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Laura Dorr is the executive editor of DPR's Modern Dental Network.
While examining how cement sets in real time, a recent study found that the cement used in dental fillings has ‘sweet points,’ that could have implications for increasing longevity and durability of dental fillings.
Watching cement dry sounds like about as much fun as watching paint do the same – but being patient and watching could have major implication for dental filling success.
While examining how cement sets in real time, a recent study out of Queen Mary University of London and Aberystwyth University found that the cement used in dental fillings has ‘sweet points,’ that could have implications for increasing longevity and durability of dental fillings.
The ‘sweet points’ were “when the cement starts to approach the toughness of the tissue that our teeth are made of and occur in first 12 hours of setting.” Researchers discovered that the cement sets in fits and starts, not continuously as previously believed, giving insight into the timeline of the formation and filling of cracks.
“Contrary to convention, we find setting is non-monotonic, characterized by abrupt features not previously detected, including a glass-polymer coupling point, an early setting point, where decreasing toughness unexpectedly recovers, followed by stress-induced weakening of interfaces,” the study reported. “Subsequently, toughness declines asymptotically to long-term fracture test values.”
The researchers examined bioactive glass ionomer cement, made from glass powder, liquid polymer and water, a popular alternative in the UK to mercury amalgam that has been used in dentistry for over 40 years. Using computer models and intense beams of neutrons, they studied the surface between the glass particles and neighboring polymer as the cement strengthened.
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“Dental fillings are really complex materials,” said co-author Professor Neville Greaves from Aberystwyth University. “Using neutrons we have discovered how mechanical toughness develops, element by element. This is fundamental physics in action for the general good.”
“Most of us have fillings in our teeth and know that a crack means a trip to the dentist for a replacement,” added co-author Dr. Gregory Chass from Queen Mary University of London. “Our work opens up the possibility of tailoring the strength of non-mercury cements by homing in on the special setting points … to make dental fillings that not only last longer but could prevent future tooth decay.”
In addition to dental fillings, the findings could have implications for other industries (such as construction or road maintenance) that use cement.
The study, “Atomic and vibrational origins of mechanical toughness in bioactive cement during setting,” was published in the journal Nature Communications.