Part of managing your practice is keeping your practice running on schedule. Your receptionist or scheduling coordinator are responsible to make sure patients are seen on time.
I recommend at approximately 10 minutes past the appointment time, if the patient is still in the reception area, that the receptionist go to the appropriate room, inform the dental assistant or hygienist that they are 10 minutes late for the patient that is waiting in reception.
This is normally done by placing a sticky note on the counter behind the patient or by placing a laminated red card on the counter. Never verbally tell the dentist or hygienist they are “late or a patient is waiting” in front of another patient.
At this point, the assistant or hygienist will explain to the receptionist or floater, why they are running behind and to give them an approximation of how much longer they will be.
The receptionist will keep the patient informed of the progress, so they don’t think you have forgotten about them.
It is always better to give the patient more communication than not enough when running late.