It looks like early caries. You should try getting it cleaned first at your dentist. If it does not go away, then you will have to get a filling done.

This might be the caries or any particle stuck there,go for scaling first ,if not gone then filling has to be done.

It is initial stage of caries Prior to its occurrence there may be very mild discoloration which can't be noticed with our eyes

Get a round of scaling done.... It looks like a good particle. If it still doesn't go off...u may need a filling

It's initiation of dental caries. You need a simple tooth color filling.

hi.. cavity can start at any point of time. But sometimes it can be just discoloration. you should visit to any near by dentist just for a check up i

Get evaluated by dentist,  it needs excavation and then filling.

It maybe dental caries.

namaskaram, Dental caries is an infectious disease process that results in damage to the various layers of the tooth: the outer enamel, inner dentin of tooth. In susceptible tooth, bacteria convert sugars from your diet into acids that damage the tooth structure, resulting in cavities. Although the infective process can vary, this bacterially produced acid usually attacks the protected areas of teeth, meaning the microscopic pits and fissures and contact areas between the teeth where a toothbrush can't reach. As enamel breaks down, the process eventually penetrates into the underlying dentin, which contains much less mineral than the enamel. The process progresses faster in the softer dentin, where it mushrooms beneath the enamel thereby undermining it, causing cavity formation. Team Shambhala