Factors Contributing to Canine Impaction in Patients With Unilateral Cleft Lip and Palate Undergoing Alveolar Bone Grafts.

Background: Patients with unilateral cleft lip and palate (UCLP) undergo alveolar bone grafting (ABG) to unite the bony segments before eruption of the maxillary permanent canine.

Purpose: This study assessed the frequency of canine impaction after ABG in the UCLP patient population and identified associated demographic, anatomical, and operative factors.

Study Design, Setting, Sample: This retrospective cohort study included 257 patients with UCLP who received ABG surgery at a single craniofacial center.

Predictor Variables: The variables were cleft characteristics, pre-ABG procedures, operative factors, and dental anomalies identified through electronic health records, radiographs, and intraoral photographs taken before ABG and at least 2 years after ABG.

Main Outcome Variable: The primary outcome variable was the presence of an impacted maxillary canine, defined as malposition of a fully developed canine following ABG with full eruption of the contralateral canine.

Analyses: The t tests, χ tests, and logistic regression analysis were used to evaluate frequency of canine impaction and test for associations with the predictor variables.

Results: Of 257 patients, 56% were male with a mean age of 9.2 years at the time of ABG. The frequency of canine impaction was 27% (n = 69, 95% confidence interval 22 to 33%). Significant associations were found for: complete clefts (30 vs 12%, P = .017), hypodivergent facial patterns (low angle: 46%; high angle: 29 vs 22% normal angle, P = .042), females (adjusted odds ratio [aOR] = 2.1, P = .015), early grafting with less than 1/3 developed canine root (aOR = 3.36, P = .024), pregraft extraction of primary canine (aOR = 2.3, P = .009) and greater permanent canine angulation (odds ratio = 1.1, P < .0001). No significant associations with pregraft orthodontic expansion or regrafting were detected.

Conclusion And Relevance: In this study, about one in four patients with UCLP had an impacted canine. Multiple factors including pregraft extraction of the primary canine and increased canine angulation were associated with impaction of the permanent canine.