A morning appointment may be best because your blood glucose tends to be controlled better at this time. Also, you've just had breakfast and taken your insulin or other diabetes medication. If your blood glucose isn't under good control, it's best to reschedule your appointment because you will risk infection and other complications. Your dentist will understand. But if you have pain and an infection already, see your dentist right away and don't postpone. Also, seeing your dentist more than twice a year will help you make sure your teeth and gums are in the best health. Seeing the dentist every 3 or 4 months is usually sufficient, but talk to your dentist.