Biomimetic approach on human periodontal ligament cells using synthetic oligopeptides.

BACKGROUND: Periodontal ligament (PDL) cells, connecting root cementum with alveolar bone, are important for periodontal wound healing. In order to obtain a predictable periodontal regeneration, selective adhesion and proliferation of PDL cells are essential. The purpose of this study was to investigate the effects of synthetic peptides mimicking cell-binding domain of fibronectin (FN) on human PDL cells. METHODS: Two types of oligopeptides, Gly3-Pro-His-Ser-Arg-Asn-Gly6-Arg-Gly-Asp-Gly (G3PHSRNG6RGDG) and Gly3-His-Pro-Asn-Arg-Ser-Gly6-Arg-Gly-Asp-Gly (G3HPNRSG6RGDG), were constructed using a solid-phase peptide synthesizer. Fibronectin type III ninth to tenth domain (FN III 9-10) and Arg-Gly-Asp-Ser (RGDS) were prepared for comparison with the effects of synthetic peptides. These peptides were coated onto 96-well cell culture plates with 0.001 approximately 100 microM concentrations. Cultured human PDL cells were then applied to the peptide-coated wells at a density of 1 x 10(4)/well. After 1 hour incubation at 37 degrees C, adhered cells were fixed, stained, and examined by phase contrast microscopy for cell spreading assay. Attached PDL cells were solubilized with 2% sodium dodecyl sulfate (SDS) for the cell attachment assay by measuring absorbance at 595 nm in microplate reader. Western blot analysis was performed to determine extracellular signal-regulated kinase (ERK1/2) activity. RESULTS: Cell attachment and spreading assays revealed that G3PHSRNG6RGDG (> or = 10 microM) possesses similar adhesive behavior to FN III 9-10. G3PHSRNG6RGDG showed a comparable ERK1/2 activity when compared to FN III 9-10. CONCLUSIONS: G3PHSRNG6RGDG enhanced an attachment and spreading of human PDL cells thereby increasing ERK1/2 activity. Taken together, it is anticipated that this peptide might be a potential tool for arranging a biologically attractive environment for PDL cells, which would enhance periodontal regeneration efficacy.

Enhanced bone augmentation by controlled release of recombinant human bone morphogenetic protein-2 from bioabsorbable membranes.

BACKGROUND: The present study was undertaken to determine the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded biodegradable membranes on bone augmentation in a rabbit calvarial model. METHODS: Five microg of rhBMP-2 was loaded into a stiff hemispherical dome membrane made of poly(L-lactide) and tricalcium phosphate (PLLA/TCP). The release kinetics of rhBMP-2 from the membrane were determined in vitro using a human BMP-2 immunoassay. Twelve rhBMP-2-loaded dome membranes (test group) and 12 control dome membranes (control group) were placed on the partial-thickness calvarial defects of 24 rabbits. The animals were sacrificed at 4 and 8 weeks, and undecalcified ground sections were prepared. Newly formed bone area and height were measured histomorphometrically and calculated by percentage ratio to the total submembranous space area and height below the dome. RESULTS: In vitro release results demonstrated that rhBMP-2 was released consistently over a 4-week period following a high initial burst release on the first day. At both 4 and 8 weeks, histomorphometric analysis revealed that the test group showed significantly higher newly formed bone heights and areas than the control group (P < 0.01). In the control group, new bone height was 36.3% of the dome height and the new bone area reached 8.2% of the submembranous space area at 8 weeks, while the test group reached 87.3% and 35.4%, respectively. CONCLUSION: These results suggest that the use of rhBMP-2-loaded PLLA/TCP membranes can result in additional bone augmentation, which is due to the osteoinductive properties of rhBMP-2 released from the membrane during healing.

A 3-year longitudinal evaluation of subpedicle free connective tissue graft for gingival recession coverage.

BACKGROUND: The purpose of this study was to longitudinally evaluate, over a 3-year period, the reduction of gingival recession through use of a subepithelial free connective tissue graft placed under a coronally advanced partial-thickness pedicle flap. METHODS: Twenty-one buccal recession defects (mean 3.67 mm; range 3 to 4.5 mm; Miller Class I, II, and III) in 15 patients were treated using this technique. Amount of gingival recession (GR), clinical attachment loss (CAL), and width of keratinized gingiva (WKG) were followed for 3 years after surgery. The measurements were performed at presurgery, and 1, 3, 6, 12, 18, 24, and 36 months postsurgery. RESULTS: GR decreased from 3.67 +/- 0.58 mm at baseline to 0.33 +/- 0.43 mm at 36 months, representing a reduction of 3.33 mm, corresponding to 91.28% mean root coverage. CAL was significantly decreased at 36 months from 5.26 +/- 0.77 mm to 2.14 +/- 0.57 mm. At 36 months, 3.12 mm of attachment gain was obtained. WKG significantly increased after 36 months (1.95 mm). GR, CAL, and WKG had the most positive outcomes at 12 months and were maintained at stable levels throughout the 36-month observation period. CONCLUSIONS: These results indicate that the connective tissue graft with a partial thickness coronal advancement pedicle is a predictable method for root coverage and, provided that optimal maintenance care is provided, the clinical outcomes gained by this technique can be well maintained.