has made huge strides since the 19th century ads for painless
dentists, but fear of pain still keeps many people from getting dental work
done. Electronic technology is helping dentists reduce pain by tricking the
brain so patients barely notice the injections of anesthetics.
Dentists long ago noticed that if they vibrated the check area around the spot
of the injection needle's entrance, nerve signals were interrupted so patients
felt less pain. Florida dentist, Dr. Steven G. Goldberg, decided to capitalize
on this idea. He first used a vibrating flosser but decided to commercialize a
more rugged product, so he linked up with an engineering team to create DentalVibe, a device now being marketed to
"We provide a vibrating lip retractor that stimulates the region and has a
light to illuminate the area," says Dave Schiff, director of engineering
at Bresslergroup, the Philadelphia contract design house that designed
DentalVibe. The fork on the handheld tool vibrates while the dentist injects
anesthetic into the patient gums, pointing the needle between the prongs of the
The engineers use an eccentric cam to vibrate the fork, which is covered with
rubber so it's soft enough to be comfortable for patients. Finding the right
durometer rubber to permit vibration was a challenge, as was figuring out how
to trick the brain so it doesn't adjust for the vibrations and let pain signals
go to the brain.
"We run at about 120 Hz with 0.5 mm of amplitude. We found that if it is
on for about a second then turns off briefly, it keeps refreshing signals to
the brain and continuously masks the pain," Schiff says.
Fitting a powerful motor into the handle was a key design challenge, one that
required getting the most vibration from the smallest motor. "One concern
was to get the maximum force so we use a dc motor that delivers the most torque
on the 1.2V the battery supplies," Schiff says.
Making the unit compact and light were also critical elements in the design.
The unit can't take up much space and it can't be bulky. The motor, light
source and battery fit in the handle. A light pipe permits illumination at the
point of injection while letting designers keep the fork thin so it's not intrusive
It uses a rechargeable battery that easily lasts the 30 seconds or less that
it's activated for injections. Simplicity in design was important to keep costs
down and ensure that electronics aren't damaged during the many washdowns endured
by dental equipment. "It's a three-part, overmolded assembly that uses a
light pipe to shine the light where the dentist will be making the
injection," Schiff says.
What makes this movie stand out from the typical high school sports story is that the teenagers are undocumented immigrants, and the big game is a NASA-sponsored marine robotics competition. Like many other Hollywood movies, however, Spare Parts only tells part of the story. What the film shows -- and doesn’t show -- raises important issues affecting STEM education in the US.
Instead of sifting through huge amounts of technical data looking for answers to assembly problems, engineers can now benefit from 3M's new initiative -- 3M Assembly Solutions. The company has organized its wealth of adhesive and tape solutions into six typical application areas, making it easier to find the best products to solve their real-world assembly and bonding problems.
Load dump occurs when a discharged battery is disconnected while the alternator is generating current and other loads remain on the alternator circuit. If left alone, the electrical spikes and transients will be transmitted along the power line, leading to malfunctions in individual electronics/sensors or permanent damage to the vehicle’s electronic system. Bottom line: An uncontrolled load dump threatens the overall safety and reliability of the vehicle.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.