The dental pathology of feral cats on Marion Island, part II: periodontitis, external odontoclastic resorption lesions and mandibular thickening.

Skulls (n = 301) of adult feral cats from Marion Island were examined macroscopically. Dental calculus was found infrequently (9.0% of cats, 0.76% of teeth), unlike the hard tissue lesions of moderate and advanced periodontitis and tooth loss (presumably due to periodontitis), which were commonly seen (61.8% of cats, 14.8% of teeth). Relatively few of these abnormalities were associated with external odontoclastic resorption lesions, which affected 14.3% of cats and 1.2% of teeth-less than in most recent surveys in domestic cats. Abnormal thickening of the mandibula, found in 39.5% of specimens, was most commonly bilateral (83.3%). The lesions ranged from a focal periosteal reaction, to localized exostosis, to generalized swelling and loss of density, to grossly enlarged mandibles with increased bone density. Mandibular swelling was significantly associated with other abnormalities (periodontitis, dental fractures, external odontoclastic resorption lesions and periapical lesions), but many cases of mandibular swelling were accompanied by only minor dental defects.