Dentist receptionist doesn't space out the appointments, how do I tell her to give more room?

I am a dental assistant and my office recently hired a receptionist that overlaps appointments. We have a lot of HMOs. Usually the schedule is so tight that we are always running behind. I understand the need for fast paced but if there was at least 2-3 minutes in between patients it would be helpful. Lately we haven't even been having time to floss the patient's teeth during their cleaning appointments! So as a dental assistant I am wondering how to tell this receptionist in a nice way that I would like her to space the appointments just a little more.