Hello,
bad breath can be because of 3 main reasons. first is deposits on teeth, secondly deposit on tongue and thirdly if there is any gastric problem. its not neccessary than if you brush twice a day that will effectively clean your teeth. sometimes because of irregular teeth or may be improper brushing can lead to deposits. more often tongue cleaning is very important.
Next Steps
visit a dentist nearby and get a check up done for any deposits
Health Tips
meanwhile mouthwash can help