Plaque induced periodontal disease in beagle dogs

The present investigation was carried out in order to study some aspects of the clinical, roentgenographical and histopathological alterations of periodontal tissues in dogs which during a 4‐year period were allowed freely to accumulate plaque. Twenty inbred Beagle dogs, at the start of the study 10 months of age, were used. During a preparatory period of eight weeks the animals were once weekly subjected to a careful prophylaxis and had their teeth brushed twice daily. At the end of this period the dogs were divided into two groups of ten (test and control). From day zero of experimentation and onwards the teeth of the control dogs were twice daily subjected to meticulous toothbrushing, whereas the teeth of the test dogs were not cleaned. Examinations of the periodontal tissues were performed at days 0, 7, 14, 21, 28 and after 2, 4, 6, 8, 12, 18, 24, 36 and 48 months. Biopsies of different tooth regions were made on day zero and after 6, 12, 18, 24, 36 and 48 months of experiment. In the sections were measured (i) the distance from the cemento‐enamel junction (CEJ) to the most apical cells of the dento‐gingival epithelium, and (ii) the distance from CEJ to the level of the marginal alveolar bone. The study demonstrated that it is possible in dogs to establish and maintain a normal gingiva simply by eliminating calculus and then subjecting the animals to daily repeated and carefully performed tooth cleanings. Dogs allowed freely to accumulate plaque rapidly developed signs of gingivitis and eventually also clinical, radiographical and histopathological signs of periodontal tissue breakdown. The observations show that at least one type of periodontal disease is induced by factors within the dental plaque.