There is no real answer to this question. Of course, the traditional answer would be to major in Biology and get a Chemistry minor (or the opposite). It's just because the DAT is majority those courses, also the first few years of dental school are these courses. It shows you are familiar with the material and could handle it in dental school.
That being said, there is no rule that you can't be different. You must complete all the bio/chem prereqs though, and strive for A's in them. Plus you have to nail the DAT. Engineering courses won't help you (directly) with the DAT. However, I know engineering is difficult and trains you to think outside the box and be a good problem solver, which could (indirectly) be very beneficial with the DAT.
My final bit of advice, which is just my own opinion and others may or may not agree, be careful how you tell your story (regarding your choice to major in civil engineering). You don't want to come across as a person who wants to be an engineer and dentistry was an after thought, or just something you thought you might want to do. Now, hear me out, I don't think this is the case at all. You sound like you are a great student and you're right on track. I believe you want to be a dentist. Alls I'm sayin is to figure out how you are going to tell your story.
Why would you major in engineering if you wanted to be a dentist? Why do you want to be a dentist? Was dentistry something you just decided to try, or do you have a real passion for it? These may be the types of things that would come up in an interview. So just be ready to stand your ground and make a good case as to why you should be accepted to their program.
A friend of mine had a non-traditional major, got to his interview, and was hit with questions like this. Luckily dentistry is in fact his passion and he killed the interview. Sorry if that's a bit lengthy, just some advice for your unique situation.
Hope this helps! Hit me up if you have any questions!
Best of luck,
Gage(D1)
