It's great that you are thinking about dentistry. If you already in BioChem major, you have a little advantage when applying for dental school in term of the courses you take for your BioChem degree will overlap with the requirement for most dental school. You may want to start thinking about preparing for the DAT. The higher the score the better. And you may also think about exposure to dentistry experiences by either volunteer or work in the dental clinic. Or if you do not have time to work in the dental clinic, you will want to spend some time shadowing a local dentist (your own dentist will probably let you do this in his clinic and a great person to talk to about the profession.)
Please read the following question on this site: https://www.careervillage.org/questions/659902/what-courses-do-i-need-to-take-in-high-school-to-in-order-to-get-in-college-to-become-an-orthodontist
Biochemistry is not major but part of subject to study in dentist. They are basic which u can further improve in dentistry..