Two-dimensional patterns of human enamel thickness on deciduous (dm1, dm2) and permanent first (M1) mandibular molars

Mahoney, Patrick

doi:10.1016/j.archoralbio.2009.11.014

Cited by 40 publications

(44 citation statements)

References 50 publications

(71 reference statements)

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“…The expectation, formulated in a purely functional perspective, of LETDI ratios < 1.0 (the M1 crown being in principle equipped with a thicker coating of enamel for resisting higher and prolonged wear-inducing loads) is not fully satisfied by the present results (for enamel proportions in extant human lower dm1s-dm2s-M1s, see Mahoney, 2010). In two representatives from as many taxa it is close to be falsified: an extant human individual (0.99), and the Australopithecus representative (0.98), even if the large majority of the ratios are around or below 0.8.…”

Section: Discussioncontrasting

confidence: 74%

“…2) show also that the opposite can occur, i.e., that the deciduous and permanent molars of both thickly-enamelled hominids (e.g., Ouranopithecus) and representatives of relatively thinly-enamelled taxa (e.g., Gorilla, Pongo) may present comparable values of lateral relative enamel thickness (3D LRET). In sum, even if present results tend to support the evidence that primate "deciduous teeth have thinner enamel than permanent teeth" (Swindler, 2002: 14), including in humans (Mahoney, 2010), the extent of their enamel proportions, at least for non-occlusal enamel, appears rather variable.…”

Section: Discussionsupporting

confidence: 67%

“…A limiting/complicating factor in our analytical approach is the use of non-occlusal enamel compared to the information imprinted occlusally, or even at specific cuspal level (e.g., Grine, 2005;Kono et al, 2002;Macho and Berner, 1993;Mahoney, 2010;Schwartz, 2000b). However, lateral enamel has its own signals that have never been previously explored as a functional unit independent of occlusal enamel thickness.…”

Section: Discussionmentioning

confidence: 99%

“…in Bailey et al, 2014Bailey et al, , 2016; see also Evans et al, 2016), i.e., they are meristic elements with a similar and serially repeated structure within the same organism (Butler, 1956(Butler, , 1967Kraus and Jordan, 1965). In this study on some extant and fossil hominids, we thus investigate the degree of covariation in enamel proportions between the dm2 and the M1 (for the extant human condition, see Gantt et al, 2001;Grine, 2005;Huszár, 1972;Mahoney, 2010;Rossi et al, 1999). In order to perform intertaxonomic comparisons, we established a so-called "lateral enamel thickness diphyodontic index" (LETDI; see § Materials and methods) as a measure of the proportions in the amount of non-occlusal enamel (Macchiarelli et al, 2016;Zanolli, 2015b).…”

Section: Introductionmentioning

confidence: 99%

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Is the deciduous/permanent molar enamel thickness ratio a taxon-specific indicator in extant and extinct hominids?

Zanolli

Bayle

Bondioli

et al. 2017

Comptes Rendus Palevol

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Handled by Roberto Macchiarelli and Clément ZanoliiKeywords: Enamel Dm2 M1 "Diphyodontic index" Hominids abstract In Primates, enamel thickness variation stems from an evolutionary interplay between functional/adaptive constraints (ecology) and the strict control mechanisms of the morphogenetic program. Most studies on primate enamel thickness have primarily considered the permanent teeth, while the extent of covariation in tooth enamel thickness distribution between deciduous and permanent counterparts remains poorly investigated. In this test study on nine extant and fossil hominids we investigated the degree of covariation in enamel proportions between 25 pairs of mandibular dm2 and M1 by a so-called "lateral enamel thickness diphyodontic index". The results did not provide an unambiguous picture, but rather suggest complex patterns likely resulting from the influence of many interactive factors. Future research should test the congruence of the "diphyodontic signal" between the anterior and the postcanine dentition, as well as between enamel and the enamel-dentine junction topography.

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Section: Discussioncontrasting

confidence: 74%

Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Is the deciduous/permanent molar enamel thickness ratio a taxon-specific indicator in extant and extinct hominids?

