UW School of Dentistry

School researchers patent new antibacterial agent

Four School of Dentistry faculty members have received a patent for a new way of using titanium-based materials to fight oral bacteria.

The patent culminates several years of work in which the group studied a novel class of substances called titanates and peroxotitanates, which can inhibit bacterial growth when bound to metal ions. These titanates could be incorporated into a gel or a solution that would be applied by a dentist after a procedure such as a root canal or a filling, reducing the chances of infection or tooth decay at that site.

Titanates could also be used in bandages, skin gels, mouthwashes and toothpaste to limit bacterial growth, said Dr. Whasun Oh Chung, one of the four researchers. The others are Dr. Daniel Chan, Dr. Bruce Rutherford and Dr. John Wataha.

The group’s work grew out of nearly a decade of research performed by Dr. Wataha and Dr. David Hobbs of South Carolina’s Savannah River National Laboratory, who is also listed on the patent as an inventor.  Their studies formed the basis for a four-year, $1.5 million federal grant by the National Institute of Dental and Craniofacial Research to the School to evaluate titanates’ antibacterial properties.

Dr. Chan, the School of Dentistry’s associate dean for clinical services, was co-principal investigator on the grant with Dr. James Bryers of the UW Department of Bioengineering.  Dr. Chung and another School of Dentistry faculty member, Dr. Albert K.H. Chung, were co-investigators.  Dr. Charles Spiekerman of the School of Dentistry’s Department of Oral Health Sciences is the group’s biostatistician, while Dr. Wataha, a member of the school’s Department of Restorative Dentistry, is  a consultant. Dr. Hobbs also was involved in securing the grant.

Metals have long been known to have antibacterial properties, said Dr. Whasun Oh Chung, but when used in concentrations high enough to be effective, they also carry a risk of toxic side effects. What makes the work with titanates promising, she said, is that the therapeutic benefits are achieved with less risk of toxicity.

“It is very new and novel,” said Dr. Chung. “Nothing has delivered materials at such a non-toxic level. We’re working with something we know is effective. Metals have been around a long time, and the bacteria haven’t become resistant to them.”

That is also an important consideration at a time when growing bacterial resistance to antibiotics places greater urgency on the need to find antimicrobial alternatives, she noted.

“The use of metal ions to control bacterial infections remains of interest as drug-resistant bacteria are becoming increasingly common and dangerous to human health,” Dr. Chung said.

Aside from their uses in the mouth or other topical applications, titanates could even be used in narrowly targeted treatments for internal organs, she said.

Titanates could also be used in dental or medical materials and devices, she said, including suture material, catheters, shunts, and dental fillings. They could even show up in toothpastes and mouthwashes some day, she said.

“[Titanate-metal complexes have] proven to be effective against endodontic, cariogenic  and periodontic bacteria,” Dr. Chung said. “The idea is to make it easy for people to use every day.” At the same time, Dr. Wataha cautioned that the practical or clinical benefits have yet to be conclusively demonstrated for the new patent-related application.

The researchers are now conducting human trials and expect to finish this spring, Dr. Chung said. However, she declined to predict when titanates might be approved for general use.