Better to visit a dentist near you for proper clinical diagnosis, because it might be a small cavity or it might be a food particle on the tooth.

Hi Seems to be a mild problem with molars. I mean wearing of enamel layer is occurring and there is lots of debris or deposits  (calculus) accumulated near the lower anterior teeth  (lingual side) which can lead to weakening of the lower front teeth. Q. Is there any sensitivity while having cold food items like ice cream?

Better to visit your dentist who would use a probe to check if there is a catch which means initial stage of a cavity which would require a filling to avoid further decay and spread of decay