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1.
World J Clin Cases ; 10(34): 12578-12586, 2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36579104

RESUMO

BACKGROUND: The vaginal microbiome plays a critical role in the health of pregnant women and their newborns. Group B Streptococcus (GBS) and vaginal cleanliness significantly affect the vaginal microecosystem and are closely associated with vaginal diseases. AIM: To explore the effects of GBS status and vaginal cleanliness on vaginal microecosystems. METHODS: We collected 160 vaginal swabs from pregnant women and divided them into the following four groups based on GBS status and vaginal cleanliness: GBS-positive + vaginal cleanliness I-II degree, GBS-negative + vaginal cleanliness I-II degree, GBS-positive + vaginal cleanliness III-IV degree, and GBS-negative + vaginal cleanliness III-IV degree. Samples were subjected to 16S rRNA gene amplicon sequencing. RESULTS: Alpha diversity analysis showed that the Shannon index did not significantly differ between the four groups. We identified significant variation in taxa abundance between the GBS-positive and GBS-negative groups and between the vaginal cleanliness I-II degree and III-IV degree groups. Principal coordinate analysis and non-metric multidimensional scaling analysis further confirmed the microbial diversity of the four groups. Moreover, the linear discriminant analysis demonstrated that Lactobacillus jensenii and Actinobacteria were strongly associated with GBS-positive status, and Lactobacillus iners, Lactobacillaceae, Lactobacillus, Lactobacillales, Bacilli and Firmicutes were closely correlated with GBS-negative status. CONCLUSION: GBS status and vaginal cleanliness significantly affect vaginal microbiome differences in pregnant women. Our findings provide instructional information for clinical antibiotic treatment in pregnant women with different GBS statuses and vaginal cleanliness degrees.

2.
Front Microbiol ; 12: 742798, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34803963

RESUMO

Three Gram-stain-positive, aerobic, motile actinobacterial strains designated as CPCC 205119T, CPCC 205215, and CPCC 205251 were isolated from different biological soil crust samples collected from Tengger Desert, China. The 16S rRNA gene sequence comparison of these three strains showed they had almost identical 16S rRNA genes, which were closely related to members of the family Geodermatophilaceae, with the highest similarities of 96.3-97.3% to the species of Modestobacter. In the phylogenetic tree based on 16S rRNA gene sequences, these isolates clustered into a subclade next to the branch containing the species of Modestobacter lapidis and Modestobacter multiseptatus, within the lineage of the genus Modestobacter. The comparative genomic characteristics (values of ANI, dDDH, AAI, and POCP) and the phenotypic properties (morphological, physiological, and chemotaxonomic characteristics) of these isolates readily supported to affiliate them to the genus Modestobacter as a single separate species. For which, we proposed that the isolates CPCC 205119T, CPCC 205215, and CPCC 205251 represent a novel species of the genus Modestobacter as Modestobacter deserti sp. nov. CPCC 205119T (=I12A-02624=NBRC 113528T=KCTC 49201T) is the type strain. The genome of strain CPCC 205119T consisted of one chromosome (4,843,235bp) containing 4,424 coding genes, 48 tRNA genes, five rRNA genes, three other ncRNA genes, and 101 pseudogenes, with G+C content of 74.7%. The whole-genome sequences analysis indicated that this species contained alkaline phosphatase genes (phoA/phoD), phosphate transport-related genes (phoU, phnC, phnD, phnE, phoB, phoH, phoP, phoR, pitH, ppk, pstA, pstB, pstC, and pstS), trehalose-phosphate synthase gene (otsA), trehalose 6-phosphate phosphatase gene (otsB) and other encoding genes for the properties that help the microorganisms to adapt to harsh environmental conditions prevalent in deserts. Strains of this species could solubilize tricalcium phosphate [Ca3(PO4)2] and phytin, assimilate pyrophosphate, thiophosphate, dithiophosphate, phosphoenol pyruvate, 2-deoxy-d-glucose-6-phosphate, and cysteamine-S-phosphate.

3.
Int J Syst Evol Microbiol ; 67(10): 4210-4215, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28920829

RESUMO

A Gram-stain-positive, non-spore-forming actinobacterial strain, designated CPCC 204077T, was isolated from the surface-sterilized root of a medicinal plant Huperzia serrata (Thunb.) collected from Sichuan Province, south-west China. The peptidoglycan type of strain CPCC 204077T was detected as A4α with an l-Lys-l-Ser-d-Asp interpeptide bridge. Galactose, glucose, rhamnose and ribose were the sugar compositions in the whole-cell hydrolysates. MK-8(H4) was the only menaquinone. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, one unidentified phospholipid and one unidentified glycolipid. The major fatty acid was iso-C16 : 0. The genomic DNA G+C content was 71.0 mol%. The phylogenetic tree based on 16S rRNA gene sequences showed that strain CPCC 204077T stood for a distinct lineage within the family Dermacoccaceaealongside the genera Branchiibius, Demetria and Barrientosiimonas, with the highest 16S rRNA gene sequence similarities to Branchiibius hedensis Mer 29717T (95.0 %), Calidifontibacter indicus PC IW02T (95.0 %), Barrientosiimonas humi 39T (94.9 %) and Demetria terragena HKI 0089T (94.7 %), and less than 94.7 % sequence similarities to all other species. Signature nucleotides in the 16S rRNA sequence showed that the strain contained the Dermacoccaceaefamily-specific 16S rRNA signature nucleotides and a genus-specific diagnostic nucleotide signature pattern. Combining the genotypic and phenotypic analyses, we propose that strain CPCC 204077T represents a novel species of a new genus in the family Dermacoccaceae with the name Allobranchiibius huperziae gen. nov., sp. nov. Strain CPCC 204077T (=NBRC 110719T=DSM 29531T) is the type strain of the type species.


