From the image, it appears to be a deep groove or natural fissure of the tooth.
Since it has been present for 4 months, with no pain and no visible change, it is likely a normal anatomical groove or a mild fissure stain rather than a progressing cavity.
If there is no sensitivity, food lodgement, or pain, it is usually not serious. However, a clinical examination can confirm whether it is only a stain or an early cavity that may need a small filling.
Answered2026-02-11 17:31:22
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