New evidence that teeth can fill their own cavities
A drug developed to combat Alzheimer’s Disease can trigger regeneration of tooth dentin.
- New research into the drug Tideglusib clarifies what it can do for damaged teeth.
- Tooth dentin can be regrown instead of needing to be replaced with man-made composite.
- Only particular cavities need apply.
Pretty much anyone can do a disturbingly accurate imitation of the sound of a dentists's drill at varying speeds as it prepares a tooth cavity for filling. It's not an experience most people savor, and it takes a special kind of person to choose to spend eight hours a day — except Wednesdays — inside other people's mouths.
A few years ago, researchers suggested that low doses of a small molecule glycogen synthase kinase (GSK-3) antagonist — in the form of anti-Alzheimer's drug Tideglusib — applied to a decayed area could stimulate the coronal pulp in a tooth to repair itself. Now scientists at King's College in London have expanded upon that research and found further evidence that Tideglusib may indeed provide a pathway toward self-healing teeth. The new research is published as a paper in the Journal of Dental Research.
Drilling may still be necessary, unfortunately, to clean decay from the affected area before treatment.
Three layers in a tooth
Image source: BruceBlaus Wikimedia
The are three elements to the structure of a tooth:
- The outer enamel — The hard outer mineralized layer that protects the tooth structure
- The dentin — Hard, calcified tissue protecting the structure's soft inner regio.
- The soft dental pulp — The inside of the tooth. It contains the tooth's nerve, blood vessels, and connective tissue.
When you get a cavity, the outer enamel has a hole in it. With that outer protection breached, infecting bacteria nestle in, causing decay that burrows ever-deeper into the tooth, causing damage to its inner layers. To repair it using traditional methods, a dentist cleans bacteria from out the inside of cavity before filling it with a cement composite that replaces the lost natural dentin.
Building new dentin
Image source: Quang Tri Nguyen/Unsplash
"In the last few years we showed that we can stimulate natural tooth repair by activating resident tooth stem cells. This approach is simple and cost effective. The latest results show further evidence of clinical viability and brings us another step closer to natural tooth repair." — lead author Paul Sharpe
Share and his colleagues were interested in understanding how large a damaged area could be repaired with Tideglusib, and where, and they hoped to analyze the composition of repaired dentin in comparison to naturally occurring dentin and/or bone.
The researchers confirmed that Tideglusib can cause the generation of sufficient replacement dentin to be of use. The paper asserts that the drug can "fully repair an area of dentin damage up to 10 times larger." More than enough to be of value.
Second, Sharpe and his team learned that Tideglusib works only on a particular kind of tooth material: the coronal pulp, that region of pulp extending to the crown of the tooth. They also learned that the drug must be applied only to the affected area to be effective, finding that untreated areas of pulp, notably the root pulp, are not adversely affected by treatment, a good thing.
Finally, analyzing repaired dentin using Raman microspectroscopy, the researchers determined that the generated dentin is chemically quite similar to natural dentin, being comprised of a similar ratios of carbonate and phosphate and mineral-to-matrix as natural dentin.
The next regeneration
One limiting factor in the use of Tideglusib, therefore, is that the coronal pulp must be exposed in a cavity in order to be treated. Nonetheless, the research stands as confirmation not only of this specific drug's talent for triggering dentin regeneration, but of something even bigger and more intriguing: That teeth have the ability to repair themselves.
There's a great deal of investigation these days into the possibilities of humans regenerating body parts much as other animals such as salamanders and axolotls do. How far all of this research will get remains an open question for now, but undoubtedly remains one of the most exciting areas of current medical research.
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Whether or not women think beards are sexy has to do with "moral disgust"
- A new study found that women perceive men with facial hair to be more attractive as well as physically and socially dominant.
- Women tend to associate more masculine faces with physical strength, social assertiveness, and formidability.
- Women who display higher levels of "moral disgust," or feelings of repugnance toward taboo behaviors, are more likely to prefer hairy faces.
