Your patient needs diagnostic casts made for an orthodontic referral

Your patient needs diagnostic casts made for an orthodontic referral. In the process of taking the initial impression, the mandibular tray does not seat properly, and the impression needs to be taken again. During the second attempt, the tray is seated but is uncomfortable for the patient. While taking the maxillary impression, the patient exhibits a strong gag reflex. After the alginate impressions are complete, the patient complains of itchiness in the mouth and difficulty swallowing. You immediately activate the EMS system. What could cause the difficulty in seating the mandibular tray? What can be done to allow the tray to be seated successfully? What steps can be taken to avoid gag reflexes? What could be causing the itchiness and difficulty swallowing? What other impression material could you use? What affects the setting time of alginate impression material? What are the components of alginate?