M. Christgau

Postoperative exposure of bioresorbable GTR membranes: effect on healing results

Abstract The goal of this investigation was to evaluate the effect of postoperative exposure of two different bioresorbable membranes on the guided tissue regeneration (GTR) healing results compared to nonexposed sites. In each of 25 patients one pair of contralateral intrabony lesions was treated either with polylactic acid (PLA) or polyglactin 910 (PG-910) membranes. Postoperative exposure occurred in 9 PLA and 13 PG-910 sites. Standardized clinical [papillary bleeding index (PBI), gingival recession (REC), probing pocket depth (PPD), probing attachment level (PAL)] and radiographic examinations (digital subtraction radiography) were performed immediately before (baseline) and 6 and 12 months postoperatively (p.o.). Subgingival bacterial samples from surgical sites were evaluated by culture at baseline, 6 weeks, and 6 and 12 months p.o. Six months after surgery the changes (Δ) of REC were significantly (P≤0.05) greater in exposed than in nonexposed sites, independently of the membrane material (median): exposed sites, ΔREC=–1 mm; nonexposed sites, ΔREC=0.0 mm. However, 12 months p.o. no significant differences were found due to a decrease in the initial recessions in exposed sites. Although a higher percentage of exposed than nonexposed sites harbored periodontal pathogens 6 weeks p.o. at the gingiva-faced membrane surface, membrane exposure did not have a significant negative effect on ΔPPD, ΔPAL, or radiographic bone density changes 6 and 12 months p.o. Both membranes showed significant gains in PAL and bone density in both exposed and nonexposed sites. In conclusion, this study demonstrates that with consistent infection control the postoperative exposure of PLA and PG-910 membranes has no significant negative effect on the regeneration outcome, although higher initial gingival recessions must be expected than in the nonexposed sites. However, in exposed sites plaque and infection control were clearly impeded by the rough, exposed membrane surfaces and by the initially negative gingival morphology.

Influence of autogenous platelet concentrate on combined GTR/graft therapy in intrabony defects: a 7-year follow-up of a randomized prospective clinical split-mouth study.

OBJECTIVES To investigate the influence of autogenous platelet concentrate (APC) on the long-term regeneration outcome 7 years after guided tissue regeneration (GTR) in deep intrabony periodontal defects. MATERIAL AND METHODS In 25 patients, two deep contra-lateral intrabony defects were treated according to GTR (randomized split-mouth-design). In the test defects, APC was additionally applied. After 7 years, healing results were assessed clinically by a blinded examiner and compared to baseline and 12-months results. Furthermore, a tooth survival analysis was performed. RESULTS After 7 years, 23 patients were available for survival analysis and 16 patients for split-mouth analysis; 84% of the test and control teeth were still in situ. In both groups, the median attachment level of 10.5 mm [(25/75%): test 9.0/13.0, control 10.0/12.0] at baseline was significantly (p ≤ 0.05) reduced to 6.0 mm [test 4.0/6.8, control 5.0/7.0] after 1 year. Six years later, it had increased again to 7.0 mm in test sites [5.3/10.0] (p ≤ 0.05) and had remained stable in control sites [5.0/7.8] (p > 0.05). Bleeding on Probing (BOP) had increased in both groups. During the last 6 years, only 26% of the patients received a structured supportive periodontal therapy in the clinic. CONCLUSION Within its limitations, the present study indicates that the clinical outcome of GTR therapy can be maintained over 7 years. However, the additional use of APC may even have a possibly negative influence on the long-term stability.