You'll get used to it. 😀
Like pathologists who get used to dead bodies in various conditions of mutilation all day, you become inured to it after a while. And believe me you will see plenty of cases like that in dental school.
There is a lot of satisfaction though when you take a patient whose mouth is in horrible condition and turn it around 180 degrees by the time you finish the treatment plan. It's amazing how much better someone's oral cavities can look even after just a prophy to get rid of all the odoriferous debris, plaque and calculus and teaching the patient how to properly brush and floss.