A blue curing light used to cure composite restorations may stunt tumor growth, according to a team of re-searchers at the Medical College of Georgia (MCG) School of Dentistry.
“The light sends wavelengths of blue-violet light to the composite, which triggers hardening,” says Alpesh Patel, a MCG School of Dentistry junior. “The light waves produce free radicals that activate the catalyst and speed up polymerization of the composite resin. In oral cancer cells, though, those radicals cause damage that decreases cell growth and increases cell death.”
Mr. Patel, who has been working with Dr. Jill Lewis, associate professor of oral biology, Dr. Regina Messer, associate professor of oral rehabilitation and oral biology, and Dr. John Wataha, adjunct professor of oral rehabilitation and oral biology, studied 10 tumor-bearing mice. Five mice were exposed to the blue curing light for 90 seconds a day for 12 days, and 5 mice were left untreated. Then the tumors were extracted, and each one was split into 2 sections. Half of the tumors were used to create slides for tissue analysis, and the other half were frozen to prepare protein extracts. Tissue analysis indicated an approximate 10% increase in cell suicide, or apoptosis, in the light-treated tumors. The frozen protein extracts revealed a nearly 80% decrease in cell growth in the light-treated tumors.
“The decrease in cell growth, combined with in-creased apoptosis, helps explain why the tumors didn’t grow as much because you have cells that aren’t dividing and you have cells that are committing suicide,” Mr. Patel said.
Dr. Lewis predicts treating the tumors with blue light sooner will increase the rate of apoptosis, possibly preventing the tumor from ever becoming measurable and easing treatment.
“One desirable feature we’ve observed with the blue light is that noncancerous cells appear unaffected at light doses that kill tumor cells,” said Dr. Lewis. “We’re thinking that some day, blue light therapy may serve as an adjunct to conventional cancer therapy. Patients may, therefore, receive lower doses of chemotherapy, which would decrease the adverse effects most cancer patients experience from standard chemotherapy regimens.”
Mr. Patel presented his findings at the 2008 American Association for Dental Research Student Research Group DENTSPLY/Caulk competition, winning third place in the basic science category. He and junior MCG School of Dentistry student Beth Rainwater were 2 of only 7 students nationwide to be selected for the competition.
(Source: ScienceDaily, June 28, 2008, sciencedaily.com, adapted from materials provided by Medical College of Georgia, via EurekAlert!, a service of the AAAS)
