Maxillary Hypoplasia in the Cleft Patient: Contribution of Dental Agenesis to Le Fort I Advancement Surgery

Maxillary hypoplasia is commonly found in cleft patients. Contributions to restricted maxillary growth have been widely accepted to be caused by two main factors: surgical intervention for cleft lip and palate repair and intrinsic growth deficiency. Intrinsic factors of maxillary deficiency have been correlated to various clinical markers including size or severity of clefting, dimensions of the premaxilla, and palatal surface area. However, there is a lack of consensus on the presence or severity of congenital dental anomalies as an independent predictor of maxillary deficiency in cleft patients. In this work, we investigated our institutional experience with dental agenesis in cleft lip and palate patients and report an association for both quantity and position of dental agenesis and need for maxillary advancement surgery.

Patients with any type of cleft lip or palate evaluated and treated at the UCLA Craniofacial Clinic between 2008-2013 were identified (n=103, mean age 18.9 years, range 14-23). These patients were reviewed for demographics, dental anomalies, and Le Fort I advancement. Maxillary hypoplasia was confirmed with cephalometric analyses using objective criteria. Lateral cephalograms of 53 patients were obtained and traced by three independent evaluators. Sagittal relationships to the skull base and mandible were determined using Steiner’s analysis. Relative maxillary vertical height was estimated using the upper facial height (nasion to A point) to lower facial height (A point to menton) ratio. Chi square tests and multivariate logistic regression analyses were performed to delineate the contribution of quantity and position of dental agenesis to maxillary hypoplasia and orthognathic surgery.

In this cohort, 63.1% were male, 68.9% had some form of dental agenesis, and 55.3% required Le Fort I advancement. The types of clefts were isolated cleft palate (11.7%), unilateral cleft lip and palate (66.0%), and bilateral cleft lip and palate (22.3%). The type and laterality of clefts did not demonstrate any statistically significant correlation to Le Fort I advancement. In patients who did not exhibit dental agenesis, 18.8% required Le Fort I advancement versus 71.8% of patients with dental agenesis (p<0.00001). In patients who were missing one tooth, 61.1% of patients required Le Fort I advancement (p=0.04). This was increased to 82.9% requiring Le Fort I advancement when patients were missing two or more teeth (p=0.04). When the position of cleft agenesis was investigated, 67.0% of patients were missing lateral incisors, followed by 9.7% for central incisors, 6.8% for cuspids, and 3.9% for bicuspids. Although loss of teeth at any of the positions correlated to an increase in Le Fort I advancement, only loss of the lateral incisor was statistically significant (72.5%, p<0.00001). Adjusting for quantity and other positions of dental genesis, multivariate logistic regression analyses demonstrated that lateral incisor agenesis is an independent predictor for Le Fort I advancement surgery (OR 6.2308, CI 2.1129-18.3741, p=0.0009).

In this work, we demonstrate that both quantity and position of dental agenesis are important factors in predicting maxillary advancement surgery. We suggest that the criteria for determining the most appropriate treatment for dental agenesis should include the absence or presence of maxillary hypoplasia. Clinicians should take into consideration the potential for restricted maxillary growth in cleft patients with missing permanent teeth.

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Wu, T. T., Ko, E. W., Chen, P. K., Huang, C. S. Craniofacial characteristics in unilateral complete cleft lip and palate patients with congenitally missing teeth. Am J Orthod Dentofacial Orthop 2013;144:381-390.