This study evaluates 150 teeth from 15 cats (average age 6.8 years). Plaque and calculus were found on the macroscopic examination of the buccal surfaces of premolars and molars, horizontal and vertical loss of alveolar bone on radiographs, and gingival and periodontal destruction signs and resorptive lacunae on histology, confirming that periodontal disease and external root resorption occur spontaneously in this species.