Compensatory growth of the dental arches in hypoplasia of the maxillary base. A biometrical analysis in the domestic cat.

When two opposing layers of mucoperiosteum are used to cover experimental mid-palatal clefts in growing cats, bone bridges regularly form between the palatal halves. This results in significantly smaller transverse dimensions of the hard palate, in a hypoplastic maxillary base. The present investigation analysed the concurrent enlargement of the dental arches in such animals. Compared with un- and sham-operated controls, no significant divergencies could be found. The cat has a deep scissor bite. A reasonable interpretation of the findings might therefore be that mandibular dental arch growth is transmitted 'orthodontically' to the maxillary teeth, through the occlusion. In cleft lip and palate patients operated on with conventional methods, similar bone bridges are frequently found, but also a favourable effect of orthodontic treatment on co-existing dental malocclusions. To some extent the findings of the present study appear to coincide with those of the clinic. The results seem to indicate that adjustment of dental arch dimensions in disproportionate jaw bases may be due more to conductible compensatory dental arch growth than to forcibly induced movements of jaw segments.