Tag Archives: Cavities

New test maps acidity in the mouth to spot cavities before they form

The phrase ‘prevention is better than the cure’ is a fundamental principle of modern health, and your oral health should be no different. One of the best ways to prevent cavities is by brushing and flossing correctly. But by now, most people do this and they still end up with some caries eventually. Taking prevention to the next level, scientists at the University of Washington have now developed an optical-based method that can identify the most at-risk teeth by mapping high acidity in the dental plaque that covers the teeth.

Shining light on teeth covered with a florescent dye solution can reveal where the enamel is most at risk from acidity. Credit: University of Washington/IEE Xplore.

Dental plaque is produced by bacteria that live in our mouths as a byproduct as they consume sugars, starches, and other bits of foods that haven’t been properly cleaned from the teeth. If plaque stays on the teeth for more than a few days, it hardens and becomes a substance called tartar. In time, the microorganisms that form on the plaque release acids that wear down the tooth enamel, then the next layer called dentin, before reaching the pulp. When acid attacks the pulp, you’ve officially gotten a new cavity.

But what if we could monitor this acidic activity and stop it before it crosses a point of no return that triggers the cavity formation? That’s exactly what researchers at the University of Washington set out to do. They’ve devised a system, which they call O-pH, that measures the pH levels, or acidity, of the plaque covering each tooth under inspection.

In order to map the acidity of the plaque, a person’s teeth are first covered in a non-toxic, safe chemical dye that reacts with light to produce fluorescent reactions. An optical probe then detects these fluorescent reactions, whose signals can reveal the exact acidity of the underlying dental plaque.

The proof of concept was demonstrated on a small sample of 30 patients, aged 10 to 18. Children and teenagers were selected because their enamel is much thinner than that of adults, which makes detecting any sign of erosion — and consequently a potential cavity — early on very important. The tooth acidity was read before and after sugar rinses, as well as pre- and post-professional dental cleaning.

In the future, this acidity test could be standard practice in dental practices. Eric Seibel, senior author and research professor of mechanical engineering at the University of Washington, says that when a patient comes in for routine teeth cleaning, “a dentist would rinse them with the tasteless fluorescent dye solution and then get their teeth optically scanned to look for high acid production areas where the enamel is getting demineralized.” The dentist and patient can then form a treatment plan to reduce the acidity and avoid costly cavities.

“We do need more results to show how effective it is for diagnosis, but it can definitely help us understand some of your oral health quantitatively,” said Manuja Sharma, lead author and a doctoral student in the UW Department of Electrical and Computer Engineering.  “It can also help educate patients about the effects of sugar on the chemistry of plaque. We can show them, live, what happens, and that is an experience they’ll remember and say, OK, fine, I need to cut down on sugar!”

The O-pH system was described in the journal IEEE Xplore.

Teeth.

Our immune systems may actually help create cavities, a new study finds

Researchers in the University of Toronto’s Faculty of Dentistry have found evidence that our own bodies could be the major driver of tooth decay and filling failure.

Teeth.

Image via Pixabay.

The study shows how the decay of dentin (the hard substance beneath our teeth’s enamel) and fillings isn’t the work of bacteria alone. Rather, they report, it’s the product of an unintentional ‘collaboration’ between bacteria and immune cells known as neutrophils. As these two do battle, our teeth suffer the collateral damage.

Carpet bombing

“No one would believe that our immune system would play a part in creating cavities,” says Associate Professor Yoav Finer, the lead author of the study and the George Zarb/Nobel Biocare chair in prosthodontics at the Faculty of Dentistry. “Now we have evidence.”

Neutrophils are a type of short-lived immune system cells that play an important role in combating inflammation throughout the body. These cells make their way into the oral cavity via the gums around our teeth, where they fight off any bacterial invaders. But as they track and engage these bacteria, neutrophils also inflict damage on the surrounding environment.

“It’s like when you take a sledgehammer to hit a fly on the wall,” Finer says. “That’s what happens when neutrophils fight invaders.”

