Does absence of maxillary lateral incisor affect the status of maxillary canine before and after secondary alveolar bone grafting in patients with unilateral alveolar cleft?

To investigate whether absence of maxillary lateral incisor (MXLI) would affect the status of maxillary canine (MXC) before and after secondary alveolar bone grafting (SABG) in patients with unilateral cleft lip and alveolus (UCLA) and unilateral cleft lip and palate (UCLP). 47 male patients with UCLA and UCLP, whose Bergland indices were type I or II after SABG, were divided into the MXLI-absence (n = 26) and MXLI-presence groups (n = 21). Using panoramic radiographs, the position, angulation, and development status of MXC on the cleft side, and the cleft width before SABG (T1) were evaluated. After full eruption of the permanent dentition (T2), the root length, root shape, and frequency of forced eruption of MXC on the cleft side were investigated. Then, statistical analysis was performed. Compared to the MXLI-presence group, the MXLI-absence group showed higher frequencies of mesial angulation of MXC at T1 (criteria: >25°; 46.2% vs 14.3%, P < .05) and dilaceration of MXC at T2 (26.9% vs 4.8%, P < .001). MXC on the cleft side showed positive correlations between horizontal position at T1 and forced eruption at T2, and between vertical position and mesial angulation at T1 and dilaceration at T2 (all P < .01). In patients with UCLA and UCLP whose SABG outcome was successful, absence of MXLI on the cleft side increased only the frequencies of mesial angulation of MXC at T1 and dilaceration of MXC at T2, not frequency of forced eruption at T2.