I plan on graduating undergrad in 3 years (I've been taking summer classes so that I will have enough credits to graduate). Would it be better to just take what would have been my senior year off as a gap year, or should I apply the summer after my second year and go to dental school immediately after graduating? (assuming I get into somewhere of course)
Don't listen to anybody who says you are going to regret it if you go the 3 year route instead of the 4 year route. It's a one year difference. College is what you make of it. As long as you are willing to get out of your comfort zone, be sociable, and try new things, I believe you will have an awesome time in college. However, if you do not force yourself to try new things and have fun, you will always be socially inept and awkward, regardless if you stay for 4+ years in college. Don't forget that dental school is 4 years of college as well. Whose to say that you won't have fun in dental school as well. Again, it's what you make of it that matters.
For taking a gap year, that's totally up to you. I love traveling
and backpacking to several countries. Our family goes atleast once a year on vacation to explore new countries, and my parents go alone on vacation without my sister and I once a year as well. So whoever says you will not have time, they are 100% wrong. The important thing to take from this is to MAKE TIME. My parent's did, and I plan onto as well.
However,
@cacajuate also said something very important as well. Make sure you learn something about yourself. Ask yourself if being a dentist is something you can be happy with for the rest of your life. I shadowed, volunteered, and worked as a dental assistant before applying to dental school. I was absolutely sure that I wanted to be a dentist, and carry on my family trade.
Also you DO NOT need to take a whole gap year to study abroad. For me, I plan on studying abroad the summer before dental school for a month or two. Personally, I think that's enough for me.