Temporomandibular disorders (TMD) represent a group of disorders involving the masticatory muscles, the temporomandibular joint and associated structures. Stress, age and gender are common risk factors for TMD.
TMD is often characterised by aural symptoms such as tinnitus, otalgia, vertigo, otic fullness sensation, hyperacousia or hypoacousia. Current understanding of TMD suggest that temporomandibular joint pain is due to pathological contraction of masticatory muscles which stimulate the realease of inflammatory molecules around the temporomandibular joint.
Several hypothesis have been suggested to explain the otological symptoms associated with TMD among which that the position of the joint disk during jaw movement increases pressure in the Eustachian tube, the ear structures and the auriculotemporal and masseteric nerve, which innervate the tympanic membrane, the anterosuperior part of the external ear and the tragus. Additionally, studies have reported that in TMD, the tensor tympani muscle is in a pathological hypertonic state that may lead to hypoacusia, tinnitius, vertigo, otalgia and otic fulness sensation. Finally, some studies showed that TMD peripherally sensitizes the V and VII nerve pairs, leading to tonic spasm of these middle ear muscles and to hearing loss.
While, I could not find a study directly correlating ear pain with hearing loss, a study (see Sources) showed that hearing loss is correlated to TMD severity. Below a table representation of the quantitative hearing loss by TMD severity among the individuals included in the study.
In this study among 464 healthy individuals, subjects were stratified into four groups: non TMD, mild TMD, moderate TMD and severe TMD. Severity of TMD was based on the score obtained after completion of an anamnestic questionnaire composed of 10 questions. Unilateral chewing and facial pain were considered in the questionnaire. In the results section, authors report that
pain in the temporomandibular joint was reported by 96 subjects. It
was experienced by 3% of the non-TMD group, 11.1% of the mild group,
8.8% of the moderate group and 70.8% of the severe TMD group.
Those results indirectly suggest that pain in the temporomandibular joint might be correlated to hearing loss, but this has of course to be confirmed.
Kitsoulis et al. BMC Ear, Nose and Throat Disorders 2011, 11:5, http://www.biomedcentral.com/1472-6815/11/5