Hello sir..
the black patches are due to deposits (PLAQUE AD CALCULUS) and stains due to coffee,tea,pan ,smoking...eventhough you brush regularly only 90% of deposits gets cleaned by tooth brush and the remaining 10% will remains there and it gets harden and become tartar (Hard deposits) after some days.. these deposits has to be cleaned by dentists(scaling and polishing).....
sometimes that black patches on grooves of the teeth may be dental caries also that needs to be removed and filled rather than scaling....
complete clinical examination is necessary to rule out the cause of depposits and for proper treatment
Next Steps
kindly visit dentist for furthur clinical examination and management
Health Tips
scaling should be done every 6 months...