Search

Over the past ten years, with the progress of science and technology and improvement of equipment, the root canal treatment level has been promoted rapidly, and the root canal treatment effect has realized qualitative improvement. The 3 elements for the success of the root canal therapy which were the understanding of the root canal, sufficient preparation, close obturation were summarized and analyzed in this paper.

Aim:To investigate the effects of anti-caries DNA vaccine-induced salivary secretory immunoglobulin A (S-IgA) antibodies on Streptococcus mutans (S. mutans) adherence and biofilms formation in vitro.Methods:Adult female Wistar rats were intranasally immunized with the anti-caries DNA vaccine pGJA-P/VAX. Their saliva samples were collected at different times after the immunization, and S-IgA antibody level in the saliva and its inhibition on S. mutans adherence were examined. The effects of S-IgA in the saliva with the strongest inhibitory effects were examined at 3 different stages, ie acquired pellicles, biofilm formation and production of mature biofilms. The number of viable bacteria and depth of the biofilm at 16 h in each stage were determined using counting colony forming units and using a confocal laser scanning microscopy (CLSM). The participation of S-IgA in acquired pellicles and its aggregation with S. mutans were also observed under CLSM.Results:The S-IgA titer in saliva reached its peak and exhibited the strongest inhibition on S. mutans adhesion at 10 weeks after the immunization. The colonies and depth of the biofilm in the saliva-pretreated group were 41.79% and 41.02%, respectively, less than the control group. The colonies and depth of the biofilm in the co-culture group were 27.4% and 22.81% less than the control group. The assembly of S. mutans and S-IgA was observed under CLSM after co-cultivation. In the mature-stage biofilm, no differences were observed between the different groups.Conclusion:These results demonstrate that the anti-caries DNA vaccine induces the production of specific S-IgA antibodies that may prevent dental caries by inhibiting the initial adherence of S. mutans onto tooth surfaces, thereby reducing the accumulation of S. mutans on the acquired pellicles. [ABSTRACT FROM AUTHOR]

PURPOSE: To develop the best fermentation process on pET20b (+)-AP/BL21 (DE3)plysS expressing recombinant Streptococcus mutans surface protein (rPAc). METHODS: The strains were activated and then cultured in orbital shakers. Pilot test of flask shaking culture was done to get optimized culture conditions, including pH value for culture, type of culture medium, range of culture volume and type of feeding medium. According to the optimal fermentation condition of flask shaking culture, fermentation was carried out with 5L fermentor. The fermentation products were analyzed by SDS--PAGE and Western blot. RESULTS: The optimum conditions of fermentations were as follows; initial pH 7.2,LB--2 culture medium, the dissolved oxygen concentration maintained at over 30%,and feeding medium 10% glycerol+5% yeast extract +5% tryptone. Recombinant protein rPAc could be expressed in the soluble protein formation in flask. The expression of rPAc was about 45% of the total bacterial protein and the final cell density (A600) was 44 in the 5L fermentor. Western blot analysis showed that the fermentation products of rPAc was able to bind anti--PAc antibodies. CONCLUSION: The established fermentative procedure provides a basis for further large-scale production of rPAc. Supported by National Natural Science Foundation of China(30600707). [ABSTRACT FROM AUTHOR]

Vitamin D is known to be closely associated with periodontitis; however, its exact mechanisms remain to be clarified. The present study aimed to investigate the influence of 1,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ) on Porphyromonas gingivalis (Pg)-stimulated cytokine production and the involved signaling pathways in macrophages. The main observation was that 1,25(OH) 2 D 3 inhibited Pg-induced interleukin (IL)-6 cytokine expression but up-regulated the expression of anti-inflammatory cytokine IL-10. Further analyses showed that 1,25(OH) 2 D 3 decreased p38 mitogen-activated protein kinase (MAPK) and extracellular signal regulated kinase (ERK)1/2 phosphorylation. Inhibited phosphorylation of p38 MAPK and ERK1/2 was associated with decreased level of IL-6 expression, but was not related to increased level of IL-10 expression in macrophages stimulated with Pg. These results suggest that 1,25(OH) 2 D 3 might exert its anti-inflammatory effects on Pg-stimulated macrophages partly through its inhibitory effect on the p38 MAPK and ERK1/2 signaling pathway.

