Chronic migraine cases are amplified by jawbone disorder

                     

In a study, researchers at the University of São Paulo's Ribeirão Preto School of Medicine (FMRP-USP), in Brazil, finds that the more frequent the migraine attacks, the more severe will be the so-called temporomandibular disorder, or TMD. The temporomandibular joint acts like a sliding hinge connecting the jawbone to the skull, therefore the disorder's symptoms includes difficulty chewing and joint tension.
"Our study shows that patients with chronic migraine, meaning attacks occurring on more than 15 days per month, are three times as likely to report more severe symptoms of TMD than patients with episodic migraine," said Lidiane Florencio, the first author of the study, which is part of the Thematic Project "Association study of clinical, functional and neuroimaging in women with migraine", supported by the São Paulo Research Foundation - FAPESP.
Previous studies already indicated that migraine is somehow associated with pain in the chewing muscles. However, this research was the first to consider the frequency of migraine attacks when analyzing its connection with TMD: eighty-four women in their early to mid-thirties were assessed, being that 21 were chronic migraine patients, 32 had episodic migraine, while 32 with no history of migraine were included as controls - the results were published in the Journal of Manipulative and Physiological Therapeutics.
Signs and symptoms of TMD were observed in 54% of the control participants without migraine, 80% of participants with episodic migraine, and 100% of those with chronic migraine.
For Florencio, central sensitization may explain the association between the frequency of migraine attacks and the severity of TMD.
"The repetition of migraine attacks may increase sensitivity to pain," she said. "Our hypothesis is that migraine acts as a factor that predisposes patients to TMD. On the other hand, TMD can be considered a potential perpetuating factor for migraine because it acts as a constant nociceptive input that contributes to maintaining central sensitization and abnormal pain processes." Nociceptive pain is caused by a painful stimulus on special nerve endings called nociceptors.
Migraine and TMD have very similar pathological mechanisms. Migraine affects 15% of the general population, and progression to the chronic form is expected in about 2.5% of migraine sufferers. On the other hand TMD is stress-related as much as it has to do with muscle overload. Patients display joint symptoms - such as joint pain, reduced jaw movement, clicking or popping of the temporomandibular joint - but also develop a muscular condition, including muscle pain and fatigue, and/or radiating face and neck pain.
Which came first?
TMD and migraine are comorbidities. However, while people who suffer from migraine are predisposed to have TMD, people with TMD will not necessarily have migraine.
"Migraine patients are more likely to have signs and symptoms of TMD, but the reverse is not true. There are cases of patients with severe TMD who don't present with migraine," said Débora Grossi, the lead researcher for the study and principal investigator for the Thematic Project.
The researchers believe that TMD may increase the frequency and severity of migraine attacks, even though it does not directly cause migraine.
"We do know migraine isn't caused by TMD," Florencio said. "Migraine is a neurological disease with multifactorial causes, whereas TMD, like cervicalgia - neck pain - and other musculoskeletal disorders, is a series of factors that intensify the sensitivity of migraine sufferers. Having TMD may worsen one's migraine attacks in terms of both severity and frequency."
The journal article concludes that an examination of TMD signs and symptoms should be clinically conducted in patients with migraine.
"Our findings show the association with TMD exists but is less frequent in patients with rare or episodic migraine," Grossi said. "This information alone should change the way clinicians examine patients with migraine. If migraine sufferers tend to have more severe TMD, then health professionals should assess such patients specifically in terms of possible signs and symptoms of TMD."

Don't blame your genes for your toothache, twin study shows

                     

For the first time, investigators have looked at the role that genes and the oral microbiome play in the formation of cavities and have found that your mother was right: The condition of your teeth depends on your dietary and oral hygiene habits. The study appears September 13 in Cell Host & Microbe.

"Limiting sugar consumption and acid buildup in the mouth have been part of the dogma of the dental community for some time," says senior author Karen Nelson, President of the J. Craig Venter Institute (JCVI). "This work introduces specific taxa of bacteria that can be acquired through the environment and that have the ability to induce cavities."

Since the early 20th century, dentists and other experts have known that Streptococcus bacteria in the mouth are linked to the formation of cavities. Now, with the ability to study studying the microbiome, the investigators were able to take a closer look at specific taxa that are important.

