Equine cheek teeth occlusal fissures: Prevalence, association with dental wear abnormalities and occlusal angles.

Summary: Background: Fissures of the occlusal surface of equine cheek teeth are commonly encountered during oral examination but their aetiology is unknown. Objectives: To examine the prevalence and characteristics of occlusal fissures in cadaver teeth. It is hypothesised that their prevalence is influenced by masticatory forces. Consequently, their possible association with wear disorders and occlusal angles were examined. Study design: Cross‐sectional survey. Methods: The dental abnormalities and occlusal fissure findings in the cheek teeth of 143 cadaver heads were recorded. The cheek teeth occlusal angles were measured using the stiff‐hinge technique. Multiple regression analyses were performed to establish possible relationships between age, sex, dental wear, occlusal angle and fissure prevalence. Results: Occlusal fissures were found in 103/143 (72%) heads. Sex and age were determining factors in the prevalence of fissures. A similar prevalence was found in mandibular (54.1%) and maxillary teeth (45.9%, OR = 1.10; 95% CI = 0.95–1.29, P = 0.2). Mandibular fissures were more commonly located on the buccal aspect (OR = 1.42; 95% CI = 1.16–1.65, P < 0.001), whereas for maxillary fissures there was no difference in prevalence between palatal and buccal aspects (OR = 1.19; 95% CI = 0.97–1.46, P = 0.1). Two main fissure types were identified. Type 1a fissures were the most prevalent type (39.5%). No significant correlation was found between the presence of wear abnormalities or the occlusal angle of cheek teeth, and the prevalence of fissures. Main limitations: No dental histories were available. Conclusion: Equine cheek teeth show a high prevalence of occlusal fissures. Despite some evidence of predilection sites on the tooth surface that might indicate a mechanical aetiology for these lesions, no associations were found with wear abnormalities or occlusal angles of affected cheek teeth. Further histological and ultrastructural studies are warranted to elucidate their aetiology and possible role in other dental diseases. [ABSTRACT FROM AUTHOR]