Teeth serve as ‘archive of life,’ new research finds

Teeth constitute a permanent and faithful biological archive of the entirety of the individual’s life, from tooth formation to death, a team of researchers has found. Its work provides new evidence of the impact that events, such as reproduction and imprisonment, have on an organism.

“Our results make clear that the skeleton is not a static organ, but rather a dynamic one,” explains Paola Cerrito, a doctoral candidate in NYU’s Department of Anthropology and College of Dentistry and the lead author of the paper, which appears in the journal Scientific Reports.

The paper’s other authors include Shara Bailey, a professor in NYU’s Department of Anthropology, Bin Hu, an associate research scientist at NYU’s College of Dentistry, and Timothy Bromage, a professor at NYU’s College of Dentistry.

The research focused on cementum, the dental tissue that covers the tooth’s root. It begins to form annual layers — similar to a tree’s “rings” — from the time the tooth surfaces in the mouth.

“The discovery that intimate details of a person’s life are recorded in this little-studied tissue, promises to bring cementum straight into the center of many current debates concerning the evolution of human life history,” says Bromage.

The Scientific Reports study tested the hypothesis that physiologically impactful events — such as reproduction and menopause in females and incarceration and systemic illnesses in both males and females — leave permanent changes in the microstructure of cementum and that such changes can be accurately timed.

“The cementum’s microstructure, visible only through microscopic examination, can reveal the underlying organization of the fibers and particles that make up the material of this part of the tooth,” notes Cerrito, who obtained her bachelor’s degree at Sapienza University of Rome.

In their work, the scientists examined nearly 50 human teeth, aged 25 to 69, drawn from a skeletal collection with known medical history and lifestyle data, such as age, illnesses, and movement (e.g., from urban to rural environments). Much of this information was obtained from the subjects’ next of kin. They then used a series of imaging techniques that illuminated cementum bands, or rings, and linked each of these bands to different life stages, revealing connections between tooth formation and other occurrences.

“A tooth is not a static and dead portion of the skeleton,” observes Cerrito. “It continuously adjusts and responds to physiological processes.

“Just like tree rings, we can look at ‘tooth rings’: continuously growing layers of tissue on the dental root surface. These rings are a faithful archive of an individual’s physiological experiences and stressors from pregnancies and illnesses to incarcerations and menopause that all leave a distinctive permanent mark.”

New York University

Psychologists find smiling really can make people happier

Smiling really can make people feel happier, according to a new paper published in Psychological Bulletin.

Coauthored by researchers at the University of Tennessee, Knoxville and Texas A&M, the paper looked at nearly 50 years of data testing whether facial expressions can lead people to feel the emotions related to those expressions.

“Conventional wisdom tells us that we can feel a little happier if we simply smile. Or that we can get ourselves in a more serious mood if we scowl,” said Nicholas Coles, UT PhD student in social psychology and lead researcher on the paper. “But psychologists have actually disagreed about this idea for over 100 years.”

These disagreements became more pronounced in 2016, when 17 teams of researchers failed to replicate a well-known experiment demonstrating that the physical act of smiling can make people feel happier.

“Some studies have not found evidence that facial expressions can influence emotional feelings,” Coles said. “But we can’t focus on the results of any one study. Psychologists have been testing this idea since the early 1970s, so we wanted to look at all the evidence.”

Using a statistical technique called meta-analysis, Coles and his team combined data from 138 studies testing more than 11,000 participants from all around the world. According to the results of the meta-analysis, facial expressions have a small impact on feelings. For example, smiling makes people feel happier, scowling makes them feel angrier, and frowning makes them feel sadder.

“We don’t think that people can smile their way to happiness,” Coles said. “But these findings are exciting because they provide a clue about how the mind and the body interact to shape our conscious experience of emotion. We still have a lot to learn about these facial feedback effects, but this meta-analysis put us a little closer to understanding how emotions work.”

University of Tennessee at Knoxville

Can Smiling Really Make You Happier?

Before we get started, do me a favor and grab a pen or a pencil. Now hold it between your teeth, as if you were about to try to write with it. Don’t let your lips touch it. Sit with it, and pay attention to how you feel. Are you glum? Cheerful? Confused? Is that any different than how you felt before? Do you feel like this weird smile tricked your brain into a slight jump in happiness?

