Why does my breath still smell after brushing and using mouth wash?

Sometimes diet: If your mouth and dentition is in good shape and well brushed and clean often times it's due to tonsils that have colonies of bacteria esp. If they are cryptic and covered with little holes to catch things in like food or other matter. Also what you eat often has a big effect as well. But dental implants and dentures can have a fetid smell as well and are hard to clean as well.