A team of researchers at Charité Julius-Wolff-Institute have found the reason why teeth are able to survive much of the wear and tear they are subjected to.
Their study revealed that it is the internal stress in the nanostructures of dentine, which helps protect teeth against and increase resistance of the biostructure. Although dentine cannot repair itself completely, the interdisciplinary team of French and German academics were able to examine it to see how it protects itself.
Dentine, which is the majority of a tooth, is made up of mineral nanoparticles that are embedded in collagen protein fibres.
The researchers used nano imaging during their study to analyse the dentine and found that when the tiny collagen fibres shrink, the attached mineral particles become increasingly compressed.
Dr Paul Zalansky, from Julius Wolff-Institute of Charité in Berlin, said the research was able to use changes in humidity to demonstrate how stress appears in the mineral in the collagen fibres.
He added that it is this compressed state, which helps prevent the cracks from developing. The team also revealed that compression happens in such a way that cracks cannot easily reach the tooth’s inner parts, which could damage the sensitive pulp.
“In this manner, compression stress helps to prevent cracks from rushing through the tooth,” Dr Zalansky added.
The study also found that dentine becomes much weaker if the tight mineral-protein link is destroyed by heating. This led the team to believe that the balance of stresses between the particles and the protein is important for “the extended survival of teeth in the mouth”.
These findings may help explain why artificial tooth replacements do not work as effectively as natural teeth as they don’t have the natural mechanisms and cannot sustain the stresses as well as normal teeth.
Dr Zalansky concluded: “Our results might inspire the development of tougher ceramic structures for tooth repair and replacement.”