These results confirm the possibility of regenerating bone by means of bioabsorbable materials, assuring at the same time the long-term success for implants inserted in regenerated sites.

This study, confined to non-smokers, evaluated guided-tissue regeneration in deep 2-wall intrabony defects using a diphenylphosphorylazide-cross-linked bovine type I collagen membrane supported by a hydroxyapatite/collagen/chondroitin-sulfate spacer in 43 adult periodontitis (AP) and 14 rapidly progressive periodontitis (RPP) patients, no more than 1 defect being randomly selected for each patient. Before surgery and 6 months after surgery, plaque (PI) and sulcus bleeding (SBI) indices, probing pocket depths (PPD), gingival margin locations (GML) and probing attachment levels (PAL) were recorded. During the post-surgical period, the biomaterials were well tolerated in all patients and PI and SBI were kept at a low level. Following therapy, there was a significant gain in PAL (4.2 mm for AP; 3 mm for RPP) and reduction in PPD (6.1 mm for AP; 4.7 mm for RPP) for both groups of patients (p < 0.05). A significantly greater gain in PAL and reduction in PPD were observed for AP compared to RPP patients (p < 0.05). The change in GML was not statistically different between groups (1.8 mm for AP; 1.6 mm for RPP). It is concluded that the combined use of a diphenylphosphorylazide-cross-linked bovine type-I collagen membrane, supported by a hydroxyapatite/collagen/chondroitin-sulfate spacer, is beneficial in improving PAL and reducing PPD in 2-wall intrabony defects in both AP and RPP patients during the quiescent phase of the disease, with statistically better results for the former group. However, longer observation periods are necessary to evaluate the stability of the improvements obtained by this combined treatment approach between and for each group of patients.

This study, confined to non-smokers, evaluated guided tissue regeneration using a diphenylphosphorylazide-cross-linked bovine type I collagen membrane in deep 3-wall intrabony defects in 52 adult periodontitis (AP) and 16-rapidly progressive periodontitis (RPP) patients, previously treated for the acute phase of the disease, no more than one defect being randomly selected for each patient. Before surgery and 6 months after surgery, plaque (PI) and sulcus bleeding (SBI) indices, as well as probing pocket depths (PPD), gingival margin locations (GML) and probing attachment levels (PAL) were recorded. During the post-surgical period, the membranes were very well tolerated in all patients and PI and SBI were kept at a low level. 6 months post-surgical, there was a significant gain in PAL (3.6 mm for AP; 2.6 mm for RPP) and reduction in PPD (5.5 mm for AP; 4.1 mm for RPP) for both groups of patients (p < 0.05). However, neither the change in GML (1.9 mm for AP; 1.5 mm for RPP), nor PPD or PAL yielded a statistically significant difference between AP and RPP patients. The results of this study demonstrated that the treatment of deep 3-wall intrabony defects with a diphenylphosphorylazide-cross-linked collagen membrane in both AP and RPP patients during the quiescent phase of the disease is a treatment modality where the conquences are predictable. However, longer observation periods are necessary to evaluate the stability of the improvements obtained for the 2 groups of patients and the differences between them.