Influence of immediate or delayed post space preparation on the apical sealing ability of different root canal sealers / 中国组织工程研究

BACKGROUND: Apical sealing ability is the key to ensure the long-term curative effect of root canal therapy. The post space preparation exposes some inevitable influence on root canal sealing ability, so how to minimize this effect becomes a hot spot.OBJECTIVE: To explore the effects of immediate or delayed post space preparation on the apical sealing ability of different root canal sealers.METHODS: Forty-eight extracted human premolar teeth were obtained, and the tooth crown was cut off. The samples were randomly divided into three groups (n=16 teeth per group). Group A underwent the immediate post space preparation; group B underwent the delayed post space preparation; group C without the post space preparation. Then all groups were subdivided into two groups, and then were filled with the gutta-percha/AH-Plus (groups A1, B1 and C 1)or the gutta-percha/mineral trioxide aggregate (groups A2, B2 and C2). The depth of apical dye penetration was measured using pressure-driven system. RESULTS AND CONCLUSION: There were no significant differences in the apical microleakage between groups A1 and B1, A2 and B2, C1 and C2 (P > 0.05). The apical microleakage in the group A1 was significantly higher than that in the group A2, and the group B1 also showed higher apical microleakage than the group B2 (P < 0.05). Our findings suggest that either immediate or delayed post space preparation exposes little influence on the apical microleakage after root canal filling with gutta-percha/mineral trioxide aggregate, which exhibits better apical sealing ability than the AH-plus.

Therapeutic effect of enhancer of Zeste homolog 2 inhibitor GSK343 on periodontitis by regulating macrophage differentiation / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To explore the therapeutic effect of enhancer of Zeste homolog 2 (EZH2) inhibitor GSK343 on periodontitis by regulating microphage differentiation.</p><p><b>METHODS</b>Macrophage RAW264.7 cells were divided into the blank (A group), control (B group), lipopolysaccharide (LPS) stimulation (C group), and LPS+GSK343 (D group) groups. Phenotype transformations was determined through Western blot analysis and enzyme-linked immunosorbent assay by detecting the differentiation of phenotypic biological markers, including tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), interleukin-10 (IL-10), and Arginase-1 (Arg-1). Metergasis was identified by performing a phagocytosis test on Escherichia coli (E. coli).</p><p><b>RESULTS</b>Macrophage RAW264.7 cells produced classical phenotypic biomarkers (M1) TNF-α and iNOS under LPS stimulation. The expression levels of IL-10 and Arg-1 increased after adding GSK343 into the culture medium. GSK343 also induced the conversion of M1 macrophages into M2 macrophages. Macrophage RAW264.7 cells exerted a phagocytic effect on E. coli, and this effect was enhanced after adding LPS into the culture medium. GSK343 regulated the macrophage RAW264.7 phagocytosis of E. coli.</p><p><b>CONCLUSIONS</b>GSK343 possibly participates in the regulation of macrophage differentiation and, consequently, in the latent treatment of periodontitis.</p>

Effects of immediate versus delayed post space preparation on coronal microleakage using different filling materials / 中国组织工程研究

BACKGROUND: At present, there is no consensus on the timing of post space preparation in the clinical medical treatment. But it can be inferred from some studies that post space preparation may affect coronal microleakage using different fil ing materials. OBJECTIVE: To compare the effects of immediate post space preparation and delayed post space preparation restoration on coronal microleakage using different fil ing materials. METHODS: Forty-eight extracted and single-rooted premolars were randomly divided into six groups (n=8 per group): premolars were fil ed with AH-plus paste and gutta-percha with the immediate post space preparation as group A1; premolars fil ed with mineral trioxide aggregate paste and gutta-percha with the immediate post space preparation as group A2; premolars fil ed with AH-plus paste and gutta-percha with the delayed post space preparation 1 week later as group B1; premolars fil ed with mineral trioxide aggregate paste and gutta-percha with the delayed post space preparation after 1 week later as group B2;premolars fil ed with AH-plus paste and gutta-percha as negative control group; premolars fil ed with gutta-percha as positive control group. Afterwards, al specimens were soaked for 4 weeks under simulated oral environment to measure the length of coronal microleakage by pressurized dye penetration method. RESULTS AND CONCLUSION: No coronal microleakage was found in the negative control group, but serious coronal microleakage occurred in the positive control group involving the entire root canal. And there was no significant difference in the length of coronal microleakage between group A2 and B2, as wel as between group A1 and A2 (P > 0.05); but the length of coronal microleakage in the group A1 and B2 was significantly less than that in the group B1 (P < 0.05). These results show that the delayed post space preparation has overt effect on the coronal microleakage of root canal fil ed with AH-plus paste.

