Objective To evaluate the long-term clinical effect of dual anti-collagen membranes in guided tissue regeneration(GTR). Methods This randomized clinical trial included 26 teeth in 24 patients, presenting a total of 31 lesions consisting of intrabony defects and furcation defects. Twenty-six teeth were divided into two groups and treated by GTR with dual anti-collagen membranes and atelocollagen membranes, respectively. At baseline, 6 months, 1, 3 and 6 years, the following parameters were recorded; clinical attachment level, probing depth, gingival recession and the quantity of alveolar bone analyzed by computer assisted densitometry image analysis (CADIA). Results At 1 year after GTR surgery, the gain of clinical attachment in dual anti-collagen membranes group was (3. 93 ± 1. 74) mm,compared with (2. 25 ± 1. 90) mm in atelocollagen group(P =0. 044). The increasing of the value of CADIA in dual anti-collagen membrane and atelocollagen group were (53. 14 ± 21. 35) and (32. 96 ± 17. 97 ), P = 0. 031. At 3 and 6 years, clinical parameters remained basically stable in both groups, compared to that at 1 year after surgery. Conclusions The regeneration of periodontal tissues obtained by GTR with dual anti-collagen membranes could be maintained on a long-term basis.

Objective To construct a recombinant human platelet-derived growth factor-B (PDGF-B) adenoviral vector and to transfect it into human periodontal ligament stem cells (PDLSC).Methods The recombinant plasmid pAd-PDGF-B was constructed by homologous recombination and confirmed by restriction endonucleases digestion.Recombinant adenovirus was packaged in HEK293 cells.PDLSC were transfected with recombinant adenovirus and PDGF-B expression was confirmed.Expression of collagen type Ⅰ gene was determined by quantitative analysis of the products of RT-PCR.The cell proliferation was determined with MTr eolorimetric assay.Results The recombinant plasmid pAd-PDGF-B was confirmed by restriction endonucleases digestion.EGFP expression was observed on the third day after transfecting,and the expression of PDGF-B was detected.Immunohistochemical methods revealed that PDGF-B was expressed in PDLSC.Levels of expression of collagen type Ⅰ gene were increased significantly by transfer of the exogenous PDGF-B gene to PDLSC.At the same time,findings indicated that Ad-PDGF-B stimulated PDLSC proliferation.MTT assay indicated the absorbance of PDLSC by stimulating with Ad-PDGF-B was (0.68±0.02),P＜0.01.Conclusions Using the AdEasy system,the human PDGF-B recombinant adenovirns can be rapidly obtained.These results indicate that recombinant adenoviruses encoding PDGF-B transgenes could modulate proliferative activity of PDLSC,enhance the high expression of collagen type Ⅰ and lay the foundation for periodontal tissue regeneration and dental implant gene therapy.