The reaction of subcutaneous connective tissues to root canal filling material pastes, made chiefly of calcium hydroxide, has been studied by means of radiography, histopathology, and electron microscopy. Radiography has revealed that embedded paste displays a well-demarcated radiopaque mass just after embedding, then gradually disappears over time. The resulting images have shown granulation tissue appearing, as well as and the phagocytosis by macrophages and giant cells, as observed histopathologically. Furthermore, there have been heterotopic calcifications within the proliferating granulation tissues in some cases, with electron microscopic examinations revealining phagocytosis. In the present study, the ultrastructural aspects of initial calcification in rat subcutaneous tissues elicited by root canal filling material paste, made up of calcium hydroxide and iodoform with the addition of silicone oil, were examined. The embedded paste caused heterotpic calcifications, which can be divided into two types: dystrophic calcification; and matrix vesicle calcification, which resembles that of bone tissue. These data suggest that the paste may elicit the differentiation of osteoblasts and/or cementoblasts from mesenchymal cells in periodontal ligament.
Editor, Toshiyuki Kawakami
Language Editor, David M Carlson
viii, 232 p. ill. (some col.)
Chapter 2 : Tissue Reaction to Root Canal Filling Material Embedded Subcutaneously in Rats
