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PloS one2017; 12(8); e0183220; doi: 10.1371/journal.pone.0183220

Uneven distribution of enamel, dentine and cementum in cheek teeth of domestic horses (Equus caballus): A micro computed tomography study.

Abstract: Hypsodont equine cheek teeth possess large dental crowns, resting partly in the bony alveolus. Over a horse's life cheek teeth erupt continuously to compensate for occlusal wear of 3-4 mm per year. Parts of the crown initially resting in the bony alveolus become progressively exposed at the occlusal surface with time. Hitherto, it is unclear whether the typical structure of the equine occlusal surface, composed of a complex arrangement of enamel, dentin and cementum, remains constant or undergoes structural changes with age. Therefore, we tested the hypothesis that the occlusal surface composition does not remain constant by a quantitative analysis of the dental substances at multiple levels along the dental crown of equine cheek teeth. Methods: Micro-computed tomography scans of 20 upper cheek teeth and 16 lower cheek teeth from 19 domestic horses were morphologically analysed using imaging and measurement software. Area for individual dental substances was measured at different levels from the apex to the occlusal surface. The data was statistically analysed to detect changes in the area of individual substance along the dental crown. The area of peripheral cementum was measured separately for levels inside and outside the bony alveolus. Results: In both, upper and lower cheek teeth, enamel area decreased in an apical direction, while dentine area increased. Peripheral Cementum increased dramatically in the occlusal/coronal extra-alveolar position. Conclusions: With increasing age the occlusal surface content of dentine increases while the content of enamel decreases. These changes are considered relevant for the detailed explanation of forage disruption in horses as well as for the recommendation of concepts in equine dentistry.
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Publication Date: 2017-08-16 PubMed ID: 28813496PubMed Central: PMC5558931DOI: 10.1371/journal.pone.0183220Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The article investigates the composition of horse teeth over their lifetime, specifically the proportions of enamel, dentin, and cementum and their changes with age. The study used micro-computed tomography to analyze these changes in 20 upper teeth and 16 lower teeth from 19 horses.

Research Process

  • Researchers used a technique called micro-computed tomography, a type of scanning that reveals fine details, to examine the anatomy of horse teeth. This technology allowed them to gather accurate data on the different components of the teeth: enamel, dentin, and cementum.
  • The study focused on cheek teeth which possess large dental crowns and are known to erupt continuously throughout the horse’s life, which compensates for the wear and tear of chewing. These teeth start out partly inside the bone, but over time, their deeper layers become exposed due to the constant use and wear.
  • The authors took measurements of the enamel, dentine, and cementum areas at various levels from the apex (the tip of the tooth’s root) to the crown (the top, showing part of the tooth).

Findings

  • The results found that the area of enamel decreases while the area of dentin increases as one moves from the crown towards the apex of the tooth.
  • Areas of cementum, especially around the periphery outside of the bony socket (alveolus), also increased significantly.
  • Overall, it was observed that the composition of a horse’s occlusal (chewing) surface changes as the horse ages—the amount of dentine increases, while the amount of enamel decreases.

Conclusions and Implications

  • The research concluded that the ratios of enamel, dentin, and cementum in horse teeth do not remain constant but change with age—specifically, dentin increases while enamel decreases over time.
  • This study provides important insights into the wear-and-tear process of horses’ teeth over their lifetimes, which is helpful for understanding how horses break down their food and also contributes to current dental care approaches for horses.
  • Such knowledge could assist in improving equine dental care and might also be useful for veterinary dentists who are designing treatment strategies or recommendations for dental care in horses.

Cite This Article

APA
Englisch LM, Kostrzewa K, Kopke S, Failing K, Staszyk C. (2017). Uneven distribution of enamel, dentine and cementum in cheek teeth of domestic horses (Equus caballus): A micro computed tomography study. PLoS One, 12(8), e0183220. https://doi.org/10.1371/journal.pone.0183220

Publication

PloS one
ISSN: 1932-6203
NlmUniqueID: 101285081
Country: United States
Language: English
Volume: 12
Issue: 8
Pages: e0183220
PII: e0183220

Researcher Affiliations

Englisch, Lauritz Martin
  • Institute of Veterinary-Anatomy, -Histology and -Embryology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.
Kostrzewa, Kathrin
  • Institute of Veterinary-Anatomy, -Histology and -Embryology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.
Kopke, Susan
  • Clinical Skills Lab, University of Veterinary Medicine Hannover Foundation, Hannover, Germany.
Failing, Klaus
  • Unit for Biomathematics and Data Processing, Justus Liebig University Giessen, Giessen, Germany.
Staszyk, Carsten
  • Institute of Veterinary-Anatomy, -Histology and -Embryology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.

MeSH Terms

  • Animals
  • Dental Cementum / metabolism
  • Dental Enamel / metabolism
  • Dentin / metabolism
  • Horses
  • Tooth / metabolism
  • X-Ray Microtomography / methods

Conflict of Interest Statement

The authors have declared that no competing interests exist.

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Citations

This article has been cited 3 times.
  1. Taylor WTT, Barrón-Ortiz CI. Rethinking the evidence for early horse domestication at Botai. Sci Rep 2021 Apr 2;11(1):7440.
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  2. Heilen LB, Roßgardt J, Dern-Wieloch J, Vogelsberg J, Staszyk C. Odontoblasts in Equine Hypsodont Teeth-How They Cope with Permanent Occlusal Wear. Animals (Basel) 2026 Jan 22;16(2).
    doi: 10.3390/ani16020341pubmed: 41594529google scholar: lookup
  3. Zhan X, Xing L, Meng L, Cheng Y, Wang J, Wang Q, Sun X. Morphological observations on the role of HERS cells in cementum development of rabbit molars. Front Bioeng Biotechnol 2025;13:1659704.
    doi: 10.3389/fbioe.2025.1659704pubmed: 41069409google scholar: lookup
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