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Bite force

Dr. Peter Buschang
Dr. Peter Buschang, professor in orthodontics, pictured here in the department's library, with some of the most recent issues of the American Journal of Orthodontics and Dentofacial Orthopedics, which feature several of the department's studies on chewing efficiency.

Orthodontics department’s use of volunteer students, staff as research subjects leads to success of ongoing clinical trials

The process starts when research subjects put the Cuttersil in their mouths. Even though it has the consistency of a pencil eraser, they chew it until it’s broken up into tiny pieces. Then, they simply spit it out.

Once their role is complete, it’s the graduate resident who must sieve the remnants of the chewy, putty-like substance to determine the particles' diameters. Sieves with holes of different sizes are used, as the Cuttersil’s final size will vary depending on each individual’s chewing capability, or masticatory function.

While described above in its most basic form, this process is the framework for more than a dozen studies the orthodontics department has conducted over the last decade. These particular studies deal with chewing efficiency, and, interestingly enough, feature Texas A&M Health Science Center Baylor College of Dentistry students and staff as research subjects.

Earlier this summer, several of these studies were published in five different journals. One in particular, published in the American Journal of Orthodontics and Dentofacial Orthopedics and titled “Relative Contributions of Occlusion, Maximum Bite Force and Chewing Cycle Kinematics to Masticatory Performance,” used 30 TAMHSC-BCD students and staff to generate its principal finding: that occlusion is the most important factor in masticatory function.

A captive audience

Creatively pooling people and resources has allowed the Department of Orthodontics to publish a bevy of studies dealing with different aspects of masticatory function — from the effect of saliva to kinematics and occlusion, among others.

Dr. Jianing He
Associate Professor Dr. Jianing He, pictured here in the graduate endodontics clinic, is building upon the orthodontics department's findings with her own clinical trials, funded with a 5-year grant from the American Association of Endodontics.

Using student and staff research subjects is nothing new to the department; at least for studies that deal with the ability to break down food. Perhaps it’s because the studies that deal with chewing capability don’t necessarily require patient abnormalities, so almost anyone can participate.

It’s not uncommon for 30 or more students and staff to act as research subjects for any given study. And after all, they are a captive audience, says Dr. Peter Buschang, professor in the orthodontics department. Plus, they’re aware of how the studies are conducted and aren’t afraid of them.

“These studies really paved the way
for our grant.”
— Dr. Jianing He

“It makes it so much easier when we use students and staff,” Buschang says.

It also is easy on the department’s operations budget, since students and staff don’t have to be compensated for their contribution as research subjects.

“We have a limited budget. We can’t go out and recruit people,” Buschang says. “You can use guys here just as easily as you can guys on the street.”

Once the results are finalized, Buschang and other faculty prepare the study for publishing and submit it to publications such as AJO-DO and The Angle Orthodontist. Patience at this stage is the key — the most recently published study using TAMHSC-BCD students and staff actually was conducted in 2008, submitted in early 2009 and just published in the May 2011 issue of AJO-DO.

Building the framework

Several years ago, building upon the framework laid by the orthodontics studies, Dr. Jianing He, associate professor in the Department of Endodontics, questioned how endodontics and periodontics factor into the equation; that is, whether a root canal treatment or implant-supported crowns help patients chew better. This pilot study, published in a 2008 issue of the Journal of Endodontics, began to explore this question.

Now, three years into a five-year grant from the American Association of Endodontists Foundation totaling more than $680,000, the endodontics department is inching closer to finding the answers — one clinical trial at a time.

A competitive edge

The current study, being conducted under the grant titled “A Comparative Analysis of Endodontic Retreatment and Single-Implant Supported Restoration,” branches out in a few key ways, including its use of TAMHSC-BCD patients, who will eventually be compensated, unlike students and staff. When patients complete the study, they will be reimbursed for 25 percent of their total treatment costs.

The current study also enables He to analyze quality-of-life issues and takes on a prospective format, rather than a retrospective one.

It’s the orthodontic department’s myriad published literature on chewing capability that He says made a huge difference as the endodontics department prepared its grant application.

“These studies really paved the way for our grant. Chewing function is a very important and relevant outcome measurement of dental treatment, however, it has not been investigated in the endodontic literature,” He says. “Having the expertise in masticatory performance right here at BCD really gave us the advantage over other institutions while competing for funding,” she adds.