The two incisors become black inside in the middle, mainly by the two reasons of calculus becoming black and dental caries, need to take the corresponding oral cleaning and restoration treatment. I. Common causes 1. Blackening of calculus: the calculus is yellowish white at first, with the occurrence of staining and calcification, the calculus becomes black, which will lead to the black situation inside the middle of two incisors; 2. Dental caries: due to not cleaning the food residue in the gap between teeth in time after eating, which leads to local tooth decay and shows as blackening in the middle of incisors. Second, treatment method 1, calculus black: timely ultrasonic cleaning treatment can effectively eliminate calculus; 2, dental caries: timely treatment should be carried out, otherwise the scope of decay is easy to gradually expand, which will cause the incisors to fall out over time and lead to oral function damage. The damage degree is different, and the corresponding treatment method is also different. (1) General treatment: If the degree of caries is mild, first of all, you should keep your mouth and teeth clean to prevent the aggravation of caries. Use fluoride toothpaste for brushing and control the sugar intake to avoid the proliferation of pathogens in the teeth; (2) remineralization treatment: early caries can be treated by fluoride remineralization treatment to restore the hardness of teeth and stop the caries process; (3) sulcus closure: if sulcus has been formed but no cavity has been formed yet, sulcus closure treatment is needed; (4) surgical treatment: if cavity has been formed, surgical treatment is needed to restore the original shape of teeth. Treatment to restore the original shape of the tooth. Filling treatment can be used to remove the decayed tissues, clean and disinfect them, and then fill them with oral professional materials to the original shape of the teeth. If the depth of the decayed tissue is close to the pulp, endodontic treatment is needed first, such as root canal treatment after killing the nerve, and then filling treatment or crown making in combination with the damage degree of the incisor. No matter what the reason is, we should pay attention to keep the oral environment hygiene, pay attention to oral cleaning, and use dental floss to clean the gap between teeth to reduce the probability of calculus and prevent the recurrence of tooth decay.