PHOTOS : PATRICK O ’ LEARY

By reproducing the motions and forces at play in human chewing , ART is invaluable for testing the performance of dental materials and guiding their development . It chews with real teeth or teeth made of any material an investigator wants to test , complete with a stream of water or artificial saliva .

Robotic Mouth and More First developed in 1983 , ART — now in its fifth generation — has become the gold standard for testing dental materials without human volunteers .

“ Our discoveries are in the technology used to evaluate materials ,” says Ralph DeLong , professor and interim chair of the Department of Restorative Sciences , who built the original apparatus with an engineer from MTS Systems Corp ., a testing and sensor technology company in Eden Prairie , Minnesota . “ ART-1 was the first artificial oral environment that chews effectively , using physiological parameters such as the force applied , where it ’ s applied , and what happens to teeth when you chew .” ART-1 won the coveted IR-100 Award for 1983 , placing it in the top 100 inventions of that year . Among the many other notable advancements by DeLong and his colleagues :

• DeLong and others developed a system to digitally map the 3-D profile of a tooth or a sample of dental material . A computer compares profiles before and after a chewing test to calculate the amount of wear . The number of chews that produce a given amount of wear indicates how well the test material will hold up in a real mouth .

• DeLong ’ s colleague Maria Pintado pioneered a tooth-brushing machine . She outfitted toothbrushes to measure

the motions and forces produced when many volunteers brushed , then programmed the machine to duplicate the various patterns and see what worked best . The results were used in toothbrush design .

• Using a micro CT scanner , researchers developed a technique to measure leakage of “ bugs ” into bonding materials that have formed gaps with the tooth structure after chewing . When a tooth with a compromised restorative material is placed in a silver nitrate solution , the silver nitrate seeps into any gaps and will show up on the scanner .

Center of Innovation In 1991 , Professor William Douglas , along with scientists from 3M , created the first University-industrial center , dedicated to putting their technologies to work in dental product development .

Called the Minnesota Dental Research Center for Biomaterials and Biomechanics ( MDRCBB ), the center has just won another major prize : a William J . Gies Award for Vision , Innovation , and Achievement — the Oscar of dental education — given by the American Dental Education Association Gies Foundation . The center won in the category of “ outstanding vision — public or private partner ,” a tribute to its history of bringing farsighted research to fruition .

The School of Dentistry now has two Gies Awards . The first , given in 2010 , came in the “ outstanding vision — academic dental institution ” category .

The center continues to evolve under Alex Fok , its director since 2007 , who has added both technical capacity and industrial partners . In addition to founding partner 3M ( whose dental manufacturing division is now 3M ESPE ), supporters include General Mills , orthodontics maker Ormco , and Spain-based dental implant company Mozo Grau .

“ The strength of the center is its ability to simulate oral challenges in the laboratory ,” says Fok . This provides “ a way for companies to identify and respond to challenges before they reach the expensive and time-consuming clinical trial phase .”

DeLong and colleagues are now designing the ART-5 machine , which

In the ART-1 artificial mouth , streams of lubricant are trained on the point of contact between chewing surfaces .

will chew real food as realistically as possible — responding , for example , to texture . “ We don ’ t know how people chew food ,” DeLong says . “ We do know there are pressure sensors in periodontal tissue , and we speculate that it gives early information about how much [ chewing ] force is necessary .”

The goal is to improve dental implants , small metal cylinders used as anchors for a new tooth . Though tough , they lack the cushioning of periodontal tissue . DeLong and his colleagues will use ART-5 to determine the best occlusion , or meshing of teeth , to minimize stress on teeth with implants . They expect to have it up and running by the end of this year .

If it seems no test of dental materials or practices is beyond MDRCBB , you ’ re probably right .

“ If you wanted to test dental floss , we ’ d figure it out ,” DeLong says .

Deane Morrison is a science writer and editor in the U of M ’ s University Relations department .

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