One reason most of us wake up with bad breath is that our mouths have been closed and sealed off from a fresh supply of oxygen. For the same reason, you may have bad breath if you haven't talked or eaten in a while. Low salivary flow is same like that in people with Xerostomia, or dry mouth that can also be a factor.

Sluggish saliva gives bacteria a chance to feed on peptides and proteins. One thing that can help prevent bad breath is acidic saliva, because the bacteria responsible for bad breath prefer alkaline saliva. So, while eating sweets is bad for your teeth, it might be good for bad breath because glucose makes saliva acidic.

Emergence of bad breath among infants
About 90% of bad breath comes from oral bacteria, but there are other causes. Tonsillitis and sinusitis are occasional culprits. On rare occasions, respiratory tract tumors can be a source. Just how often-gastrointestinal problems cause bad breath is up for question.

Some experts say that the thin, tube-like esophagus that carries food from the mouth to the stomach is normally collapsed. So smelly gas from a bad stomach couldn't escape. That doesn't preclude foul-smelling belches, however. Fetor hepaticus, or liver breath, is the term for bad breath peculiar to people with cirrhosis, a kind of liver disease. If bad breath persists, the culprit may be certain foods, tobacco, a sinus infection, or gum disease.

Conclusion
If one thinks that the problem may be a sinus infection, see a doctor. And if it's gum disease, a periodontist can help recommend a course of action. Diuretics, antihistamines, and some antidepressants can cause bad breath. If one takes these drugs, keep breath mints on hand.

Rinsing, flossing, and brushing your teeth, gums, inside cheeks, and hard palate can eliminate morning breath. One should use a soft-bristle toothbrush and fine, unwaxed floss. Infantile hypertrophic pyloric stenosis (IHPS) occurs when the muscle surrounding the outlet from the stomach becomes overgrown and obstructs the passage of food into the intestines.

The condition, which generally arises in the first three to five weeks of life, causes projectile vomiting. This can lead to dehydration, weight loss, and electrolyte imbalances that affect kidney function. In most cases, good professional oral care combined with a daily regimen of oral hygiene including interdentally cleaning, deep tongue cleaning and optional use of an efficacious mouth rinse, will lead to improvement.