New Attachment Outcomes Differ After Demineralization of Dentin, Cementum or Pulpal Surfaces

Objectives: Objectives: New connective tissue attachment occurs to dentin and cementum after surface demineralization with citric acid, but not after tetracycline (Polson 2007, 2008). This study compares directly these new connective tissue attachment systems on dentin, cementum, or pulpal surfaces, and is very important for clarification of regenerative and wound healing outcomes.
Methods: Methods: Dentin or cementum specimens were obtained from areas beneath attached periodontal ligament fibers on extracted normal human teeth. Each rectangular specimen had a face of either root surface dentin or cementum, and an opposite surface composed of pulpal dentin. Both groups were treated with citric acid alone (pH 1 for 3 minutes), and two other groups were untreated controls. Specimens were implanted transcutaneously into incisional wounds on the dorsal surface of rats with one end protruding through the skin. Four specimens in each group were available for examination 1 and 10 days after implantation. Histologic and statistical histometric analyses of the dentin, cementum, or pulpal surfaces included counts of adhering cells, evaluation of connective tissue fiber relationships, and assessment of epithelial migration.
Results: Results: At 1 day, surface demineralization was present on dentin and cementum and pulpal groups, and these had numerically greater cell attachment than controls. At 10 days, cell attachment was reduced in all groups, but dentin and cementum and pulpal groups had significantly greater cell attachment than controls (p<0.01). Connective tissue fiber attachment occurred on treated dentin, cementum, and pulpal surfaces, but was absent from exfoliating non-treated controls. Both attached connective tissue fiber density and diameter were significantly greater on treated cementum surfaces compared to dentin or pulpal surfaces (p<0.01).
Conclusions: Conclusions: Citric acid surface demineralization enhanced cell attachment to dentin and cementum and pulpal surfaces, and resulted in an outcome of new connective tissue fiber attachment. The significantly greater fiber attachment system on the cementum may relate to biochemical, spatial, and nano characteristics of the surfaces. Supported by NIDR-7061, Penn Periodontal Fund, Alpha Omega Foundation.