Donkey dental anatomy. Part 1: Gross and computed axial tomography examinations.

The research article discusses a study carried out on 19 donkey skulls to analyse donkey dental anatomy, comparing this to horses, and suggesting a new endodontic numbering system for equid cheek teeth.

Research Conduct & Methodology

• The research involved the study of 19 donkey skulls post-mortem. This sample was used to make gross and computed axial tomography (also known as CAT or CT scans) examinations of donkey dental morphology.
• Teeth were collected from 14 of these skulls (totaling 108 teeth). These specimens were examined both macroscopically (grossly) and using computed axial tomography for a more detailed analysis.

Findings and Observations

• The researchers found that donkeys have a more significant level of anisognathia – the width difference between the upper and lower jaws – than horses. On average, donkeys had a 27% difference while horses had a smaller 23% difference.
• Among the cheek teeth studied, those in the mandible (lower jaw) had a higher degree of peripheral enamel infolding than those in the maxilla (upper jaw). This suggests a anatomical characteristic specific to the donkey species.
• All cheek teeth exhibited a considerable increase in peripheral cementum from the apical region (tooth tip) towards the clinical crown. This observation was statistically significant, showing that this isn’t a random occurrence but a trait of the donkey dental anatomy.
• Each of the donkey cheek teeth had at least five pulp cavities. Two types of these cheek teeth, the 06s and the 11s, had six pulp cavities. This finding is important as pulp cavities, which contain the tooth’s sensitive tissues, affect dental health and treatment procedures.

Proposals and Conclusion

• Based on these findings, the researchers proposed a new endodontic numbering system specifically for equid cheek teeth to help future veterinary and biological studies.
• It was observed that older donkeys (more than 16 years old) had a greater depth of secondary dentine on the occlusal surface (chewing surface) of the teeth compared to their younger counterparts. This occurrence is suspected to be due to the natural dental wear over time.
• Ultimately, despite the species-specific traits, the study concluded that the dental anatomy of donkeys is largely similar to that of horses, which can provide a reference point for equine dental care.