An estimated 10 million Americans suffer from temporomandibular disorders (TMDs). The National Institutes of Health describes TMDs in three general categories:​ myofascial, internal derangement, and osteoarthritis (TMJOA). Rodent models enable us to better understand TMD etiology and progression, so that future research can attempt to reverse disability and alleviate resulting pain related behavior. Several methods of analyzing orofacial sensitivity and joint dysfunction of current rodent models exist, but devices inducing less animal stress and more quantitative analysis are necessary. Operant behavioral devices have successfully filled this need specifically for assessing thermal orofacial sensitivity;​ however, operant designs to assess tactile sensitivity could be improved upon. Using principles from operant based devices and reward-conflict paradigms, two novel devices were created to aid in analyzing tactile sensitivity and TMJ function in rodent models of orofacial pain and TMD.

A device used to assess tactile sensitivity in rodents was developed. This device functioned on a reward-conflict paradigm where stainless steel wire impeded access to a reward bottle. Contact with this reward bottle moved the bottle further from the cage, thus increasing required pressure on the facial region to reach the bottle. A maximum tolerated distance threshold was found. To analyze jaw function, a bite strength device was developed where rodents were given access to a slightly pressurized tube. A puncture time was noted where the rodent was able to puncture the tube. These devices were validated using capsaicin models of orofacial pain, where capsaicin models were shown to have a significant decrease in tolerated bottle distance and a significant increase in time to puncture.

Efficacy of these devices in assessing TMDs was investigated in three injection models of TMJ pain and degeneration:​ carrageenan, capsaicin, and monoiodoacetate (MIA). Capsaicin and carrageenan injections were shown to produce pain-related behavior;​ however, MIA did not produce significant behavioral changes regardless of TMJ degeneration.

The sensitivity of these devices allows for investigation of future preclinical models. Developing rodent models that not only mimic clinical disease progression, but present pain related symptoms similar to their clinical counter parts, is necessary to determine disease etiologies and to develop disease specific treatments and therapies.