Long-term granular diet may lead to declined resistance to trauma of the temporomandibular joint

This study was carried out to determine the effect of food texture on the r esponse to trauma of the temporomandibular joint in mice. Animals were fed either a solid or granular diet after weaning. At 8 weeks old, condylar hyp ermobility was induced by forcing the mouth wide open ten times under ether anaesthesia. This procedure was repeated 10 times once daily for 10 consec utive days. The temporomandibular joint tissues were observed microscopical ly on day 0 and then 2 days, 5 days, 2 weeks, 3 weeks and ri weeks after th e last forced opening. Eighteen male mice were used in total, three for eac h timepoint. A proliferation in synovial surface cells and an increased num ber of capillaries were seen at day 2 in the mice fed a granular diet, but not in those fed a solid diet. Multiple cell layers of the synovial membran e, dilated capillaries and fibrin deposits were expanded further between da y 2 and week 5 in the mice fed a granular diet, but not until day 5 to week 5 in the mice that had been fed a solid diet. At week 3, the mice fed a gr anular diet showed erosion of the anterior articular disc. This was observe d in both dietary groups at week 5. This study suggests that, in advanced c ountries, people who habitually eat easily chewable food should be advised that such practice may lead to a decline in the resistance to trauma of the masticatory system.