Plan to be at Mission of Mercy for at least several hours. Patients are seen on first-come, first-served basis, so how long it takes depends how many people are ahead of you. The first people into the clinic should be done around 7 a.m. Once you enter the clinic area doors, registration and your initial exam will take approximately 30 minutes. We will have 100 dental chairs, and patients will spend an average of 45 minutes in the treatment chair.