Personal Science Week - 240229 Dentistry
Oral health, plus more links
PS Week 220929 detailed my experience testing my oral microbiome with an easy microbiome test.
This week we’ll review some new information about dentistry, plus some links we think you’ll find useful.
Oral Microbiome
I’ve long been interested in the microbiome and its affect on health. Regular readers might remember a detailed review I wrote about an easy $170 microbiome test from Bristle Health. As with most direct-to-consumer diagnostics, whenever possible I like to test twice, both to confirm that the test is consistent and because you always learn more from trends than from a single snapshot in time. The microbiome changes a lot throughout the day, so it’s critical to pay attention to the time you test.
Here’s how much mine changed just from morning to evening
The main differences come from a shift in the relative abundance of Prevotella, a generally innocuous breed that grows better overnight when there’s less competition from microbes that need a little bit more air. See a more in-depth analysis at the Personal Science Guide to the Microbiome, or view my raw data.
Bristle has expanded their business to sales of $50/month probiotic supplements (which I won’t evaluate since my oral microbiome seems generally fine). But those probiotics are nothing compared to a new one from Lantern Bioworks, a biotech startup hoping to make an oral microbiome treatment that mutates your microbes so they generate alcohol instead of enamel-decaying lactate. Scott Alexander looked into it but ultimately decided not to try it, yet. I don’t blame him: unless you have a serious problem with cavities, do you really want to mess with your oral microbes in a potentially irreversible way?
Bristle Health’s David Lin explains why these claims border on fraudulent:
S mutans creates incipient lesions by making acid, incipient lesions are micro environments where the low pH that causes enamel decay is determined by the biofilm on its surface. S mutans cannot thrive in environments with neutral or high pH. the existing community (including other Streptococcus species) create local alkaline environment via multiple metabolic pathways, including the most well studied and prevalent arginine deiminase system. A “normal” healthy community antagonizes S mutans by maintaining a normal pH in saliva and the tooth surface, preventing stable colonization by S mutans.
Without acid production, S mutans cannot stably colonize. and is readily outcompeted by the existing community. Any novel strains of S mutans to “compete for the same niche” will suffer the same weakness unless they create acid. but if this “probiotic” also creates acid, then by definition it also causes cavities.
Read the 2018 academic paper that explains the process in more detail. You can supposedly make your own mutant bacteria with this recipe. This might be a great project for one of the many DIY bio labs around the country (like SoundBio from Seattle). Let us know if you try!
Dentists
Substack writer Matt Yglesias summaries all the reasons modern American dentistry is bad:
The lack of standardization of care and cost are major issues. In this way, dentistry is decades behind conventional medicine. Also, unlike normal preventative medicine, it seems that the need for dental care varies a lot between individuals. Some people will have high expenses early, but most will not.
He quotes a 2019 Atlantic article that surveys the many “creative diagnoses” that too many dentists seem to provide, to earn more money for themselves of course but also because so little of the dentistry profession has undergone the rigorous study it would take to decide if the treatment actually works.
The Cochrane Organization has reviewed dozens of treatments, the majority of which turn out to be backed by little supporting evidence. Fluoride toothpaste and sealants are a clear yes, antibiotics seem to reduce implant failures, but most of the rest are meh. No proof of effectiveness for halitosis treatments, laser treatments for cavities, or for any of those COVID-related mitigations your dentist charged you extra for to keep you safe.
Fluoridated water always seemed to me like a bad idea. The US is one of only a few countries that does it, and although it does seem to reduce incidence of tooth decay, nobody can explain why dumping it on everyone is preferable to simply giving drops to people at risk. (I personally know people who traced their gut issues to fluoridated water).
But then X user @cremieuxrecueil surveys the latest evidence and dismisses broader fears about, say, lower IQs from fluoridated water. Here’s the takeaway chart, based on a large study in Sweden:
I’m still skeptical. A key observation of personal science is there are always outliers, and these general studies are irrelevant if you are the outlier. Why change the drinking water for everyone, old and young? Even if you could convince me that added fluoride has no affect on intelligence in anybody at all, how are you so sure it doesn’t affect something else that we don’t even track yet?
Links worth your time
BookPecker.com ran an AI summarizer on 15,000 popular non-fiction books to give you a clear 5-point summary of each one. It’s totally free: they make their money from Amazon commissions.
Here’s what it says about James Nestor’s Breath:
1. Nasal Breathing: Nestor highlights the health benefits of nasal breathing, including air filtration and nitric oxide production.
2. Over and Under-breathing: The book warns about the dangers of hyperventilation and hypoventilation, both of which can harm the body.
3. Breathing and Stress: Nestor links breathing patterns to stress levels, explaining how slow, deep breaths can reduce stress.
4. Breathing Techniques: The book presents various breathing methods, like the Buteyko and Wim Hof techniques, which can boost health and performance.
5. Evolution and Breathing: Nestor discusses how evolution has impacted our breathing, suggesting that lifestyle changes have made breathing more difficult. He advocates for healthier breathing habits.
10 technologies that won't exist in 5 years: a summary of some medical innovations that are achievable but unlikely to make it to market.
(Also see the footnotes for more details)
The COVID pandemic brought a new wave of people who helped with crowd-sourced symptom tracking, which many of us found useful as an up-to-date source of information about outbreaks. Good personal scientists continue to post information to these sites, even when we’re not feeling any symptoms. Boston Children’s Hospital and Harvard Medical School sponsor my favorite of these sites, OutbreaksNearMe, They send me an email each Monday to ask about symptoms. It takes me less than 30 seconds and I get a real-time rough look at how others in my neighborhood are faring. Of the 7M+ people in their database, here’s how the country looks this week:
If you’re not already contributing to OutbreaksNearMe, please join!
Finally, we’ve released our first version of the Personal Science Guide to AI, which joins our Personal Science Guide to the Microbiome as my attempt to write everything I know about a subject. These are rough drafts, updated regularly as we learn more. Check them out and let us know what you think.
About Personal Science
Listen to experts, but be skeptical. That’s the idea behind Personal Science, where we use the techniques of science to understand and solve personal questions. Paid subscribers can access our series on Unpopular Science, including this week’s summary of the track records of COVID-19 experts.
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