Purpose: To develop the best fermentation process on pET20b(+)-AP/BL21(DE3)plysS expressing recombinant Streptococcus mutans surface protein(rPAc)., Methods: The strains were activated and then cultured in orbital shakers. Pilot test of flask shaking culture was done to get optimized culture conditions, including pH value for culture, type of culture medium, range of culture volume and type of feeding medium. According to the optimal fermentation condition of flask shaking culture, fermentation was carried out with 5L fermentor. The fermentation products were analyzed by SDS-PAGE and Western blot., Results: The optimum conditions of fermentations were as follows:initial pH 7.2,LB-2 culture medium,the dissolved oxygen concentration maintained at over 30% and feeding medium 10% glycerol+5% yeast extract+5% tryptone.Recombinant protein rPAc could be expressed in the soluble protein formation in flask. The expression of rPAc was about 45% of the total bacterial protein and the final cell density(A600) was 44 in the 5L fermentor. Western blot analysis showed that the fermentation products of rPAc was able to bind anti-PAc antibodies., Conclusion: The established fermentative procedure provides a basis for further large-scale production of rPAc.

Objective: To investigate the effects of pro-inflammatory cytokine interleukin-1β (IL-1β) on mineralization potential of dental pulp stem cells (DPSC)., Methods: Rat DPSC were cultured in vitro and randomly divided into three groups, IL-1β (10 µg/L), osteogenic inductive medium and non-osteogenic inductive medium. After 3, 7, and 12 days of treatment, the cultures were evaluated for cell proliferation and calcium deposit. Real-time polymerase chain reaction was used to detect the gene expression levels of osteocalcin (OC), bone sialoprotein (BSP), dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP-1). In vivo test, after 3 day's treatment with IL-1β, the cell-scaffold complexes were implanted subcutaneously in mice for 8 weeks. Histological analysis was performed to evaluate hard tissue formation., Results: In vitro test, after 3-day's treatment, IL-1β improved cell proliferation to 137.22 DNA µg/L and cell viability becomes (97.12 ± 7.18)% of control. The gene expression levels of OC, BSP, DSPP and DMP-1 are (378.19 ± 16.22)%, (427.12 ± 18.22)%, (247.19 ± 10.11)% and (198.29 ± 10.23)% respectively. The results of IL-1β's group was notable increased compared with non-osteogenic induction medium and the statistical differences are significant. IL-1β induced the odontogenic differentiation of DPSC. However, these effects tended to continuously decrease with treatment time. Histological analysis demonstrated that in the group treated with IL-1β hard tissue was markedly formed in vivo., Conclusions: IL-1β may induce the mineralization of DPSC and play an important role in host defenses and tissue repair.

Objective: To evaluate the long-term clinical effect of dual anti-collagen membranes in guided tissue regeneration (GTR)., Methods: This randomized clinical trial included 26 teeth in 24 patients, presenting a total of 31 lesions consisting of intrabony defects and furcation defects. Twenty-six teeth were divided into two groups and treated by GTR with dual anti-collagen membranes and atelocollagen membranes, respectively. At baseline, 6 months, 1, 3 and 6 years, the following parameters were recorded: clinical attachment level, probing depth, gingival recession and the quantity of alveolar bone analyzed by computer assisted densitometry image analysis (CADIA)., Results: At 1 year after GTR surgery, the gain of clinical attachment in dual anti-collagen membranes group was (3.93 ± 1.74) mm, compared with (2.25 ± 1.90) mm in atelocollagen group (P = 0.044). The increasing of the value of CADIA in dual anti-collagen membrane and atelocollagen group were (53.14 ± 21.35) and (32.96 ± 17.97), P = 0.031. At 3 and 6 years, clinical parameters remained basically stable in both groups, compared to that at 1 year after surgery., Conclusions: The regeneration of periodontal tissues obtained by GTR with dual anti-collagen membranes could be maintained on a long-term basis.

