As you prepare for a career in dentistry, it is important to gain some experience working directly with patients in a clinical setting. It is particularly important that you spend time working, shadowing, and/or volunteering in a dentist office or clinic. This is extremely beneficial for your own professional development, so that you know for sure that you will enjoy working as dentist. Moreover, when dental schools review applications, they will look for indications that you are truly enthusiastic about health care and have sought out opportunities to learn more about the field. Most positions require only a minimal time commitment - as little as 3 hours a week - so it should be possible for you to get involved while juggling a difficult academic course load.
Below are links to organizations and clinics near West Philadelphia and Center City. This is not an exhaustive list of dental-related opportunities. is the center for student-led community service on campus and maintains a great deal of information on and community agencies. Also, you might use a search engine like volunteermatch.com.