A cephalometric study of the relationship between the level of velopharyngeal closure and the palatal plane in patients with repaired cleft palate and controls without clefts.

To find out whether the palatal plane is a useful indicator for evaluating the level of velopharyngeal closure, we did a cross-sectional study from early childhood to puberty of the vertical relationship between the palatal plane and the level of velarpharyngeal contact during velopharyngeal functioning in 61 patients with repaired cleft palate (unilateral cleft lip and palate = cleft group) and 82 controls without clefts (control group). Measurements on the vertical dimension were derived from a coordinate system and landmarks on lateral cephalograms, and the significance of differences in measurements was analysed using Student's t-test. Changes in the points of velarpharyngeal contact in relation to the palatal plane with growth showed a consistent tendency though differed between the two groups. In the control group, the PPW (point where palatal plane extension intersects the posterior pharyngeal wall) was maintained at a level that did not differ significantly from the level of midpoint of velarpharyngeal contact during phonation of /a/, and was maintained at a level that did not differ significantly from the level of the inferior point of velarpharyngeal contact. In the cleft group, however, it was maintained at a level that was slightly higher than the superior point of velarpharyngeal contact both during phonation of /a/ and during blowing. These results suggest that the palatal plane is useful as an indicator for evaluating the level of velopharyngeal closure.