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

Cheek-tooth diastemata are a common dental abnormality in horses and are considered a major predisposing factor for periodontal disease. However, the influence of diastema type and anatomical location on disease severity remains incompletely understood. To determine the prevalence and distribution of open and closed cheek-tooth diastemata and evaluate their association with periodontal disease severity in horses, while assessing the influence of age, sex, jaw location and laterality, fifty equine cadaver heads obtained from an abattoir were examined. Diastemata were identified through visual and manual examination and classified as open or closed. Periodontal disease severity was graded using a previously described clinical scoring system (0–4). Statistical analysis included multinomial logistic regression modelling to assess associations between scores of periodontal disease and explanatory variables ‘Jaw’ (‘mandible’, ‘maxilla’) and ‘Diastema’ (‘open’, ‘closed’), and ‘Age of the horse’. Non-parametric testing was also used for comparisons in periodontal disease severity. A total of 317 diastemata were identified, of which 63.1% were open and 36.9% closed. Diastemata were more frequently observed in the maxilla (68.8%) than the mandible (31.2%). Periodontal disease was present in 62.5% of diastemata. Open diastemata were significantly associated with higher periodontal disease scores. Mandibular sites showed greater disease severity despite a lower overall prevalence of diastemata. Age was associated with increased periodontal disease severity, with advanced lesions more common in older horses, particularly in mandibular arcades containing open diastemata. Mares demonstrated higher odds of open diastemata and greater periodontal disease severity compared with geldings. In conclusion, cheek-tooth diastemata, particularly open diastemata and mandibular lesions, are strongly associated with periodontal disease in horses. Early detection and targeted dental examination are essential to improve preventative management and reduce disease progression.