Silencers reduce the harmful sound pressure wave before it can be conducted by bone. As such, they are much more effective at mitigating harm.
Any sources to support this because I couldn't find any. Even the ASA doesn't make this claim.
In March, 2017, the National Hearing Conservation Association’s Task Force on Prevention of Noise-Induced Hearing Loss from Firearm Noise stated that “using firearms equipped with suppressors” is one of “several strategies [that] can be employed to reduce the risk of acquiring NIHL and associated tinnitus from firearm noise exposure.