Enamel thickness and the topography of the enamel–dentine junction in South African Plio-Pleistocene hominids with special reference to the Carabelli trait

Schwartz, Gary T.; Thackeray, J. Francis; Reid, Cynthia; Reenan, J.F van

doi:10.1006/jhev.1998.0239

Cited by 77 publications

(59 citation statements)

References 42 publications

(66 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, measurements derived from flat-plane radiographs are unlikely to accurately reflect the true values as defined by physical sections . Grossly inaccurate measurements result with the use of standard CT methods (Grine, 1991), and accurate linear values of thickly enameled teeth can be obtained only by employing specific CT instrumentation and protocols (Spoor et al, 1993;Schwartz et al, 1998).…”

Section: Specimen Preparation and Examinationmentioning

confidence: 99%

Enamel thickness of deciduous and permanent molars in modern Homo sapiens

Grine

2004

American J Phys Anthropol

128

156

View full text Add to dashboard Cite

This study presents data on the enamel thickness of deciduous (dm2) and permanent (M1-M3) molars for a geographically diverse sample of modern humans. Measurements were recorded from sections through the mesial cusps of unworn teeth. Enamel is significantly thinner on deciduous than on permanent molars, and there is a distinct trend for enamel to increase in relative thickness from M1 to M3. The relatively thicker enamel of M2s and especially M3s can be related to the overall reduction in size of more distal molar crowns, which has been attained through a differential loss of the dentine component. Enamel tends to be thicker on the protocone than on the paracone, and thicker on the protoconid than on the metaconid, but its distribution is not wholly concordant with models that predict increased thickness as a means by which to counter heavier attritional loss on these "functional" cusps. Indeed, the thickness of enamel tends to be more variable on cusp tips and occlusal surfaces than over the lateral aspects of cusps. The proportionately thicker enamel over the lateral aspects of the protocone and protoconid more likely serves as a means to prolong functional crown life by preventing cusp fracture, rather than being an adaptation to increase the attritional longevity of wear facets. The present data suggest that the human dentition is not predisposed to develop a helicoidal wear plane through the disposition of molar enamel thickness.

show abstract

Section: Specimen Preparation and Examinationmentioning

confidence: 99%

Enamel thickness of deciduous and permanent molars in modern Homo sapiens

Grine

2004

American J Phys Anthropol

128

156

View full text Add to dashboard Cite

show abstract

“…One suggestion of an optimal measure for comparative purposes is volume of enamel over the entire tooth (Martin, 1983), which necessitates either the use of destructive procedures such as separating the enamel cap from the underlying dentine surface (e.g., Kraus, 1952;Korenhof, 1960;Nager, 1960;Achermann, 1970;Sakai, 1967;Corruccini, 1987a,b), or noninvasive imaging modalities such as computed tomography (e.g., Conroy, 1991;Schwartz, 1997;Schwartz et al, 1998;Hlusko and Suwa, 2002;Kono, 2004). Linear measurements of tissue thickness (e.g., Macho and Berner, 1993;Schwartz, 2000a,b) may be less ideal representations of total tissue volumes than area measurements and the indices derived from those areas (Martin, 1983;Molnar et al, 1993;Shellis et al, 1998).…”

mentioning

confidence: 99%

Sexual dimorphism in modern human permanent teeth

Schwartz

Dean

2005

Am. J. Phys. Anthropol.

