Effect of Secondary Alveolar Bone Grafting on the Maxillary Growth: Unilateral Versus Bilateral Cleft Lip and Palate Patients

The purpose of this study was to investigate the effect of secondary alveolar bone grafting (SABG) on the maxillary growth in patients with unilateral (UCLP) and bilateral cleft lip and palate (BCLP). The samples consisted of 40 Korean boy cleft patients who had the similar initial skeletal characteristics and were treated with the identical treatment protocol. They were divided into UCLP group (N=25; mean SABG age, 9.9 years; mean follow-up duration, 42.3 months) and BCLP group (N=15; mean SABG age, 10.2 years; mean follow-up duration, 40.6 months). In the lateral cephalograms taken 1 month before (T1) and at least 2 years after SABG (T2), cephalometric variables were measured. At T1 stage, the 2 groups did not exhibit significant differences in the cephalometric variables except posterior maxillary height (P-HRP) (P<0.05). At T2 stage, both groups exhibited the reduced sagittal growth (UCLP, ANB, P<0.001; AB to facial plane angle (AB-FPA), P<0.01; BCLP, A to N perpendicular, P<0.05; ANB and AB-FPA, P<0.001) and the undisturbed vertical growth (A-HRP and P-HRP, all P<0.001) of the maxilla. During T1 to T2, BCLP group experienced more aggravation of Class III skeletal pattern than UCLP group (AB-FPA, P<0.05). There, however, were no differences in the amounts of changes in the maxillary vertical position and mandibular plane angulation between the 2 groups. Two-stage SABG procedure subgroup in patients with BCLP demonstrated a more retrusive maxilla compared with 1-stage SABG procedure subgroup (SNA, P<0.05). Patients with BCLP, especially who underwent 2-stage SABG procedure, might have a possibility of poor sagittal growth of the maxilla compared with patients having UCLP.