Can we heal teeth? The quest to repair tooth enamel, nature’s crystal coat



The enamel on your teeth is what makes them sparkle. It also acts as a protective coating on the teeth.
From shutterstock.com

Arosha Weerakoon, The University of Queensland

Tooth enamel is one of the hardest tissues in the human body. It acts as a protective layer for our teeth, and gives our smile that pearly white shimmer. But when enamel erodes, it can’t regrow itself.

In a significant scientific breakthrough, researchers recently discovered a way to regrow human tooth enamel.

Scientists from China have invented a gel that contains mineral clusters naturally found in teeth. In partially acid-damaged teeth, the gel stimulates crystal regrowth to restore tooth enamel back to its original structure.

While the method is yet to be tested on people, one day this could mean saying goodbye to painful needles, the dreaded dentist drill, and even fillings.




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What is tooth enamel?

Enamel is the outermost layer of our teeth, and protects our pearly whites from wear and tear. It also insulates us from feeling pain and sensitivity.

When this protective coat erodes, our teeth soften and become vulnerable to developing cavities (holes in the teeth) which may require dental treatment such as fillings.

Enamel is the protective outer layer of our teeth.
From shutterstock.com

Tooth enamel contains the same minerals, calcium and phosphate, found in bone. Unlike bone though, enamel contains relatively more mineral, and enamel crystals are arranged in a complex geometrical pattern.

Under a microscope, enamel crystals are shaped like long ribbons, or spaghetti strands. These crystal strands are assembled into clusters, like packets of dry spaghetti, orientated at 60 degrees to each other. The ribbon clusters, which weave together like honeycomb, are known as rods and inter-rods.

When destroyed, this weave is difficult to recreate, because the cells that form enamel die as our teeth emerge from our gums.

Why does our tooth enamel erode?

While enamel is very hard, it’s also brittle and susceptible to erosion. This occurs when tooth mineral dissolves into our saliva.

Our saliva is constantly trying to balance any “bad guys” it encounters with “good guys” at its disposal. When we get acid in our mouth (a bad guy) the mineral in our saliva (a good guy) tries to bind to it to neutralise the acid, and prevent it from causing harm. This is known as buffering.

If there’s too much acid, or the quality and quantity of our saliva is inadequate, we run out of mineral to buffer the “acid attack”. So in a final effort to neutralise the acidity in our mouth, the mineral in our teeth will dissolve into our saliva. This is when our teeth erode and become vulnerable.




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Like the erosion we see in our beaches and river beds, under a microscope, eroded enamel surfaces appear moth-eaten and uneven. This is because erosion destroys the crystal organisation I described above.

Current dentist-recommended products repair enamel but cannot regrow the complex crystal structure to recreate a pearly white shimmer. This is why globally, the dental community are very excited about this research.

Can we control erosion?

Our teeth erode when we eat and drink foods rich in acid, including wine, cola beverages, fruit juices, sour lollies, and energy and sports drinks. As a general rule, anything that tastes sour is high in acid. It’s best to avoid or limit acidic food and drinks where possible.

People with medical conditions such as bulimia or acid reflux may be at greater risk of their teeth eroding. If you suffer from these conditions, in addition to getting help from your doctor, it’s best to seek regular dental check-ups.

We know lollies aren’t good for teeth. But sour lollies in particular contain acid, which contributes to erosion.
From shutterstock.com

When our enamel erodes, it makes our teeth appear yellower. Often, we may also experience toothache or sensitivity because we’ve lost the enamel’s natural insulation.

If your teeth are eroding, a dentist and/or dental hygienist will be able to monitor and help you manage your oral health. In addition to brushing and cleaning between your teeth, your dental professional may also recommend:

  • rinsing with a bicarbonate and salt water mouthwash
  • chewing sugar-free gum to stimulate an increase in mineral-rich saliva
  • using a dentist-recommended toothpaste, special cream and/or mouthwash to help replace lost mineral and repair your teeth
  • delaying cleaning your teeth after an “acid attack” to prevent removing softened enamel.



