Occlusal Angles of Equine Incisors.
Abstract: The angulation of equine incisors is frequently used as a parameter for dental corrections. However, the term incisor angle is only vaguely defined, and no studies exist presenting a series of reliable measurements in individual incisors of multiple horses. The aim of this study was to establish an exact method to determine incisor angles and to test whether clinically accessible landmarks (facial crest and bars) are suitable to estimate incisor angles. Eighteen horses were used to create 3-dimensional (3D) reconstructions of the skulls from computed tomography (CT) data sets. Reference planes (median and transverse plane) were calculated using defined anatomical landmarks. Subsequently, occlusal planes for incisors and for incisor quadrants were calculated. Occlusal table angles were measured in relation to the reference planes. For each incisor, sagittal and transverse angles were measured. Mean values of individual incisor angles ranged from 3.5° to 6.8° (transverse angle) and from 32.6° to 44.9° (sagittal angle). No significant differences were detected in mean between the left and the right side when teeth in same Triadan positions were compared. However, in individual horses, marked differences between the left and the right side of the jaws occurred. Mandibular incisors showed significantly steeper sagittal angles than maxillary incisors. Furthermore, angles of opposing incisors were correlated with each other. The facial crest and the upper jaw bars featured a curved shape and were therefore of limited use to estimate the angulation of the upper incisors. In contrast, the lower jaw bars were suitable to determine the angulations of lower incisors.
Publication Date: 2017-11-14 PubMed ID: 29130414DOI: 10.1177/0898756417739465Google Scholar: Lookup
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- Journal Article
Summary
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The research focuses on defining a precise method to measure the angles of horse incisors and examining if certain visible facial features can help estimate these angles. Through CT scans and mathematical models, the researchers found varied incisor angles among horses, invalidating the use of some visible traits, but confirming others as accurate indicators of these angles.
Study Design and Conduct
- The researchers started the study with eighteen horses and performed Computed Tomography (CT) scans on their skulls to obtain comprehensive images.
- All the skulls were reconstructed into 3-dimensional forms using these scan data, and anatomical landmarks were employed to infer median and transverse planes for reference.
- They then calculated occlusal (contact between teeth) planes for every individual incisor and quadrant of incisors, and measured their angles against the established reference planes. Sagittal (vertical) and transverse (horizontal) angles were derived for each tooth.
Results and Findings
- The research discovered that means of individual incisor angles varied between 3.5° to 6.8° for the transverse angle and 32.6° to 44.9° for the sagittal angle.
- There were no significant differences identified in mean angles between the left and right sides when teeth were matched in similar dental positions (Triadan system), however individual horses displayed noticeable differences between teeth on opposite sides of their jaws.
- Mandibular (lower jaw) incisors were found to have significantly steeper sagittal angles than maxillary (upper jaw) incisors, with the opposing incisors having correlated angles.
Evaluation of Visible Landmarks
- The researchers assessed the usefulness of visible anatomical features in estimating incisor angles and found that the facial crest and upper jaw bars, due to their curved shape, were not reliable measures for upper incisors’ angulation.
- On the other hand, the lower jaw bars proved to be embedded with useful indicators that could accurately align with the angulations of the lower incisors.
Conclusion
- This study formed a precise way to determine incisor angles in horses and demonstrated that certain visible hallmarks of equine facial anatomy, specifically the lower jaw bars, can help estimate these angles effectively.
- This work offers a valuable contribution to equine dentistry, paving the way for improved dental correction techniques and overall dental health for horses.
Cite This Article
APA
Listmann L, Schrock P, Failing K, Staszyk C.
(2017).
Occlusal Angles of Equine Incisors.
J Vet Dent, 34(4), 259-267.
https://doi.org/10.1177/0898756417739465 Publication
Researcher Affiliations
- 1 Faculty of Veterinary Medicine, Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University Giessen, Giessen, Germany.
- 1 Faculty of Veterinary Medicine, Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University Giessen, Giessen, Germany.
- 2 Unit for Biomathematics and Data Processing, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
- 1 Faculty of Veterinary Medicine, Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig-University Giessen, Giessen, Germany.
MeSH Terms
- Animals
- Dental Occlusion
- Female
- Horses / anatomy & histology
- Incisor / anatomy & histology
- Male
- Mandible / anatomy & histology
- Maxilla / anatomy & histology
Citations
This article has been cited 2 times.- Kau S, Motter KS, Moser VJ, Kunz JR, Pellachin M, Hartl B. Intra- and Interexaminer Measurement Variability Analysis of an Orthodontic Gauge Device to Determine Incisor Occlusal Surface Angles in the Horse.. Vet Sci 2022 Sep 7;9(9).
- Kau S, Failing K, Staszyk C. Computed Tomography (CT)-Assisted 3D Cephalometry in Horses: Interincisal Angulation of Clinical Crowns.. Front Vet Sci 2020;7:434.
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