Electric toothbrushes were shown to both brighten and protect teeth in lab demonstrations, according to a recent study.
Even with regular brushing, teeth can become stained from genetic factors or consuming foods and drinks like tomatoes and coffee. Chemical whiteners can help, but they can also damage teeth in the process. So, researchers have designed a prototype teeth-whitening powder that is activated by the vibrations from an electric toothbrush.
The system both brightened and protected teeth in lab demonstrations. "This work offers a safe, at-home teeth whitening strategy integrating whitening, enamel repair and microbiome balance for long-term oral health," said study investigator Min Xing, who is with the Chinese Academy of Sciences, the Science and Technology Commission of Shanghai Municipality.
Peroxide-based bleaching with strips, gels and mouth rinses is a popular option for whitening stained teeth. This type of chemical whitening generates reactive oxygen species (ROS), compounds that break apart stain-causing molecules. However, many whitening techniques can damage the tooth enamel, which might result in easier re-staining or other oral problems.
Now, researchers are developing a tooth-whitening compound that generates ROS when activated by electric toothbrush vibrations while strengthening and repairing teeth at the same time. The researchers combined strontium and calcium ions with barium titanate in a solution and then heated and formed it into a ceramic powder, dubbed BSCT. When vibrated, the powder generates a small electric field that causes ROS-generating chemical reactions.
In initial lab tests using human teeth artificially stained with tea and coffee, brushing with BSCT and an electric toothbrush caused visible whitening. The treated teeth were almost 50% whiter than the control group stained in the same way but brushed with saline. For teeth with damaged enamel and dentin, BSCT brushing regenerated these structural components because the strontium, calcium and barium ions included in the powder formed deposits on the tooth surface. Researchers are now developing a toothpaste formula with the BSCT powder, which could provide a new effective, at-home treatment for safely whitening teeth and promoting oral health.
A new approach to treatment-resistant depression
About 20% of U.S. adults experience major depression in their lifetime. For some individuals symptoms improve within a few treatment attempts. However, up to one-third of patients have treatment-resistant depression, for which standard antidepressant medication or psychotherapy isn't enough. Now, a study shows that a small, implanted device may provide substantial, long-lasting relief to adults with the most severe treatment-resistant depression.
Researchers at Washington University School of Medicine in St. Louis, Missouri helped develop this device, which stimulates the vagus nerve. They found it produced improvements in depressive symptoms, quality of life and other measures. On average, each patient in the clinical trial had already tried 13 treatments that failed to help them, including interventions such as electroconvulsive therapy and transcranial magnetic stimulation.
"We believe the sample in this trial represents the sickest treatment-resistant depressed patient sample ever studied in a clinical trial," said lead author Dr. Charles Conway, a professor of psychiatry and director of the WashU Medicine Treatment Resistant Mood Disorders Center. "There is a dire need to find effective treatments for these patients, who often have no other options. With this kind of chronic, disabling illness, even a partial response to treatment is life-altering, and with vagus nerve stimulation we're seeing that benefit is lasting."
The study was designed to evaluate whether adding vagus nerve stimulation (VNS) to existing treatment improves outcomes for treatment-resistant depression. The therapy involves implanting a device under the skin in the chest that emits carefully calibrated electrical pulses to the left vagus nerve (a major conduit between the brain and internal organs).
The trial enrolled nearly 500 patients at 84 sites across the U.S. Three-quarters of the participants were so ill they were unable to work. VNS devices were implanted in each patient, but for study control purposes, only half of the devices were turned on during the first year of the trial. Treatment outcomes were measured in terms of depression symptom severity, quality of life and daily function.
Among the 214 patients receiving active treatment from the beginning of the trial, about 69%, (147 individuals) had a meaningful response at 12 months. Among those patients who experienced a meaningful benefit at 12 months, more than 80% maintained or increased benefits at 24 months across all measures of depression, quality of life and function. Among patients who had a substantial response at one year (defined as 50% or greater symptom reduction) 92% were typically still experiencing a benefit at the two-year mark, across all measures.
Interestingly, nearly one-third of participants who had not responded after one year of treatment reported benefits at the end of the second year, suggesting the treatment might take more time to work in some people. Among those who experienced benefits at one year, relapse rates were consistently low, especially for the strongest responders. The researchers found that more than 20% of treated participants (39 adults) were in remission after 24 months, meaning their symptoms had improved to the point where they could function normally in daily life. This was a finding Conway said was particularly striking.
"We were shocked that one in five patients was effectively without depressive symptoms at the end of two years," Conway said. "Seeing results like that for this complicated illness makes me optimistic about the future of this treatment. These results are highly atypical, as most studies of markedly treatment-resistant depression have very poor sustainability of benefit, certainly not at two years. We're seeing people getting better and staying better."
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at medicalminutes@gmail.com
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute.
