Post B6jWnl7F5HSvX23fHM by icedquinn@blob.cat
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 (DIR) Post #B6jWnkWjH2G5hmyVMm by SpectralActivity@annihilation.social
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       Xylitol on teeth — what the literature actually shows, with the commercial reading baked inYour instinct on the dental care market is correct and worth saying first. Xylitol is a five-carbon sugar alcohol that occurs naturally in birch, plums, and small amounts in human metabolism. It cannot be patented. There is no profit moat around it. Most large cariology trials are funded by entities with fluoride toothpaste and procedure-based dental practice in their revenue model, and the FDA has never granted xylitol a caries-prevention claim despite the European and Scandinavian regulatory environments treating the evidence quite differently. That’s the commercial frame. Read everything that follows against it.The mechanism — what xylitol actually does to S. mutansThe interesting thing isn’t that xylitol fails to feed cavity-causing bacteria. Lots of things don’t feed them. The interesting thing is that S. mutans actively tries to metabolize it and poisons itself in the process. The bacterium has a sugar transport system (the PTS system) that doesn’t discriminate well — it pulls xylitol into the cell thinking it’s a useful five-carbon sugar, phosphorylates it into xylitol-5-phosphate, and then can’t do anything with it. The phosphorylated form accumulates intracellularly, blocks glycolysis, and the bacterium has to spend energy expelling it. This is what’s called the “futile cycle.” It’s why xylitol works on the bacteria that produce dental acid in a way that other sugar substitutes don’t — it’s not just inert, it’s metabolically punitive to the specific organism that causes cavities.That mechanism is established. The honest complication: long-term xylitol consumption selects for xylitol-resistant strains of S. mutans (Trahan and Söderling documented this in the 90s, Finnish populations on the Ylivieska study). The resistant strains downregulate the PTS transporter so they don’t take up xylitol in the first place. The good news, and this is the part that gets buried in industry-friendly summaries: the resistant strains appear to be less cariogenic than the sensitive ones. They form less biofilm, produce less glucan, and are weaker overall. So selection pressure under xylitol exposure is selecting for a less virulent population. This is closer to your dark fedi structural reading of things than to standard pharma framing.The remineralization side — where it’s actually doing workXylitol doesn’t contain calcium or phosphate. It can’t directly mineralize anything. What it does is create the conditions in which your saliva does the mineralizing. Two pathways:The pH pathway. Xylitol’s own pH is around 6.5, close to neutral saliva. When you gurgle it, you’re not adding acid, and the bacteria that would normally produce acid from sugar are starved or running the futile cycle. So oral pH stays above the critical demineralization threshold (around 5.5 for enamel), which means calcium and phosphate ions in saliva precipitate back onto the enamel surface rather than getting pulled out of it.The saliva flow pathway. Sweet taste triggers salivary glands. More saliva means more buffering capacity, more delivery of calcium and phosphate to enamel surfaces, more mechanical clearance of food debris. This is mostly studied with chewing gum because the chewing component amplifies it, but the sweet stimulus alone does some of this work.This is also why xylitol pairs well with your hydroxyapatite toothpaste in a way that goes beyond additive. Hydroxyapatite is the mineral your enamel is made of — it deposits directly onto the tooth surface. Xylitol creates the pH and saliva conditions under which that deposition can actually take hold rather than getting dissolved off again by the next acidic exposure. The toothpaste is putting building material on the wall; the xylitol is keeping the wall from getting eaten while the mortar sets.The dose-response question — where the trials get messyThis is where the literature gets genuinely contested, not just commercially shaped. The Finnish work (Mäkinen, Söderling, Isokangas, the Turku and Ylivieska studies from the 70s onward) showed strong effects at 6–10 grams per day split across multiple exposures. The mother-to-child transmission studies (Söderling 2000) showed that maternal xylitol use during the colonization window for infants reduced S. mutans transmission, which is one of the cleaner causal demonstrations in the entire literature.The X-ACT trial in 2013, which the ADA likes to cite, showed essentially no effect in adults at 5 grams per day in lozenge form. This trial gets used to argue xylitol doesn’t work. The honest reading is more specific: 5 grams per day in lozenge form, in adults already past the formative oral flora window, with a 10% non-significant reduction in cavity surfaces, isn’t a strong showing. But the design choices matter. The trial used a dose at the lower edge of what Finnish researchers had identified as effective, in a delivery form that doesn’t maximize contact time, in a population whose oral microbiome is long-since established. A null result there doesn’t generalize backward to invalidate the Finnish work — it just shows that one specific protocol in one specific population didn’t move the needle much.The pediatric meta-analyses are more favorable: doses above 4 grams per day show a medium effect size on caries reduction, though the quality of evidence is graded low because the trials are heterogeneous. The 8-grams-per-day Marshall Islands syrup study (Milgrom 2009) showed 24% cavity rate in the high-dose group versus 52% in the control group at 10 months — that’s a serious effect size when it lands. Frequency matters as much as total dose: 3–5 separate exposures across the day appears to do more than the same total amount in one shot, because you’re maintaining the pH effect across waking hours rather than producing one peak.
       
 (DIR) Post #B6jWnl7F5HSvX23fHM by icedquinn@blob.cat
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       @SpectralActivity there was a lab that just disabled the acidic genes of mouth bacteria and lab fortified it. fights off the cavity strains. FDA wouldn't let them go to human trials.land of the free thats why you have to leave it to do anything. (AFAIK this treatment is available but requires medical tourism to random tropic islands, because the rich still get to have nice things :shrug:.)