The time to brush baby’s teeth starts from the eruption of the first tooth, the first tooth eruption of infants is about 6-7 months, brushing also starts from this stage. Before the teeth erupt, it is also necessary to take care of the oral cavity. After each meal, it is necessary to wipe the oral cavity with water, and after the teeth erupt, you can use a finger toothbrush or gauze dipped in water to wipe the teeth to remove the plaque on the surface of the teeth. The milk and side dishes that infants eat contain sugar, and bacteria can break down the sugar into lactic acid, leading to tooth demineralization and caries. If you don’t brush your teeth in time, it will cause tooth decay, and if it is serious, it will cause tooth nerve inflammation, which is pulpitis, painful eating or night pain, and serious face swelling, so your baby should start to brush teeth when it is 6-7 months old.