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How did the scientists regrow enamel?

In a lab, extracted teeth were treated with acid to simulate erosion, then painted with a special gel. This gel contained calcium phosphate ion clusters – mineral clusters naturally found in teeth – mixed with an ingredient called triethylamine
(TEA).

After two days in a simulated mouth-like environment, the previously eroded enamel was checked for crystal growth, size, shape, organisation and composition using special microscopes.

The spaghetti-like crystals had regrown seamlessly, and the crystal clusters had correctly orientated themselves to form the rod and inter-rod honeycomb weave.

When will we be able to regrow enamel?

While this technology is something to look forward to, the short answer for now is “not yet”. This study has only been performed on extracted teeth. The researchers are hoping to test their method on mice, and then people soon after.

One of the significant limitations to moving towards animal and human trials is the toxicity of the essential ingredient, TEA. Another challenge is the enamel thickness they were able to repair was at a microscopic level.




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But all is not lost. The scientists hope to find a safe way to use TEA with the intention of growing enamel thick enough to fix larger sections of eroded enamel.

For now, the thought of not having to get fillings at the dentist is an exciting prospect on the horizon. So watch this space.The Conversation

Arosha Weerakoon, Lecturer, General Dentist & PhD Candidate, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Time doesn’t heal all wounds: how DNA damage as we age causes cancer


File 20181004 52678 1kfc9sn.jpg?ixlib=rb 1.1
Our risk of cancer is determined by a complex mix of genes, environment and lifestyle factors.
Claudia van Zyl

Ian Majewski, Walter and Eliza Hall Institute and Edward Chew, Walter and Eliza Hall Institute

As we age, our bodies inevitably deteriorate. Some changes, like grey hair and wrinkles, are easily visible. Others, like high blood pressure, often go unnoticed, but can be deadly.

Just as our body shows signs of ageing, so does our genome. Damage comes from chemical reactions that alter our DNA, and from errors introduced when it is copied. Our cells protect against these ravages, but these mechanisms are not foolproof and cells gradually accumulate DNA damage over a lifetime.

As a consequence of this damage, your genome is not the same in every cell; you are a patchwork of cells with subtle differences in their DNA. When a cell divides it will pass on these changes, and as they accumulate there is more and more likelihood that there will be consequences.

If these changes – we call them mutations – chip away at the systems that govern cell proliferation and survival, this can lead to cancer.

Our latest research, published today in the journal Blood, provides new clues about how our cells protect their genome and guard against cancer.

Guarding the genome

Nearly 10% of cancers have a familial component. Genes like BRCA1 and TP53 are among the best known cancer susceptibility genes, and both are involved in coordinating the cell’s response to DNA damage.

BRCA1 helps to repair a specific type of DNA damage, in which both strands of DNA are broken. Inheriting a defective BRCA1 gene elevates the lifetime risk of both breast and ovarian cancer.




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When DNA repair mechanisms break down, cells can accumulate staggering numbers of mutations, and cancer becomes almost inevitable.

Beyond genetics, a complex mix of environmental and lifestyle factors modify cancer risk.

When we read the genome of a cancer it is possible to attribute mutations to certain types of stress. UV radiation, for example, will fuse certain DNA bases. The UV damage signature is writ large in melanoma, a cancer linked to sun exposure.

Lung cancers from smokers and non-smokers have different mutation patterns because of the action of chemicals in cigarette smoke that attack the DNA.

We can also use this approach to diagnose defective DNA repair, as each defect triggers a characteristic pattern of mutations. In this way, mutation signatures can help us understand why a cancer has developed.

A ticking genetic clock

Smoking, UV radiation and X-rays all damage your DNA, but damage also comes from reactive molecules present within the cell. These molecules are fundamental to the chemistry of life – take water, for example.




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Water is a very reactive molecule and can do damage to our DNA. One of the most common mutations, either in cancer or in normal cells, results from water molecules reacting with methylated DNA.

