[Effects of non-surgical periodontal therapy on serum inflammatory markers and metabolic level in obese rats].

OBJECTIVE: To investigate the effects of non-surgical periodontal therapy on serum inflammatory factors and metabolism levels in obese rats with experimental periodontitis. METHODS: Sixteen obese rats with experimental periodontitis were randomly divided into treatment group and control group with non-surgical periodontal therapy and no treatment, respectively. Oral glucose tolerance test was performed before treatment and 2 weeks after the treatment. All the rats were sacrificed 2 weeks after treatment and the orbital vein blood was taken to detect fasting blood glucose, fasting insulin, and serum level of C-reactive protein (CRP). Results Two weeks after periodontal treatment, fasting blood glucose (t=2.445, P=0.034) and beta cell function index (t=-2.543, P=0.027) were significantly lower in the treatment group than in the control group. Compared with those in the control group, CRP level (t=2.388, P=0.028) and the area under the curve in the oral glucose tolerance test (t=12.053, P=0.000) decreased significantly in the treatment group. CONCLUSION: Non-surgical periodontal treatment can reduce serum CRP level and improve glucose metabolism in obese rats.

[Beneficial effect of periodontal therapy on insulin resistance and lipid metabolism in obese rats with periodontitis].

OBJECTIVE: To investigate the effect of periodontal therapy in controlling periodontitis and on insulin resistance and lipid metabolism in obese rats with periodontitis. METHODS: Sprague-Dawley rats were randomized into normal group (group C), obese group (group O), periodontitis combined with obesity group (group P) and periodontal treatment group (group T). The obese rats in groups P and T were subjected to ligation of the maxillary second molar with silk thread to induce experimental periodontitis, and the rats in group T received periodontal therapy after the ligation. All the rats were sacrificed at the age of 24 weeks for measurement of blood lipids, insulin and blood glucose levels, and insulin resistance index (HOMA-IR) was calculated. The expressions of insulin receptor substrate-1 (IRS-1) and IRS-2 in the liver tissues were detected using real-time quantitative polymerase chain reaction (RT-PCR). RESULTS: Compared with the obese rats in group O, the rats in group P showed significantly higher HOMA-IR and LDL-C and lower expressions of IRS-1 and IRS-2 mRNA expression and HDL-C level (P<0.05). Compared with those in group P, the mRNA expressions of IRS-1 and IRS-2 and HDL-C level were significantly increased and LDL-C level, TC level and HOMA-IR were all decreased in group T (P<0.05), but the level of TG was comparable between the two groups. Pathological examination revealed lessened inflammatory cell infiltration and tissue destruction in the upper jaw of the rats in group T; the rats in group P presented with the most obvious upper jaw destruction and steatosis and inflammatory cell infiltration in the liver. CONCLUSION: Periodontal inflammation can downregulate the expression of IRS-1 and IRS-2 and increase insulin resistance and dyslipidemia in obese rats. Periodontal therapy produces a beneficial effect in improving insulin resistance and reducing dyslipidemia in obese rats.

[Cytotoxicity evaluation of three kinds of perforation repair materials on human periodontal ligament fibroblasts in vitro].

OBJECTIVE: To select three kinds of perforation repair materials, mineral trioxide aggregate (MTA), Z350, amalgam. And to evaluate the cytotoxicity of three kinds of perforation repair materials on human periodontal ligament fibroblasts (HPDLF) in vitro. METHODS: The proliferation of HPDLF to three perforation repair materials were examined by methyl thiazolyl tetrazolium (MTT) assay at 1, 3 and 5 days. The mRNA expression levels of bone-associated alkaline phosphatase (ALP) and osteocalcin (OC) were determined using a real-time quantitative polymerase chain reaction (PCR). RESULTS: MTA shew almost no inhibition to HPDLF, the expression of ALP mRNA and OC mRNA in the HPDLF cultured on MTA were higher. Z350 induced a slight inhibition to HPDLF, and the expression of ALP mRNA but there was no difference in the expression of OC mRNA. Cell proliferation was significantly impaired by amalgam with grade 3, and the expression of ALP mRNA and OC mRNA were significantly reduced. CONCLUSION: MTA have minimum cytotoxicity on HPDLF and can promote cell differentiation and regenerate of periodontal tissue. Z350 have lower cytotoxicity on HPDLF. Amalgam show highest cytotoxicity on HPDLF in the three materials and inhibit cells differentiation.

[Morphology and microleakage study of repairing subpulpal wall perforation with resinous inlay].

OBJECTIVE: The purpose of this study is to study the sealing ability and the furcal appearance of repairing subpulpal wall perforation with resinous inlay. METHODS: Fifty newly extracted human molars were randomly divided into three experiment groups (group A, group B, group C, 15 teeth each) and one control group (5 teeth). In experiment groups, perforations were made perpendicularly to the center of the pulp chamber floor. Perforations of group A and B were repaired with resinous inlay and sealed by AH Plus sealer and luting glass-ionomer, respectively. Perforations of group C were directly repaired using light-cure composite resin. Perforations were not made in five teeth of control group. The furcal appearances were evaluated under stereomicroscope after repairing. Microleakage was measured by glucose oxidase detection. RESULTS: The fineness rate of furcal appearances with resinous inlay repairing were 83.3%, while the fineness rate of furcal appearances with light-cure composite resin directly repairing were 46.7%. There were statistics difference between resinous inlay repairing and light-cure composite resin directly repairing (P<0.05). There were statistics difference among the daily microleakage of three experiment groups, group A

[Study of apical diffusion of three different kinds of calcium hydroxide preparations in vitro].

PURPOSE: To investigate the diffusion effect of calcium hydroxide in periapical simulation of the diffusion model. METHODS: Pipetman pipette tips, plastic syringes and BHI agar were prepared to be periapical simulation of the diffusion model. 120 simulation models were divided into three groups. Group 1: 100 microl 20% calcium hydroxide suspension were sealed in pipette tips; group 2: 100 microl 90% calcium hydroxide cataplasm were sealed in; group 3: 100 microl calcium hydroxide points were sealed in. By different apical aperture (15#,25#,40#,80#), each group was divided into four subgroups (each subgroup contained 10). Preparation of 12 other simulation models sealed with distilled water were as a control. pH values and Ca(2+) concentration were measured by PH analyzer and calcium analyzer respectively. The data was collected to establish a database, using SPSS13.0 software package, randomized block design ANOVA was performed. RESULTS: The average pH value (8.26, S=0.86) of group 1 was significantly higher than that in group 2 (7.96, S=0.702) and Group 3 (7.83, S=0.59) (P<0.05), but no significant difference was found between group 2 and group 3. The average calcium concentration of group 1 (29.87 ppm. S=10.76) was significantly higher than that in group 2 (24.62 ppm. S=10.40) and group 3(16.42 ppm, S=5.70). There were significant differences among the three groups (P<0.05). The results also showed that the average pH value and the average calcium concentration were increased with apical aperture. There were significant differences between each group (P<0.05). CONCLUSION: The diffusion effect of calcium hydroxide suspension in periapical simulation of the diffusion model is better than calcium hydroxide cataplasm and calcium hydroxide points; the diffusion effect is also proportional to the apical aperture. Supported by Key Research Project of Science and Technology Bureau of Sichuan Province (Grant No.05SG022-007).