Prevents and Helps Heal Tongue Sores Caused by Dental Expanders Custom fit soft trays that conform to your mouth for a comfortable and reliable fit. Dental expanders and other dental appliances can cause great discomfort and often infected cuts on the tongue. The metal used to make these dental appliances often cause an allergic reaction and cause painful sores which will get infected. Set of 3 in each package. Prevents tongue sores and infection Custom molds to fit your mouth Promotes healing to tongue sores and infections Keeps tongue off painful dental appliance 3 trays to make new guards as you mouth changes shape