To separate the role of heritability versus the environment, Nelson and her team turned to a popular method for studying such interactions: identical and fraternal twins. Specifically, they profiled the oral microbiomes of 485 twin pairs between the ages of 5 and 11. There were 280 fraternal twins and 205 identical twins--and one set of triplets. The samples were obtained with mouth swabs.

"We decided to focus on children because we hypothesized twow things--that the oral microbiome rapidly changes with age, and also that child twin pairs are likely to have a shared environment," Nelson says. "This allowed us to better control the influence of shared and unique environments."

Their results--driven with significant analysis input from co-authors Josh Espinoza (JCVI Engineer) and Chris Dupont (JCVI Associate Professor)--showed that identical twins had oral microbiomes that were more similar to each other than those of fraternal twins, indicating that there is genetic contribution to which kinds of bacteria are likely to be present in the mouth. However, the taxa that were linked most closely to heritability were not the ones that play a role in cavity formation. In addition, they found that the heritable strains of bacteria decrease in abundance as people get older, whereas the ones linked to the environment increase.

An important additional finding was the link between certain bacterial species and sugar consumption. Bacteria that were associated with fewer cavities were in lower abundance in twins who had a lot of added sugar in their food and drinks. In contrast, bacteria that are more common in children who consume a lot of sugar were associated with having more cavities.

The team plans to continue studying the twins over repeat visits to examine changing patterns in the oral microbiome. They are also looking at functional differences in the oral microbiomes of identical and fraternal twin pairs that have various states of oral health.
  

Many middle-aged adults report dental pain, embarrassment and poor prevention

The dental health of middle-aged Americans faces a lot of problems right now, and an uncertain future to come, according to new results from the University of Michigan National Poll on Healthy Aging.

One in three Americans between the ages of 50 and 64 say they're embarrassed by the condition of their teeth. A slightly larger percentage say dental problems have caused pain, difficulty with eating, missed work or other health problems in the past two years. Forty percent of those polled don't get regular cleanings or other preventive care that can help prevent dental problems.

Insurance coverage appears to have a lot to do with this lack of care. Overall, 28 percent of respondents said they don't have dental coverage. But that percentage was much higher -- 56 percent -- among those who say they only seek care for serious dental problems.

As for the future, 51 percent of those surveyed said they simply didn't know how they will get dental insurance coverage after they turn 65.

Another 13 percent of middle-aged adults expect to count on Medicare or Medicaid to cover their oral care needs after that age. Traditional Medicare does not cover routine dental care, and Medicaid dental coverage is often limited.

The poll, based on a nationally representative sample of older adults, was conducted by the U-M Institute for Healthcare Policy and Innovation with support from AARP and Michigan Medicine, U-M's academic medical center.

"Our findings highlight a stark divide among middle-aged Americans in terms of their oral health now, and a real uncertainty about how they will get and pay for care as they age," says associate poll director Erica Solway, Ph.D. "This is not out of disregard for the importance of preventive dental care - more than three-quarters of the people we polled agree that regular care is important to preventing problems later. But it does highlight opportunities to improve access to care and insurance options after age 65."

Solway and poll director Preeti Malani, M.D., a professor of internal medicine at the U-M Medical School, divided the poll respondents into three groups based on their responses about their use of dental care:

• prevention-focused: about 60 percent of the sample, who got regular preventive care as well as getting attention for dental problems
• inconsistent prevention: the 17 percent who sought preventive dental care occasionally
• problem-only: the 23 percent who went to the dentist only for serious dental problems.

"We know that oral health is a critical factor in overall wellness, and this research helps us identify some key issues - such as affordability and coverage - that we can focus on to address those 40% who are not prevention-focused," stated Dr. Alison Bryant, Senior Vice President of Research for AARP.

A clear divide
Poll respondents who were female, white, had higher incomes or had insurance were much more likely than others to take a prevention-focused approach to dental care. Men, African Americans, Hispanics, those with lower income, or those without insurance were more likely to seek dental care for problems only.

The differences among the three groups was also apparent when the U-M team asked about how easy it was to get care, and why they might not have sought care.

Among those who were prevention-focused, only 13 percent said they had delayed or hadn't received dental care when they needed it in the last two years. But that jumped to 35 percent in the inconsistent-prevention group, and 56 percent in the problem-only group.