Objective: To construct a new fusion anti-caries DNA vaccine pGJGAC/VAX encoding antigens of both S. mutans and S. sobrinus so as to enhance the protective effect of DNA vaccine against S. sobrinus infection., Methods: The CAT fragment of S. sobrinus OMZ176 gtf-I was amplified by semi-nest PCR and then inserted into the plasmid pGJA-P/VAX to construct the recombinant plasmid pGJGAC/VAX. The CHO cell was transfected and the expression of fusion protein detected using cellular immunohistochemistry and Western blot. Mice were immunized with pGJGAC/VAX and control plasmids via the intramuscular (i.m) or intranasal (i.n) routes. During the experiment, blood and saliva samples were collected at a 2-week interval for antibody assay by ELISA. Rats were orally challenged with S. mutans Ingbritt or S. sobrinus 6715 and then immunized i.n with pGJGAC/VAX, pGJA-P/VAX or pVAX1. The Keyes method was used to determine the caries activity., Results: (1) CAT sequence was identical to the related sequence of gtf-I (OMZ176) in GenBank. The recombinant plasmid pGJGAC/VAX encoded the genes of antigens of both S. mutans and S. sobrinus. The expressed protein could respond to specific anti-PAc, anti-GLU and anti-CAT antibodies respectively. (2) As for antibody reactions, mice in the experiment group had significantly higher levels of anti-PAc, anti-GLU and anti-CAT IgG antibodies than those in the pVAX1 group (P < 0.01). The peak responses of specific anti-CAT antibodies were observed at 8 weeks (GAC/i.m) and 10 weeks (GAC/i.n) and were approximately 62.13 microg/ml and 11.43 microg/ml respectively. The peak responses of specific anti-CAT IgA antibodies were seen at 8 weeks (GAC/i.m) and 10 weeks (GAC/i.n) and were approximately 0.67% and 0.80% respectively. (3) In the group infected with S. mutans or S. sobrinus, the pGJGAC/VAX-immunized rats showed significantly fewer E, Ds and Dm lesions than pVAX1-immunized rats (P < 0.05) and decreased Ds and Dm levels than pGJA-P/VAX-immunized rats (P < 0.05) while there was no obvious difference in E lesions between the two groups (P > 0.05)., Conclusion: A new fusion anti-caries DNA vaccine pGJGAC/VAX encoding antigens of both S. mutans and S. sobrinus is constructed successfully and expressed correctly in eukaryotic cells. It induces effective mucosal and systematic humoral responses so as to provide a better protection against S. sobrinus.

Objective: To evaluate the shaping ability of hand-used ProTaper on curved canals using Endodontic Cube., Methods: Fifty-four curved root canals in vitro were selected and divided into three groups according to the curved degree (alpha), group A: 0 degrees < or = alpha < 25 degrees , group B: 25 degrees < or = alpha < 40 degrees , group C: 40 degrees < or = alpha < 55 degrees . Endodontic Cube was assembled, and each sample was sectioned perpendicular to the axis of the tooth into four sections with Isomer-Buhler in low speed. Then the root canals were prepared with hand-used ProTaper. Before and after shaping, photograph of all the sections were taken under a stereomicroscope. Statistical analyses were performed., Results: The dentin cutting quantity of the whole canal prepared with ProTaper in group B and C was larger than that of group A. The deviation distance of the whole canal prepared by ProTaper in group C was significantly larger than that in group A, and the deviation distance in middle portion larger than that in group B. The maintaining ability in the middle portion of group C by ProTaper was worse than that of group A and B., Conclusions: The curvature of root canal may increase the cutting quantity of the -dentin and reduce the ability of remaining original canal shape prepared by ProTaper.

Objective: To investigate the distribution pattern of the Secretion complex in Streptococcus mutans by means of the subcellular localization of SecA and SecY., Methods: The specificity of anti-SecA antibody and the anti-SecY antibody were examined by Western blot. An indirect postembedding immunogold method was used to determine the subcellular localization of the SecA and SecY in the cytoplasmic membrane of the Streptococcus mutans GS-5., Results: Immunoblotting results showed that the anti-SecA antibody and the anti-SecY antibody specifically recognized a single band of about 95 000 and 47 800 respectively. Immunogold electron microscopy revealed a single intense focus of gold particles at a discrete location on the cytoplasmic membrane of the Streptococcus mutans GS-5., Conclusions: SecA and SecY clustered to an asymmetric microdomain, which suggests that Sec complex present a uni-site on the cytoplasmic membrane of Streptococcus mutans.