dental anatomy

Donkey dental anatomy. Part 2: histological and scanning electron microscopic examinations

Ten normal cheek teeth (CT) were extracted at post mortem from donkeys that died or were euthanased for humane reasons. Decalcified histology was performed on three sections (sub-occlusal, mid-tooth and pre-apical) of each tooth, and undecalcified histology undertaken on sub-occlusal sections of the same teeth. The normal histological anatomy of primary, regular and irregular secondary dentine was found to be similar to that of the horse, with no tertiary dentine present. Undecalcified histology demonstrated the normal enamel histology, including the presence of enamel spindles. Scanning electron microscopy was performed on mid-tooth sections of five maxillary CT, five mandibular CT and two incisors. The ultrastructural anatomy of primary and secondary dentine, and equine enamel types-1, -2 and -3 (as described in horses) were identified in donkey teeth. Histological and ultrastructural donkey dental anatomy was found to be very similar to equine dental anatomy with only a few quantitative differences observed.

Volume
176
Issue
3
Start page
345
End page
353
Publication date
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Donkey dental anatomy. Part 1: gross and computed axial tomography examinations

Post-mortem examination of 19 donkey skulls showed that donkeys have a greater degree of anisognathia (27% width difference between upper and lower jaws) compared to horses (23%). Teeth (n = 108) were collected from 14 skulls and examined grossly and by computed axial tomography (CAT). A greater degree of peripheral enamel infolding was found in mandibular cheek teeth (CT) compared to maxillary CT (P < 0.001). A significant increase in peripheral cementum from the apical region to the clinical crown was demonstrated in all CT (P < 0.0001). All donkey CT had at least five pulp cavities with six pulp cavities present in the 06s and 11s. A new endodontic numbering system for equid CT has been proposed. A greater occlusal depth of secondary dentine (mm) was present in older donkeys (>16 years) than in the younger (<15 years) donkeys studied. Based on gross and CAT examinations, donkey dental anatomy was shown to be largely similar to that described in horses.

Volume
176
Issue
3
Start page
338
End page
344
Publication date
Country

Normal donkey dental anatomy

Nicole du Toit
Susan A. Kempson
Padraic M. Dixon
Presentation date

This study examined normal donkey teeth using gross anatomical inspection, computed axial tomography (CAT), radiography, scanning electron microscopy (SEM) and, decalcified and undecalcified histology to determine their normal gross anatomy, histology and ultrastructure. CAT findings have shown donkey endodontic anatomy and the density (in Hounslow units) of donkey calcified dental tissues, i.e. enamel, dentine and cementum to be similar to values recorded in horses. Decalcified and undecalcified histology has identified donkey cheek teeth to have a similar histological appearance to that which has been described in the horse. SEM of donkey dental tissue has demonstrated minor differences to normal horse dental ultrastructure. Now that normal donkey dental anatomy has been clearly defined, pathological changes can be identified in diseased teeth and supporting structures and will allow a better understanding of the pathophysiology of common donkey dental disorders. Ultimately the results of this project will enable better dental care specifically developed for donkeys, promoting welfare in the donkey.

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Published as conference proceedings
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