168

163

View full text Add to dashboard Cite

On average, males possess larger tooth crowns than females in contemporary human populations, although the degree of dimorphism varies within different populations. In previous studies, different amounts of either enamel or dentine were implicated as the cause of this dimorphism. In this study, we attempt to determine the nature of sexual dimorphism in the crowns of permanent modern human teeth and to determine if two contrasting tooth types (permanent third molars and canines) show identical patterns of dimorphism in enamel and dentine distribution. We estimated the relative contributions of both enamel and dentine to total crown size, from buccolingual sections of teeth. Our sample consisted of a total of 144 mandibular permanent third molars and 25 permanent mandibular canines of known sex. We show that sexual dimorphism is likely due, in part, to the presence of relatively more dentine in the crowns of male teeth. However, whatever the underlying cause, dimorphism in both tooth root and tooth crown size should produce measurable dimorphism in tooth weight, though this has not been previously explored. Therefore, we provide some preliminary data that indicate the usefulness of wet tooth weight as a measure of sexual dimorphism. Both male permanent third molars and canines are significantly heavier than those of females. The weight dimorphism reported here for both classes of teeth may prove a useful finding for future forensic studies. In particular, weights of canines may be more useful as a means of sexing modern human skeletal material than linear or area measurements of teeth.

show abstract

“…Computed tomography (CT) has also been utilized to quantify enamel thickness in recent and fossil hominin teeth (e.g., Zonneveld and Wind, 1985;Conroy, 1991;Conroy and Vanier, 1991;Macho and Thackeray, 1992;Conroy et al, 1995;Schwartz et al, 1998). With the exception of the study by Schwartz et al (1998), however, these analyses have employed standard CT scans, a technique that has been demonstrated to be grossly inaccurate in the measurement of enamel thickness (Grine, 1991).…”

mentioning

confidence: 99%

“…With the exception of the study by Schwartz et al (1998), however, these analyses have employed standard CT scans, a technique that has been demonstrated to be grossly inaccurate in the measurement of enamel thickness (Grine, 1991). Standard CT images generally exaggerate enamel thickness compared to values obtained from mechanical sections (Grine, 1991).…”

mentioning

confidence: 99%

Assessment of the accuracy of dental enamel thickness measurements using microfocal X‐ray computed tomography

2006

View full text Add to dashboard Cite

Tooth enamel thickness has long been an important character in studies of primate and especially hominin phylogeny, taxonomy, and adaptation. Current methods for accurately assessing enamel thickness involve the physical sectioning of teeth, because measurements of enamel thickness using some radiographic techniques are unreliable. However, because destructive methods limit sample sizes and access to important fossil specimens, it is desirable that they be replaced with nondestructive techniques. Although microfocal X-ray computed tomography (mCT) has been used recently in studies of enamel thickness, the accuracy of this technique has yet to be established. The present research compares physical sections to computer-generated mCT sections of teeth from a variety of primate and nonprimate, recent and fossil taxa to examine whether enamel thickness, tooth size, and diagenetic remineralization (fossilization) impact the ability of mCT to measure enamel thickness accurately. Results indicate that recent teeth of varying size and thickness are clearly and accurately depicted in mCT scans, with measurements from nearly identical planes in physical and mCT sections differing by 3-5%. A fossil papionin molar (ca. 2 Myr) was also accurately measured using mCT scans, although thinner enamel in much older therapsid (ca. 263-241 Myr) teeth could not be distinguished from dentine. mCT is thus an accurate technique for measuring enamel thickness in recent taxa, although heavily mineralized teeth pose an obstacle to the ability of mCT to distinguish dental tissues. Moreover, absolutely thin enamel (less than ϳ 0.10 mm) is difficult to resolve adequately in raw mCT images based on pixel values alone. Therefore, caution must be exercised in the application of mCT to the study of fossilized teeth. © 2006 Wiley-Liss, Inc.Key words: mCT; microfocal X-ray computed tomography; enamel thickness; measurement accuracy; diagenesis; dental enamel; dentine Tooth enamel thickness has long been considered to be of importance in the interpretation of human evolution because of its purported taxonomic and phylogenetic value

show abstract

Enamel thickness and the topography of the enamel–dentine junction in South African Plio-Pleistocene hominids with special reference to the Carabelli trait

Cited by 77 publications

References 42 publications

Enamel thickness of deciduous and permanent molars in modern Homo sapiens

Enamel thickness of deciduous and permanent molars in modern Homo sapiens

Sexual dimorphism in modern human permanent teeth

Assessment of the accuracy of dental enamel thickness measurements using microfocal X‐ray computed tomography

Contact Info

Product

Resources

About