The dental pathology of feral cats on Marion Island, part I: congenital, developmental and traumatic abnormalities.

Skulls (n = 301) of adult feral cats from Marion Island, a sub-Antarctic island, were examined macroscopically. Congenital anomalies, which were rare, included a few supernumerary premolars, located mesially to those normally present. Supernumerary roots, mainly of the maxillary third premolar, were found in just over 10% of cases. The maxillary second premolar was absent in 16.8% of skulls; dichotomous and double-formed roots of this tooth were present in 20.1% and 1.9% of cases, respectively. Enamel hypoplasia, which is most unusual in this species, was noted in 24.6% of cases, and persistent deciduous teeth in 2.0%. Dental abrasion, which was noted in 19.3% of cats, affected only 2.3% of teeth, most commonly the lower fourth and upper third premolars. Dental fractures, mainly complicated crown fractures and root fractures, were noted in 54.8% of cats and 7.0% of teeth. Fractures were found most commonly in the canine and carnassial teeth, as also were periapical lesions, which were often severe. Mandibular fractures in various stages of healing were found in 11 cats (3.7%); such fractures most frequently affected the body of the mandible and resulted in malunion. It was concluded that the high prevalence of dental fractures and associated periapical lesions probably exerted a significant adverse effect on health and survival in this population of feral cats.