Beards and perceptions of masculinity<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjU5OTg0MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NzkxMjM3N30.cH-GqNwP5GVqvstgJWAhBPn1B_lYpVEAI0I7iax7EQw/img.jpg?width=1245&coordinates=0%2C1900%2C0%2C849&height=700" id="caae6" class="rm-shortcode" data-rm-shortcode-id="cb0a355a4e8e1899789bc45f3f7aef56" data-rm-shortcode-name="rebelmouse-image" />
Photo Credit: Wikimedia<p>The study used 919 American (mostly white) women ages 18-70 who rated 30 pictures of men they were shown with various stages of facial hair growth. The photographs depicted men with faces that had been digitally altered to look more feminine or more masculine, with a beard and without a beard. The women rated the men according to perceived attractiveness for long-term and short-term relationships. The study found that the more facial hair the men had, the higher the men were rated on their attractiveness, particularly for their suitability for a long-term relationship.</p><p>Part of this might be attributed to facial masculinity — i.e. protruding brow ridge, wide cheekbones, thick jawline, and deeply set narrow eyes — which conveys information to a woman about a man's underlying health and formidability. Women tend to associate more masculine faces with physical strength and social assertiveness. It can also indicate a man with a superior immune response. The researchers suggested that their findings favoring bearded men could be due to the fact that facial hair enhances the masculine facial features on a man's face, like creating the illusion of a thicker jaw line. This could communicate direct benefits to women like resources and protection that would enhance survival among mothers and their infants. In other words, while a beard doesn't mean superior genetics in and of itself, it might be a primitive, ornamental way of saying, "Hey girl, I'm a testosterone-fueled lean, mean, pathogen fighting machine." <br></p><p>It could also be that a beard becomes its own destiny. The researchers in this study cite prior research that found that by growing a beard, men felt more masculine and had higher levels of serum testosterone, which was linked to a higher level of social dominance. They also tended to subscribe to more old-school beliefs about gender roles in their relationships with women as compared to men with clean-shaven faces.<span></span><br></p>
What does disgust have to do with beard preference?<p>Obviously, not all women dig beards. The researchers were particularly interested in what traits make a women prefer bearded men over clean-shaven faces. They looked into several factors including a woman's disgust levels on various concepts, her desire to become pregnant, and her exposure to facial hair in her personal life. </p><p>According to the study, women who were not into facial hair were turned-off by potential parasites or other critters they imagined could be in the hair or skin. Women ranking high on this "ectoparasite disgust" scale might have viewed beards as a sign of poor grooming habits. However, women who ranked higher in levels of "pathogen" did find the bearded men to be desirable, possibly because they perceived beards as a signal of good health and immune function. An intriguing discovery in the study was links to morality. Women who displayed higher levels of "moral disgust," or feelings of repugnance toward taboo behaviors, were more likely to prefer hairy faces. The authors opined that this could reflect a link between beardedness, politically conservative outlooks, and traditional views regarding performances of masculinity in heterosexual relationships.</p>
Additional findings<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjU5OTg1My9vcmlnaW4uZ2lmIiwiZXhwaXJlc19hdCI6MTYyNDI1NjUyOX0.P9B8WbmJR0q4nfzYZKbuNSA-2SAigVWJgrQE-_Gxlds/img.gif?width=980" id="49143" class="rm-shortcode" data-rm-shortcode-id="2ed3b1d6f20fc170bf2974646e565e8d" data-rm-shortcode-name="rebelmouse-image" />Giphy<p>The correlations that existed between married and single women's rating on the attractiveness of beards were not particularly clear, although the researchers noted that single and married women who wanted children tended to find beards more attractive than the women who didn't want children. They also found that women with bearded husbands found beards to be more attractive, which might indicate that social exposure to beards influences how desirable they are perceived of as being. Or it could be that men with wives who like beards grow beards.</p><p>It's important to note that culture plays a huge role in how attractive women perceive certain male characteristics as being. This study looked at a small, culturally specific group of American women, so no big, universal claims should be made about masculinity, facial hair, and male desirability to women. However, research like this is important in highlighting how human grooming decisions are driven by much more than fashion trends. Sociobiological, economic, and ecological factors all play a part in the way we choose to present ourselves.</p>
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