Experimental study of calvarial critical size defect in rats with type 2 diabetes mellitus / 实用口腔医学杂志

Objective:To explore the calvarial critical size defect (CSD)in rats with type 2 diabetes mellitus(T2DM).Methods:T2DM model of SD rats(weighted 300-320 g)was induced by high fat and high sugar diet and low dose intraperitoneal streptozotocin (STZ)injection.The rats with T2DMand the normal controls were divided into 4 groups(n=3)respectively.Defects with the diame-ter(mm)of 2,3,4 and 5 were made on the central calvaria of each rat.General observation,X-ray examination and histological study were performed 8 weeks postoperatively.Results:In the T2DM group,only the defects of 2 mm diameter were healed completely,X-ray resistance and new bone formation were observed;the defects of 3,4 and 5 mm diameter were unhealed,X-ray transmission was observed and newly formed bone was insufficient.In the control group,the defects of 2,3 and 4 mm diameter were healed completely, X-ray resistance and new bone formation were observed;the defects of 5 mm diameter were unhealed,X-ray transmission was ob-served,newly formed bone was insufficient.Conclusion:The calvarial CSD of T2DM rat model can be defined as the defect with the diameter of 3 mm.

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.

The Bone Regenerative Effects of Chitosan on the Calvarial Critical Size Defectin Sprague Dawley Rats / 대한치주과학회지

The major goals of periodontal therapy is 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. There have been increasing interest on the chitosan made by chitin. Chitin is second only to cellulose as the most abundant natural biopolymer. It is a structural component of the exoskeleton of invertebrates(e.g., shrimp, crabs, lobsters), of the cell wall of fungi, and of the cuticle of insects. Chitosan is a derivative of chitin made by deacetylation of side chains. Many experiments using chitosan in various animal models have proven its beneficial effects. The aim of this study is to evaluate the osteogenesis of chitosan on the calvarial critical size defect in Sprague Dawley rats. An 8 mm surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into two groups: Untreated control group versus experimental group with 50mg of soluble chitosan gel. The animals were sacrificed at 2, 4 and 8 weeks after surgical procedure. The specimens were examined by histologic, histomorphometric and radiodensitometric analyses. The results are as follows: 1. The length of newly formed bone in the defects was 102.91+/-25.46micrometer, 219.46+/-97.81micrometer at the 2 weeks, 130.95+/-39.24micrometer, 212.39+/-89.22micrometer at the 4 weeks, 181.53+/-76.35micrometer and 257.12+/-51.22micrometer at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. But, there was no statistically significant difference between the two groups. 2. The area of newly formed bone in the defects was 2962.06+/-1284.48micrometer2, 5194.88+/-1247.88micrometer2 at the 2 weeks, 5103.25+/-1375.88micrometer2, 7751.43+/-2228.20micrometer2 at the 4 weeks and 8046.02+/-818.99micrometer2, 15578.57+/-5606.55micrometer2 at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. 3. The density of newly formed bone in the defects was 14.26+/-6.33%, 27.91+/-6.65% at the 2 weeks, 20.06+/-9.07%, 27.86+/-8.20% at the 4 weeks and 22.99+/-3.76%, 32.17+/-6.38% at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. These results suggest that the use of chitosan on the calvarial defects in rats has significant effect on the regeneration of bone tissue in itself