Check with the schools to see how many and what kind they require. It is better to send more than to send less or the wrong types. I had two science professors, a dentist, and a theology professor write mine. Then my advisor (also my science professor and the committee chairperson) sent the letters in a packet with a cover letter. The committee letter is not necessary, but if possible, it is a good thing to get. But again, more letters are better than less but I would not send more than 4 or 5. Make sure you ask people who know you and who can comment on your character, work ethic, desire to be a dentist, ability to succeed, etc
