In Quest for Pearly Whites, Tooth Sensitivity Is Fleeting
One of the drawbacks of teeth-whitening procedures is that sometimes teeth become sensitive, leading to discomfort while eating.
But a recent study found that teeth that become touchy after the first week of bleaching become less sensitive over the course of treatment. And some people don’t experience any extra sensitivity at all, researchers found.
The four-week study involved 100 men and women at the Naval Medical Center in San Diego. People were prescribed a tooth-whitening treatment to use at home and were custom-fitted with a mouth tray to hold the whitening gel. Half of the group was given a 15% carbamide peroxide and fluoride gel; the other half got a placebo--or ineffective--gel. They were instructed to wear the gel-filled devices for three to four hours a day.
After the first week, about half of the volunteers in both groups reported some mild sensitivity.
However, the sensitivity diminished as treatment continued. After four weeks, only 8% of those in the whitening-gel group reported mild discomfort, compared with 6% of the placebo group.
Four percent of those using the whitening gel reported severe sensitivity after the first week, which caused them to avoid certain foods. No one in either group had severe sensitivity after two weeks.
Michael Jorgensen, an associate professor of clinical dentistry at the USC School of Dentistry, who collaborated with the Naval Medical Center researchers, says people with receding gums are more likely to experience sensitivity during whitening.
Because mild sensitivity occurred in some of those using the placebo gel, the researchers speculate that it’s not only the bleaching agent, but close contact with the gel itself, that caused the initial problem. Another possible explanation is that people tend to brush their teeth more vigorously when they participate in a dental study.
Journal of the American Dental Assn. 133: 1076-1082
Is Your Child Acting Twitchy? Don’t Worry, Researchers Say
Repetitive twitches, shoulder shrugs, grimaces, eye-blinking and other tics are the most common movement disorders in young children. Understandably, parents who notice a tic are concerned, but researchers have found that most tics eventually go away. And, the researchers report, children with a tic are no more likely to have behavior problems than other kids.
Researchers at the National Institute of Mental Health studied more than 500 healthy children, ranging in age from kindergarten to sixth grade, by observing them for tics for eight months. In the monthly observations, the researchers also looked for behaviors such as irritability, inattention, anxiety, tension and impulsivity. Teachers and parents were asked to report any tics or behavior problems.
The researchers report that about one in four children had at least one movement in some part of their body. Eye-blinking was the most common tic, affecting 68% of children with movement disorders. Boys were twice as likely to have tics than girls and, for unexplained reasons, tics were more common during the winter. In about 6% of the children, the tics were present for more than three months or showed up in two nonconsecutive months.
For most children, however, these movements may be just a phase of development that the nervous system is passing through, says Dr. Lisa A. Snider, a study co-author and a clinical research fellow at the NIMH in Bethesda, Md. Still, parents should check with a pediatrician if they notice a repetitive movement.
Pediatrics 110 (2): 331-336
Bandage Sometimes Works as Well as Stitches, an ER Study Shows
If you’ve ever gone to the emergency room with a badly cut finger and asked, “Does this need stitches?” you may have wondered how the doctor decided whether to suture the cut. Though not exactly guesswork, your doctor’s decision may have been based more on experience than hard science.
Researchers at UC San Francisco decided to address this problem by studying how patients with cuts less than an inch long fared when some received stitches and some did not.
Ninety-one people who came to the UCSF hospital emergency department were randomly assigned to have their cuts either sutured or not. All the patients were examined, and none had tendon or nerve injuries, or excessive bleeding. Those with stitches had them removed within eight to 10 days.
Those who got stitches had more discomfort, of course, than those who only had their wounds cleaned and an antibiotic ointment and bandage applied. In all other measures of successful treatment, however, there was little difference between them. The two groups resumed normal activities at about the same time--in 3.4 days, on average. There was only one infection, and that occurred in a person who had stitches. Doctors evaluating the cosmetic appearance of the healed wounds in photos taken three months later saw no significant difference. And ratings of the wounds’ appearance by the patients themselves were similar.
The researchers concluded that stitching a simple hand cut provided no benefit. However, they caution, their results can’t be generalized to larger wounds or to other areas of the body.
British Medical Journal 325: 299-301
Can Eating Bananas Help Prevent Stroke?
If you take a diuretic, consuming food rich in potassium such as bananas, milk and green leafy vegetables may lower your risk of stroke. Scientists have previously noted a connection between potassium intake and death from stroke, but a new study adds to the evidence linking low levels of the mineral to a greater risk of stroke.
Researchers followed more than 5,600 participants in the Cardiovascular Health Study, an ongoing study involving people from four communities in California, Maryland, North Carolina and Pennsylvania. When the study began, none of the men and women, who were 65 or older, had suffered a stroke. Over the next four to eight years, 473 strokes occurred among them.
The study is the first to look at stroke risk in people who take diuretics, drugs commonly prescribed to treat high blood pressure and to help prevent strokes. The drugs are known to increase potassium loss.
Those who consumed the least potassium were 1.5 times more likely to have a stroke, compared with those with the highest intake. Among those taking diuretics, the risk of stroke was 2.5 times greater in those who had low levels of potassium in their blood compared with those with high levels.
If the person taking diuretics with a low potassium level also had an irregular heartbeat--a condition known as atrial fibrillation--the risk of stroke increased 10 times compared with diuretic users with a higher level of potassium and a normal heart rhythm.
“Our study was the first to report this intriguing observation, says Dr. Deborah M. Green, assistant clinical professor of medicine at the University of Hawaii in Honolulu and a study co-author. Because the study sampled a relatively small number of people with the heart condition, a larger study is needed to confirm the findings, she says.
Neurology 59 (3): 302-303 (editorial), 314-320 (study)
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Dianne Partie Lange can be reached by e-mail at diannelange@cs.com.
