The effect of human demineralized freeze-dried xenograft on vertical bone formation in beagle dogs / 대한치주과학회지

PURPOSE: The purpose of this study was to evaluate exophytically vertical bone formation in the mandibular premolar area of beagle dogs by the concept of guided bone regeneration with a titanium reinforced e-PTFE membrane combined with human demineralized freeze-dried bone. MATERIALS AND METHODS: Four one-year old beagle dogs were divided into control and experimental group. All mandibular premolars were extracted and surgical vertical defects of 5 mm in height were created in the extracted sockets. At 8 weeks after the extraction, TR e-PTFE membrane sized with 8 mm in length, 5 mm in width, and 4 mm in height was placed on the decorticated mandible, fixed with metal pins and covered with full-thickness flap and assigned as control group. In experimental group, decorticated mandibule was treated with TR e-PTFE membrane and human demineralized freeze-dried bone. The animals were sacrificed at 16 weeks after the regenerative surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. RESULTS: Average of new bone formation was 38% in the control group, whereas was 25% in the experimental group (p<0.05). Average of connective tissue formation was 42% in the experimental group, whereas was 30% in the control group (p<0.05). The lamellar bone formation with haversian canals was observed in the both groups. In the experimental group, the particles of human demineralized freeze-dried bone were observed after 16 weeks and complete resorption of graft was not observed. CONCLUSION: On the basis of these findings, we conclude that titanium reinforced e-PTFE membrane may be used alone for vertical guided bone regeneration, but demineralized freeze-dried bone has no additional effect on vertical guided bone regeneration.

Clinical and histopathological study using platelet-rich plasma and bone graft in the localized alveolar bone defects / 대한치주과학회지

Alveolar ridge defects may limit or restrict placement of implants. The purpose of this study was to evaluate clinical and histopathologic results which occur following guided bone regeneration using platelet-rich plasma, bovine bone powder and e-PTFE membrane in the localized alveolar bone defects. Ten patients who required guided bone regeneration in implant placemnet, were slelected. Alveolar crest height and width were measured at baseline and, afer 2nd surgery 5 months later At 5 months , we obtained histopathological results as follows: 1. Alveolar crest height was an average of 8.20+/-3.74 mm preoperatively and decreased to an average of 7.40 +/-1.84 mm postoperatively. There was no significant difference. 2. Alveolar crest width was an average of 4.25+/-2.03 mm preoperatively and significantly increased to an average of 7.20+/-2.44 mm postoperatively (P<0.01) 3. The change of Alveolar crest height and width were 0.80+/-1.40 mm, 2.95+/-1.09 mm 4. Histopathological evaluations revealed new bone formation with graft material and laminated bone containing the presence of osteocyte-like cell In conclusion, guided bone regeneration using platelet-rich plasma, bovine bone powder and e-PTFE membrane would provide a viable therapeutic alternative for implant placement in the localized alveolar defect or implant failure

Intermediate-term Result of e-PTFE Membrane Implant Surgery for Refractory Glaucomas

Recently, various tube-shunt implants have been used in treating refractory glaucomas.They have large volumed reservoir portion made of hard materials.We made a new implant with soft and freely malleable membrane[expanded polytetrafluoroethylene, e-PTFE]as a reservoir portion attached to the conventional silicone tube. Based on the encouraging result from experimental animal study, we performed a clinical trial for the membrane-tube implant.We performed Glaucoma Tube-Shunt Implant surgery using double layers of e-PTFE membrane and silicone tube with its one end fixed between the two layers.The subjects had refractory glaucomas without useful vision who visited our hospital from May 1991 to Sep.1995. There were 40 eyes of 37 patients and their mean follow-up period was 32.6 months.We could control the IOP within 6~21 mms of mercury in 26 eyes[65.0%, Success].In remaining 14 eyes, we could not control the IOP or additional surgery was needed to control the IOP or treat severe complications[35.0%, Failure].The Kaplan-Meier Survival for IOP control was 78.4% at 1 yr, 71.6%at 2 yr, and 60.3%at 3 yr.The complications were similar to those of other commercially available Glaucoma implants. This new implant is made of soft, freely malleable membrane for the reservoir portion with small volume which can be inserted with smaller incision on the conjunctiva with less complication.We have obtained comparable result from this membrane-tube implant to other implants, and it may be considered as an another substitute for the treatment of refractory glaucomas.

THE INFLUENCE OF POLYTETRAFLUOROETHYLENE MEMBRANE ON CELL GROWTH OF PERIODONTAL MEMBRANE AND EXPERIMENTAL REGENERATION OF PERIODONTAL TISSUE / 解放军医学杂志

The effects of polytetrafluoroethylene (e PTFE) membrane on periodontal ligament cell (PDLC) growth and periodontal tissues and new cement regeneration were studied, and the prospects of clinical application of e PTFE membrane were discussed. The results showed that PDLC grew well on the e PTFE membrane and no toxicity or inhibition was found. Close adhesion of the cells to the membrane was observed by scanning electron microscope. Histological studies suggested that the peculiar porous structure of e PTFE membrane protects and promotes healing of alveolar bone defect when the membrane edge was sealed perfectly on the crown side,exhibiting inhibition of growth of epithelium towards tooth root. The membrane was beneficial to regeneration of new alveolar bone and cement and establishment of new adhesion,and was regarded as a good substitute of old materials.