Joining clubs/ organizations at my new college?

Although you are looking to become a Dentist and not a Medical Doctor, I strongly encourage you to joint the Medical Interest Group because it will provide you with some information on related topics such as insurances, and it would give you an idea of what Professional Schools are looking for in their candidates. Another good one would be Volunteers in Action because it will show your leadership skills, sense of belonging in your community, responsibility, and dedication and pion for those things that really matter to you. Plus, in all of these clubs/organizations, you will build relationships that will help you with networking, as well as improve your communication skills, not that I think they need improvement, but having strong communication skills is important for admissions.