For a long time, psychologists thought exercises like this one did make us happier. If that were true, it would have implications for what emotion is, how we experience it and where emotions come from. Psychologists have believed that “facial feedback” from emotional expressions like smiling (or frowning) gives the brain information that heightens, or even sparks, an emotional experience.

It made so much sense that it was almost too good to check.

But then scientists did check. What they found poked holes in one of psychology’s textbook findings — which raised a whole new set of questions. Now, a huge group of scientists has banded together to try to get to the bottom of smiles, even if it means working with people who think they’re wrong.

The idea that smiling can make you feel happier has a long history. In 1872, Darwin mused about whether an emotion that was expressed would be felt more intensely than one that was repressed. Early psychologists were musing about it in the 1880s. More than a hundred studies have been published on the topic. And it’s a trope of pop wisdom: “Smile, though your heart is aching,” sang Nat King Cole in 1954. “You’ll find that life is still worthwhile, if you’ll just smile.”

In 1988, social psychologist Fritz Strack published a study that seemed to confirm that facial feedback was real. The researchers asked participants to do more or less what I asked you to do earlier: hold a pen in their mouths in a position that forced them either to bare their teeth in a facsimile of a smile or to purse their lips around the pen. To ensure that no one was clued in to the researchers’ interest in smiles, the experimenters told participants that they were exploring how people with physical disabilities might write or perform other ordinary tasks.

When both groups were shown a set of newspaper comics — specifically, illustrations from Gary Larson’s The Far Side — the teeth-barers rated the images as funnier than the lip-pursers did. This was a big deal for the facial feedback hypothesis: Even though participants weren’t thinking about smiling or their mood, just moving their face into a smile-like shape seemed to affect their emotions. And so the finding made its way into psychology textbooks and countless news headlines. Decades of corroboration followed, as researchers published other experiments that also showed support for the facial feedback hypothesis.

But in 2016, all at once, 17 labs failed to replicate the pen study.

hose 17 studies, coordinated by Dutch psychologist E.J. Wagenmakers, repeated the original study as closely as possible to see if its result held up, with just a few changes. They found a new set of cartoons and pre-tested them to check they were about as funny as the old set. They also changed how they checked up on the participants’ pen technique: The original had an experimenter watching over things, but Wagenmakers and his team filmed participants instead.

When all 17 studies failed to replicate the original result, the effect was “devastating for the emotion literature,” said Nicholas Coles, a psychology grad student whose research focuses on the facial feedback effect. “Almost all emotion theories suggest that facial feedback should influence emotions.” While there are plenty of other methods for looking at facial feedback, many of them are more likely to make participants figure out the real purpose of the experiment, which makes their results trickier to interpret. The pen study had been solid — until it wasn’t.

These kinds of failed attempts to replicate other researchers’ results have been piling up in psychology’s “replication crisis,” which has called the reliability of psychology’s back catalogue into question. Past experiments may be unreliable because they relied on small sample sizes, buried boring or inconclusive results, or used statistical practices that make chance findings look like meaningful signals in what is really random noise. The result has been a morass of uncertainty: Which findings will hold up? And when one doesn’t, what precisely does that mean?

Wagenmakers and his team are just one of the many collaborations hoping to reshape psychology in the image of more established sciences like physics and genetics, where huge international consortia are already commonplace. Some collaborations, like the “Many Labs” projects, conduct multi-lab replications similar to the attempt to confirm the pen study and cover a broad swath of famous psychology studies. Others — like the ManyBabies Consortium, which conducts infant research — concentrate on a niche.

Then there’s the Psychological Science Accelerator, which is more focused on creating the infrastructure for collaboration, allowing its members to democratically elect studies to be run across its network of 548 labs in 72 countries. A recent paper by a group of reforming researchers called this kind of crowdsourced science one of the routes to “scientific utopia.”

Across six multi-lab replication projects, each trying to replicate multiple studies, only 47 percent of the 190 original results were successfully replicated. The failed attempt to replicate the pen study is in good company.

