Dental abrasion as a cutting process.
A mammalian tooth is abraded when a sliding contact between a particle and the tooth surface leads to an immediate loss of tooth tissue. Over time, these contacts can lead to wear serious enough to impair the oral processing of food. Both anatomical and physiological mechanisms have evolved in mammals to try to prevent wear, indicating its evolutionary importance, but it is still an established survival threat. Here we consider that many wear marks result from a cutting action whereby the contacting tip(s) of such wear particles acts akin to a tool tip. Recent theoretical developments show that it is possible to estimate the toughness of abraded materials via cutting tests. Here, we report experiments intended to establish the wear resistance of enamel in terms of its toughness and how friction varies. Imaging via atomic force microscopy (AFM) was used to assess the damage involved. Damage ranged from pure plastic deformation to fracture with and without lateral microcracks. Grooves cut with a Berkovich diamond were the most consistent, suggesting that the toughness of enamel in cutting is 244 J m(-2), which is very high. Friction was higher in the presence of a polyphenolic compound, indicating that this could increase wear potential.
Department of Bioclinical Sciences, Faculty of Dentistry , Kuwait University , PO Box 24923, Safat 11310 , Kuwait.
Peter W
PW
Lucas
Department of Mechanical Engineering, School of Engineering and Applied Science, Science and Engineering Hall, 800 22nd St NW, Washington, DC 20052 , USA.
Mark
M
Wagner
Department of Mechanical Engineering , Kuwait University , PO Box 5969, Safat 13060 , Kuwait.
Khaled
K
Al-Fadhalah
Department of Chemical Engineering , Kuwait University , PO Box 5969, Safat 13060 , Kuwait.
Abdulwahab S
AS
Almusallam
Department of Bioclinical Sciences, Faculty of Dentistry , Kuwait University , PO Box 24923, Safat 11310 , Kuwait.
Shaji
S
Michael
Nanotechnology Research Facility, College of Engineering and Petroleum , Kuwait University , PO Box 5969, Safat 13060 , Kuwait.
Lidia A
LA
Thai
Department of Anthropology , Washington University in St Louis , Campus Box 1114, One Brookings Drive, St Louis, MO 63130-4899 , USA.
David S
DS
Strait
Department of Bioclinical Sciences, Faculty of Dentistry , Kuwait University , PO Box 24923, Safat 11310 , Kuwait.
Michael V
MV
Swain
Max Planck Weizmann Center for Integrated Archaeology and Anthropology , Max Planck Institute for Evolutionary Anthropology , Deutscher Platz 6, 04103 Leipzig , Germany.
Adam
A
van Casteren
Department of Anatomy, Faculty of Medicine , Kuwait University , PO Box 24923, Safat 11310 , Kuwait.
Waleed M
WM
Renno
Nanotechnology Research Facility, College of Engineering and Petroleum , Kuwait University , PO Box 5969, Safat 13060 , Kuwait.
Ali
A
Shekeban
Department of Bioclinical Sciences, Faculty of Dentistry , Kuwait University , PO Box 24923, Safat 11310 , Kuwait.
Swapna M
SM
Philip
Department of Bioclinical Sciences, Faculty of Dentistry , Kuwait University , PO Box 24923, Safat 11310 , Kuwait.
Sreeja
S
Saji
School of Construction Management and Engineering , University of Reading , Whiteknights, PO Box 219, Reading RG6 6AW , UK.
Anthony G
AG
Atkins
biomechanics; cutting; dental function; dental wear; mammalian diets