Bear in mind that the tonsils are hard to see - they hide along the side of the tongue. Dentists don't typically have the specialized mirrors that ENT's use and it might be much more difficult for them to visualize the tonsils and larnyx area. Although I am all for any kind of screening, I am not convinced that dentists are going to catch everything. Whenever they are screening me, they invariably check all of the highly visible areas that I could see myself - tongue, under the tongue, gums, inner cheeks, etc. I wouldn't rely on it as 100% screening. Some screening is better than no screening.

In my case the tumor got SO large that it was readily visible and they STILL couldn't figure it out (this large, 6x3cm, tan rubbery blob). They said that from literally thousands of patients they rarely have seen any oral cancer - maybe 2 or 3 at best. They were performing regular cancer screening long before I got my oral cancer and are much more careful about it now (because of me). My dentist is in an affluent area and maybe that's a factor. A big city dentist may see more oral cancer cases.

My gp missed it as well but at least he eventually gave me a referal to an ENT after 2 rounds of antibiotics did nothing.

My opinion now is that if you have engaged in risky behaviors such as using tobacco products, excessive drinking or have had viruses such as EBV or HPV than you should be examined annually by an ENT or H&N surgeon as a component of a regular annual physical exam.