Effect of rhBMP-2 produced by Escherichia coli expression system on bone formation in rat calvarial defects / 대한치주과학회지

PURPOSE: Recombinant human bone morphogenetic protein-2(rhBMP-2) has been evaluated as potential candidates for periodontal and bone regenerative therapy. In spite of good prospects in BMP applications, there is economically unavailable for clinical use in dental area. The purpose of this study was to evaluate the osteogenic effect of rhBMP-2 produced by E.coli expression system. MATERIALS AND METHODS: Eight-mm critical-size calvarial defects were created in 48 male Sprague-Dawley rats. The animals were divided into 6 groups of 8 animals each. Each group received one of the following: Negative control(sham-surgery control), positive control(absorbable collagen sponge(ACS) alone) and experimental(ACS loaded with rhBMP-2). Defects were evaluated by histologic and histometric parameters following 2- and 8-week healing intervals. RESULTS: The experimental group showed significant defect closure at 2 and 8weeks than the sham surgery and positive control groups. Moreover, the experimental group showed significantly greater new bone and augmented area than the other groups at both 2 and 8weeks. CONCLUSION: rhBMP-2 produced by E.coli expression system may be effective for bone regeneration.

THE BONE REGENERATIVE EFFECTS OF PARADIOXANONE ON THE CALVARIAL CRITICAL SIZE DEFECT IN SPRAGUE DAWLEY RATS / 대한치주과학회지

The major goals of periodontal therapy are the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. Bone graft & guided tissue are being used for the regeneration of destroyed periodontium these days. Non-resorbable membranes were used for Guided tissue regeneration in early days, however more researches are focused on resorbable membranes these days. The aim of this study is to evaluate the osteogenesis of paradioxanone membrane on the calvarial critical size defect in Sprague Dawley rats. An 8 mm diameter surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into three groups: Untreated control group, Biomesh(R) group and paradioxanone group. The animals were sacrificed at 4, 8 and 12 weeks after surgical procedure. The specimens were examined by histologic, histomorphometric analyses. The results are as follows: 1. In histological view on Biomesh(R), no visible signs of resorption was observed at 4 weeks but progressive resorption was observed at 8 weeks through 12 weeks. Paradioxanone membrane expanded at 4 weeks, and rapid resorption was observed at 8 weeks. In both the membranes, inflammatory cells were observed around them. Inflammatory cells decreased with time but were still present at 12 weeks. More inflammatory cells were observed in paradioxanone membranes than in Biomesh(R) membrane. 2. The area of newly formed bone in the defects were 0.001+/-0.001, 0.006+/-0.005, 0.002+/-0.003 at the 4 weeks, 0.021+/-0.020, 0.133+/-0.073, 0.118+/-0.070 at the 8 weeks and 0.163+/-0.067, 0.500+/-0.197, 0.487+/-0.214 at the 12 weeks in the control group, Biomesh(R) group and experimental group respectively. Compared to the control group, Biomesh(R) group displayed significant differences at 4,8, and 12 weeks and the paradioxanone group at 8 and 12 weeks.(P<0.05) 3. The area of residual membranes were 1.143+/-0.499, 2.599+/-1.012, at the 4 weeks, 0.666+/-0.140, 0.314+/-0.131 at the 8 weeks and 0.365+/-0.110, 0.076+/-0.050 at the 12 weeks in the Biomesh(R) group and experimental group respectively. Between the two groups, significant differences were displayed at 4 weeks.(P<0.05) According to the results, when paradioxanone membrane was used in calvarial critical size defect in Sprague Dawley rat, initially the membrane expaned and regeneration of newly formed bone was small however after 8weeks new bone was formed with simultaneous resorption for the membrane. If a few problems could be solved, previously used membranes could be replaced in periodontal guided tissue regeneration.

Resorbability and histological reaction of bioabsorbable membranes / 대한치주과학회지

The major goals of periodontal therapy are the functional regeneration of periodontal supporting structures already destructed by periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. With the development of non-resorbable membrane, GTR has proved to be the representive technique of periodontal regeneration. However, due to various clinical problems of non-resorbable membrane, resorbable membrane was developed and it showed to be clinically effective. The newly developed Para-Dioxanone membrane has a characteristic of non-woven fabric structures which is different from the generally used membranes with structure of mesh form. In addition, Chitosan membrane has been developed to apply its adventage maximally in GTR. Although a number of different types of membranes had been clinically used, researches on absorption rate of membranes were inadequate and limited to subjective opinions. However, since long term period of resorption and space maintenance are required in implant or ridge augmentation, accurate verification of resorption rate is clinically important. In this study, we had implanted Resolut(R), Biomesh(R), Para-Dioxanone membrane and Chitosan membrane (Size : 4mmx4mm) on dorsal side of Sprague Dawley rat, and sacrificed them after 4 weeks, 8 weeks, 12 weeks respectively. Histologic observation was carried out, and the following results were obtained by calculating the objective resorption rate. 1. In case of Resolut(R), external resorption took place initially, followed by internal resorption. Surface area are 5.76+/-2.37mm2, 4.91+/-1.06mm2, 4.90+/-0.98mm2 at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 31.6+/-4.5%, 52.8+/-9.4%, 56.4+/-5.1% respectively. 2. Biomesh(R) showed a pattern of folding, relatively slow resorption rate with small size of membrane. Surface area are 3.62+/-0.82mm2, 3.63+/-0.76mm2, 4.07+/-1.14mm2 at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 26.1+/-5.8%, 30.9+/-3.4%, 29.2+/-3.6%, respectively. 3. Para-Dioxanone membrane was surrounded by fibrous conncetive tissue externally, and resorption took place internally and externally. Surface area are 5.96+/-1.05mm2, 4.77+/-0.76mm2, 3.86+/-0.84mm2 at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 30.7+/-5.1%, 53.3+/-4.4%, 69.5+/-3.1%, respectively. 4. Each fiber of Chitosan membrane was surrounded by connective tissue and showed external resoption pattern. It showed little invasion of inflammatory cells and excellent biocompatability. The resorption rate was relatively slow. Surface area are 6.01+/-2.01mm2, 5.49+/-1.3mm2, 5.06+/-1.38mm2 at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 31.3+/-3.6%, 38.4+/-3.8%, 39.7+/-5.6%, respectively. Consequently, Para-Dioxanone membrane and Chitosan membrane are found to be clinically effective for their excellent tissue reaction and biocompatibility. Futhermore, the advantage of bone regenerating ability as well as the relatively long resorption period of Chitosan membrane, it might be widely used in implant or ridge augmentation.