JASLOW, C.R.*; LANIER, B.; HILL, E.: Early Development of Interdigitation in Rat Cranial Sutures

The cranial sutures are highly variable, ranging from relatively straight edges to highly interdigitated interfaces between neighboring bones. Sutural interdigitation has been correlated with patterns of loading encountered by the sutures. However, it remains unclear whether sutural interdigitation is caused by extrinsic loading, or whether it develops independently. The frontopremaxillary suture in rats is an example of a highly interdigitated suture that is likely exposed to extrinsic mechanical loads generated by incisor use. This study quantified the changing external complexity of the frontopremaxillary suture in rats during early development to test the hypothesis that the increase in sutural interdigitation follows the onset of functional loading via incisor occlusion. The frontonasal sutures, which are unlikely to be loaded in the same way by incisor activity, were also measured for comparison. Both sutures had nonlinear patterns of increasing interdigitation, with a significant increase seen in the frontopremaxillary suture prior to the onset of occlusion. These results indicate that increases in sutural interdigitation are not dependent on extrinsic loading of the sutures during early development.