| Periodontitis is one of the most common oral diseases, is the main cause of tooth loss,the etiology and pathogenesis is not yet fully clear. Periodontitis of the teeth part of the root surface of the dental bone exposed to the periodontal pocket, the infection will occur after structural and physical and chemical changes, seriously affect the periodontal functional cells in the root surface growth and attachment, hinder periodontal tissue regeneration repair. Human periodontal ligament fibroblasts (hPDLFs) are important cells that form the periodontal ligament, which can directly destroy or trigger the immune response under the action of periodontal pathogens and their toxic products. This study is mainly observed effects of lipopolysaccharides on the proliferation and IL-8 secretions of periodontal ligament fibroblasts, changes of cementum lipopolysaccharide levels in different teeth with periodontitis treated with different methods, influence of the periodontal ligament fibroblasts with different treatment methods of periodontitis cementum. To study the pathogenesis of periodontitis, provide a basis for the selection of clinical periodontitis treatment.This study is divided into three parts of the experiment its purpose, methods and results are as follows:PART 1: Effects of lipopolysaccharides on the proliferation and IL-8 secretion of periodontal ligament fibroblastsObjective: To observe the effects of different concentrations of lipopolysaccharides on the proliferation of periodontal ligament fibroblasts and the secretion of IL-8. Methods: The experiments were divided into five groups, human periodontal ligament fibroblasts (PDLFs)group (negative control group) , 1?g/ml LPS group, l0?g/ml LPS group, 100?g/ml LPS group, 200?g/ml LPS group. The cells were cultured and MTT assay was used to observe the cell proliferation. The cell supernatant after cultured for 24h and 96h was collected for IL-8 ELISA. Results: Compared with PDLFs group, the promotion of the proliferation of PDLFs was observed in 10?g/ml LPS group. 200?g/ml LPS, significantly inhibited the proliferation of PDLFs, significant statistical differences were detected in 200?g/ml LPS groups for 24h, significant statistical differences were detected in 100?g/ml LPS, 200?g/ml LPS groups for 96h. Conclusion: Different concentrations of lipopolysaccharides can regulate the proliferation of periodontal ligament fibroblasts and the synthesis and release of IL-8.PART 2: Changes of cementum lipopolysaccharide levels in different teeth with periodontitis treated with different root conditioningObjective: To observe the changes of lipopolysaccharide levels after different teeth with periodontitis were treated with different methods. Methods: Six healthy premolars extracted for orthodontic reasons and 36 posterior teeth extracted due to severe periodontitis were selected. Each tooth was different root conditioning to from two 4 mmx4 mmxl mm cementum pieces under the cementum-enomel junction 2 mm, each tooth with periodontitis was numbered. Healthy teeth were served as negative control group; one of the two tablets from each periodontitis tooth was selected in the periodontitis group, which was not treated with root surface treatment. The remaining 36 teeth with periodontitis were randomly divided into 6 groups: SRP group ,SRP + antimicrobial peptide A group , SRP + antimicrobial peptide B group, SRP + EDTA group, SRP + Er:YAG laser group and SRP + Nd: YAG laser group. Lipopolysaccharide concentration in each tooth was determined by the chromogenic substrate Limulus reagent. The lipopolysaccharide concentration in each tooth was recorded according to the serial number,and the changes of lipopolysaccharide concentration were calculated before and after root conditioning. SPSS 17.0 software package was used to analyze the data. Results:Compared with the teeth with periodontitis, lipopolysaccharide concentration decreased to varying degrees,there were significant differences in each treatment group (P <0.01).Compared with SRP group, lipopolysaccharide levels in SRP + antimicrobial peptide A group, SRP + antimicrobial peptide B group, SRP + Er: YAG laser group were significantly (P<0.01).No significant difference decreased was from between SRP + EDTA group and SRP + Nd: YAG laser group were not statistically significant (P>0.05).Conclusion: Treatment of teeth with periodontitis using different methods can decrease the level of lipopolysaccharide, and the treatment of periodontitis root surface with antimicrobial peptide A + SRP may be more effective.PART 3: Effect on cytokine production of the periodontal ligament fibroblasts with different treatment methods of periodontitis cementumObjective: To observe the effect of different treatment methods of periodontitis cementum on cytokine production of human periodontal ligament fibroblasts. Methods:Periodontitis cementum and orthodontic cementum described in Part2 were used to co-culture with PDLFs. The levels of TNF-a, IL-6 and IL-8 were detected by ELISA.Results: (1) Compared with SRP group, the levels of IL-6, IL-8 and TNF-a in the other groups were lower than those in SRP group (P <0.01). (2) There was no significant difference in IL-6 content between antibiotic peptide A + SRP group and healthy tooth group (P> 0.05). (3) There was no significant difference in IL-8 content between the root treatment groups and the healthy tooth group (P> 0.05), except for the SRP group. (4)There was no significant difference in TNF-a content between Nd: YAG laser + SRP group,Er: YAG laser + SRP group and healthy tooth group (P> 0.05). Conclusion: The levels of IL-8 and TNF-a in antimicrobial peptides (A, B), Er: YAG laser, Nd: YAG laser and EDTA combined with SRP were lower than those in SRP group and there was no difference in IL-8 levels between these groups. The content of IL-6 in antimicrobial peptide A + SRP was the lowest in the treatment group. The content of TNF-a in Nd: YAG laser + SRP group was the lowest in the treatment group. |
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