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from the articles-to-sink-your-teeth-into dept.
New artificial enamel is harder and more durable than the real thing
Enamel enables teeth to take a stomping and keep on chomping. The hardest tissue in the human body is tough enough to resist dents, yet elastic enough not to crack during decades of jaw smashing. It's so incredible that scientists haven't created a substitute that can match it—until now. Researchers say they have designed an artificial enamel that's even tougher and more durable than the real thing.
"This is a clear leap forward," says Alvaro Mata, a biomedical engineer at the University of Nottingham who was not involved with the study. The advance, he says, could have uses beyond repairing teeth. "From creating body armor to strengthening or hardening surfaces for floors or cars, there could be many, many applications."
[...] In the new study, scientists tried to mimic nature's enamel assembly. Instead of peptides and other biological tools, they used extreme temperatures to coax the wires into an orderly formation. As with earlier construction of artificial enamels, the team built its new material from wires of hydroxyapatite—the same mineral that makes up real enamel. But unlike in most other synthetic enamels, the researchers encased the wires in a malleable metal-based coating.
This coating on the crystalline wires is the secret ingredient that makes this artificial enamel so resilient, says study co-author Nicholas Kotov, a chemical engineer at the University of Michigan, Ann Arbor. The coating makes the wires less likely to snap, because the soft material around them can absorb any powerful pressure or shock. Although the wires in natural enamel feature a magnesium-rich coating, the researchers upgraded to zirconium oxide, which is extremely strong and still nontoxic, Kotov says. The result was a chunk of enamellike material that could be cut into shapes with a diamond-bladed saw.
Also at Scientific American.
Journal Reference:
Hewei Zhao, et. al.,Multiscale engineered artificial tooth enamel, Science (DOI: https://www.science.org/doi/10.1126/science.abj3343)
(Score: 3, Interesting) by ChrisMaple on Tuesday February 08 2022, @01:48AM (11 children)
Given a good diet, proper care, and a long night without eating, the body rebuilds teeth every day. Good tooth enamel won't last a lifetime if it isn't regenerated frequently.
(Score: 0) by Anonymous Coward on Tuesday February 08 2022, @02:02AM (1 child)
Aside from finally being able to make teeth tough enough to bite other teeth, I'd be surprised if anybody bothers to put this in people's mouths. For one thing, it's going to take a lot of work to prove that it's safe to be put into people's mouths and for another harder teeth aren't necessarily better for the mouth, the rest of the tissues assume that the teeth are only a certain hardness, having harder teeth could lead to unforeseen consequences like extra strain on the rest of the mouth as tougher foods are eaten.
That being said, this won't result in the need for full tooth replacements, so it's probably going to find applications outside of the mouth if they can make this reliabley.
(Score: 3, Interesting) by driverless on Tuesday February 08 2022, @02:07PM
Thing is, you don't want to have something that's tough enough to bite other teeth, because anything tough enough to do that will also shatter other teeth. The reason why most dentists will install gold crowns rather than ceramic/porcelain crowns, or stuff like lithium disilicate or zirconia (which, incidentally, are also as hard as this new artificial enamel) is that gold is soft enough that it won't damage the other teeth it grinds/impacts against. In the case of wear or damage you want the crown to lose, not the other tooth.
(Score: 2) by optotronic on Tuesday February 08 2022, @02:39AM (3 children)
Do you have a source for that? My understanding, and quick checks, suggest enamel does not grow back. Yellowing teeth, a symptom of aging, is the yellow dentin showing through the thinning enamel.
(Score: 3, Interesting) by coolgopher on Tuesday February 08 2022, @04:59AM
Yeah my dentist was pretty damn clear about the enamel I'd worn off from grinding my teeth in my sleep wasn't coming back.
(Score: 1, Interesting) by Anonymous Coward on Tuesday February 08 2022, @06:32AM
He's both right and wrong. Your saliva does remineralize your teeth when you're healthy enough, but that remineralization isn't fast enough to heal large amounts of damage. It'll only keep 'natural levels' of damage at bay so if you're consuming lots of acidic things, lots of cabs, hard things like seeds, etc... your enamel will get worse despite the remineralization. Think of it like sanding something with 800 grit sandpaper. You'll never smooth out a scratch but the scratch itself will be damn smooth.
Yellowing teeth isn't a sign of aging, it's a sign of food staining your teeth. It shows up in older people more because it takes awhile for it to build up to notable levels, but teeth left to themselves don't turn yellow. The dentin showing though thin enamel isn't the yellowing everyone thinks of when they think of yellow teeth. My enamel is almost gone because I used to eat a lot of lemons and citric acid based candy (Cry Babies). My teeth are more white than yellow and I've never used whiteners. Whiteners come in two main categories: abrasives or stains. Abrasives wear away the stained enamel and stains stain the enamel white. If the yellowing was due to the underlying dentin showing through, neither type would work.
The enamel itself doesn't grow back. What happens is your saliva slowly deposits more minerals to build up the outer layer. Technically that isn't the enamel growing. If you don't have the proper nutrients available or your mouth PH is off then this won't happen effectively. If you're constantly eating then your mouth PH will always be too far off.
(Score: 0) by Anonymous Coward on Tuesday February 08 2022, @02:29PM
Yes and no, the enamel constantly remineralizes if you've got the appropriate conditions to do so. A bit of minor damage or scratching probably will heal on its own, but there is definitely a point where it's gone and can't be regenerated by natural methods.
That being said, there's supposed to be a consistent flow of minerals going to the teeth and to the surface that allows for teeth to maintain their strength and health. But, if the materials aren't getting there or there's more damage going on than that can fix, you'll wind up with issues. And gum disease/jaw bone damage are what cause tooth loss typically. (When the tooth itself isn't knocked out)
(Score: 3, Interesting) by HiThere on Tuesday February 08 2022, @04:57AM (3 children)
I'm pretty sure you're wrong about that. There's stuff on the insides of teeth that keeps growing, but the enamel is the stuff on the outside, and it's isolated from the blood stream and other sources of repair.
If you've got a source, I'd really like to check it out, though I'll admit that they'd need a fair bit of evidence that supported the assertion before I'd take it seriously.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Tuesday February 08 2022, @02:31PM
The pulp and dentin in a tooth definitely do get replenished regularly over the course of the day and night. I'm not personally so sure about the enamel, but I'd wager that probably doesn't as it could potentially block the miles of tubes in a tooth that are used for replacing lost minerals. If you want to strengthen the enamel, the best way is from the outside. But, if we had more effective ways of replacing teeth, that wouldn't be particularly necessarry.
(Score: 0) by Anonymous Coward on Tuesday February 08 2022, @03:02PM (1 child)
The calcium, phosphate etc from saliva can help remineralize the enamel. https://en.wikipedia.org/wiki/Remineralisation_of_teeth#Natural_tooth_remineralization [wikipedia.org]
(Score: 1, Redundant) by HiThere on Wednesday February 09 2022, @04:03AM
IIUC, the remineralized surface is not nearly as rugged as the original enamel. It would be nice to be wrong, but I don't think I am. (And I don't trust wikipedia for medical advice. It often leaves out important details. E.g. too much fluoride causes the tooth surfaces to be brittle. The right amount is beneficial, but I don't think I'd trust wikipedia for what the right amount is. I'd rather trust the ADA or even Proctor & Gamble (i.e. Crest).)
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 1, Insightful) by Anonymous Coward on Tuesday February 08 2022, @09:14AM
It only ever needed to last about 10 or 20 years. After that, it's just a bonus.
Natural selection is a bitch that didn't prepare us to live 70+ years.