It's because of deposits in between ur teeths which are unable to be removed by brushing .these deposit are removed by ultrasonic scalers .All toothpaste work the same it's the way u brush n using a soft or medium bristled brush would do the trick .
bad breath has many reasons. you probably need to get your teeth cleaned professionally once with a dentist. only using toothpaste of any brand or mouthwash won't solve the problem. Also drinking more water daily will help.