In addition to racking up frequent flyer miles, some travelers may also experience bad breath, and possibly a condition known as "tooth squeeze," while flying the friendly skies.

Bad breath while traveling happens when the salivary glands slow down the production of saliva, which allows bacteria to grow inside the mouth and bad breath to develop. Many travelers alter their food intake while at the airport and on the plane, and then will ignore their oral care hygiene routine. "Many people increase their fast food and soda intake while traveling," says J. Nick Russo, DDS, FAGD, past president of the Academy of General Dentistry. "This leaves food particles in the mouth that produce a sulfur compound and cause bad breath."

On the other end of the spectrum, bad breath can also be associated with hunger or fasting, which is also a common habit of some frequent fliers. "Even if you have brushed your teeth, but have not eaten a meal all day, 'morning mouth' may reoccur later in the day," says Dr. Russo.

Another condition that may happen while traveling but is less common than bad breath is known as "tooth squeeze," or barodontalgia, which describes a toothache or dental pain resulting from any change in barometric pressure during flight. The pain may, or may not, become more severe as altitude is increased, but descent almost invariably brings relief. The toothache often disappears at the same altitude at which it was first observed on ascent.

"Common sources of this difficulty are abscesses, cavities or fillings," says Dr. Russo. He advises any holiday travelers who experience a toothache at high altitudes should see a dentist without delay for examination and treatment.