Their findings show that different features of the occlusal surface antagonize tensile stresses in the tooth to tooth contact during the chewing process. They further show that tooth wear with its loss of dental tissue and the reduction of the occlusal relief decreases tensile stresses in the tooth. Thus, when the condition of the occlusal surface changes, the biomechanical requirements on the existing dental material change as well – an evolutionary compromise for tooth preservation.
Maximal principal stress distribution observed in three gorilla teeth of an unworn (left), a lightly worn (middle) and a worn (right) condition. © MPI f. Evolutionary Anthropology
First, the researchers created 3D digital models of three gorilla lower second molars differing in wear stages. In a second step they applied a Software tool (Occlusal Fingerprint Analyser) developed in the Senckenberg Research Institute to precisely determine tooth to tooth contacts. They then used an engineering approach, finite element analysis (FEA), to evaluate whether some dental traits usually found in hominin and extant great ape molars have important biomechanical implications.
The results show that in unworn and slightly worn molars (with a well-formed occlusal relief that is most effective for processing food) tensile stresses concentrate in the grooves of the occlusal surface. In such a condition, the different crests of a molar carry out important biomechanical functions, for example, by reinforcing the crown against stresses that occur during the chewing process. Due to a loss of tooth tissue and a reduction of the occlusal relief the functionality of these crests diminishes during an individual’s lifetime. However, this reduced functionality of the crests in worn teeth is counterbalanced by an increase in contact areas during tooth to tooth contacts, which ultimately contributes to a dispersion of the forces that affect the occlusal surface.
This suggests that the wear process might have a crucial influence in the evolution and structural adaptation of molars enabling to endure bite forces and to reduce tooth failure throughout the lifetime of an individual. “It seems that we observe an evolutionary compromise for long tooth preservation. Even though worn teeth are not as efficient they still fulfill their task. This would not be the case if they were lost prematurely“, says Stefano Benazzi of the Max Planck Institute for Evolutionary Anthropology. He adds: “Tooth evolution and dental biomechanics can only be understood, if we further investigate tooth function in respect to the dynamic changes of tooth structures during the lifespan of individuals”.
“The results have strong implications for understanding the functional biomechanics of dental traits, for deciphering the evolutionary trend of our masticatory apparatus and might have important implications in modern dentistry for improving dental treatments”, says Jean-Jacques Hublin, director of the Department of Human Evolution at the Max Planck Institute for Evolutionary Anthropology. [SJ]
Dr. Sören Dürr | Senckenberg
Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society
127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
18.01.2017 | Power and Electrical Engineering
18.01.2017 | Materials Sciences
18.01.2017 | Life Sciences