DNA methylation is a small chemical modification that acts as a signpost on top of our genetic code. It helps to control which genes are switched on or off. This fine-tuning is essential for normal development, but methylation also makes DNA more susceptible to damage. Most of these events are quickly repaired, but the damage is unrelenting and some sneak through.

Cells accumulate mutations when DNA repair mechanisms break down.
K.D.P/Shutterstock

Methylation damage is the most prominent feature of an ageing genome. It’s so pervasive and reliable it has been proposed as a molecular clock that marks ageing. But our new research shows this process occurs more rapidly in some people.

We found and studied three people whose pathways to repair methylation damage had broken down. They all lacked a DNA repair protein called MBD4, which led to a marked accumulation of methylation damage – as though their cells were ageing prematurely.

All three developed an aggressive form of leukaemia in their early 30s, a cancer which usually wouldn’t be seen until the person is in their 60s or 70s.

Methylation damage plays a role in most cancers, but in these cases it was the primary driver of the disease.

While complete inactivation of MDB4 – as occurred in the three participants – is extremely rare, our findings raise the question of how more subtle differences in DNA repair shape cancer risk, particularly in the context of ageing.

Turning back the clock

Ageing contributes to cancer risk in myriad ways. While we’ve focused here on the buildup of DNA damage, our immune system also plays an important role and tends to fade as we get older.

Lifestyle factors – such as obesity, stress and diet – also provide a cumulative risk that builds over a lifetime.




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Understanding the interplay between these factors is key to finding strategies that will effectively diffuse the health consequences associated with ageing.

Our research is helping to tease apart the contribution of DNA damage in different disease processes. Our findings suggest that some people accumulate more DNA damage than others – their clocks are ticking a little faster – and measuring these differences may help to spot people at risk of developing cancer, or help match them with more effective treatments.The Conversation

Ian Majewski, Laboratory Head & Victorian Cancer Agency Fellow, Cancer & Haematology Division, Walter and Eliza Hall Institute and Edward Chew, PhD candidate, Cancer and Haematology Division, Walter and Eliza Hall Institute

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Egyptian Couple Shot by Muslim Extremists Undaunted in Ministry


Left for dead, Christians offer to drop charges if allowed to construct church building.

CAIRO, Egypt, June 9 (CDN) — Rasha Samir was sure her husband, Ephraim Shehata, was dead.

He was covered with blood, had two bullets inside him and was lying facedown in the dust of a dirt road. Samir was lying on top of him doing her best to shelter him from the onslaught of approaching gunmen.

With arms outstretched, the men surrounded Samir and Shehata and pumped off round after round at the couple. Seconds before, Samir could hear her husband mumbling Bible verses. But one bullet had pierced his neck, and now he wasn’t moving. In a blind terror, Samir tried desperately to stop her panicked breathing and convincingly lie still, hoping the gunmen would go away.

Finally, the gunfire stopped and one of the men spoke. “Let’s go. They’re dead.”

 

‘Break the Hearts’

On the afternoon of Feb. 27, lay pastor Shehata and his wife Samir were ambushed on a desolate street by a group of Islamic gunmen outside the village of Teleda in Upper Egypt.

The attack was meant to “break the hearts of the Christians” in the area, Samir said.

The attackers shot Shehata twice, once in the stomach through the back, and once in the neck. They shot Samir in the arm. Both survived the attack, but Shehata is still in the midst of a difficult recovery. The shooters have since been arrested and are in jail awaiting trial. A trial cannot begin until Shehata has recovered enough to attend court proceedings.

Despite this trauma, being left with debilitating injuries, more than 85,000 Egyptian pounds (US$14,855) in medical bills and possible long-term unemployment, Shehata is willing to drop all criminal charges against his attackers – and avoid what could be a very embarrassing trial for the nation – if the government will stop blocking Shehata from constructing a church building.

Before Shehata was shot, one of the attackers pushed him off his motorcycle and told him he was going to teach him a lesson about “running around” or being an active Christian.

