Guided tissue regeneration in human Class II furcation defects using a diphenylphosphorylazide-cross-linked collagen membrane: a consecutive case series.

Several bioabsorbable collagen membranes are either currently available or under investigation for use in guided tissue regeneration (GTR) procedures. The aim of this 12-month reentry study was to evaluate a diphenylphosphorylazide (DPPA)-cross-linked bovine type I collagen membrane in the healing of mandibular Class II furcation defects. The DPPA technique prevents the inclusion of foreign cytotoxic cross-linking substances in the reticulated molecules, thus providing a more biocompatible product. Forty non-smoking periodontally compromised adult subjects volunteered for this study, and one defect was randomly selected in each patient. At baseline, plaque index (PI), gingival index (GI), probing depth (PD), gingival margin location (GML), clinical attachment level (CAL), and width of the attached gingiva (AG) were measured. Intrasurgical hard tissue measurements consisted of the vertical open probing attachment level (V-OPAL) and horizontal open probing attachment level (H-OPAL), as well as furcation entrance width (FW) and height (FH) and subclassification of defects according to vertical bone loss. All soft tissue measurements were repeated 12 months after membrane placement using conservative flap reentry surgeries; hard tissue parameters were also assessed at this time. DPPA-cross-linked collagen membranes demonstrated good handling characteristics, and no postoperative adverse tissue reactions or clinically detectable localized allergic responses were observed. GI and PI remained low during the entire study period. When the one year reentry values were compared to the baseline measurements, a significant reduction in PD (1.9 +/- 1.4), FW (2.1 +/- 1.7), FH (2.9 +/- 1.6), and gain in CAL (1.7 +/- 1.5), V-OPAL (2.1 +/- 1.9), and H-OPAL (4.7 +/- 1.4) were observed (P < or = 0.05). However, there were no significant differences in GML or AG. Hard tissue improvements resulted in the complete closure of 30% (12) of the defects, and transformation of 67.5% (27) of the defects to Class I, while one defect remained a Class II (2.5%). Based on this 12-month clinical reentry study, a DPPA-cross-linked collagen membrane could be beneficial in GTR treatment of Class II mandibular furcation involvements, both in terms of soft and hard tissue improvements.