Molecular forms and concentration of fibronectin and fibrin in human gingival crevicular fluid before and after periodontal treatment.

A total of 23 periodontitis-affected sites from seven adults was selected for the study. Crevicular fluid (CF) samples were collected with paper strips before treatment (scaling, root planing, and curettage) and 2, 5, 10, 20, and 40 days after treatment. Each sample was eluted into sterile saline and two aliquots were drawn for gel electrophoresis: one for fibronectin and one for fibrin analysis. Peptides were transferred to nitrocellulose membranes, and molecules were detected by specific antibodies. The proportions of different molecular forms of fibronectin and fibrin were analyzed by laser densitometry. Plaque Index, Papilla Bleeding Index, and pocket depth were recorded before and 40 days after treatment. Radiologic bone loss was estimated from orthopantomograms. Two days after treatment, an increase was seen in the proportions of intact fibronectin, fibronectin fragments larger than 70 kDa, and fibrin-positive material with a greater molecular mass than intact fibrin. Between days 5 and 10, the proportions of these large fragments decreased. The highest fibronectin and fibrin concentrations were seen 10 days after treatment. These changes probably reflect degradation of the subgingival fibrin clot formed after treatment, and indicate resolution of the clot during the first 10 days of healing. This agrees well with previous observations of CF plasmin activity and concentration of collagen synthesis markers in CF after periodontal treatment, and with the histologic changes seen during periodontal healing. Results of the present study, together with earlier reported findings of collagen synthesis after periodontal treatment, also support the hypothesis of sequential appearance of fibronectin and collagens during the process of wound healing.