Timothy C. Hain, MD Hearing Page Page last modified: March 30, 2017
As of 2017, there were more than 100 papers in Pubmed concerning hearing loss having "dental" in their title. The main things that happen during dental work that might be associated with hearing loss are noise exposure, injections for blocks, and the psychological impact of the procedure.
As the ear and the teeth are not directly connected, one would expect that there would have to be transmission of the cause for hearing loss through the temporal bone. Reasonably logical sources might be loud noise, vascular effects, and perhaps modulation of tinnitus. For the noise induced mechanism, one would expect a mid-frequency loss. Other patterns, including delayed hearing loss, would be more likely due to vascular effects. A "neurovascular" connection -- damage to a nerve from a "block", followed by a blood vessel spasm seems concievable. Activation of a herpetic infection, again from the block, also would seem worth considering, although there are no reports in the hearing+dental literature as of 2017.
Of course, for any intervention of any kind, there is always the possibility of a chance temporal proximity as well as psychological sources of hearing complaints, including malingering. One might also serendipitiously pick up a pre-existing hearing loss after dental work. As conventional hearing tests incorporate subjectivity, a more "objective" test such as a diagnostic OAE would seem prudent in persons with hearing loss at higher frequencies (i.e. above 2K).
Loud noise is a well known cause of hearing loss as well as temporary threshold shifts. There is a significant literature about noise exposure in the dental setting. This mainly is a problem for the people who work in the dental office, rather than their patient's. Daud et al (2011) reported that some hearing loss might occur in about 5% of dental nurses.
Nevertheless, as dental work can involve loud high-speed drills, there is a reasonable possibility that there might be a transient hearing loss in patients as well, around the frequency of the noise exposure, associated with dental work. Ahmed et al (2016) reported that hearing complaints are common in dental students. Burk reported that noise levels can be as high as 103 dB.
Altinoz et al (2001) reported that the mean frequency for 5 dental air turbines was around 6860 Hz. One would expect that noise induced hearing loss, in patients, should also show loss around the frequency of the drill (i.e. mid-frequencies). As dental technology evolves, there is likely a tendency towards higher frequencies, and less damage at relevant frequencies (i.e. 0-8000).
In single case reports, it is difficult to know if these are just "chance" jutaxposition of a sudden hearing loss with temporal proximity to dental work, or whether there is a causal connection. In persons who had their work done under general, it would seem likely that there might be more noise exposure, as unconscious patients cannot complain.