Cell and fiber responses to cementum from periodontitis‐affected root surfaces after citric acid treatment

Abstract The purpose of this study was to assess connective tissue and epithelial responses to periodontitis‐affected cementum (from exposed roots of human teeth) after surface demineralization with citric acid. Cementum specimens were obtained from root surfaces covered by calculus. Each rectangular specimen had a face of cementum and an opposite surface composed of pulpal dentin. One half of the specimens were treated with citric acid (experimental group), while the remainder served as untreated control specimens. Specimens were implanted vertically into incisional wounds on the dorsal surface of rats with one end of the implant protruding through the skin. 4 specimens in each group were available for examination 1, 3, 5, and 10 days after implantation. Histologic and histometric analyses of the implants included counts of adhering cells, evaluation of attached connective tissue fiber density and diameter, and assessment of epithelial migration. At 1 day, a distinct zone of surface demineralization was not present on the surface of the cementum in the experimental group, although such a zone was present on the dentin surfaces of the same specimens. Histometric comparisons between experimental and control groups at 1 day showed no differences in cell attachment or length of cementum surface within connective tissue. By 10 days, there was a trend for greater cell attachment to demineralized cementum, but the differences were not statistically significant. Although connective tissue fiber attachment has been shown to occur to demineralized dentin and to normal cementum in this model system, fiber attachment did not occur to the cementum in the present study, It appears that the citric acid treatment failed to sufficiently demineralize the periodontitis‐affected cementum and expose a hospitable collagenous matrix.