Why dentists say you shouldn't rinse after brushing | Hacker News Reader

Why dentists say you shouldn't rinse after brushing

washingtonpost.com

44 pointsbookofjoe48 comments

There's a probiotic that aims to prevent cavities forever by replacing your mouth microbiome with harmless bacteria that outcompetes the harmful bacteria.

https://www.luminaprobiotic.com/

I'm temped to try it. But I'm waiting for others to review it first.

> The original patent holder shelved it because they were unwilling or financially unable to meet the FDA's testing requirements. So no human trials to confirm efficacy or side effects. (There was excellent efficacy and no short or long term side effects in rat studies.)

> There is no publicly available info about Lumina (street address, phone, financing, key personnel, facilities, etc.)

> Lumina is headquartered in Próspera, on the tourist island of Roatán in Honduras, South America. While the city is known for crypto, it is not known for the high tech pharmacological manufacturing and expertise that BCS3-L1 would require.

> Próspera is not subject to Honduran laws, taxes, (or FDA), because it was, for practical purposes, sold to billionaire Peter Theil and his investors . Because of a sketchy area of international law, Theil, et al, are able to sue (and are suing) Honduras for wanting to get out of the bad deal Honduras made with him. I.e., there could be resultant production issues for companies in Próspera. (Look up "ZEDE" and "Investor-State Dispute Settlement" if you're up for a major rabbit hole.)

Who or what are you quoting?

Someone else's info on the issue.

Or you can try gum/candy containing xylitol.

excerpts from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4232036/:

    The recommended dose for dental caries prevention is 6–10 g/d....

    Xylitol reduces the levels of mutans streptococci (MS) in plaque and saliva by disrupting their energy production processes, leading to futile energy cycle and cell death. It reduces the adhesion of these microorganisms to the teeth surface and also reduces their acid production potential.

    ...Thus, xylitol inhibits S. mutans growth essentially by starving the bacteria. Xylitol can inhibit the growth of harmful oral bacteria such as S. mutans, but its benefits do not stop in the oral cavity. Xylitol alcohol has been shown to impact growth of nasopharyngeal bacteria such as S. pneumonia and S. mitis, and hence has a role to play in nasopharyngeal pneumonia.

    Xylitol decreases the incidence of dental caries by increasing salivary flow and pH and reducing the number of cariogenic (MS) and periodontopathic (Helicobacter pylori) bacteria, plaque levels, xerostomia, gingival inflammation, and erosion of teeth.

    The predominant modality for xylitol delivery has been chewing gum. Chewing gum accelerates the processes of rinsing away acid and uptake of beneficial calcium phosphate molecules to remineralize tooth enamel. The recommended length of time for chewing after eating is approximately 20 minutes.

    Consumption of xylitol chewing gum for ≥3 weeks leads to both long-term and short-term reduction in salivary and plaque S. mutans levels. A decrease in caries incidence has been reported among children exposed to the daily use of xylitol for 12–40 months. The long-term benefits have been observed up to 5 years after cessation of xylitol use. A prospective controlled, double-blind clinical trial confirmed that MS levels in plaque decreased as exposure to xylitol increased. However, a plateau effect was observed between 6.88 g/d and 10.32 g/d. The caries preventive effect was observed to be long term in relation to the teeth erupting during the period of xylitol use.

I wouldn't trust this based on some online reviews. i would want to see clinical trails. Reviewers, if not straight up bought, will probably be very sensitive to placebo effects.

Why yes, sir, I'd love to insert some new genetically engineered species into my body that has never been tested on humans. That sounds like a brilliant idea. Just tell me how much money I should give you.

If I just eat an apple after my meal, my teeth retain a sqeaky clean feeling. Don’t know how replicable this is but I highly recommend trying it.

That's the acid from the apple wearing your enamel down. The "squeak" is from the increased friction on the surface of the teeth.

You can get the same feeling from a Coke.

Couldn't agree more.

But eat good apples—Envy, Braeburn, Pink Lady, or at least a Royal Gala. Toss the Red Deliciouses into the bin.

Interesting. I’m 44 years old and never had a cavity. Perhaps it’s a genetic thing, or my diet?

See https://www.astralcodexten.com/p/defying-cavity-lantern-biow... for a good discussion about it.

This post reads like a parody...

A lightweight "conflict of interest notice" brushing off the concerns and providing plausible deniability ("Well, I did tell you"),

the company unironically described as "mostly rationalists",

gems like "if you eat a normal Western diet, your mouth microbiome is already pretty far from the design specs, and it’s unclear if using Lumina makes things worse."

"So probably this isn’t a risk for some kind of weird pandemic"

Q: "If you wanted to get rid of it, could you? A: Some kind of extreme course of oral antibiotics that nukes everything growing in your mouth would probably eradicate BCS3-L1, but this hasn’t been tested and would have side effects".

This isn't new information from viral tik tok videos. I was taught not to rinse at school 30 years ago. Regardless, I do rinse. Preventing tooth decay is about not consuming sugar. Like obesity.

The tl;dr: If your toothpaste contains Flouride, it needs to stay on your teeth for 20-30 minutes in order to work properly. If you don't want to do that—or you don't have a toothpaste containing Flouride—you can followup the brushing with a Flouride-containing mouthwash, which you do not wash out.

This is what I do. I use a mouthwash with Flouride, and don't rinse my mouth for ~30 minutes after using it.

