Teeth with a black line may be pigmented tartar accumulation, at this time there is no need for fillings, general cleaning to remove can be. If the teeth for the hidden crack line or caries need to consider the decay filling. 1. Pigmented tartar accumulation. The black line on the teeth may be a long-term smoking or eating food containing pigment, exogenous substances deposited on the teeth, can be removed through periodontal scaling tartar and pigment on the teeth. 2. Hidden crack line or caries. The black line on the teeth may be teeth bite hard objects, resulting in cracks on the surface of the teeth, after examination, generally need to use instruments to prepare cavities for the surface of the hidden crack line repair. It may also be a black line caused by tooth decay, which can be filled with resin. If it has caused symptoms of pulpitis, root canal treatment is also required before filling. If there are black lines on the teeth that have damaged the dental tissues, it is usually examined to determine whether a filling should be considered, and it is recommended that you seek medical attention in a timely manner.