Rationale behind brushing in morning

[Slobo]

Dear all,

There are many sources that claim that we should wait at least 30 minutes to brush after having a meal. The reason being that pH increases while we eat (and demineralization of enamel occurs), which makes our teeth "less hard", and it takes some time for the pH to stabilize.

On the other hand, many sources suggest that we should brush in morning. But also many sources state that our saliva is the most acidic in mornings. Moreover, I have performed some tests with pH strips on myself, and in fact my saliva is usually more acidic in morning that right after having a meal. It drops below 7.0 almost only in mornings.

So, why brushing in morning doesn't damage teeth given that saliva is acidic then? Also, do you know how low acidity of saliva of a healthy person drops during the night?

Thank you.

Best,

 

[Busybee]

I have no idea how acidic my saliva is on waking, but I always brush straight after getting up in the morning rather than after breakfast.

 

[Slobo]

I have no idea how acidic my saliva is on waking, but I always brush straight after getting up in the morning rather than after breakfast.

Thanks. I do exactly the same, and in addition I avoid brushing teeth for at least 40ish minutes after a meal (e.g., a dinner). But still, it would be good to know what is the difference (if any) of acidity caused by processes in mouth during night, and the processes occurring during/after meals.

 

[Busybee]

My reasoning is that if you remove any overnight plaque before eating then there is little there for a plaque acid attack from breakfast. I would still floss after eating, but you don't have to wait to do that. Also you get the max protection from fluoride etc.

 

[MattKW]

Saliva maintains a close balance of between 6.8 and 7.0 over a daily cycle in the absence of eating food. I've never heard of it changing more severely than this because the body works hard to maintain homeostasis.If you cleaned your teeth before bedtime, then there should be very little plaque growth overnight (no snacking!). So, the next intake of food at breakfast will result in plaque growth, metabolism, and hence pH drop. But if it's a normal meal and not acidic e.g. citrus fruits, then there is no need to wait 30mins before brushing Your oral pH has to drop to about 5.5 before you get softening of teeth. This is more associated with acidic foods and drinks like soft drinks, sports drinks, etc than everyday food. So, you brush the plaque off your teeth AFTER breakfast. there is no advantage doing it before breakfast.

 

[Busybee]

It works fine for me MattKW. I do drink fresh squeezed orange juice at breakfast.

 

[MattKW]

It works fine for me MattKW. I do drink fresh squeezed orange juice at breakfast.

Then you should rinse out with water and wait 30mins before brushing, giving time for the saliva to reminineralise your teeth.

 

[Slobo]

Thanks for your replies, and also thank you very much for the article. If you have more on this subject, I would appreciate if you share. I search for them when I have some question, but usually it is hard to find a right one.

Saliva maintains a close balance of between 6.8 and 7.0 over a daily cycle in the absence of eating food. I've never heard of it changing more severely than this because the body works hard to maintain homeostasis.

In mornings the pH of my UWS is low 6. :| Sometimes it takes several hours to bring it to ~7pH.

Your oral pH has to drop to about 5.5 before you get softening of teeth.

Oh, I never got exactly what happens when the teeth are softened. Does it mean that at 5.5 layers of teeth start dissolving and ‚‚disappearing'', or only means that it is easier to damage the surface by hard objects (e.g., tooth brush)?

 

[MattKW]

It is softened, therefore if you leave it alone for 30mins, the salivary minerals will allow rehardening. It's all a matter of moderation. If you just have the occasional acidic drink, like BusyBee's OJ in the morning, then you'll probably get insignificant erosion. Some people, esp tradespeople who might have a vending machine and do hot, thirsty work are the one who drink a lot and get severe erosion.

 

[Slobo]

It is softened, therefore if you leave it alone for 30mins, the salivary minerals will allow rehardening. It's all a matter of moderation. If you just have the occasional acidic drink, like BusyBee's OJ in the morning, then you'll probably get insignificant erosion. Some people, esp tradespeople who might have a vending machine and do hot, thirsty work are the one who drink a lot and get severe erosion.

Oh, I don't drink those drinks. The only acidic drink I have is coffee, almost exclusively in afternoons. Do you think I should report to a doctor that my UWS is at low 6 in mornings?

By the way, the reason why I asked whether lower pH dissolves layers of enamel or not is that many sources on the web say that stomach acid "wears away" tooth enamel. So, not sure how to understand that.

 

[MattKW]

I would be very wary of pH tests that you can buy from shops or online; there can be wide variation in accuracy.
Stomach acid becomes a problem if you have reflux, or bulimia and are then bringing up stomach acid. It develops a particular pattern of erosion on teeth that is easily diagnosed.

 

[Busybee]

i'm wondering how fast saliva neutralises acidic food. If saliva has a normal healthy PH surely it gives excellent protection pretty fast?

 

[Slobo]

I would be very wary of pH tests that you can buy from shops or online; there can be wide variation in accuracy.
Stomach acid becomes a problem if you have reflux, or bulimia and are then bringing up stomach acid. It develops a particular pattern of erosion on teeth that is easily diagnosed.

Thanks. I see now that information, for instance, at https://www.mouthhealthy.org/en/az-topics/e/tooth-erosion-and-acid-reflux. Out of curiosity, why the inside surface of teeth suffer more than the outside surface? Indeed, they are more exposed to products coming from stomach, but also more exposed to saliva which neutralizes acid.

 

[Slobo]

i'm wondering how fast saliva neutralises acidic food. If saliva has a normal healthy PH surely it gives excellent protection pretty fast?

From what I understood from many sources on the web, in a healthy person it takes around 30 minutes to stabilize pH level and having re-mineralization do its job. As I recall, some sources, but very few, mention the time of one hour. 30 minutes seems to be the rule of thumb.