Why didn't poll respondents get needed dental care? Cost was the most commonly reported answer, given by 69 percent who said they did not get or delayed needed care. Respondents also reported they were afraid of the dentist, couldn't find time to go, or couldn't find a dentist. Of the people who didn't receive care they needed, one in five cited fear of the dentist as a major factor.

Uncertain future
Looking ahead to the years beyond their 65th birthday - an age when most Americans become eligible for Medicare- the poll respondents were uncertain about how they'd get dental insurance.
Some - 16 percent - said they counted on employer-based coverage or a retirement-based plan. Another 12 percent said they planned to buy supplemental dental insurance.

And in addition to the half of respondents who indicated that they didn't know whether they will have dental insurance at all after age 65, another eight percent said they'd just go without it.

But it's the remaining respondents - the 13 percent who expect Medicare or Medicaid to cover their dental care in their older years - that concern the poll leaders the most.

"Traditional Medicare does not cover dental care, and many states offer very limited or no dental coverage for adults with Medicaid," says Malani. "Even those who were diligent about seeing the dentist and had dental insurance throughout adulthood may find it harder to afford dental care as they get older and coverage options may be more limited."

The nationally representative sample included 1,066 people ages 50 to 64, who answered a wide range of questions online; laptops and Internet access were provided to those who did not already have it.

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A full report of the findings and methodology is available at http://www.healthyagingpoll.org.

New dental imaging method uses squid ink to fish for gum disease

Squid ink might be a great ingredient to make black pasta, but it could also one day make getting checked for gum disease at the dentist less tedious and even painless. By combining squid ink with light and ultrasound, a team led by engineers at the University of California San Diego has developed a new dental imaging method to examine a patient's gums that is non-invasive, more comprehensive and more accurate than the state of the art.

"The last time I was at the dentist, I realized that the tools that are currently being used to image teeth and gums could use significant updating," said Jesse Jokerst, a nanoengineering professor at UC San Diego and senior author of the study.

The conventional method for dentists to assess gum health is to use an instrument called a periodontal probe -- a thin, hook-like metal tool that's marked like a tiny measuring stick and inserted in between the teeth and gums to see whether and how much the gums have shrunk back from the teeth, creating pockets. This method of measuring pocket depth is the gold standard used in dentistry. A pocket depth measuring one to two millimeters indicates healthy gums while three millimeters and deeper is a sign of gum disease. The deeper the pockets, the more severe the gum disease.

However, procedures using the periodontal probe are invasive, uncomfortable and sometimes painful for the patient. Measurements can also vary greatly between dentists, and the probe is only capable of measuring the pocket depth of one spot at a time.

In a paper published on Sept. 7 in the Journal of Dental Research, Jokerst and his team at UC San Diego introduced an innovative method that can image the entire pocket depth around the teeth consistently and accurately, without requiring any painful poking and prodding.

"Using the periodontal probe is like examining a dark room with just a flashlight and you can only see one area at a time. With our method, it's like flipping on all the light switches so you can see the entire room all at once," Jokerst said.

The method begins by rinsing the mouth with a paste made of commercially available food-grade squid ink mixed with water and cornstarch. The squid-ink-based rinse serves as a contrast agent for an imaging technique called photoacoustic ultrasound. This involves shining a light signal -- usually a short laser pulse -- onto a sample, which heats up and expands, generating an acoustic signal that researchers can analyze. "Light in, sound out," Jokerst said.

Squid ink naturally contains melanin nanoparticles, which absorb light. During the oral rinse, the melanin nanoparticles get trapped in the pockets between the teeth and gums. When researchers shine a laser light onto the area, the squid ink heats up and quickly swells, creating pressure differences in the gum pockets that can be detected using ultrasound. This method enables researchers to create a full map of the pocket depth around each tooth -- a significant improvement over the conventional method.

Researchers tested their photoacoustic imaging method in a pig model containing a mix of shallow and deep pockets in the gums. While their results closely matched measurements taken using a periodontal probe, they were also consistent across multiple tests. On the other hand, measurements with the periodontal probe varied significantly from one test to another.

"It's remarkable how reproducible this technique is compared to the gold standard," Jokerst said.
Moving forward, the team will be collaborating with dentists and testing their method in humans. Future work also includes minimizing the taste of the squid ink oral rinse -- it's salty and somewhat bitter -- and replacing laser lights with inexpensive, more portable light systems like LEDs. The team's ultimate goal is to create a mouthpiece that uses this technology to measure periodontal health.