Meet MARC

Dr. Richard Price and Marc (Measurement ofAccuracy when Resin Curing). (Danny Abriel Photo)

The trick to baking a perfect birthday cake lies in temperatureand duration. If the oven is too hot, the cake will overcook. Ifthe cake is removed too soon, it will be uncooked in themiddle.

The same goes for the tooth-coloured resin fillings dentists useto fill cavities. These fillings are put into a tooth in a soft,malleable state, after which the dentist shines a bright blue lighton the white filling to harden it. Too much light and it willovercook—not only the tooth but surrounding tissues andnerves. Too little light and it won’t harden properly andprobably won’t last.

But how can a dentist know how much light to apply so thefilling is just right? Just ask MARC.

MARC (Measurement of Accuracy when Resin Curing) is thebrainchild of Dr. Richard Price, a practicing dentist and professorwith the School of Biomedical Engineering and the Faculty ofDentistry at Dalhousie, and his assistant Christopher Felix. Usingcustom-designed computer software, the invention—a simulatedpatient head complete with realistic teeth, tongue, cheeks andlips—accurately measures the amount of total energy beingdelivered to a filling in the mouth.

Dalhousie’s Industry Liaison and Innovation Office haslicensed MARC to a new spinout venture called BlueLight analyticsinc. based in Halifax. In addition, MARC is already being used toteach dental students and practicing dental professionals at theFaculty of Dentistry.

“MARC can tell you how long you need to cure the fillingso it will get sufficiently hard,” explains Dr. Price.“It all depends on such things as where the cavity is in themouth, the design of the curing light and the type of resin beingused—all these factor into how long you need to shine thelight for.”

The same problems did not exist years ago when dentistsprimarily used silver amalgam fillings. But these days, thepreference is for composite resin fillings that are the same coloras teeth. “The majority of the fillings put in today in NovaScotia are white fillings,” says Dr. Price. “Somedentistry schools don’t even teach about the other onesanymore.”

The energy is delivered to the filling using a pen-shaped curinglight. Some manufacturers say the dentist only needs to shine thelight for five seconds, others for more than a minute. Testingusing MARC—who bears a passing resemblance to Don Draper onMad Men—showed Dr. Price that the effectiveness of the lightsvaried greatly depending on their strength, ergonomic design andeven how they were held.

“MARC is the closest thing to clinical reality you canhave,” says Mr. Felix, as MARC opens wide on the countertopbeside him. “We’re able to say how much light is neededin the most clinically-relevant setting – themouth.”

BlueLight analytics is receiving financial supportfrom Atlantic Canada Opportunities Agency.