A study of the thickness of cheek teeth subocclusal secondary dentine in horses of different ages.
Authors: White C, Dixon P M
Journal: Equine veterinary journal
Summary
White and Dixon's investigation into subocclusal secondary dentine thickness in equine cheek teeth addresses a significant gap in our understanding of pulp protection during dental procedures. By longitudinally sectioning 408 permanent cheek teeth extracted post mortem from 17 horses aged 4–30 years and measuring secondary dentine depth above each pulp horn, the researchers revealed substantial individual variation: subocclusal secondary dentine ranged from a mean of 12.8 mm in a 4-year-old to 7.5 mm in a 16-year-old, with some pulp horns protected by as little as 2 mm of dentine. Counter-intuitively, occlusal secondary dentine thickness did not increase with age, though subocclusal thickness did, and mandibular cheek teeth had significantly thicker subocclusal secondary dentine than maxillary teeth. These findings carry critical implications for farriers and veterinarians performing routine occlusal reductions: the considerable variability between individual teeth and even between pulp horns within the same tooth means that modest overgrowth reductions carry genuine risk of pulp exposure or thermal damage leading to apical infection, necessitating a staged approach to larger reductions and meticulous technique regardless of the horse's age or apparent margin for error.
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Practical Takeaways
- •When performing cheek tooth overgrowth reductions, be aware that some pulp horns may be protected by only 2 mm of secondary dentine—risk of pulp exposure and thermal damage is significant even with modest reductions
- •Large cheek tooth overgrowths should be reduced in stages rather than aggressively in one procedure to minimize pulp exposure risk
- •Individual variation in secondary dentine thickness is too great to rely on age-based assumptions; conservative technique is essential regardless of horse age
Key Findings
- •Subocclusal secondary dentine thickness decreases with age, from mean 12.8 mm in 4-year-old to 7.5 mm in 16-year-old horses
- •Thickness varies greatly between individual pulp horns within the same tooth, ranging from 2-33 mm, with some pulp horns covered by as little as 2 mm of secondary dentine
- •Mandibular cheek teeth have significantly thicker subocclusal secondary dentine than maxillary teeth
- •Occlusal secondary dentine thickness did not increase with age, contrary to expectations