Dental problems a hundred years ago were not as problematic as we think. I’m Indigenous Canadian and my parents were born and raised in the bush and judging from family photos I’ve seen from a hundred years ago … most people had decent teeth. I have photos of my grandmothers parents who must have been in the 60s or 70s and they all had full teeth, probably not the best but they had obvious white teeth.
Cavities and tooth problems are a modern problem from wealth … we eat too much starch and sugar and generally just eat way too much of everything. Before the modern era, up to about the mid 1800s, the average person ate about five pounds of refined sugar a year - today the average person consumes about 100 lbs of sugar a year. … and those are the averages! Back a hundred years ago, you were wealthy if you could get sugar … most people just couldn’t afford to eat it … most people couldn’t afford to eat! And they ate more simple diets and less often.
The biggest fear I have about going back to the past is just getting a flesh wound, a hang nail or a scratch that could fester into an infection and either take a limb or kill me.