The gap on the surface of the big tooth which is also known as the sulcus is black does not necessarily need to be filled, you can let the doctor conduct a systematic oral examination and probe the black area with a special oral probe. If the black area has formed a cavity and can hook the probe, it needs to be filled in time to avoid further aggravation of the caries, which will affect the pulp and lead to pulpitis. If no obvious cavity is found through the probing, it can be temporarily not to carry out filling treatment, the patient must brush the sulcus point gap carefully after returning home, and if necessary, preventive filling can be carried out, for example, if the patient has more caries in the mouth itself, preventive filling can be carried out for this kind of cavity not formed. It is recommended that the general public should visit the stomatology department once every six months to a year to check whether there is any caries or periodontal lesion in the mouth.