But as powerful as multi-lab replication efforts like these are, they aren’t necessarily the last word. When psychology tries to solve its replication crisis, it can sometimes create a crisis of a different kind, opening up a knowledge vacuum where an apparently reliable finding had previously stood.

Fritz Strack, the lead researcher on the original pen-in-mouth study from 1988, doesn’t think that Wagenmakers’s study tells us all that much — the world is constantly changing, and re-running an old experiment could produce new results not because the idea being tested is flawed but because the experiment itself is now out of step with the times. Although he suggested the replication effort himself, and advised on the design and the materials of the study, he refused to be fully involved. Instead, he said, he wanted the freedom to comment on the problems as he saw them without pulling any punches.

When the results were released, Strack found plenty of things to critique. He was concerned that newspaper cartoons would not have packed the same humor punch these days that they did in the Midwest of the 1980s. The filming, he said, was another problem: It could be that filming made participants unusually self-conscious, affecting their experience of the task.

Strack thinks that it’s a mistake to focus on testing a method rather than a hypothesis. A method that fails might have been a bad test of the hypothesis, but the hypothesis is really what counts.

In this case, the hypothesis was that facial feedback can create an emotional effect even when people aren’t aware that their facial expression is an emotional one. Perhaps, Strack argued, his exact methods from the 1980s are no longer the best way to test that.

“Exact” replications are impossible, he said. “Things are changing — times are changing, the zeitgeist is changing, the culture is changing, the participants are changing. It’s not under your control.” What if you did the pen study with memes instead of cartoons? What if you didn’t use cameras? What would the differences tell us about facial feedback and when it comes into play?

Strack has been vocally critical of the credibility revolution, arguing that the term “replication crisis” is overblown. He says he prefers to focus on arguments about the quality of the research methods, rather than the statistical framework that is at the core of the credibility revolution’s concerns.

But similar critiques of massive replications come from inside the movement. Psychologist Tal Yarkoni, an ardent reformer, thinks that large-scale research efforts would do more good if they were used to test a huge array of different ways of getting at a question. A failed attempt to replicate a particular experiment doesn’t really tell you anything about the underlying theory, he said; all it tells you is that one particular design works or doesn’t work.

Wagenmakers doesn’t think his team’s replication is the final word on the facial feedback theory, either. “It’s a sign of good research that additional questions are raised,” he said. But he does think a failed replication like the one he led shifts the burden of proof. Now, he says, proponents of the facial feedback hypothesis should be the ones coming to the table with new evidence. Otherwise, “the replicating team will be like a dog playing fetch,” he said. “A person throws a ball and the [replication] team brings it back, but oh, it’s not quite right! I’m going to throw it in another direction. … It could go on forever. It’s clearly not a solution to the problem.”

Multi-lab studies can look large and impressive, said psychologist Charles Ebersole, who coordinated two Many Labs projects in grad school. Even so, it’s not clear how much confidence people should have in their results — the studies are big, which can improve confidence in their outcomes, but they’re subject to flaws and limitations just like smaller studies are. “Some people do an excellent job of not listening to [multi-lab studies] at all; maybe that’s the right answer? Some people bet a lot on them; maybe that’s the right answer? I don’t know.”

The way out of the replication crisis clearly isn’t brute replication alone.

When Wagenmakers and his colleagues published their replication study in 2016, Coles was digging deeply into the facial feedback literature. He planned to combine all of the existing literature into a giant analysis that could give a picture of the whole field. Was there really something promising going on with the facial feedback hypothesis? Or did the experiments that found a big fat zero cancel out the exciting findings? He was thrilled to be able to throw so much new data from 17 replication efforts into the pot.

He came up from his deep dive with intriguing findings: Overall, across hundreds of results, there was a small but reliable facial feedback effect. This left a new uncertainty hanging over the facial feedback hypothesis. Might there still be something going on — something that Wagenmakers’s replication attempt had missed?

Coles didn’t think that either Wagenmakers’s replication or his own study could put the matter to rest. The technique he used, called a meta-analysis, comes with its own problems. Specifically, if the studies thrown into the mix aren’t great to start with, the result isn’t particularly reliable — or, as Coles put it, “crap in, crap out.”

