Abstract
Palatal bone biopsies from nine children 22 to 24 months of age, with complete unilateral cleft, showed that palato-vomer plasty results in uninterrupted osseous closure of the cleft in the hard palate. The newly formed bone had fused with the nasal septum, but no suture had developed corresponding to the fusion. The bone contributed to the vertical growth of the nasal and oral cavities, but in spite of an extremely active suture on the non-cleft side the osseous closure of the cleft seems to inhibit transverse maxillary growth. Periosteal biopsies from the same children obtained from the buccal aspect of the maxilla from the region of the second deciduous molar on both sides, showed reduced appositional growth activity on the cleft side. Periosteal biopsies from nine unoperated children aged 2 months with the same type of cleft showed equal appositional growth activity on both sides. It is recommended to avoid any surgical procedure resulting in osseous closure of the cleft in the hard palate until the sutural growth of the upper face has terminated.