An in vitro screening model to evaluate root conditioning protocols for periodontal regenerative procedures

Background: Preclinical studies have shown that the condition of the root surface may play a decisive role for outcome of wound healing between a mucogingival flap and a denuded root surface. Root surface demineralization has been shown to promote the establishment of a new connective tissue attachment. Conversely, root conditioning with extracellular matrix proteins or fluorides has produced outcomes characterized by a long junctional epithelium. Collectively, present evidence suggests that early events in the healing sequel; i.e., the adsorption and adhesion of blood elements to the root surface are critical for outcomes of wound healing between a mucogingival flap and a denuded root surface. Ultimately understanding and control of these events are vital for successful design and execution of periodontal regenerative protocols, particularly those involving root conditioning. Consequently, the objective of this study was to develop a screening model for immediate evaluation of the influence of root conditioning protocols on the adsorption and adhesion of blood to dentin surfaces. Methods: Planed and citric acid-treated human dentin surfaces were exposed to fresh blood allowed to clot and were then rinsed before scanning electron microscopy evaluation. Results: Citric acid treated planed dentin surfaces presented a thick network of fibrin directly attaching to the dentin surface entrapping cellular elements, mainly erythrocytes. In contrast, untreated, planed dentin exhibited an amorphous appearance with sparse strands of adsorbed fibrous proteins and few adherent erythrocytes. Conclusions: This in vitro screening model may effectively distinguish dentin surfaces with potential for enhanced adsorption and adhesion of blood elements. Periodontal regenerative protocols involving root conditioning unsuccessful in maintaining the experimentally imposed fibrin clot in this model may have lesser clinical significance than those that do.