Why “morning mouth”? Why not “afternoon mouth”?

Our golden rule for oral disease prevention and bad breath (halitosis) prevention: Brush and floss at bedtime, and no snacks afterwards.  The last thing that should touch your teeth at night is fluoride. The idea behind this is simple:  Bacteria are very hungry, let’s starve them.

Please consider:  Why does everyone have “morning mouth”, that is, bad breath,  after 8 hours of sleeping? Why not “afternoon mouth”, at 5 PM, after 8 hours of eating and drinking?

At bedtime,  your mouth, in a sense, goes to sleep as well, and the normal bacteria in your mouth grow undisturbed. A major factor is reduced saliva production, which normally “washes”  bacteria off oral surfaces; eating and drinking, to an extent, “scrub” as well. Note that reduced saliva at night is a normal part of the body’s daily rhythm (footnote 1), and can unfortunately be exacerbated by the side effects of many medications.

Thus, the bad breath of “morning mouth” is normal. However, it can be reduced significantly by good brushing and flossing.  Mouth bacteria happily double their numbers every 3 hours, so removing food debris,  their energy source,  can limit their growth considerably. This simple habit will markedly reduce your lifetime incidence of oral disease and make your partner happy as well.


1. “The biological significance of decreased saliva during sleep is unknown and it is unclear how the oral cavity compensates for this period of relative dryness. The amount of saliva produced is greatest during the waking hours of the day and diminishes dramatically during sleep and may represent another process in the human body that displays a circadian rhythmicity.” https://www.ncbi.nlm.nih.gov/pubmed/12531122

Tags: , , , , , , ,