A family research affair: Mother and daughter study dental fillings together
By Diane Peters
Last summer, Eszter and Lily Somogyi-Ganss traveled together between their Harbourfront home and the Faculty of Dentistry, either by subway or on foot, chatting as they went.
“I got all the adventures from that day’s lab experiments and what was working and what was not,” recalls Eszter, a prosthodontist and associate professor, teaching stream. She listened closely because she’s always fascinated by what Lily has to say — and because this mother-daughter duo was collaborating on the same research project.
It’s a first-ever study that impacts how dentists prepare a tooth for a filling. “This is a fundamental clinical procedure that we do pretty much every day,” says Eszter.
The study, “Balancing Demineralisation and Collagen Integrity: A Nanoscale Analysis of Etching Time in Human Dentin,” is now published in the International Dental Journal.
Eszter worked on analysis, writing and editing while Lily — a second year bio-medical science student at the University of Guelph who was part of Dentistry’s Undergraduate Summer Research Program — did hands-on lab work.
The study’s results reveal that the length of time dentists conventionally apply phosphoric acid to the dentin of teeth to prepare for a filling — you must remove some of the minerals on the surface and expose the collagen so dental adhesive can stick — is too long and compromises collagen integrity.
“There was no real scientific evidence on this in the literature. This is the first paper to actually investigate what happens to the collagen fibres and how long we should be etching,” says Eszter.
Lily took part in doing a series of timed lab experiments on the dentin of third molars. She and the team discovered that 10 seconds is the sweet spot to allow adhesive to stick while preserving collagen integrity — that’s critical for the filling to stay bonded and avoid failing prematurely.
“Manufacturers’ instructions usually say 15 seconds,” says lead author and Faculty PhD candidate Wafa Alzubaidi, who notes these instructions don’t cite a reason for this recommendation. “Dentists should know how much acid affects collagen. If it gets damaged, the bond will not last.”
Alzubaidi, who hopes to wrap up her degree by the end of the year, is part of the Bozec Lab. Professor Laurent Bozec came up with the idea for the study — it used the lab’s atomic force microscope (AFM), scanning electron microscope and fourier transform infrared spectroscopy to gain never-before-seen nano topographic images of dentin’s collagen impacted by acid.
She admits there’s a good reason no other study has analyzed dentin after etching. “It’s very hard to image dentin,” Alzubaidi says. Dentin is made up of tubules, so the AFM’s probe often comes up against empty space. “You have to work in between the tubules and go over it again and again.”
The images from the study show just how much the basic structure of collagen — which is made up of a repeated molecular pattern called D-banding — gets disrupted by acid etching. Although no one etches for 60 seconds, imaging showed that at that time period the entire collagen matrix collapses.
Alzubaidi was impressed with Lily’s work, especially since most participants in the summer program are early-year DDS students who know dentistry and have often already completed a degree. “I can’t say enough about her. She’s very smart and detail-oriented and precise in everything she does.”
As well, Alzubaidi — who may add an MSc in prosthodontics to her resume in Canada before returning to Saudi Arabia, where she has a role as an assistant professor at King Abduhaziz University — admired how mother and daughter worked together.
“It was very interesting to see that collaboration between them. She was like a mentor to her daughter. I think that strengthened the study.”
The family has a long history with dentistry and research. Eszter’s father was a dentist and Lily’s dad, Faculty professor Bernhard Ganss, served as vice dean, research for over two decades.
Lily recalls visiting 124 Edward St. as a child, and he’d show her a beaker with a magnetic bar in it that could stir a solution until changed colour. “I thought it was the coolest thing in the world.”
She’s also observed Eszter in her role as a prosthodontist at Sunnybrook Health Sciences Centre. “I've seen how she interacts with patients and the impact that she has on their lives. That's been really inspiring to me.”
Coming up, the entire research team wants their study to have an impact on patient care. “We hope dentists will change their habits,” says Eszter.
Meanwhile, Lily’s upcoming summer will sidestep research to focus on academics; she plans to take summer courses and write her MCAT. She’s hoping to get into medical school, looking to specialize in neurology or neurosurgery.
“She’s going to be brilliant,” says her mother. “She has very good hand skills. She’s extremely smart and she also has good people skills.”
Adds Eszter. “If I’m good, she’s going to be even better.”
Top photo: Lily and Eszter Somogyi-Ganss at Lily's high school graduation (courtesy Somogyi-Ganss family)