A very active case of external-internal root resorption.
Abstract A case of external-internal root resorption which may have been stimulated to a very active phase by bacterial contamination is presented.
Relationship between surface and inflammatory resorption and changes in the pulp after replantation of permanent incisors in monkeys.
The etiology of surface and inflammatory root resorption after replantation of incisors was examined in green vervet monkeys. The teeth were examined histologically and histobacteriologically for pulpal healing and root resorption two and eight weeks after replantation. In contrast to surface resorption, inflammatory resorption was related to infected necrotic tissue or an infected leukocyte zone in the root canal. The following theory for surface and inflammatory resorption is presented. Damaged periodontal ligament areas and damaged parts of the root surface are attacked by a resorption process, whereby resorption of cementum and dentin may occur. Inflammatory resorption or surface resorption will then occur, depending on the pulpal status and the depth of the resorption cavity. If the resorption cavity penetrates the intermediate layer of cementum and contacts dentinal tubules that are in communication with infected necrotic pulp tissue or an infected leukocyte zone, then inflammatory resorption will take place as a result of the diffusion of toxic elements from the pulp canal to the resorption cavity. However, if the resorption cavity is shallow and does not penetrate the intermediate layer of cementum, a tooth that displays similar pulpal changes will elicit only surface resorption because the intermediate layer of cementum will tend to arrest the diffusion of toxic elements. Finally, if the pulp contains vital, inflamed or noninflamed tissue, or if root canal treatment has been performed, surface resorption will occur, irrespective of the depth of the cavity.
Tissue changes in the monkey following root torque with the Begg technique.
Abstract The histologic reaction of the maxillary incisors and the periodontium of monkeys subjected to lingual root torque with Begg light-wire mechanics is reported here. Two maxillary incisors on each of three monkeys whose ages corresponded approximately to the human ages of 12 to 18 years were subjected to continuous lingual root torque for intervals of 68 to 89 days. The appliance was fabricated in the routine manner with few modifications. The forces were accurately measured and recorded. A fourth monkey served as the control. Gross changes included demonstrable lingual root torque registered by means of lateral cephalograms, study models, and clinical observations. Histologic findings in all experimental specimens revealed osteoclastic activity on the pressure side and osteoblastic activity on the tension side. These findings were divided into two categories: one group of five incisors subjected to 7 ounces of force and one incisor subjected to 4 ounces of force. The group subjected to 7 ounces of force showed a greater compression of the periodontal membrane and also had numerous root resorptions varying from slight to severe penetration of the dentine. The incisor subjected to 4 ounces of force exhibited few root resorptions, and these did not penetrate into the dentine but were completely contained within the cementum.