Zanolli

Bayle

Bondioli

et al. 2017

Comptes Rendus Palevol

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“…Toro-Moyano et al (2013:2) claimed erroneously that the enamel thickness of BL5-0 "is clearly thinner than in human teeth." The lateral enamel thickness in the molars of adult early Homo varies from 1.2 to 2.1 mm (Beynon and Wood 1986), the lateral enamel thickness in the lower M1 of extant Homo from 0.96 to 2.19 (Mahoney 2010), and lateral thickness of dm1 and dm2 in extant Homo from 0.32 to 1.27 mm (Mahoney 2010). Therefore, the thickness of the enamel of BL5-0, 1.2 mm, falls within human variability (figs.…”

Section: Comparison With Hippo Deciduous Teeth and With Human Tooth Bmentioning

confidence: 69%

Two Deciduous Human Molars from the Early Pleistocene Deposits of Barranco León (Orce, Spain)

Ribot¹,

Gibert²,

Ferràndez-Cañadell³

et al. 2015

Current Anthropology

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Human deciduous mandibular molar incremental enamel development

Mahoney¹

2010

American J Phys Anthropol

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Quantitative studies of incremental markings retained within human enamel have reconstructed the duration and rate (crown and cusp formation times, initiation and completion, daily enamel secretion rates) of permanent tooth development. This approach has provided one way of estimating human age-at-death, and facilitated comparative dental studies of primate evolution. Similar applications from deciduous enamel are inhibited because developmental reconstructions from incremental markings for these teeth are less frequently reported in the literature. This study quantified the duration and rate of enamel development for mesial (protoconid, metaconid) and distal cusps (hypoconid, entoconid) for first (dm1) and second (dm2) deciduous mandibular molars from an archaeological sample of modern human juveniles. Crown formation time can be calculated from the dm1 protoconid because growth initiates and completes in this cusp, and from the dm2 protoconid combined with the final period of hypoconid growth. The dm1 postnatal crown formation time included the time taken for the tubercle of Zuckerkandl to develop, and differed slightly compared to radiographic methods. The majority of dm1 protoconid cuspal (occlusal region) enamel formed before birth. The dm2 entoconid enamel formed mainly after birth. Birth reduced daily enamel secretion rates, changed the visibility of incremental markings, and disrupted enamel growth for 3 to 8 days. Findings presented here can contribute to age-at-death estimates for human infants aged 13-postnatal months or less, and should facilitate comparisons of primate deciduous incremental enamel development in an evolutionary context. Regression equations are included so that cuspal formation time can be estimated from enamel thickness. Human deciduous molar enamel development (crown and cusp formation times, initiation and completion, growth rates) has been documented from studies of radiographs, measurements of tooth length, and direct observation of the developing fetal dentition (e.g., Logan and Kronfeld, 1933;Schour and Massler, 1941;Kraus, 1959;Fanning, 1961;Moorrees et al., 1963;Gilster et al., 1964;Kraus and Jordan, 1965;Fanning and Brown, 1971;Demirjian et al., 1973;Liversidge et al., 1993;Liversidge and Molleson, 2004). Standards of formation time have been developed from some of these studies, which are routinely used to estimate age-at-death for human skeletons recovered from bioarchaeological and forensic contexts (e.g., Demirjian et al., 1973). Others have used a different methodology and calculated formation times from histological studies of incremental markings retained within enamel (Boyde, 1963). Though these histologically-derived formation times are well reported for permanent teeth in the literature (e.g., Reid and Dean, 2006), they are scarcely reported for deciduous teeth (FitzGerald et al., 1999;Katzenberg et al., 2005; also see Shellis 1984, and comments by Smith et al., 2006). This lack of data is mainly due to the poor preservation of these markings in deciduous...

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Two-dimensional patterns of human enamel thickness on deciduous (dm1, dm2) and permanent first (M1) mandibular molars

Cited by 40 publications

References 50 publications

Is the deciduous/permanent molar enamel thickness ratio a taxon-specific indicator in extant and extinct hominids?

Is the deciduous/permanent molar enamel thickness ratio a taxon-specific indicator in extant and extinct hominids?

Two Deciduous Human Molars from the Early Pleistocene Deposits of Barranco León (Orce, Spain)

Human deciduous mandibular molar incremental enamel development

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