Guided Tissue Regeneration In The Treatment Of Class Ⅱ～Ⅲ Furcation Defects

Guided tissue regeneration(GTR) is a new biological principle that is developed on the basis of recognizing progenitor cells in the periodontal tissue which have the potential for regeneration. GTR can restore those supporting tissues lost as a result of the disease process including alveolar bone, periodontal ligament and cementum and gain new attachment. Now the hot point of GTR is to study the barrier membranes in the treatment of periodontal defects. According to the barriers absorbtability, we defined non-absorbable membrane such as polytetrafluoroethylene (e-PTFE) membrane or absorbable membrane .-such as collagen membrane. The e-PTFE membrane and the collagen membrane have been proved good biocompatibility and clinical results. But whether these two membranes' clinical results have differences has seldom been reported in China. We use the two barriers to treat the class II ~III furcation defects. Through analyzing the clinical indicates, radiographs and the levels of alkaline phosphatase(ALP) in gingival crevicular fluid(GCF), we evaluated the clinical healing of the two barriers. The e-PTFE membranes were retrieved after 5 weeks and examined by scanning electron microscopy(SEM) for histological changes in different levels of the membranes' external surface.23 adult patients with 31 sites were selected and divided into three groups including e-PTFE group, collagen membrane group and control group. The sites in e-PTFE group and collagen membrane group received e-PTFE membranes and collagen membranes respectively. The control group received flap operation. Clinical indicates, radiographs and GCFs were collected before surgery and 3 months after surgery. The ALP in GCF was investigated. The data were analyzed statistically.A paired / test was used to compare the pre- and post- treatment clinical measurements. All of the clinical parameters measured were significant difference (P<0.05), except for the changes of gingival index (GI) in test groups. For the flap operation sites, probing depth (PD) reduction and clinical attachment levels (CAL) gain were significant difference (P<0.05), while there were no significant in the change of GI and probing furcation depth (PFD). As compared to the control group, all the clinical parameters measured in the e-PTFE group were significant difference (PO.05); the PD reduction and CAL gain were significant (PO.05), while there were no statistically significant difference (P>0.05) in GI and PFD gain. As compared to the collagen group, there were no significant differences between the two test groups for any of the clinical parameters measured, except for the change hi PFD gain. The radiographs show the alveolar bone in both test groups and control group becomes more density. The vertical bone gain was significant difference (PO.05) between the test groups and the control group. As compared to the collagen group, there were no significant differences (P>0.05) in the vertical bone gain hi e-PTFE group. No significant difference (P>0.05) in gingival crevicular fluid (GCF) flow. There was significant difference between the pre- and post- levels of alkaline phosphatase (ALP) in GCF (PO.05). GCF-ALP was significant lower hi the test groups than in the control group. There was no significant difference in the change of GCF-ALP between the two test groups. The scaning electromicroscopy show that the external upper surfaces have the large amount of lymphocytes, with little bacterial contamination of the membranes being observed. The external lower surface is full of fibrocytes, red blood cells and lymphocytes.From the above results, we can conclude that during the short term of the observation, GTR is prior to the flap operation. The e-PTFE and collagenmembranes have good biocompatibility and similar clinical results. A long term of the observation would be necessary to determine if one membrane was superior to the other.