To remove the black line on teeth, first of all, we need to judge the reason of black line on teeth, according to the reason of black line on teeth, choose the suitable method to achieve better effect. 1.If it is the black line caused by the attachment of calculus, tartar and pigment on the surface of teeth, ultrasonic scaling can be carried out, through the effect of ultrasonic high frequency vibration, the calculus, tartar and pigment on the surface of teeth can be cleaned up. If the patient is not suitable for ultrasonic scaling, the doctor needs to manually scaling to remove the black line on the teeth through professional techniques; 2, tooth decay, clinically, oral instruments can be used to remove the decayed tooth tissue at the black line, and then use composite resin-like materials for filling to restore the appearance and beauty of the teeth.