Because of his ministry, the 34-year-old Shehata, a Coptic Orthodox Christian, was arguably the most visible Christian in his community. When he wasn’t working as a lab technician or attending legal classes at a local college, he was going door-to-door among Christians to encourage them in any way he could. He also ran a community center and medical clinic out of a converted two-bedroom apartment. His main goal, he said, was to “help Christians be strong in their faith.”

The center, open now for five years, provided much-needed basic medical services for surrounding residents for free, irrespective of their religion. The center also provided sewing training and a worksite for Christian women so they could gain extra income. Before the center was open in its present location, he ran similar services out of a relative’s apartment.

“We teach them something that can help them with the future, and when they get married they can have some way to work and it will help them get money for their families,” Shehata said.

Additionally, the center was used to teach hygiene and sanitation basics to area residents, a vital service to a community that uses well water that is often polluted or full of diseases. Along with these services, Shehata and his wife ran several development projects, repairing the roofs of shelters for poor people, installing plumbing, toilets and electrical systems. The center also distributed free food to the elderly and the infirm.

The center has been run by donations and nominal fees used to pay the rent for the apartment. Shehata has continued to run the programs as aggressively as he can, but he said that even before the shooting that the center was barely scraping by.

“We have no money to build or improve anything,” he said. “We have a safe, but no money to put in it.”

 

Tense Atmosphere

In the weeks before the shooting, Teleda and the surrounding villages were gripped with fear.

Christians in the community had been receiving death threats by phone after a Muslim man died during an attack on a Christian couple. On Feb. 2, a group of men in nearby Samalout tried to abduct a Coptic woman from a three-wheeled motorcycle her husband was driving. The husband, Zarif Elia, punched one of the attackers in the nose. The Muslim, Basem Abul-Eid, dropped dead on the spot.

Elia was arrested and charged with murder. An autopsy later revealed that the man died of a heart attack, but local Muslims were incensed.

Already in the spotlight for his ministry activities, Shehata heightened his profile when he warned government officials that Christians were going to be attacked, as they had been in Farshout and Nag Hammadi the previous month. He also gave an interview to a human rights activist that was posted on numerous Coptic websites. Because of this, government troops were deployed to the town, and extremists were unable to take revenge on local Christians – but only after almost the
entire Christian community was placed under house arrest.

“They chose me,” Shehata said, “Because they thought I was the one serving everybody, and I was the one who wrote the government telling them that Muslims were going to set fire to the Christian houses because of the death.”

Because of his busy schedule, Shehata and Samir, 27, were only able to spend Fridays and part of every Saturday together in a village in Samalut, where Shehata lives. Every Saturday after seeing Samir, Shehata would drive her back through Teleda to the village where she lives, close to her family. Samalut is a town approximately 105 kilometers (65 miles) south of Cairo.

On the afternoon of Feb. 27, Shehata and his wife were on a motorcycle on a desolate stretch of hard-packed dirt road. Other than a few scattered farming structures, there was nothing near the road but the Nile River on one side, and open fields dotted with palm trees on the other.

Shehata approached a torn-up section of the road and slowed down. A man walked up to the vehicle carrying a big wooden stick and forced him to stop. Shehata asked the man what was wrong, but he only pushed Shehata off the motorcycle and told him, “I’m going to stop you from running around,” Samir recounted.

Shehata asked the man to let Samir go. “Whatever you are going to do, do it to me,” he told the man.

The man didn’t listen and began hitting Shehata on the leg with the stick. As Shehata stumbled, Samir screamed for the man to leave them alone. The man lifted the stick again, clubbed Shehata once more on the leg and knocked him to the ground. As Shehata struggled to get up, the man took out a pistol, leveled it at Shehata’s back and squeezed the trigger.

Samir started praying and screaming Jesus’ name. The man turned toward her, raised the pistol once more, squeezed off another round, and shot Samir in the arm. Samir looked around and saw a few men running toward her, but her heart sank when she realized they had come not to help them but to join the assault.

Samir jumped on top of Shehata, rolled on to her back and started begging her attackers for their lives, but the men, now four in all, kept firing. Bullets were flying everywhere.