Byproducts of these engagements are the problem, the team explains. On their own, neutrophils can’t cause meaningful damage to teeth; these cells can’t produce any acid to attack the mineral-rich compounds. However, as they engage in an attack, oral bacteria do employ acids in a bid to defend themselves — and these demineralize teeth.

It’s here that the problem starts. The now-weakened teeth become susceptible to enzymes released both by bacteria and neutrophils, and these enzymes start boring through the demineralized area of teeth and tooth-colored fillings. Dentin and tooth-colored fillings sustain damage “within hours” of a bacteria-neutrophil showdown, the team reports. The research helps better explain why so many patients who had cavities filled with tooth-colored fillings face high rates of recurrence of the cavities. Most tooth-coloured fillings fail within five to seven years, costing Canadians an estimated $3 billion a year, the paper explains.

“It’s a collaboration of destruction – with different motives,” says study author Michael Glogauer, professor of the Faculty of Dentistry and acting chief dentist at the Princess Margaret Cancer Centre.

“Ours is the first basic study to show that neutrophils can break down resin composites (tooth-coloured fillings) and demineralize tooth dentin,” says master’s student and first author of the paper, Russel Gitalis. “This suggests that neutrophils could contribute to tooth decay and recurrent caries.”

While the findings may seem bleak, they actually point the way towards new potential treatment strategies. The findings may also help us develop new filling materials and test their resilience in the lab, potentially leading to much more durable fillings.

The paper “Human neutrophils degrade methacrylate resin composites and tooth dentin” has been published in the journal Acta Biomaterialia.

14,000-year-old molar gives us oldest proof of dentistry, and will make you love your dentist’s drill

Just as today — or a little less often, as we tend to abuse our teeth quite a bit nowadyas – early humans had to deal with cavities. An infected 14,000 year old molar may give us a glimpse into how they treated such afflictions, and is the oldest known evidence of dentistry.

You won’t find any fancy anesthetics or sterile, steel tools here — the procedures were performed with sharp, hand-crafted stone tools in a rudimentary but effective fashion.

The study, published in the journal Scientific Reports, analyzed a molar from a well-preserved 25-year-old male skeleton, whose remains were first discovered in a rock shelter in Belluno, Italy, in 1988. Researchers found evidence that the molar had been infected and was partially treated with sharp, flint tools.

“The treatment went unnoticed for all these years. The cavity was described as a simple carious lesion,” lead researcher Stefano Benazzi from the University of Bologna told Discovery News.

(A) Occlusal view of the RM3. (B) Detailed view of the large occlusal cavity with the four carious lesions and the chipping area on the mesial wall. Section A-A is directed mesio-distally, passing through the larger carious lesion. (C) MicroCT slice of the Villabruna RM3 in correspondence with section A-A.
Image via Nature

“The treatment went unnoticed for all these years. The cavity was described as a simple carious lesion,” lead researcher Stefano Benazzi from the University of Bologna told Discovery News.

Researchers looked at the molar under an electron microscope and found chippings and striations, suggesting intentional removal of material from the tooth using sharp tools. They then attempted to replicate the findings using materials that early humans had access too: wood, bone, and stone.

The tests confirmed that the striations found on the infected tooth were a result of scratching and chipping, with flint producing results most similar to those found on the molar. Researchers also note that the painful procedure occurred while the individual was alive.

“The discovery suggests, moreover, that in the Upper Palaeolithic era, humans were aware of the damaging effects of cavity infections and of the necessity of treating them, using stone instruments to remove the infected material and to clean out the cavity,” Benazzi told an Italian newspaper, Il Resto del Carlino, The Telegraph reports.

The ancient tooth represents “the oldest archaeological evidence of” dentistry, the study notes.

It predates the next oldest-known evidence of a dental procedure by 5,000 years. Researchers suggest the findings may show how early humans adapted the toothpicking technique to early forms of dentistry that included scratching cavities using microlithic points.