Mandibular growth in patients with cleft lip and/or cleft palate--the influence of cleft type.

A total of 229 adult white patients with cleft lip or palate were evaluated, through cephalometric radiographs, to determine cleft-type influence on mandibular structure and spatial position. The sample includes adult patients with unilateral complete cleft lip and alveolus (n = 50), complete cleft lip and palate (n = 118), and isolated cleft palate (n = 61). A group of 65 subjects with normal occlusion and without cleft lip or palate was used as a control group. All groups were matched according to sex. When compared, the cleft groups and the normal group showed that the mandibular structure was significantly different. The mandible in the cleft groups displayed shorter mandibular ramus and body length, without difference between the cleft types. Mandibular position relative to cranial base was similar in the cleft groups with involvement of the palate, and differed significantly from that observed in the group with cleft lip and alveolus and in the subjects without cleft. Palatal clefts induce a significant downward and backward rotation of the mandible associated with a more obtuse gonial angle. Thus a small mandible is a structural characteristic of all cleft types studied. However, mandibular shape and spatial position are strongly influenced in clefts that involve the palate.