title: Structure-function relations of primate lower incisors: a study of the deformation of Macaca mulatta dentition using electronic speckle pattern interferometry (ESPI).
abstract: Teeth adopt a variety of different morphologies, each of which is presumably optimized for performing specific functions during feeding. It is generally agreed that the enamel cap is a crucial element in controlling the mechanical behavior of mammalian teeth under load. Incisors are particularly interesting in terms of structure-function relations, as their role in feeding is that of the 'first bite'. However, little is known how incisor cap morphology is related to tooth deformation. In the present paper we examine the mechanical behavior of mandibular central incisors in the cercopithecine primate Macaca mulatta under loads similar to those encountered during ingestion. We map three-dimensional displacements on the labial surface of the crown as it is compressed, using electronic speckle pattern interferometry (ESPI), an optical metrology method. In addition, micro-computed tomography is used to obtain data regarding the morphology of the enamel cap, which in the M. mulatta lower incisors exhibits missing or very little enamel on the lingual face. The results showed that although compressed along a longitudinal axis, deformation in the incisors mostly occurred in the lingual direction and orthogonal to the direction of the applied load. Both isolated, embedded teeth and teeth in the mandible showed considerable lingual deformation. Incisor deformation in the mandible was generally greater, reflecting the additional freedom of movement enabled by the supporting structures. We show that the association with adjacent teeth in the arch is significant for the behavior of the tooth under load. Finally, loading two teeth simultaneously in the mandible showed that they work as one functional unit. We suggest that these results demonstrate the importance of enamel cap morphology in directing deformation behavior; an ability stemming from the stiffness of the enamel cap overlying the more pliable dentin.
authors.affiliation: Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel. lev-tov-chattah@weizmann.ac.il
authors.forename: Netta Lev-Tov
authors.initials: NL
authors.lastname: Chattah
authors.forename: Kornelius
authors.initials: K
authors.lastname: Kupczik
authors.forename: Ron
authors.initials: R
authors.lastname: Shahar
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Hublin
authors.forename: Steve
authors.initials: S
authors.lastname: Weiner
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003743:Dental Enamel / Q000033:anatomy & histology; D003799:Dental Stress Analysis; D021621:Imaging, Three-Dimensional; D007180:Incisor / Q000033:anatomy & histology* / Q000502:physiology*; D007368:Interferometry / Q000379:methods; D008253:Macaca mulatta; D013314:Stress, Mechanical; D055114:X-Ray Microtomography
references.citation: Dent Mater. 2000 Nov;16(6):412-9
references.pmid: 10967190
references.citation: J Anat. 2008 Apr;212(4):486-500
references.pmid: 18380867
references.citation: J Biomed Opt. 2001 Apr;6(2):224-30
references.pmid: 11375733
references.citation: Crit Rev Oral Biol Med. 2003;14(1):13-29
references.pmid: 12764017
references.citation: J Dent Res. 1976 Nov-Dec;55(6):1004-11
references.pmid: 1069748
references.citation: J Struct Biol. 2009 Dec;168(3):511-20
references.pmid: 19635570
references.citation: J Dent Res. 1993 Nov;72(11):1526-31
references.pmid: 8227704
references.citation: Am J Phys Anthropol. 2003 Sep;122(1):38-50
references.pmid: 12923903
references.citation: J Biomed Opt. 2005 Mar-Apr;10(2):024020
references.pmid: 15910094
references.citation: Dent Mater. 2003 May;19(3):159-66
references.pmid: 12628426
references.citation: J Dent. 2006 Jan;34(1):12-8
references.pmid: 15907356
references.citation: Arch Oral Biol. 1999 Oct;44(10):813-22
references.pmid: 10530914
references.citation: J Prosthet Dent. 1999 Mar;81(3):345-55
references.pmid: 10050124
references.citation: Am J Phys Anthropol. 1990 Oct;83(2):219-37
references.pmid: 2248381
references.citation: Arch Oral Biol. 1996 Jan;41(1):9-13
references.pmid: 8833584
references.citation: J Biomech. 1998 Feb;31(2):135-41
references.pmid: 9593206
references.citation: Aust Dent J. 2002 Sep;47(3):218-22
references.pmid: 12405461
references.citation: Am J Phys Anthropol. 1998 Aug;106(4):467-82
references.pmid: 9712476
references.citation: Am J Phys Anthropol. 1986 Sep;71(1):103-13
references.pmid: 3777142
references.citation: Opt Lasers Eng. 2007 Aug;45(8):843-851
references.pmid: 18670581
references.citation: Am J Phys Anthropol. 2007 Jul;133(3):986-93
references.pmid: 17455285
references.citation: J Hum Evol. 2009 Mar;56(3):275-85
references.pmid: 19285590
references.citation: J Mater Sci Mater Med. 1999 Aug;10(8):485-8
references.pmid: 15348117
references.citation: Am J Phys Anthropol. 1976 Sep;45(2):299-308
references.pmid: 822732
references.citation: J Hum Evol. 2006 Jun;50(6):663-72
references.pmid: 16530808
references.citation: Am J Primatol. 1996;38(2):145-156
references.pmid: 31918473
references.citation: J Struct Biol. 2006 Feb;153(2):188-99
references.pmid: 16414277
references.citation: Arch Oral Biol. 2002 Apr;47(4):281-91
references.pmid: 11922871
references.citation: J Hum Evol. 2009 Mar;56(3):263-74
references.pmid: 19249076
references.citation: Science. 1975 Sep 26;189(4208):1095-8
references.pmid: 808855
references.citation: Arch Oral Biol. 2000 Jul;45(7):543-50
references.pmid: 10785517
references.citation: Crit Rev Oral Biol Med. 1993;4(5):679-728
references.pmid: 8292714
references.citation: Calcif Tissue Int. 2001 Sep;69(3):147-57
references.pmid: 11683529