Perhaps not everyone knows that ... for the ICD10, the tenth revision of the International Statistical Classification of Diseases, these are two of the items that describe health problems!
But without talking about diseases, why does dry mouth and/or throat bother us and can they be harmful?
Let's point out that both mouth and throat are humid environments.
The mucous membranes, the linings of the walls of the mouth, pharynx and tongue are subject to continuous friction: when we speak, chew, swallow, yawn, snort ... it is a continuous rubbing of the tongue, teeth, food often under the desiccant action of 'air.
"Did you brush your teeth? Keep your mouth shut, shut up when others speak, don't eat with your mouth open, blow your nose!" Do you remember grandma's advices? Who would have thought you would read them in an article on oral health? Yet they are basic principles of hygiene of the oral cavity and throat.
Blowing your nose ensures good nasal breathing. Thus the air that reaches the throat will be purified, humidified and brought to body temperature, in a word it will be suitable for the humidity of our throat and lungs. If the nose is blocked ? We breathe through the mouth! But the mouth, which also cares about its humidity, is not made to humidify the air like nose does. On the contrary, air that goes out and air that enters, or rather continuing to speak and breathing through the mouth, results in a drying effect.
Hence, keeping the mouth closed allows us to mitigate dryness a little, because we can aspirate from the upper part of the pharynx to the mouth air that has been humidified in the nose, while at the same time saliva is emitted into the oral cavity.
As well, the recommendation of pauses with closed mouth while we speak or sing, giving space to the interlocutors, to the music, to other performers, is the most practical, simple and immediate system to resume with a "hydrated" voice.
Why eating with an open mouth will dry your throat??
With our mouth open we chew badly, the spaces increase, the tongue is unable to form and adequately hydrate with saliva the bite, while the air, again, dries saliva if inhaled from the mouth ... not to mention the unpleasant effects of swallowed air in the stomach that… burps! And belching, coming from the stomach, always brings acid vapours, irritating the throat... which dries up.
So Grandma was saying so for our good? And the teeth? What does brushing your teeth has to do with a dry throat?? We are a planet for microbes. To the point that we describe with the word "microbiota" the sets of microbes that colonize parts of our body. There is a microbiota for the intestine, one for the skin, for the genital and urinary areas, for the nose/lungs and for…mouth and throat! Proper teeth cleaning, as well as promoting good chewing, salivation, and providing the tongue with healthy walls where it can move, ensures a good microbiota in our mouth and throat. The microbes will more easily balance each other, without letting prevail the pathogens, not only those that make us ill, but also those just irritants... those that lead to a sense of dryness. So let's brush our teeth well, but don't overdo it with oral and throat disinfectants, just as we wouldn't always wash our hands with alcohol and disinfectants.
Since we know how to use emollient creams for dry hands, we must remember to use suitable emollients, such as hedge mustard or mallow, for example, and avoid the constant use of overly irritating mouthwashes.