Regular brushing removes the soft layer of plaque but does not remove the hard deposits called as calculus. They need to be removed professionally by a dentist through a procedure called as scaling. Although you might be brushing twice daily but if your technique is faulty, gum inflammation will not be eliminated completely. Your dentist can explain a proper brushing technique which you can follow to maintain oral hygiene after the session of scaling. Don't forget to clean your tongue also using your toothbrush after every time you brush. Regards.