So he set about designing a different kind of multi-lab collaboration. He wanted not just to replicate the original study, but to test it in a new way. And he wanted to test it in a way that would convince both the skeptics and those who still stood by the original result. He started to pull together a large team of researchers that included Strack. He also asked Phoebe Ellsworth, a researcher who was testing the facial feedback effect as far back as the 1970s, to come on board as a critic.

This partnership founded in disagreement is meant to get the game of fetch out of the way before the study even gets off the ground. Coles’s group, called the Many Smiles Collaboration, is far from the only one using this tactic; although some massive collaborations try to replicate old studies as closely as possible, others choose to workshop a new experiment methodology in excruciating detail before pulling the trigger. Ideally, this means that everyone will be convinced by the results, regardless of what they were personally rooting for or expecting. “It isn’t groupthink,” said Coles. “We’re actually trying to get at the truth.”

The Many Smiles Collaboration is based on the pen study from 1988, but with considerable tweaking. Through a lengthy back-and-forth between collaborators, peer reviewers and the journal editor, the team has refined the original plan, eventually arriving at a method that everyone agrees is a good test of the hypothesis. If it finds no effect, said Strack, “that would be a strong argument that maybe the facial feedback hypothesis is not true.”

An early pilot of the Many Smiles study indicated that the hypothesis might not be on its last legs just yet: The results suggested that smiling can affect feelings of happiness. Later this year, all the collaborators will kick into gear to see if the pilot’s findings can be repeated across 21 labs in 19 countries. If they find the same results, will that be enough to convince even the skeptics that it’s not just a fluke?

Well … maybe. A study like Wagenmakers’s sounds, in principle, like enough to lay a scientific question to rest, but it wasn’t. A study like Coles’s sounds like it could be definitive too, but it probably won’t be. Even Big Science can’t make science simple. “I’m still a little unsure, even though I’ve now replicated the effects successfully in my own labs,” said Coles. “I’ll hold my breath until the full data set comes in.”

By: Cathleen O’Grady

The Benefits of Digital Orthodontics

The field of orthodontics has been keeping up with the exciting new medical advancements currently sweeping across the medical field; digital and computer technologies are a tool we frequently utilize here at Sunna Orthodontics in order to better serve our patients seeking braces, clear aligners or any other type of orthodontic care!

Specifically, digital imaging and advanced graphic interfaces are technologies that have proven to be incredibly helpful in diagnosing and treating orthodontic issues.
These technologies offer an abundance of benefits from both a patient and a professional perspective, helping to keep Sunna Orthodontics on the cutting edge of orthodontic care!

Improved Accuracy

New advancements in computerized imaging has greatly improved the ability of oral health professionals to diagnose and treat various conditions that occur within the teeth; these highly-detailed images are able to capture contours within the teeth that are traditionally difficult to view with detailed accuracy.
This improved accuracy has a trickle-down effect of sorts across other areas of orthodontic treatment; mis-diagnosis could soon become a thing of the past, and rare conditions can be spotted and immediately, allowing treatment to begin before the condition is allowed to worsen.

Greater Efficiency

Digital Orthodontics could very well make your next appointment at Sunna Orthodontics go by much quicker; computerized imaging is making the examination process exponentially faster, while also making other elements of oral health care (such as, again, diagnosis) go by much faster.
Offices will also now be able to see and treat more patients, and spend even more time on each individual case, putting most of the focus on treating problems rather than simply locating them.

Increased Patient Comfort

The great news is that there’s nothing invasive whatsoever about computerized image processing; no putty, and other types of bad-tasting contrast agents necessary! Patients can sit back and relax while the computerized images are taken, and then move on with their appointment.

More Customizable Care

Digital Orthodontic Technologies further allow oral health professionals to create even more-personalized plans for those with specific conditions; both doctors and patients can better track their treatment and stay even more organized!

Simply reading about the benefits of Digital Orthodontics is one thing, but experiencing it for yourself is another thing completely; if you’d like to experience the amazing benefits of Digital Orthodontic Technology first-hand, or continue learning about this incredible new technology, visit us online at, or call +962 6 593 6677 to schedule your next visit with Sunna Orthodontics!

A Basic Guide For Parents On How Braces Work

A Basic Guide For Parents On How Braces Work

During the process of getting braces, patients and parents often express tremendous curiosity about how braces work to straighten teeth. Many patients are also curious as to why some people’s brace have to stay on so long – occasionally, braces will stay on for 3 to 4 years! 

