Bony or connective tissue union of operated experimental palatal clefts: implications on growth of the dentomaxillary complex. A biometrical study in the domestic cat.

Operated human cleft palates heal with formation of bone and/or connective tissue in the mended defect (Prydsö, Holm, Dahl & Fogh-Andersen, 1974; Enemark & Jörgensen, 1978). In domestic cats with experimental palatal clefts, reparation by hard or soft tissue appears to be conditioned by the type of palatoplasty applied (Freng, 1979a; 1979b;). Both tissue responses led to reduced transversal growth of the maxillary base (Freng, 1979c; 1981). As regards the concurrent dental arch growth, however, no difference from unoperated controls was found in individuals with bone postoperatively bridging the palatal mid-line (Freng & Voss, 1982). A submucous cleft led to a significant reduction in transversally directed arch development (Voss & Freng, 1982). The present study aimed to find out if these observations could be due to a relatively smaller width of the maxillary base in operated cleft palates healing with connective tissue. However, no significant difference in maxillary base width appeared when the two groups were compared. To some extent, the effect of the cat's scissor bite, on the dental occlusal relationship, may simulate the effect of orthodontic appliances in humans by transmitting mandibulary growth into laterally directed movement of the upper jaw's teeth. The difference in dental arch growth between the two groups might therefore be interpreted either as expressing a better preservation of obtained compensatory transversal maxillary teeth movements in palates healing with bone bridges, or a tendency for the upper dental arch to collapse in cases with submucous mid-palatal clefts.