You’ve probably seen the hype. 3-D printing is everywhere, from startup tech companies to the aisles at Best Buy to your child’s grade school science lab. Soon, you may have a 3-D printer in your practice, producing custom surgery guides, scaffolds, and even implants. Maybe someday, you’ll use one to print out new teeth.
“You could manufacture many things in the dental office if you could make a sterile environment and have the right materials,” said Dr. William Giannobile, chair of the department of periodontics and oral medicine at the University of Michigan School of Dentistry.
Giannobile was a member of the team that created the first dental “replacement part” in a laboratory using bioengineering and 3-D printing to help a patient with periodontal disease—a custom scaffold built to stimulate regeneration of periodontal tissues.
“Many of the patient’s teeth had been slated for extraction due to the severity of the disease,” Giannobile said, because there was so much bone loss around the tooth. “We really didn’t have any other options, so the patient became the first we seriously considered to make a replacement part for.”
Giannobile worked with Dr. Giulio Rasperini of the University of Milan to advise their 54-year-old patient of his options. They told him that 3-D printing had never been utilized to fabricate a replacement part that would be used in a patient’s mouth before and that the risks included infection due to the exposure to an external substance. Since the tooth would otherwise be lost, the patient agreed to the procedure.
Drs. Giannobile and Rasperini took a CAT scan of the patient’s lower jaw. Sophia Pilipchuk, a PhD student in the University of Michigan department of biomedical engineering, used the scan to design and manufacture the scaffold based on the topography of the patient’s periodontal wound using a 3-D printer.
“The scaffolding was made out of a polymer material called polycaprolactone, or PCL, and hydroxyapatite. It was a very small amount of hydroxyapatite, but it was a combination of those 2 materials,” Giannobile said.
The team soaked the scaffold in a synthetic growth factor approved by the Food and Drug Administration to treat periodontal disease. The scaffold was then shipped to Italy, where Rasperini placed it in the patient’s mouth. The scaffold successfully maintained the soft tissues around the tooth for more than a year.
“However, after about 14 months, the patient had an exposure and an infection, and part of it had to be removed,” said Giannobile. “So it was a short-term success, but not a long-term success. Dr. Rasperini and I have been looking into ways we can fabricate a scaffold and place it in a patient’s mouth/oral cavity for a much longer period of time.”
The researchers collected the residual material and performed a microscopic evaluation, showing that bone and some new tissue had formed. They also performed a molecular analysis of the scaffold and found 75% of it remaining, while 25% had dissolved.
“We may want to use materials that dissolve a bit more quickly because that might have been a reason why this complication occurred,” Giannobile said. “The oral cavity has that constant challenge of all the bacteria, and that might have been part of the reason why it failed.”
While 3-D printing assists the healing process, it is not meant to replace the patient’s original body parts—yet.
“We want the body to replace that template or scaffold with new living tissue and then eventually eliminate the need for a scaffold. The best tissue is your own living tissue,” Giannobile said. “We’re just trying to develop these templates that can rebuild the big defects that we can’t normally repair with our conventional techniques.”
Researchers already have their eyes on more complicated procedures involving 3-D printing than this single scaffold.
“I think it could be used in many different applications. It could be used to rebuild bone. Maybe teeth have been lost as a result of periodontal disease. Or tumor resection. You could have large defects where teeth are lost. And then you could potentially use 3-D printed scaffolds that would rebuild the bone and allow the placement of dental implants in those patients,” Giannobile said.
Already, 3-D printing is being used to create customized surgical guides for dental implant placement. Location is critical for proper function and aesthetics. Plus, dentists need to avoid structures like the sinus, jaw, and nerve canal during surgery. CAT scans provide this information, which the 3-D printer uses as a guide to fabricate a replacement part.
“Surgical guides basically have these precut holes, almost like a cookie cutter, that shows the hole where the drill needs to go,” Giannobile said. “You can 3-D print that scaffold. The surgeon would have it available at the chairside.”
The dental implants themselves may be 3-D printed as well. These implants would be customized to each patient’s bony topography and be almost the same size as the original tooth that was lost. Of course, these implants wouldn’t be designed to dissolve like the scaffolding, so researchers are now investigating potential materials. But they aren’t stopping there.
“Maybe you could even 3-D print the tooth and construct a completely new tooth,” Giannobile said. “That could be something in the future where we could transplant stem cells in that 3-D printed tooth-shaped object. That would then lead to eventual formation of all the tissues of the tooth: the enamel, pulp, dentin, cementum, all those different structures. That’s something that we have been working on in the laboratory.”
Giannobile plans on more clinical studies to identify the optimal materials and conditions for using 3-D printed devices. The full report of his initial work will be published in the September issue of the Journal of Dental Research.
“You’re seeing 3-D printers everywhere, in grade schools, in middle schools, in the classroom. We’re seeing them in biomedical engineering, using them for so many different applications, and it’s a way to manufacture very different materials,” he said. “I think it’s a very promising technology that may help those of us in oral healthcare and some of our patients.”
