Fluoride is a natural mineral that exists in the earth’s crust and is found abundantly in nature, and is used in two ways: 1. Systemic For example, the fluoride available in drinking water,the fluoride in foods and vegetables,fluoride as a tablet, which can only be used with a doctor’s prescription and locally,fluoride varnish,fluoride gel,fluoride in mouthwashes,and fluoride in toothpastes. The local application of fluoride (direct contact with teeth) strengthens the dental structure against decay and prevents new decays effectively. At the same time, it can stop or slow down early decays on the teeth. In some cases, the dentist prefers to deliver a high concentration of local fluoride to the child, which takes approximately 10 minutes and doesn't require local anesthesia. The procedure is as follows (fluoride gel): 1. First, all dental surfaces are cleaned with a toothbrush.2. Then all teeth are dried with a sterile gauze.3. All dental surfaces are smeared with fluoride gel (sometimes one side of both jaws in one stage, and the other half in the next),4. Fluoride gel remains on the teeth for 1 to 4 minutes.5. In all stages, the child’s back is vertical and the head is tilted slightly forward to prevent the child swallowing fluoride.6. After the allotted time, the extraneous gel is removed with a sterile gauze or cotton. At this stage, the child spits out all the saliva.7. The child should not rinse their mouths after fluoride therapy and should avoid eating or drinking for half an hour. During this time, the saliva in the mouth should be discharged.8. Fluoride therapy can be done in 6 months-old children who have erupting teeth (for younger ages, it is advisable to use varnish).9. Fluoride therapy takes place periodically (every 6 months) at the dentist’s discretion and reduces decays by 30 to 60%.10. Fluoride therapy can be done for both milk and permanent teeth.