Epidemiology of open and closed diastemata in equine cheek teeth and associations with periodontal pathology.

Overview

• This study investigated how open and closed diastemata (gaps) between cheek teeth in horses are distributed and how they are associated with the severity of periodontal (gum) disease.
• The research aimed to understand the influence of diastema type, anatomical location, age, sex, and jaw position on the development of periodontal pathology in horses.

Study Background and Purpose

• Cheek-tooth diastemata are common dental gaps in horses and are a known risk factor for periodontal disease.
• There are two types of diastemata:
  • Open diastemata – where the gap is visible and unobstructed.
  • Closed diastemata – where the gap is narrow or sealed off but still abnormal.
• The severity of periodontal disease may vary depending on the type and location of the diastema, but this relationship was not fully understood before this study.
• The objective was to quantify the prevalence of open and closed diastemata and analyze their relationship with periodontal disease severity in different jaws, age groups, and sexes.

Methods

• Sample: 50 equine cadaver heads sourced from an abattoir were examined.
• Examination: Teeth were visually and manually inspected for diastemata, which were then classified as open or closed.
• Periodontal disease was scored on a scale from 0 (no disease) to 4 (severe disease) based on a clinical scoring system.
• Data analysis included multinomial logistic regression to assess how disease severity was affected by:
  • Jaw type: mandible (lower jaw) vs. maxilla (upper jaw)
  • Diastema type: open vs. closed
  • Age of horses
• Non-parametric tests compared periodontal disease severity across groups.

Key Findings

• Total diastemata identified: 317
  • Open diastemata: 63.1%
  • Closed diastemata: 36.9%
• Distribution:
  • More diastemata found in the upper jaw (maxilla) – 68.8%
  • Less frequent in the lower jaw (mandible) – 31.2%
• Periodontal disease presence:
  • Detected in 62.5% of identified diastemata.
  • Open diastemata were significantly linked to higher periodontal disease scores compared to closed diastemata.
• Mandibular sites (lower jaw) had more severe disease despite fewer diastemata overall.
• Age Effects:
  • Older horses showed higher periodontal disease severity.
  • Severe lesions were especially common in older horses with open diastemata in the mandible.
• Sex Differences:
  • Mares (female horses) had higher odds of having open diastemata.
  • Mares also exhibited greater periodontal disease severity compared to geldings (castrated males).

Conclusions and Implications

• Open diastemata, especially in the mandible, are strongly associated with increased severity of periodontal disease in horses.
• Although diastemata are more common in the upper jaw, disease tends to be more severe in the lower jaw where fewer gaps occur.
• Older age and female sex are additional risk factors for developing advanced periodontal pathology in relation to diastemata.
• These findings emphasize the importance of:
  • Early detection of diastemata, particularly open types.
  • Targeted dental examinations focusing on mandibular cheek teeth in aging mares.
  • Implementing preventative dental care to limit periodontal disease progression in horses.