To answer some of the questions that parents may have, we’ve put together a basic guide for parents and patients regarding how braces work!

The process of installing braces begins when the orthodontist attaches a bracket to each tooth using a bonding product. Each bracket is designed especially for the needs and structure of its specific tooth. Then, the brackets are connected to each other using arch wire.

The process begins with very thin, round wire, which will be replaced repeatedly until thick, rectangular wire is in place. This is because repositioning teeth and their roots is best done at a gradual pace. Plus, starting your child with hard wires would cause him or her tremendous pain. Once the teeth are better positioned, a more flexible wire will be placed so that the orthodontist can fine-tune the alignment by bending the wires. For patients with under- or overbites, rubber bands may be used to move the jaw into a straighter bite position.

Throughout the orthodontic process, the pressure place on the periodontal membrane shifts. The bone structure of the tooth roots changes, which allows for the continued movement of each tooth. It can take up to a year for this bone remodeling process to be completed, and that is the main reason why many patients wear braces and/or retainers for so long.

Dr. Samer Sunna and the rest of the team at Sunna Orthodontics know that your child’s desire for straight teeth is delicately balanced against your concerns for their safety and comfort. We work hard to ensure that all of your questions and concerns are fully addressed before planning for your child’s braces! 

If you have questions or concerns regarding your child’s future or present braces (or questions or concerns regarding other orthodontic treatments) give us a call at +962 6 593 6677, or visit us online at!

Caring for Braces on Vacation

When on vacation, fun in the sun and down time with your family and friends can overshadow taking care of your braces. However, maintaining strong oral health practices is the key to a lifetime of healthy smiles!

The team at Sunna Orthodontics have put together a list of must-have items for those with braces when you’re on vacation:

  • Floss Picks, proxabrushes or other interdental cleaners
  • Toothbrush
  • Orthodontic wax to cover poking wires
  • Travel sized-toothpaste and mouthwash

Packing these items together in a handy oral health kit is a great way to stay on top of oral hygiene when out of town!

Eating out can also be a common occasion when you’re on vacation; to avoid wire distortion and broken brackets, try to avoid the following and similar foods:

  • Hard candies
  • Chewing gum
  • Pop corn
  • Corn on the cob
  • Nuts
  • Chewy and sticky foods

Follow these steps for a vacation free of oral health worries! As always, if you have any questions about these tips, or have any other oral health questions or concerns, don’t hesitate to call us at +962 6 593 6677 to speak to our knowledgeable staff, or visit us online at!

4 Tips for a Better Invisible Aligner Experience

For most adults who want straighter teeth, braces aren’t always the first choice of treatment. While some adult patients may specifically require them, many adults would prefer a more discreet, but still fully effective option for teeth straightening. Instead of braces, many adults turn to invisible aligners. The best part about invisible aligners is that at a conversational distance, friends and colleagues won’t be able to tell that you’re undergoing orthodontic treatment. The fact that aligners are removable make treatment results dependent on compliance. If patients don’t wear the aligners as instructed, then optimal results will not occur and teeth will not align properly. Under the supervision of Dr. Samer Sunna and his team, excellent aligner results can be achieved. Here is our team’s list of top tips for a better invisible aligner experience! 

  1. Remember to always wear you aligners except for when eating or drinking. This may sound like an easy task, but not wearing your aligners constantly can result in your teeth shifting back to their original position.
  2. Always store your aligners in their case. This will keep dirt and other small pieces of debris from finding their way onto your aligners, keeping them nice and clean.  
  3. Remove your aligners before exercise. For those who frequently exercise, be sure to remove your aligners before a workout. Leaving them in will result in extreme mouth dryness. 
  4. Brush after meals and snacks. Not only should you not eat and drink in your aligners, but it’s also a good idea to brush after snacks and meals. This will keep your aligners as clean as possible! 

Sunna Orthodontics is happy to say that we specialize in adult orthodontics! Call us at +962 6 593 6677 to schedule your next appointment with Sunna Orthodontics, or visit us online at to learn about the amazing benefits of invisible aligners!