Transversal maxillary growth in experimental submucous mid-palatal clefts. A roentgen-cephalometric study in the cat.

At the average age of 2 1/2 months the mid-palatal suture and adjacent bone was extirpated in 24 domestic cats resulting in a 5 mm wide submucous cleft in the hard palate. In 16 other animals the corresponding mucoperiosteal flap was elevated and replaced without resection of the suture, i.e. testing the effect of the soft resection of the suture, i.e. testing the effect of the soft tissue trauma implied. Twenty-eight unoperated cats of corresponding age served as controls. The transversal maxillary growth was then studied radiographically by measuring the increase in distance, on cephalograms, between metallic implants inserted into both sides of the hard palate. Up to 50% reduction of transversal growth appeared where the mid-palatal suture had been extirpated. The palatal dimensions of the sham operated- and the unoperated groups did not diverge. The results obtained seem to indicate that growth in the mid-palatal suture is a combination of active growth due to proliferation of the sutural tissue, and passive growth induced by external forces exerting a traction in lateral direction.