Silk fibroin scaffold for repair of buccal mucosa defects / 中国组织工程研究

BACKGROUND:Fibroin is a natural macromolecular material with Arg-Gly-Asp peptide structure that is a special tripeptide structure closely related to cel adhesion, and it can promote cel migration, adhesion, and proliferation and influence cel morphology and function. OBJECTIVE:To compare the effects of different silk fibroin scaffolds to repair buccal mucosa defects in rats. METHODS:Ninety Sprague-Dawley rats were selected to make unilateral buccal mucosa defect models, and randomly divided into three groups, 30 rats in each group: porous silk fibroin scaffold was implanted into the buccal mucosa defect in experimental group, multi-layered crosslinked silk fibroin film was implanted into the buccal mucosa defect in control group, and vaseline gauze was used to cover the buccal mucosa defect folowed by suturing in blank control group. After 15 days, wound diameter was detected; after 30 days, bone defect tissues were taken for hematoxylin-eosin staining. RESULTS AND CONCLUSION:At postoperative 15 days, the wound diameter was significantly smaler in the experimental group than the control and blank control groups (P < 0.05), as wel as smaler in the control group than the blank control group (P < 0.05). Hematoxylin-eosin staining showed that at 30 days after operation, there were more epithelial spikes and fibroblasts, but less inflammatory cels in the experimental group than the other two groups (P < 0.05), and fibroin fibers were partialy absorbed and degraded in the experimental group. These findings indicate that porous silk fibroin scaffold for buccal mucosa defect repair can accelerate epithelialization and wound healing.

Nano-cellulose proteinversusacellular matrixinoral mucosarepair / 中国组织工程研究

BACKGROUND:The sensitivity andmucus secretion of theoral mucosamake oral soft tissues difficult to repair, so patients cannot achieve satisfactory outcomes after treatment. Nano-celulose protein mainly composed of glycine, alanine and serine has good histocompati bility. However, there is a lack of comparative study about the effect of nano-celulose protein and acelular matrix in oral mucosa repair, and the clinical effects of the two materials are stil under discussion. OBJECTIVE:To investigate the effects of nano-celulose proteinver susacelular matrix in oral mucosa repair. METHODS:Oral mucosadefect models were preparedinrats, and these rat models were randomly divided into four groups:oral mucosa defectswere repaired by vaseline (control group), nano-celulose protein, bovine skin acelular matrix and human skin acelular matrix, respectively. Repair effects were compared among different materials within 2 months after surgery. RESULTS AND CONCLUSION:The diameter of oral mucosa defect measured using a vernier caliper, had no significant differences among groups at 1 day after surgery (P> 0.05); the diameter of oral mucosa defect in the nano-celulose protein group was significantly lower than that in the other groups at 3, 5 and 7 days after surgery (P 0.05);but there were significant differences in the number of newborn capilary endothelialcels between the control group and the other three groups (P< 0.05). Furthermore, at 21 days after surgery, closely aligned and thicker new epithelialtissuecould be found in the nano-celulose protein group; in the bovine acelular matrix group,thedefect regionwasrepaired wel, new epithelialtissueappeared andthe number of inflammatory cels decreased; in the human acelular matrix group, inflammatory cels appearedobviously, and new epithelialtissueformed with the normal thickness. In contrast,abundant inflammatory cels and thinner epithelial tissues appeared in the control group. To conclude,bothnano-celulose protein and acelular matrix can accelerate wound healing by promoting oral mucosal epithelial hyperplasia.