Why do people brush their teeth first thing in the morning?

Because that is better for your teeth. Talk to your dentist about it. https://www.healthline.com/health/should-you-brush-your-teeth-before-or-after-breakfast
- This website is wack:
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  I wasn't expecting the website to outright refuse me from accessing it after refusing to be tracked, and with such bullshit lingo too
  
  Not sure about this particular site, but in my experience with sites that don’t have full time web developers on staff and only get a small percentage of their traffic from the UK/EU/EEA, complying is simply cost prohibitive since it will require a significant development budget without much payback, so by law, they are forced to block access to their site in affected countries.
  
  You're not wrong. I'm on my phone but if you can, please provide another source. Tbh I've just got the cookie modal blocked with ublock and the cookies autodelete
- I talked to my dentist about this, actually.
  His conclusion was: preferably brush after breakfast, yes it's ideal to wait For 30-60 mins but that rarely happens so just do it when you can after it's not that big a deal
  I'm summarizing, of course. But that was the gist of it
  
  My dentist says that if that 30 min isn't there, it's better to do it before. Probably it comes down to any tooth brushing is better than none
- I find minty toothpaste makes it a lot more difficult to eat afterwards. My grandad used to work in Egypt and he'd bring the orange toothpaste home and it was much easier to wake up, brush then eat using that stuff.
- The article doesn’t back up your statement.
  What it does say is that:
  brushing teeth regularly is important
  brushing teeth when enamel is weakened by acidity is destructive
  breakfasts foods tend to be acidic (well, acidity raises after a meal in general)
  And with this it reaches the conclusion that brushing your teeth before breakfast is safer than brushing right afterwards, and is more likely to become a routine than if you wait 30-60 minutes after your first meal. It even ends up with:
  Brushing in the morning, whenever you’re able to do it, is still better than skipping brushing your teeth at all.
  And if you’re from a country where visiting a dentist is affordable, you have probably heard an additional advice - visit a dentist for a checkup and a professional cleaning at least twice a year.
  
  brushing teeth when enamel is weakened by acidity is destructive
  breakfasts foods tend to be acidic (well, acidity raises after a meal in general)
  And with this it reaches the conclusion that brushing your teeth before breakfast is safer than brushing right afterwards
  This is what my point is. What are you arguing?

For me it's because my mouth tastes terrible and I want that gone asap
- Yeah morning breath is fucking rank.
  I want that gone before I go to work. I have breakfast at work at like 9am after starting at 7am. I aint waiting 2.5 hours to brush them bad boys.
- I hate the taste of coffee with toothpaste residue in my mouth, so I never brush before breakfast.
  
  I use Therabreath toothpaste. It doesn’t have that crap mint taste and doesn’t have the chemicals that makes food (especially orange juice) taste like crap. Also it really works to keep your breath nice without that fake disgusting flavor.
  Edit: there is a mint flair but it’s really undertoned
  Note. I just use it and like it. No financial incentive.
  
  Brush, shower, get ready, breakfast
- For me, just drinking some water gets rid of that.
- That might be the reason why my breakfast is coffee&cigarettes
  
  That makes it worse!
  
  Please brush your teeth before drinking your morning coffees
- Wouldnt your breakfast over power the taste?
  
  Maybe, but I'd have to wait foe breakfast and I want the taste out of my mouth immediately

I don't eat breakfast.
- I'm in (hopefully the same boat) with toothbrushing for breakfast. If I eat in the morning I feel terrible.

Healthier on the enamel, tho I don't do it (and most of the reason you brush is to get off the built up stuff from overnight, not clean off breakfast)
- But what about the rests of food from the breakfast???
  
  You save it in the secret food stash for energy boost
  
  Wait 30 mins and brush then

Because acid in your breakfast can damage your the enamel of your teeth when you brush. (I'm not a dentist but that's what I found from most health-related websites.)
https://www.healthline.com/health/should-you-brush-your-teeth-before-or-after-breakfast
- Who the fuck eats acid for breakfast?
  
  Orange juice is a pretty common breakfast drink.
  Or did you mean acid of the lysergic variety? That won't damage your teeth, though you'll have an interesting work day
  
  Food is generally acidic, basic food would taste bitter and awful.
  
  that Hunter S. Thompson guy i guess.. most of his friends..
- I've seen articles and dentist recommendations both ways. But the consensus seems to lean towards after. You want the fluoride to sit on the teeth and get absorbed as much as possible. This should provide a larger benefit than the damage of brushing when your teeth are, and not brushing means just leaving that gunk on the teeth even longer to mess them up more. But yeah, I guess you aren't supposed to wash your mouth out after brushing or mouthwash, and avoid eating/drinking for about 30 minutes. Just try and spit it out as best you can, that's how I've done it for years, takes a little getting used to but isn't something I notice anymore.
  
  Afaik, brushing your teeth doesn’t weaken the enamel or anything like that, or at least it shouldn’t. When brushing it’s not actually the bristles that are supposed to be doing most of the work, it’s the toothpaste which acts as polishing paste (it has tiny little micro abrasive particles or something like that). So if a dentist ever asks you what kind of toothbrush you use, soft, medium, or hard bristles, if you answer anything other than soft they’re probably going to recommend switching to soft bristles. Medium and hard bristles can damage the gums and with hard enough brushing overtime can be macro-abrasive and wear away your teeth. Better to use soft bristles and let the toothpaste do the polishing work.
  Source: dentists told me so, lol
- Just a heads up that Healthline, although it largely provides accurate information, is also known to pedal a lot of quackery.
  https://mediabiasfactcheck.com/healthline/

If you smell your breath first thing in the morning it stinks. This is a sign of bacterial overgrowth. During the day, the biggest barrier to this is natural saliva production and agitation through movement of the mouth. These things are drastically reduced while you sleep and thus leads to a build up of bacteria. This is why it is advised that you brush your teeth after waking.
Technically, it is also advised that you brush your teeth after each meal but that is not practical for most.

