The American Dental Association confirms in research that the main source of bad breath comes from bacteria on the rear of the tongue surface.
The ADA, the largest professional association of Dentists in the U.S. lists bacteria on the rear of the tongue as the primary cause of bad breath. The metabolic processes of these bacteria create VSC’s (volatile sulfur compounds) which cause bad breath.
For more information, see “What Causes Bad Breath”.
or visit the ADA website