Many children have some pigmentation on the surface of their teeth, what causes it? There are black matter deposits on the tooth surface, even if you brush your teeth, there may be some reasons as follows, but first of all, let’s talk about the elemental sulfur in food, most of the food contains elemental sulfur, among which leek, onion, garlic and other foods have the highest content, if you do not brush your teeth in time after the meal, or by food residues by bacteria, will release the elemental sulfur to chemical reaction with iron or lead, forming insoluble black precipitates Attached to the surface of teeth. 1, due to anemia supplementation of iron without timely rinsing the mouth, resulting in the reaction of iron residues in the mouth with sulfur elements in the food in the mouth, forming black insoluble ferrous sulfide deposits; so children with iron supplementation (usually iron is taken after meals) should drink some water and rinse their mouth after taking the medicine to prevent their teeth from blackening. 2.If the lead load in children’s body is high, the elemental lead in the mouth and the elemental sulfur in food will also form insoluble lead sulfide deposits, which are also black and difficult to scrape down even if the dentist uses professional tools. But when treated with lead repellent medication, even if no other measures are taken, teeth will become whiter day by day! Because the medication penetrates into the mouth and acts on the surface of the teeth to dissolve the black lead sulfide, it will also whiten the teeth. 3, there is also if the mercury load in children’s body is high, there will also be black teeth, because the mercury in saliva and the role of sulfur in food to form insoluble black precipitates, will also occur black teeth.