“I was scared. I thought I was going to die and that the angels were going to come and get our spirits,” Samir said. “I started praying, ‘Please God, forgive me, I’m a sinner and I am going to die.’”

Samir decided to play dead. She leaned back toward her husband, closed her eyes, went limp and tried to stop breathing. She said she felt that Shehata was dying underneath her.

“I could hear him saying some of the Scriptures, the one about the righteous thief [saying] ‘Remember me when you enter Paradise,’” she said. “Then a bullet went through his neck, and he stopped saying anything.”

Samir has no way of knowing how much time passed, but eventually the firing stopped. After she heard one of the shooters say, “Let’s go, they’re dead,” moments later she opened her eyes and the men were gone. When she lifted her head, she heard her husband moan.

 

Unlikely Survival

When Shehata arrived at the hospital, his doctors didn’t think he would survive. He had lost a tremendous amount of blood, a bullet had split his kidney in two, and the other bullet was lodged in his neck, leaving him partially paralyzed.

His heartbeat was so faint it couldn’t be detected. He was also riddled with a seemingly limitless supply of bullet fragments throughout his body.

Samir, though seriously injured, had fared much better than Shehata. The bullet went into her arm but otherwise left her uninjured. When she was shot, Samir was wearing a maternity coat. She wasn’t pregnant, but the couple had bought the coat in hopes she soon would be. Samir said she thinks the gunman who shot her thought he had hit her body, instead of just her arm.

The church leadership in Samalut was quickly informed about the shooting and summoned the best doctors they could, who quickly traveled to help Shehata and Samir. By chance, the hospital had a large supply of blood matching Shehata’s blood type because of an elective surgical procedure that was cancelled. The bullets were removed, and his kidney was repaired. The doctors however, were forced to leave many of the bullet fragments in Shehata’s body.

As difficult as it was to piece Shehata’s broken body back together, it paled in comparison with the recovery he had to suffer through. He endured multiple surgeries and was near death several times during his 70 days of hospitalization.

Early on, Shehata was struck with a massive infection. Also, because part of his internal tissue was cut off from its blood supply, it literally started to rot inside him. He began to swell and was in agony.

“I was screaming, and they brought the doctors,” Shehata said. The doctors decided to operate immediately.

When a surgeon removed one of the clamps holding Shehata’s abdomen together, the intense pressure popped off most of the other clamps. Surgeons removed some stomach tissue, part of his colon and more than a liter of infectious liquid.

Shehata could not eat normally and lost 35 kilograms (approximately 77 lbs.). He also couldn’t evacuate his bowels for at least 11 days, his wife said.

Despite the doctors’ best efforts, infections continued to rage through Shehata’s body, accompanied by alarming spikes in body temperature.

Eventually, doctors sent him to a hospital in Cairo, where he spent a week under treatment. A doctor there prescribed a different regimen of antibiotics that successfully fought the infection and returned Shehata’s body temperature to normal.

Shehata is recovering at home now, but he still has a host of medical problems. He has to take a massive amount of painkillers and is essentially bedridden. He cannot walk without assistance, is unable to move the fingers on his left hand and cannot eat solid food. In approximately two months he will undergo yet another surgery that, if all goes well, will allow him to use the bathroom normally.

“Even now I can’t walk properly, and I can’t lift my leg more than 10 or 20 centimeters. I need someone to help me just to pull up my underwear,” Shehata said. “I can move my arm, but I can’t move my fingers.”

Samir does not complain about her condition or that of Shehata. Instead, she sees the fact that she and her husband are even alive as a testament to God’s faithfulness. She said she thinks God allowed them to be struck with the bullets that injured them but pushed away the bullets that would have killed them.

“There were lots of bullets being shot, but they didn’t hit us, only three or four,” she said. “Where are the others?”

Even in the brutal process of recovery, Samir found cause for thanks. In the beginning, Shehata couldn’t move his left arm, but now he can. “Thank God and thank Jesus, it was His blessing to us,” Samir said. “We were kind of dead, now we are alive."

