A new recipe for a bone-graft biomaterial that is supercooled before application should make it easier to create aesthetic smiles while eliminating the pain associated with harvesting bone from elsewhere in the body, according to researchers at Tohoku University.
“The exacting aesthetic demands of the patient make a procedure that is already difficult for clinicians due to the tricky anatomy of these parts of the mouth even more challenging,” said Shinji Kamakura, a professor at the university’s Bone Regenerative Engineering Laboratory.
To overcome these challenges, clinicians have tended to employ bone grafts using nonessential bits of bone taken from other parts of the same patient such as the chin or pelvis in a process called autologous grafting. But this process requires additional surgical sites and increases pain at that site. Also, there is a very limited amount of nonessential bone.
Synthetic alternatives made of minerals that already appear in the body but with similar mechanical properties to bone are sometimes used for other types of bone grafts. But these biomaterial substitutes have low bone regenerative properties compared to the gold standard of autologous grafts.
The conventional recipe for an octacalcium phosphate combined with collagen (OCP/Col) preparation still runs into problems with appositional bone growth, or increase in width, due to compressional stress on the material from the bone itself.
So, OCP/Col has been supported by a Teflon ring structure to retain its shape while the bone is forming. But the body cannot absorb Teflon, which ultimately needs to be removed.
The researchers, then, developed a recipe for OCP/Col that increases its density and supercooled it with liquid nitrogen down to –196°C before application on their rodent test subjects, producing the bone shape retention that dental surgeons are looking for.
Next, the researchers aim to test the recipe on larger animals and then engage in clinical trials in human beings.
In the last 15 years, OCP/Col has appeared as a likely candidate because it has bone regenerative properties superior to earlier substitutes. OCP provides the basis of the mineral crystals that make up bone. Following years of clinical trials, commercialization of OCP/Col for oral surgery recently was approved in Japan.
The study, “Influence of Pre-Freezing Conditions of Octacalcium Phosphate and Collagen Composite for Reproducible Appositional Bone Formation,” was published by the Journal of Biomedical Materials Research.