate traumatic incidents can have a positive long-term outcome through accurately judging and grasping the timing of sequential treatment.