As a medical practitioner, she should have been more patient and understanding of your stuttering. She should have allowed you the time to express yourself and convey your wishes for YOUR treatment. They are your teeth, and you will go through the procedures that YOU deem fit. Don't beat yourself up over the experience, you just had a bad day at the occurrence of something you have no control over. BUT, she has control over how she reacts to it and she chose to relegate her patient's needs and throw a tantrum. Leave her clinic a review and highlight your experience.