University of Rochester

Dual Light to Help Dentists in Color-Matching for Indoors and Outdoors

September 5, 2007

University of Rochester Students and Corporation Design Dental Device

A new lighting device that switches between natural light and incandescent may soon shine on crowns and veneers as dentists color-match teeth for indoor lighting and sunlight. The prototype of the handheld device is the result of a design partnership between University of Rochester students and a corporation.

Kevin McGuire, president of Tailored Lighting Inc, located in Rochester, N.Y., is investing in taking the students' design from prototype to market.

McGuire was the senior-design project customer and advisor to the SoLux Smile R&D team of biomedical engineering majors Amber Czajkowski, Kai Kao, Elizabeth LaLime, and Reggie Sandhu. The students made up one of eight teams in this past year's senior design class taught by Amy Lerner, associate professor in the Department of Biomedical Engineering.

"To make the process more realistic, we seek out people with a problem to solve," said Lerner. "The course is set up to be customer driven and students apply to work on a project as if they are applying for a job. The project-based course helps students put together pieces of what they've learned, to make something that demonstrates a concept in biomedical engineering."

An alumnus of the University's Institute of Optics, McGuire is the inventor of SoLux, a light source that closely replicates daylight and is used in places where color accuracy is important, such as color-choosing displays at Home Depot and museums such as the Memorial Art Gallery, the Van Gogh Museum, and the National Gallery of Art.

McGuire originally approached the senior design class with the project idea, wanting to add to his line of products. "One of my main criteria for the students was to produce a device you could hold, turn on and off, and change the lighting conditions, all with one hand," he said. "The most difficult mechanical part was the trigger design. The trigger actuates a filter inside that switches the light from daylight to incandescent, the two lights required for color matching."

Team supervisor Nick Kuzma, assistant professor in biomedical engineering and imaging sciences, provided some optics coaching. He discussed implementation of the students' design, which involved optical fibers and lenses to focus the light from the SoLux bulb. Packaging the design required machining of special lens mounts with Paul Osborne in the Department of Electrical and Computer Engineering. Osborne, campus mechanical guru, heads a machine shop outfitted with a cache of inventor tools: machine lathes, soldering equipment, and mills. And busy chalkboards. "Engineers talk with their fingers," he said. "Pencils, chalk, scribbles on the backs of napkins."

At first, the approach was to make the device stationary. According to Lalime, they had the idea that if the light were on a stand, they could aim it. Originally, the students designed a fiber-optic extension, but ended up planting the fiber optics inside the shell and creating a removable cap.

Czajkowski, who earned a concentration in optics along with her biomedical engineering major, said the team cannibalized a hair dryer and an electric drill for some of the parts. Kao developed computer drawings to detail inner workings of the device, and three-dimensional renderings of external features.

Coming up with the workable hand painted device with its smile-enhanced SoLux logo, created by Czajkowski, took all semester. According to Sandhu, who has a concentration in electrical and computer engineering, developing the 12-volt, 3.9 amp-drawing device required up to 20 or 30 hours a week on the part of each student, using Mondays as meeting time to catch up on individual and collective tasks to meet milestones.

"The devil is in the detail," said McGuire. "Ideas are cheap, but when it comes to executing them and making them work, it's difficult."

Other projects this year included devices for surgery, for medical treatments, and for daily task assistance for children with disabilities. The course Web site shares details of the project and contact information for proposing new projects at

The SoLux Smile team won first place in the Forbes Entrepreneurial Competition, sponsored by the University's School of Engineering and Applied Sciences.