title: Unravelling the functional biomechanics of dental features and tooth wear.
abstract: Most of the morphological features recognized in hominin teeth, particularly the topography of the occlusal surface, are generally interpreted as an evolutionary functional adaptation for mechanical food processing. In this respect, we can also expect that the general architecture of a tooth reflects a response to withstand the high stresses produced during masticatory loadings. Here we use an engineering approach, finite element analysis (FEA), with an advanced loading concept derived from individual occlusal wear information to evaluate whether some dental traits usually found in hominin and extant great ape molars, such as the trigonid crest, the entoconid-hypoconulid crest and the protostylid have important biomechanical implications. For this purpose, FEA was applied to 3D digital models of three Gorillagorilla lower second molars (M2) differing in wear stages. Our results show that in unworn and slightly worn M2s tensile stresses concentrate in the grooves of the occlusal surface. In such condition, the trigonid and the entoconid-hypoconulid crests act to reinforce the crown locally against stresses produced along the mesiodistal groove. Similarly, the protostylid is shaped like a buttress to suffer the high tensile stresses concentrated in the deep buccal groove. These dental traits are less functional in the worn M2, because tensile stresses decrease physiologically in the crown with progressing wear due to the enlargement of antagonistic contact areas and changes in loading direction from oblique to nearly parallel direction to the dental axis. This suggests that the wear process might have a crucial influence in the evolution and structural adaptation of molars enabling to endure bite stresses and reduce tooth failure throughout the lifetime of an individual.
authors.affiliation: Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany. stefano_benazzi@eva.mpg.de
authors.forename: Stefano
authors.initials: S
authors.lastname: Benazzi
authors.forename: Huynh Nhu
authors.initials: HN
authors.lastname: Nguyen
authors.forename: Ottmar
authors.initials: O
authors.lastname: Kullmer
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Hublin
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001696:Biomechanical Phenomena; D001734:Bites, Human; D003743:Dental Enamel / Q000033:anatomy & histology; D003766:Dental Occlusion; D020342:Finite Element Analysis; D018732:Forensic Anthropology; D006071:Gorilla gorilla / Q000033:anatomy & histology; D015186:Hominidae / Q000033:anatomy & histology*; D006801:Humans; D008962:Models, Theoretical; D008963:Molar / Q000033:anatomy & histology; D013314:Stress, Mechanical; D057085:Tooth Wear
references.citation: Clin Oral Investig. 2014;18(2):369-75
references.pmid: 23504207
references.citation: Acta Biomater. 2010 Dec;6(12):4560-5
references.pmid: 20656077
references.citation: J Anat. 2011 Sep;219(3):259-72
references.pmid: 21615398
references.citation: Am J Phys Anthropol. 1975 Sep;43(2):195-216
references.pmid: 810034
references.citation: J Hum Evol. 2004 May;46(5):579-94
references.pmid: 15120266
references.citation: J Prosthet Dent. 1996 Feb;75(2):140-7
references.pmid: 8667271
references.citation: Am J Phys Anthropol. 2009 Dec;140(4):653-60
references.pmid: 19890852
references.citation: Med Biol Eng Comput. 2009 Apr;47(4):367-74
references.pmid: 18679734
references.citation: Dent Mater. 2010 Sep;26(9):e211-9
references.pmid: 20542552
references.citation: J Prosthet Dent. 2007 Aug;98(2):89-100
references.pmid: 17692590
references.citation: Acta Biomater. 2009 Jul;5(6):2213-21
references.pmid: 19268644
references.citation: Am J Phys Anthropol. 1999 Jun;109(2):211-27
references.pmid: 10378459
references.citation: J Hum Evol. 2008 Jul;55(1):60-74
references.pmid: 18243275
references.citation: J Biomed Mater Res B Appl Biomater. 2007 Jan;80(1):78-85
references.pmid: 16615075
references.citation: Am J Phys Anthropol. 2000 Feb;111(2):221-44
references.pmid: 10640949
references.citation: J Morphol. 2011 Jan;272(1):50-65
references.pmid: 20960463
references.citation: Nature. 2005 Aug 4;436(7051):693-5
references.pmid: 16079844
references.citation: J Oral Rehabil. 2013 Jan;40(1):69-79
references.pmid: 22882571
references.citation: J Hum Evol. 2004 May;46(5):605-22
references.pmid: 15120268
references.citation: Bioessays. 2008 Apr;30(4):374-85
references.pmid: 18348196
references.citation: J Hum Evol. 2009 Jan;56(1):76-85
references.pmid: 18986683
references.citation: Am J Phys Anthropol. 1974 Mar;40(2):227-56
references.pmid: 4815136
references.citation: Proc Natl Acad Sci U S A. 2003 Apr 1;100(7):3874-7
references.pmid: 12634426
references.citation: J Dent Res. 1993 Nov;72(11):1526-31
references.pmid: 8227704
references.citation: Science. 2011 Oct 14;334(6053):190-3
references.pmid: 21998380
references.citation: J Biomech. 2009 Aug 25;42(12):1947-51
references.pmid: 19559438
references.citation: J Hum Evol. 2010 Jan;58(1):23-32
references.pmid: 19783029
references.citation: Acta Biomater. 2012 Dec;8(12):4426-37
references.pmid: 22902822
references.citation: Acta Biomater. 2009 Jun;5(5):1663-7
references.pmid: 19269906
references.citation: Acta Biomater. 2011 May;7(5):2285-92
references.pmid: 21296195
references.citation: Anat Rec (Hoboken). 2012 May;295(5):846-52
references.pmid: 22419654
references.citation: Anat Rec (Hoboken). 2010 Apr;293(4):594-606
references.pmid: 20235316
references.citation: Int J Periodontics Restorative Dent. 2002 Oct;22(5):425-33
references.pmid: 12449302
references.citation: Int J Biomater. 2010;2010:
references.pmid: 20706535
references.citation: J Dent Biomech. 2010;2010:902537
references.pmid: 20981154
references.citation: Acta Biomater. 2009 Oct;5(8):3045-56
references.pmid: 19433137
references.citation: Biol Rev Camb Philos Soc. 2011 Nov;86(4):959-74
references.pmid: 21507194
references.citation: Am J Phys Anthropol. 1984 Jan;63(1):39-56
references.pmid: 6422767
references.citation: Proc Natl Acad Sci U S A. 2009 May 5;106(18):7289-93
references.pmid: 19365079
references.citation: Dent Mater. 2011 Nov;27(11):1127-34
references.pmid: 21908033
references.citation: J Dent Res. 1983 Feb;62(2):82-6
references.pmid: 6571871
references.citation: J Biomech. 2009 Jul 22;42(10):1533-1538
references.pmid: 19446816
references.citation: J Prosthet Dent. 1992 Sep;68(3):421-7
references.pmid: 1432755
references.citation: Am J Phys Anthropol. 2012 Jan;147(1):128-34
references.pmid: 21952986
references.citation: PLoS One. 2013 Apr 24;8(4):e62263
references.pmid: 23638020