This reminds me of a change that my dentist's office made a few years ago: Apparently dental insurance (at least my plan) has added coverage for a Flouride treatment with every office visit, so they have me do a Flouride rinse—probably with a higher-concentration rinse—at the end of each visit.

I need to rinse after brushing to feel clean, so my solution has been to swish around a tiny dab of toothpaste in my mouth afterward and spit out the excess.

Floss, rinse thoroughly with water, brush with fluoride toothpaste (and do not rinse after).

Is the don't-rinse advice still needed in areas where water is fluoridated, since that's what I'm rinsing with?

My understanding is that fluoridation of municipal water supplies serves a different purpose than fluoride in toothpaste. The fluoride in the water supply is low concentration and is intended to cause teeth to develop with stronger cavity resistance, toothpaste is a much more superficial and immediate measure.

I used to rinse with mouthwash after brushing but was told the toothpaste has a much higher concentration, so it's better to leave the toothpaste.

You could also rinse the toothpaste from the brushing, and then you can apply additional toothpaste and swish it around some (and not rinse).

That may seem odd to do, but if the main reason you rinse is to wash away the junk that you loosened by brushing then it makes sense.

> I use a mouthwash with Flouride

Does anyone want to commit? Name a brand and why?

Most mouth wash seems to have fluoride and they don't say how much, but you also have a fluoride mouth rinse.

I just bought a fluoride mouth rinse that was Sodium Fluoride 0.2mg/mL (Equivalent to 220 PPM Fluoride ION) which matches this study - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3525928/ - "the weekly use of 0.2% sodium fluoride mouthwash program has been successful in elementary schools of Tabriz"

How much is in normal mouth wash?

There is no way I could avoid rinsing. That just leaves a feeling of being unclean.

I'm the same, so I just:

brush -> rinse -> brush again (with new toothpaste)

This way I get to rinse and naturally brush longer.

There are fluoride gels designed to apply after rinsing that you might consider. E.g., CTX4 [1]. There is an over-the-counter version and a prescription version, with the prescription version having a much higher fluoride level.

Many dentists sell the prescription version, often without the formality of a prescription as long as you are a patient of theirs. They are maybe 2 or 3 times as expensive as regular toothpaste, but in my experience a tube lasts way longer than a tube of regular toothpaste.

That's because when you are just using them to apply fluoride at the end rather than to clean you don't need very much. Just put a small amount on a toothbrush and rub it over all the teeth.

[1] https://www.drugs.com/pro/ctx4-gel-5000.html

It's the exact opposite though. Washing away the cleaning agent

Not rinsing also leaves all the food residue, germs (dead or alive) and debris that has collected in your mouth throughout the day. Not rinsing my mouth after brushing feels like showering and leaving the soap on.

Germs will be in your mouth whether you rinsed or not. The bacteria matter, those are the reason you don't want food there in the first place, and those are killed better by not rinsing.

Think of the paste more like something you need to apply and let sit, and less as some kind of fancy soap to wash the teeth with.

My dentist told me this in my last visit. It makes sense, but it's such a hard habit to break after decades of rinsing!

Why are teens getting so many cavities?

Some people are convinced that it's due to a lack of vitamin K2 in the western diet (not K1). I personally believe this too, at least as a contributing factor.

K2 is what pulls calcium from your blood into your bones (and teeth). It's mostly found in fermented foods (natto, kefir, cheese). Your body can make your own, but it's thought that it's not be enough to stop tooth decay and osteoporosis. It's my understanding that it's only been about 15 years since we have discovered that people might not be getting enough vitamin K2, so the science might not be settled yet, but there's evidence eg this [0] recent periodontitis study found that people with periodontitis had lower serum levels of vitamin K2.

Other vitamins and minerals that are often lacking that contribute are vitamins D and A, and magnesium. People often get insufficient amounts of vitamin D and magnesium in the modern day too.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10670967/

My teenage cavities stopped after 1) eating less sugar, and 2) switching to a non-fluoride toothpaste. Now that I'm in my 30s, I have had no cavity issues thus far, but I do have a lot of chipped teeth. I should try fluoride toothpaste again, in order to see 1) if it was the lack of sugar that reduced my cavities, and 2) potentially strengthen my teeth.

Have you tried hydroxyapatite? Just curious. (The chemical name is hydroxyLapatite, but it's usually spelled without the L in toothpastes. There's a heated debate about this on the wikipedia talk page.)

I can't say for sure. The first non-fluoride toothpaste, and the one I used for the longest amount of time, was Coral White brand[0]. Hydroxy(l)apatite is not listed as an ingredient, but I also found that it has been derived from coral since at least 1974[1]. Best I can do is... maybe?

[0] https://coraltoothpaste.com/products/coral-white-mint-toothp...

[1] https://www.nature.com/articles/247220a0

It was the sugar, not removing fluoride.

Toothpaste is a fantastic and cheap abrasive that makes short work of cleaning up hard metals. I don’t want that stuff anywhere near my teeth.

Vibes > clinical trials

Clinical trials of toothpaste va other methods are welcome. Can’t find any. I do have anecdata, which is that I go to the dentist every year and no caries for the past 15 years.

“Toothpaste is a strong abrasive” is fact, not vibes.

https://www.batemandentistry.com/blog/posts/what-about-all-t...

Why are teens eating so much sugar?

Why are corn subsidies so high?

"Dentists advise eating trace amounts of toothpaste every day".

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