Association between the timing of secondary alveolar bone grafting and maxillary permanent central incisor development in unilateral cleft lip and palate.

Secondary alveolar bone grafting (SABG) supports the eruption of impacted permanent teeth and the establishment of a proper dental arch in patients with cleft lip and palate (CLP) or cleft lip and alveolus (CLA). However, the optimal timing for SABG remains controversial. This retrospective study aimed to evaluate the developmental changes of the maxillary permanent central incisor (MPCI) following SABG in patients with unilateral CLP (UCLP), using cone-beam computed tomography (CBCT). CBCT scans were collected from 49 patients (aged 4-10 years) with UCLP before and 12 months after SABG. The positional change and axial angulation of the MPCI within the alveolar cleft were quantitatively assessed. The greatest change in displacement and angulation changes of the MPCI were observed in patients who underwent SABG between 4 and 7 years of age, regardless of postoperative orthodontic intervention. The early SABG (aged 4-7 years) group showed greater axial angulation changes compared to the late group (aged 8-10 years). These findings suggest that early SABG may facilitate bone bridge formation, thereby supporting the physiological development of the MPCI on the cleft side. CBCT evaluation may be a useful tool for guiding clinical research and optimizing surgical timing in patients with UCLP.