Effect of Food Consistency on Temporomandibular Joint Morphology: An Experimental Study in Pigs

Aims: To investigate whether there are any correlations between increased masticatory loading, degree of tooth wear, and the size, form, and macroscopic surface of the temporomandibular joints (TMJs). Methods: The degree of tooth wear and different TMJ variables were compared in 2 groups of domestic pigs. One group of 8 pigs had been raised indoors (ID group), and the other group of 9 pigs had been raised outdoors (OD group). The pigs in the ID group were fed a soft diet and were not provided any straw in their pens. The OD group was fed a solid diet and could also grub in the soil, resulting in an exposure to more abrasive components and to greater chewing demands. All pigs were sacrificed at the age of 22 months. Results: The pigs in the OD group exhibited significantly more tooth wear compared to the ID group. No difference in mediolateral size of the condyles could be found between the 2 groups. Form and surface changes of the TMJs varied substantially between individuals, but not between the 2 groups. No correlation could be found between the degree of tooth wear and any of the TMJ variables. Conclusion: Exposure to a tougher diet containing more abrasive substances has a significant impact on the degree of tooth wear but seems to have no consequences either for the size of the TMJ condyles or for form or surface changes of the TMJs. Keywords: animal trial, osteoarthrosis, temporomandibular joint, tooth attrition