Associated parameters of canine impaction in patients with unilateral cleft lip and palate after secondary alveolar bone grafting: a retrospective study

To compare parameters related to impacted canines at the cleft versus the normal contralateral side and with non-impacted canines at the cleft side in unilateral cleft lip and palate (UCLP) patients. We also aim to search for possible associated parameters enabling prediction of canine impaction in these patients. Ninety-five non-syndromic UCLP patients were included and divided into group A (n = 41 patients) with unilateral impacted canines at the cleft side (A1) and spontaneously erupted canines at the non-cleft side (A2) and group B with spontaneously erupted canines at the cleft side (n = 54 patients). Clinical information and radiographic parameters on panoramic radiographs were collected and compared between groups using a generalized linear mixed model, a Mann-Whitney U-test, a Fisher's exact test, and receiver operating characteristic tests. Impaction of the maxillary canine at the cleft side in UCLP patients can be suspected in case of delayed canine root development, a higher vertical position and sector score (P < 0.05) and higher angles between the canine and the midline, as well as between canine and lateral incisor and between first premolar (P < 0.001). Results clearly indicate that the erupting canine position at the cleft side, even when not impacted, is different from the non-cleft side. There is a great risk for canine impaction at the cleft side in UCLP patients when the canine position is more apical than one-third of the root of the adjacent lateral incisor and when the angles between canine and midline and between canine and first premolar are higher than 23.82 and 16.1 degrees, respectively. These associated parameters should have to be studied in a prospective setting to confirm their predictive value.