Still, Samir admits that sometimes her faith waivers. She is facing the possibility that Shehata might not work for some time, if ever. The couple owes the 85,000 Egyptian pounds (US$14,855) in medical bills, and continuing their ministry at the center and in the surrounding villages will be difficult at best.

“I am scared now, more so than during the shooting,” she said. “Ephraim said do not be afraid, it is supposed to make us stronger.”

So Samir prays for strength for her husband to heal and for patience. In the meantime, she said she looks forward to the day when the struggles from the shooting are over and she can look back and see how God used it to shape them.

“There is a great work the Lord is doing in our lives, we may not know what the reason is now, but maybe some day we will,” Samir said.

 

Government Opposition

For the past 10 years, Shehata has tried to erect a church building, or at a minimum a house, that he could use as a dedicated community center. But local Muslims and Egypt’s State Security Investigations (SSI) agency have blocked him every step of the way. He had, until the shooting happened, all but given up on constructing the church building.

On numerous occasions, Shehata has been stopped from holding group prayer meetings after people complained to the SSI. In one incident, a man paid by a land owner to watch a piece of property near the community center complained to the SSI that Shehata was holding prayer meetings at the facility. The SSI made Shehata sign papers stating he wouldn’t hold prayer meetings at the center.

At one time, Shehata had hoped to build a house to use as a community center on property that had been given to him for that purpose. Residents spread a rumor that he was actually erecting a church building, and police massed at the property to prevent him from doing any construction.

There is no church in the town where Shehata lives or in the surrounding villages. Shehata admits he would like to put up a church building on the donated property but says it is impossible, so he doesn’t even try.

In Egypt constructing or even repairing a church building can only be done after a complex government approval process. In effect, it makes it impossible to build a place for Christian worship. By comparison, the construction of mosques is encouraged through a system of subsidies.

“It is not allowed to build a church in Egypt,” Shehata said. “We can’t build a house. We can’t build a community center. And we can’t build a church.”

Because of this, Shehata and his wife organize transportation from surrounding villages to St. Mark’s Cathedral in Samalut for Friday services and sacraments. Because of the lack of transportation options, the congregants are forced to ride in a dozen open-top cattle cars.

“We take them not in proper cars or micro-buses, but trucks – the same trucks we use to move animals,” he said.

The trip is dangerous. A year ago a man fell out of one of the trucks onto the road and died. Shehata said bluntly that Christians are dying in Egypt because the government won’t allow them to construct church buildings.

“I feel upset about the man who died on the way going to church,” he said.

 

Church-for-Charges Swap

The shooters who attacked Shehata and Samir are in jail awaiting trial. The couple has identified each of the men, but even if they hadn’t, finding them for arrest was not a difficult task. The village the attackers came from erupted in celebration when they heard the pastor and his wife were dead.

Shehata now sees the shooting as a horrible incident that can be turned to the good of the believers he serves. He said he finds it particularly frustrating that numerous mosques have sprouted up in his community and surrounding areas during the 10 years he has been prevented from putting up a church building, or even a house. There are two mosques alone on the street of the man who died while being trucked to church services, he said.

Shehata has decided to forgo justice in pursuit of an opportunity to finally construct a church building. He has approached the SSI through church leaders, saying that if he is allowed to construct a church building, then he will take no part in the criminal prosecution of the shooters.

“I have told the security forces through the priests that I will drop the case if they can let us build the church on the piece of land,” he said.

The proposal isn’t without possibilities. His trial has the potential of being internationally embarrassing. It raises questions about fairness in Egyptian society during an upcoming presidential election that will be watched by the world.

Regardless of what happens, Shehata said all he wants is peace and for the rights of Christians to be respected. He said that in Egypt, Christians have less value than the “birds of the air” mentioned in the Bible. According to Luke 12:6, five sparrows sold for two pennies in ancient times.

“We are not to be killed like birds, slaughtered,” he said. “We are human.”

Report from Compass Direct News