Hello Please go for cleaning of the teeth

That opinion we can give without a look at the clinical condition of the teeth is that because only one teeth is showing change of colour, it may be due to Cavitation which requires filling at the earliest. If the cavity is Deep and x-ray picture also supports it, root canal treatment might also be required. The best thing would be to consult the dentist as soon as possible so that the right diagnosis can be made at the earliest. Regards