[Histopathological study on the experimental formation of the food impaction in rat (author's transl)].

Abstract

This investigation was made on the process of destruction of the periodontal tissues as the result of impacting of food particles into the interproximal space by masticatory force. The experiment performed on 98 male Wistar strain rats was done by grinding off a part of the adjacent marginal ridges between the upper bilateral 1st (M1) and 2nd molars (M2), and inducing the impaction of food particles in the interproximal spaces. Histopathologically, the initial responses in the periodontal tissues were seen at 3 hours after the beginning of the experiment, then the changes turned to acute exacerbation with time. These changes, however, gradually decreased and became more chronic after 2 to 3 weeks. In this stage, it has been observed that the periodontal tissues have a tendency to repair partially.The result will be described as follows:1. From 3 to 6 hours, after the experimental procedure, the gingiva was observed to become pressed apically.2. From 12 to 24 hours, destruction of the epithelium, the lamina propria and a part of the alveolar bone by pressure and impingement of food particles were observed.3. From 3 to 7 days, the deep pocket formation and the severe destruction of the periodontal tissues were observed between M1 and M2.4. From 2 to 3 weeks, there appeared gradual slowing down of the inflammatory changes in the periodontal tissues immediately below the impacted area.5. In the interradicular septum, the periodontal tissues were intact until one day afer the food impaction.6. From 3 to 5 days, however, there appeared inflammatory changes in the interradicular periodontal tissues and a partial bony resorption.7. At 7 days, most cases showed abscess formation at the bifurcation.8. At 3 weeks, in the interradicular septum the epithelium migrated deeply in the periodontal tissues and inflammatory cells circumscribed.