OBJECTIVES: This study aimed to assess the efficacy of active presurgical orthopaedics appliances in infants presenting with complete unilateral cleft lip and overlapped alveolus (T-shaped alveolus). MATERIALS AND METHODS: A retrospective and prospective longitudinal study was performed. Infants diagnosed with complete unilateral cleft lip and overlapped alveolus, received treatment with the active presurgical orthopaedics appliances from June 2020 to June 2023, at Children's Hospital 1, Ho Chi Minh City. The treatment duration averaged 3 months. Pre- and posttreatment casts of noses and alveolus were scanned using TRIOS3 Wireless intraoral scanner (3Shape, Denmark) and analysed with Slicer 5.2.2 software. There were 16 quantitative variables. A pair t-test and Wilcoxon signed ranks were used for analysis. The statistical significance was adopted as p <
0.05. RESULTS: A total 40 patients (17 males, 23 females, mean age 23.85 ± 19.22 days) were evaluated. After treatment, the nostril height increased by 2.62 ± 0.22 mm and the deviation columella decreased by -23.45° ± 2.29°. There was a reduction in cleft gap (-3.77 ± 2.01 mm), and in the overlap of alveolus (-3.71 ± 1.83 mm), the growth of cleft segment increased by 2.27 ± 2.00 mm, while the rotation of the noncleft side alveolus decreased by -5.29° ± 5.31°. The changes were statistically significant (p <
0.001). CONCLUSIONS: Active presurgical orthopaedics appliances improved the nasal deformity and overlapped alveolus morphology in infants with complete unilateral cleft lip and T-shaped alveolus.