New Attachment Outcomes Differ Spacially After Demineralization of Dental Surfaces.

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 when pulpal surfaces are spacially orientated. Study important for regenerative outcomes.
Methods: Dental 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. In addition, specimens consisted of the root from the tooth itself. Groups were treated with citric acid (pH 1 for 3 minutes), and the 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 were available for examination 1 and 10 days after implantation. Histologic and statistical histometric analyses of the surfaces included counts of adhering cells, evaluation of connective tissue fiber relationships, and epithelial migration.
Results: At 1 day, surface demineralization was present on all treated groups , and these had numerically greater cell attachment than controls. At 10 days, cell attachment was reduced in all groups, but all treated groups had significantly greater cell attachment than controls (p<0.01). Connective tissue fiber attachment occurred on treated 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). In specimens of the root where the pulpal surfaces were parallel, an orientated cell and fiber attachment system had developed resembling periodontal ligament.
Conclusions: Citric acid surface demineralization enhanced cell attachment to all surfaces, and resulted in new connective tissue fiber attachment. The greater fiber attachment system on the cementum may relate to biochemical, spatial, and nano characteristics of the surfaces. Similarly, an orientated cell and fiber attachment system resembling a periodontal ligament had formed between the parallel pulpal surfaces.