Research shows how to improve the bond between implants and bone

Research carried out recently at the Canadian Light Source (CLS) in Saskatoon has revealed promising information about how to build a better dental implant, one that integrates more readily with bone to reduce the risk of failure.

“There are millions of dental and orthopedic implants placed every year in North America and a certain number of them always fail, even in healthy people with healthy bone,” said Kathryn Grandfield, assistant professor in the Department of Materials Science and Engineering at McMaster University in Hamilton.

A dental implant restores function after a tooth is lost or removed. It is usually a screw shaped implant that is placed in the jaw bone and acts as the tooth roots, while an artificial tooth is placed on top. The implant portion is the artificial root that holds an artificial tooth in place.

Grandfield led a study that showed altering the surface of a titanium implant improved its connection to the surrounding bone. It is a finding that may well be applicable to other kinds of metal implants, including engineered knees and hips, and even plates used to secure bone fractures.

About three million people in North America receive dental implants annually. While the failure rate is only one to two percent, “one or two percent of three million is a lot,” she said. Orthopedic implants fail up to five per cent of the time within the first 10 years; the expected life of these devices is about 20 to 25 years, she added.

“What we’re trying to discover is why they fail, and why the implants that are successful work. Our goal is to understand the bone-implant interface in order to improve the design of implants.”

>Read more on the Canadian Light Source website

Tungsten accumulation in bone raises health concerns

McGill University scientists have identified exposure to tungsten as problematic after they determined how and where high levels of the metal accumulate and remain in bone.

“Our research provides further evidence against the long-standing perception that tungsten is inert and non-toxic,” said Cassidy VanderSchee, a PhD student and a member of a McGill research group headed by chemistry professor Scott Bohle.

Tungsten is a hard metal with a high melting point and, when combined with other metals and used as an alloy, it’s also very flexible.

Because of these properties and under the assumption that tungsten is non-toxic, it has been tested for use in medical implants, including arterial stents and hip replacements, in radiation shields to protect tissue during radiation therapy, and in some drugs. Tungsten is found in ammunition as well as in tools used for machining and cutting other metals.

Tungsten also occurs naturally in groundwater where deposits of the mineral are found. Exposure to high levels of tungsten in drinking water in Fallon, Nevada, was investigated for a possible link with childhood leukemia in the early 2000s. This investigation lead scientists to question the long-held belief that exposure to tungsten is safe and prompted the Centers for Disease Control and Prevention in the U.S. to nominate tungsten for toxicology and carcinogenesis studies.

>Read more on the Canadian Light Source website

Image: Cassidy VenderSchee

Marianne Liebi winner of Swedish L’Oréal-Unesco For Women in Science 2018

L’Oréal-Unesco For Women in Science Prize is awarded in Sweden for the third time. The purpose of the prize is to pay attention to and reward young women who have shown great potential in science, while offering positive female role-models. Researchers Marianne Liebi, Chalmers, and Ruth Pöttgen, Lund University, get L’Oréal-Unesco For Women in Science Award, supported by Sweden’s young academy 2018.

Marianne Liebi gets the award “for the constructive use of advanced imaging methods for biomaterials with the aim of understanding the connection between molecular and mechanical properties”. Marianne Liebi uses powerful X-ray technology to study how, for example, the smallest building blocks, collagen fibrils, the bone tissue, look and are organised. The goal is to develop a mimicking, biomimetic material, where nature’s own design principles are imitated and applied to develop artificial bone and cartilage.
“It’s important to show that in research, it does not matter where you come from or who you are – what matters is passion and dedication. At best, this kind of award will not be needed in the future, it would be aimed at all young researchers. It would not matter who you were, says Marianne Liebi.

>Read more on the MAXIV Laboratory website

Photo: Researchers Ruth Pöttgen (left), Lund University, and Marianne Liebi (right), Chalmers, get L’Oréal-Unesco For Women in Science Award 2018, supported by Young Academy Sweden.
Credit: Emma Burendahl

A better quality of tomography images

A research group composed of Dr. Naoki Sunaguchi (Gunma University), Prof. Tetsuya Yuasa (Yamagata University), M.D. Rajiv Gupta (Massachusetts General Hospital), Shin-ichi Hirano (Mercian Cleantec Corporation, MiZ Company Limited), and Prof. Masami Ando (Tokyo University of Science and Emeritus Professor at KEK) developed a new algorithm to improve the quality of an X-ray phase-contrast image.

X-ray phase-contrast imaging can provide far higher contrast in soft tissue compared to classical absorption-based imaging. Many groups have been developing a variety of imaging methods for potential clinical use. All these imaging methods suffer from a common problem: severe imaging artefacts arise when x-ray phase alternation exceeds the dynamic range of the imaging system, typically in the vicinity of bones and dense calcifications. These artefacts are similar to the metal and beam-hardening artefacts seen in traditional attenuation-based X-ray computed tomography (CT) even though they tend to be more severe and have a different physical basis. A particularly worrisome part of this type of artifact is the fact that it spreads broadly across a wide area on CT image even when the dense tissue responsible for it localized.

>Read more on the Photon Factory website

Image: A rat foot model of rheumatoid arthritis. Left: Absorption image, Middle: Phase image using conventional algorithms, and Right: phase image employing the proposed algorithm. All images were taken at the BL-14C, Photon Factory, KEK.