Maxillary growth impairment in cleft lip and palate patients: a simplified approach in the search for a cause.

No true consensus exists regarding the causes of maxillary growth restriction in cleft lip and palate patients. The aim of this study was to evaluate a simplified method to identify the causes of this growth impairment. We analyzed a sample of 82 consecutively treated 5-year-old patients with unilateral complete cleft lip and palate, operated on by the same surgeon (R.B.). Multiple cephalometric measurements of the sample revealed a wide distribution of maxillary growth values. We selected Sella-Nasion A point angle (SNA) as a value describing maxillary position, and we arbitrarily isolated 2 "extreme" groups of patients: the 20 patients with the highest SNA were called "good growers" (group A), and the 20 patients with the lowest SNA were called "poor growers" (group B). Parameters investigated to search for different influencing factors within the groups were initial cast measurements, timing of lip and of gingivoalveoloplasty/palatal surgery, presence of lateral incisors, and family history of maxillary hypoplasia. Statistical differences were investigated with an independent-samples t-test. The 2 extreme groups had a significant difference (P < 0.01) in SNA and in lip protrusion relative to true vertical line. Cranial base angle was larger in group A. Timing of lip surgery in group B was earlier than in group A, but only close to significance. Timing of gingivoalveoloplasty did not differ. In group A, the permanent lateral incisor was missing in 20% of the patients; whereas in group B, it was missing in 82% of the patients (P < 0.01). Selecting cleft lip and palate population with different growth pattern might help in isolating the factors responsible for maxillary growth impairment. Congenitally missing laterals that could indicate inherent tissue hypoplasia seems to be the most important factor.