Doctor Uses 3-D Printing to Rebuild a Chin

Shirley Anderson had to have his Adam’s apple and mandible both removed after his tongue cancer returned, leaving the 68-year-old man from Evansville, Ind, without a chin. But traditional prosthetic materials were bulky and cumbersome.

“This was a unique case,” said Dr. Travis Bellicchi, a second-year maxillofacial prosthodontics resident at the Indiana University School of Dentistry at Indiana University-Perdue University Indianapolis. “It’s a much larger prosthesis that what we normally work on. Typically we might do a nose or an ear. This is maybe 4 or 5 times larger.”

Bellicchi, an Indiana University School of Medicine Maxillofacial Prosthetics Fellow, typically serves as a bridge between restorative dental and medical specialties for patients who have had cancer surgery or who have experienced facial trauma from car accidents, gunshot wounds, or burns.

“My training allows me to provide prostheses when surgical intervention or reconstructions are insufficient to provide a good aesthetic or a functional result,” Bellicchi said. “Then I come in and make something out of silicone or acrylic resin that would restore function or, in this case, aesthetics.”

Bellicchi relies on medical, information technology, design, and engineering experts from across Indiana University and Purdue University. His interdisciplinary team is creating a hybrid digital and analog approach, using 3-D printing to create molds with negative space inside of them. The negative space becomes the prosthesis itself.

“Then I use traditional materials, for now, to fill that space,” Bellicchi said. “My motivation to use traditional materials is that they are predictable, they are biocompatible, they have research behind them, and we know how to do the characterization to make them lifelike.”

Anderson was first diagnosed with tongue cancer in 1997 and treated with radiation. The disease returned in 2012. After new radiation treatment, he developed osteoradionecrosis of the jaw. Head and neck surgeons attempted to reconstruct his mandible using pieces of bone from his fibula and a titanium bar, but were unsuccessful.

So, Bellicchi turned to a digital solution. He and his team have completed digital imaging and modeling of Anderson’s face, and they soon expect to use 3-D printing to produce a prototype of a 3-D printed prosthesis itself. Anderson, who currently breathes through a tracheotomy and is fed through a tube in his stomach, hopes some semblance of normal will return with a better looking and fitting prosthetic.

“Shirley really believes in helping us as an institution,” Bellicchi said. “He totally gets the work we are trying to do on the discovery side of this as well as the patient-care side. He is a problem solver and a funny guy. I couldn’t have asked for a better person to spend a year with as I come up with different prosthesis solutions and explore the digital protocol.”

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Oral Bacteria Linked to Stroke Risk

Researchers at the National Cerebral and Cardiovascular Center in Osaka, Japan, have discovered a potential link between oral health and the risk of stroke. According to their data, 26% of their patients who had experienced intracerebral hemorrhage had cnm-positive Streptococcus mutans in their saliva. Meanwhile, only 6% of patients who suffered from other types of stroke tested positive for the bacterium.

Also, MRIs revealed significantly higher numbers of cerebral microbleeds in subjects with cnm-positive S. mutans than in those without the bacterium. Cerebral microbleeds are small brain hemorrhages that may cause dementia and often underlie intracerebral hemorrhages. The researchers believe S. mutans may bind to blood vessels weakened by age and high blood pressure, causing arterial ruptures in the brain and leading to small or large hemorrhages.

“This study shows that oral health is important for brain health. People need to take care of their teeth because it is good for their brain and their heart as well as their teeth,” said Robert P. Friedland, MD, co-author of the study and the Mason C. and Mary D. Rudd endowed chair and professor of neurology at the University of Louisville School of Medicine.

“The study and related work in our labs have shown that oral bacterial are involved in several kinds of stroke, including brain hemorrhages and strokes that lead to dementia,” Friedland said. He also noted that the cnm-negative strain of S. mutans causes tooth decay and is found in approximately 10% of the population. Currently, he is researching how oral bacteria may influence other diseases affecting the brain.

“We are investigating the role of oral and gut bacteria in the initiation of pathology in the neurodegenerative disorders Alzheimer’s and Parkinson’s with collaborators in the United Kingdom and Japan,” he said.

The study, “Intracerebral Hemorrhage and Deep Microbleeds Associated with cnm-positive Streptococcus Mutans; a Hospital Cohort Study,” was published by Scientific Reports.

- See more at: http://www.dentistrytoday.com/news/industrynews/item/749-oral-bacteria-linked-to-stroke-risk#sthash.EjE28gZ1.dpuf

-DentistryToday

Shark Genes Offer Clues to Tooth Regeneration

Sharks are infamous for their ability to regrow teeth throughout their lifetime, while human beings only get a couple of sets. Researchers at the University of Sheffield in the United Kingdom, though, have identified the genes that give sharks their regenerative capacity, with an eye on someday giving people the same ability.

“We know that sharks are fearsome predators, and one of the main reasons they are so successful at hunting prey is because of their rows of backward-pointing, razor-sharp teeth that regenerate rapidly throughout their lifetime and so are replaced before decay,” said Dr. Gareth Fraser of the University of Sheffield.

The researchers have identified how a special set of epithelial cells, known as dental lamina, forms in sharks. These cells are responsible for lifelong tooth development and regeneration in sharks, conserved throughout 450 million years of evolution. Human beings have these cells too, but they only form baby and adult teeth before they are lost.

“The Jaws films taught us that it’s not always safe to go into the water, but this study shows that perhaps we need to in order to develop therapies that might help humans with tooth loss,” said Fraser.

By analyzing the teeth of catshark embryos, the researchers characterized the expression of genes during stages of early shark tooth formation. They found that these genes participate in the initial emergence of the teeth and are redeployed for further tooth regeneration.

At the beginning of the sharks’ evolutionary history, the researchers said, their teeth most likely were continuously regenerated and used a core set of genes from members of key developmental signaling pathways that were instrumental in evolving to redeploying the genes to replace teeth when needed.

Shark dentition is formed and patterned via these highly conserved signals, which are used by all toothed vertebrates, the researchers said. Slight genetic alterations, they added, could be the difference between the limited replacement supply of teeth that mammals have and the unlimited dentition that sharks have.

The study, “An Ancient Dental Gene Set Governs Development and Continuous Regeneration of Teeth in Sharks,” was published by Science Direct. It was supported by the Natural Environment Research Council and the Leverhulme Trust.

- See more at: http://www.dentistrytoday.com/news/industrynews/item/744-shark-genes-offer-clues-to-tooth-regeneration?highlight=WyJzaGFyayIsInJlZ2VuZXJhdGlvbiJd#sthash.qExoksZ1.dpuf

-DentistryToday