Not a dentist, but the reason dentists gave me for doing it in that order is that bacteria and plaque build up a lot while you sleep, since your teeth are just kind of sitting there doing nothing. So I guess waiting until after breakfast is just an unnecessary delay.

The health related reasons others gave are interesting, but my reasoning is this pretty simple: On normal weekdays I don't really have breakfast, so brushing my teeth as one if the first things makes sense. On weekends I like to have breakfast with my family so I'd like to get rid of morning breath before I talk to people.

huh, TIL brushing before is apparently better
I go 1, 3, 2 because it was easier for me to form the habit that way. I don't always have time for breakfast in the morning, so I anchor it to 1 instead of 2

Build up of bacteria at noght means that if you eat in the morning before brushing there will be more bacteria to break down the food into acid which will break down your teeth.
Ideal is to brush first but also brush after each meal*
*as long as the acidity in your mouth is 5.5pH or less your teeth are being broken down by the acid (which means that brushing would be scrubing them with acid and making it worse) in which case you should wait until your spit (which is a buffer solution) returns your pH to normal. Since most foods are acidic the recommendation is to wait 30i mnutes after eating and then brush. Or you can eat suger free gum right after a meal, this will trick your brain to produce more spit which will return the normal pH faster.
My personal system is like so:
Wake up
Use dental jet floss (water floss)
Brush teeth
After any foods eaten chew gum for 10-30 minutes Floss
Dental jet (if at home)
If I'm at home and have 30 minutes to wait between mouthwash and brushing then I use mouthwash, wait 30 min then brush, if not then just brushing and if I'm not at home then just mouthwash.
Repeat for as many things as I eat that day.
Before bed:
Floss
Dental jet
Mouthwash
Wait 30 min
Brush

you know how your teeth feel smooth after you brush? that smoothness helps things like coffee not stick to them, in turn helps avoid stains
brushing before coffee is legit the thing to do
- @SuperRecording I've always been told the opposite. As long as you brush soon after you actually prevent stains. And to always make sure to at least rinse with water after coffee.
  @zephyr
  
  Brushing immediately after anything acidic,like coffee, is highly damaging to the enamel of your teeth.

Also, I get toothpaste stains on my good clothes if I brush after breakfast

Because you have to wait 30 minutes after eating before you brush your teeth or you damage them. I don't have that time.
So I rather brush first, then shower, then make breakfast.

Having to wear a removable retainer at night means I wake up with congealed spit stuck to my gums and teeth. The visceral ick of swallowing that is indescribable, so I will brush my teeth first thing, then eat breakfast.

For me it's a habit formed as a young boy because my uncle taught me that while I'm asleep Satan shits in my mouth and if you eat before brushing your teeth you're eating Satan shit. True story.
I dunno, if I gag while brushing and I've recently eaten, I'll throw up. Also I don't usually eat for several hours after waking up, it's coffee then late lunch then dinner, so waiting to brush doesn't make a lot of sense.
- So what else did your Uncle "teach" you?
  
  Why is teach in quotes?

- I do the same.

Cuz my mouth and throat feel disgusting in the morning. Eating or drinking right after brushing doesn't bother me either.
- Interesting, it's kind of the other way around for me! I wake up ready for food. After brushing, my taste buds are knocked off by the toothpaste and I loose all apetite.

Because it's gross and if I eat all that nasty shit gets rubbed off onto my food. I also don't eat breakfast right away so there's time for the toothpaste taste to wear off before I eat.

I don't usually eat breakfast and I try to be vigilant about brushing my teeth, so doing it first thing is pretty natural for me.
My dilemma is usually closer to whether I brush my teeth before or after taking a shower.
- During
  
  Shower Brushers mater race
- I brush before the shower, as usually my wife is in the shower then. She brushes after her shower, when I'm in there. BTW we both do that after breakfast.
  Brushing before breakfast can be done against the morning smell, but when you brushed before going to bad, there shouldn't be anything on or between your teeth.

The fluoride in toothpaste creates fluorapatite in your teeth which is harder than your regular enamel and more resistant to acids.

You should wait about 30min after eating something acidic: https://www.cuimc.columbia.edu/news/brushing-immediately-after-meals-you-may-want-wait . Some people don't have time to wait. Myself I don't eat breakfast at home, I brush my teeth, go to work and eat when I arrive.

Coffee, weed, take a dump, breakfast, brush my teeth take my vitamins etc, rub one out, shower.

I wear a night guard for tooth grinding and I take a sublingual sleeping pill every night, so my mouth feels kind of mulchy after I get up. Also I get first shower and I best hustle through getting ready or my husband will be in there shitting for thirty minutes and I'll be late for work.

I brush teeth right when I wake up. There's a dogwalk before breakfast.

I’ve read that brushing your teeth actually helps protect your teeth from food and sugars you consume throughout the day. So eating beforehand bypasses that protection (unless you ask brush at night, which I imagine would be good enohgh).
- my toothpaste says 24h protection so if brushing once a day isn't good enough I'll be suing someone for my dentures.