Professional Questions and Answers

The following forum is a space within dentistry on line for professionals to submit questions which we will attempt to have answered by experts, whose replies will be published here. We regret that we cannot answer all questions submitted, and that experts writing here cannot answer individual unpublished questions.

Q

"I am experiencing normal hearing in my right ear from 20Hz to about 2000Hz with a *radical* hearing loss after 2000 Hz. A test of brainstem response (ABR) indicates a "blockage" or problem in the cochlea. Everything else normal, including physical attributes of eardrum, eustachian tube etc. Cause is unknown, but said to be from 'inflammation' of the soft tissues in the area. CT Scan (with contrast) reveals no acoustic neuroma or other tumours.

I have an impacted wisdom tooth on the same side as the hearing loss, as well as noises in my jaw on that same side and a feeling of fullness or mild pressure on the right side. Is it possible (never mind probable) that the root from this wisdom tooth has compressed the tissues around the cochlea and thus has caused this hearing problem? (I understand it's possible that the tissues around the cochlea can become inflamed and constrict blood flow to the cochlea. The inflammation itself does not cause the hearing loss, but over time the constricted blood flow causes damage to the cochlea, which in turn affects the hearing)

I would appreciate any information you may have on this question. I'm stumped. (and a bit deaf...)"

A

"High frequency hearing loss is a common cochlear disorder and is normally due to a pathological process in the basal turns of the cochlear. The commonest causes of this disorder are: vascular deficiency, noise induced, aminoglycoside toxicity and hair cell presbyacusis. This type of sensiro-neural deafness appears to have been fully investigated in the correspondents question. The use of brainstem evoked response audiometry is normally used to exclude serious pathology such as an acoustic neuroma, that was ruled out in this case by the CT scan.

The question of relationship to inflammed wisdom teeth sounds initially far fetched even taking referred pain into account. However an acoustic neuroma, a slow growing tumour at the cerebello-pontine angle, occurs at the confluence of cranial nerves V, VII and VIII. Thus hearing loss mediated by disruption of the VIII nerve can co-exist with sensory disturbance in the region of the Vth cranial nerve. Hence, the rare chance of sensory disturbance around wisdom teeth being associated with a central 'brain tumour'. Thankfully this has been excluded in the investigations performed in this case.

It is important to note that sensory loss around the face should be referred for an expert opinion."

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