There are black gaps in the big teeth, consider the fossa staining or caries and other reasons. 1. Fossa staining: normal teeth fossa color is yellowish brown, normal fossa smooth, enamel intact, but after eating food with color, it will deepen the fossa color black gap, this does not need special treatment, through brushing can be cleaned. 2. Dental caries: poor oral hygiene, long-term retention of food debris in the fossa can not be cleaned up in a timely manner, to enhance the role of bacteria in the mouth, easy to destroy the enamel in the fossa, dental caries, black gaps, fossa rough, the need for timely fillings. Large teeth with black gaps, you need to consult a doctor in time, under the guidance of the doctor to check and deal with, to avoid delaying the condition.