Experimental periodontitis in the Beagle dog

The purpose of the present investigation was to study the sequential stages in the development of a periodontal lesion starting from a healthy periodontium. Twenty inbred Beagle dogs 10 months of age and weighing 10–12 kilos were used. The animals were equally divided into one experimental and one control group. Throughout the experiment all dogs were given a diet containing 400 gm pellets and 25 gm soya flower. From day zero the teeth (in the left jaws) of the control dogs were twice dally subjected to a careful but gentle brushing with tooth brush and dentifrice. The teeth of the experimental group animals were not cleaned. The dogs were examined at regular intervals during an 18 month period. The results show that it is possible in young dogs to induce gingivitis which gradually develops into periodontitis simply by allowing plaque to accumulate on teeth. The cleaned teeth did not show signs of gingivitis or periodontitis during the entire experiment. It is proposed that in the Beagle dog the progression of the lesion during an 18 month period may occur in three stages: I) subclinical gingivitis, II) clinical gingivitis and III) periodontal breakdown. Subclinical gingivitis was characterized by a rapidly increasing gingival exudation and migration of crevicular leukocytes, i. e. signs off acute inflammation. Clinical gingivitis was characterized by changes in gingival colour, texture and bleeding tendency but only minor alterations of the number of crevicular leukocytes. Periodontal breakdown, characterized by loss of subgingival fiber attachment, occurred only in areas of clinical gingivitis.