Assuntos
Actinomycetales/classificação , Huperzia/microbiologia , Filogenia , Raízes de Plantas/microbiologia , Actinomycetales/genética , Actinomycetales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , China , DNA Bacteriano/genética , Ácidos Graxos/química , Glicolipídeos/química , Peptidoglicano/química , Fosfolipídeos/química , Plantas Medicinais/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
4.
Int J Syst Evol Microbiol ; 67(6): 1867-1872, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28629493

RESUMO

An endophytic, short rod-shaped, non-motile and non-spore-forming actinobacterium, designated strain CPCC 204135T, was isolated from a surface-sterilized medicinal plant, Huperzia serrata (Thunb.), collected from Sichuan Province, south-west China. Strain CPCC 204135T was observed to grow at temperatures between 20 and 37 °C (optimum, 28-32 °C), at pH 6.0-9.0 (optimum, pH 7.0-8.0) and in the presence of 0-9.0 % (w/v) NaCl (optimum, 0-3 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CPCC 204135T belonged to the genus Naumannella, showing the highest level of 16S rRNA gene sequence similarity with Naumannella halotolerans DSM 24323T (97.2 %), the only species of the genus Naumannella in the family Propionibacteriaceaewith avalidly published name. The DNA-DNA hybridization value between strain CPCC 204135T and N. halotolerans DSM 24323T was 20.1±1.8 %, which is far below the accepted 70 % threshold for species delineation. The cell-wall hydrolysates contained ll-diaminopimelic acid, alanine, glycine and glutamic acid, with the peptidoglycan type of A3γ. Diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid, one unidentified aminolipid, one unidentified polar lipid and several kinds of glycolipids were detected in the polar lipids profile. MK-9(H4) was identified as the predominant menaquinone. The major cellular fatty acids (>10 %) were anteiso-C15 : 0 and iso-C16 : 0. The G+C content of the genomic DNA of strain CPCC 204135T was determined to be 71.8 mol%. On the basis of phylogenetic analysis, and phenotypic and chemotaxonomic characteristics, we concluded that strain CPCC 204135T represents a novel species of the genus Naumannella, for which the name Naumannella huperziae sp. nov. is proposed, with strain CPCC 204135T (=DSM 101717T=NBRC 111773T) as the type strain.


Assuntos
Huperzia/microbiologia , Filogenia , Propionibacteriaceae/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , China , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Glicolipídeos/química , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , Plantas Medicinais/microbiologia , Propionibacteriaceae/genética , Propionibacteriaceae/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
5.
Int J Syst Evol Microbiol ; 66(10): 3972-3977, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27413046

RESUMO

A novel endophytic actinobacterium, designated strain CPCC 204076T, was isolated from surface-sterilized tissue of the medicinal plant Huperzia serrata (Thunb.) collected from Sichuan Province, south-west China. The taxonomic position of the isolate was investigated by a polyphasic approach. The strainwas aerobic, Gram-stain-positive, non-motile, non-spore-forming and rod-shaped. Growth was observed at 10-37 °C, at pH 5.0-10.0 and with 0-3.0 % (w/v) NaCl. The polar lipid fraction consisted of diphosphatidylglycerol, a phospholipid, an aminolipid, a glycolipid, an aminophospholipid and phosphatidylinositol. The cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid and the peptidoglycan was of type A4γ. The menaquinone system consisted of MK-9(H4) and MK-8(H4). The major cellular fatty acids (>10 %) were iso-C16 : 0 and anteiso-C17 : 0. The genomic DNA G+C content of strain CPCC 204076T was found to be 71.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that CPCC 204076T belongs to the genus Jatrophihabitans with highest sequence similarity to Jatrophihabitans endophyticus DSM 45627T (96.5 %), Jatrophihabitans soli DSM 45908T (96.5 %) and Jatrophihabitans fulvus JCM 30448T (96.1 %), and much lower similarities (<95.0 %) to other available 16S rRNA gene sequences from validly described pure cultures. However, DNA-DNA hybridyzation values between strain CPCC 204076T and the three recognized Jatrophihabitans species were 31±3.1 % (J. endophyticus DSM 45627T), 33±2.9 % (J. soli DSM 45908T) and 37±1.7 % (J. fulvus JCM 30448T), which were all far below the recommended cut-off value of 70 %. The phenotypic and genomic characteristics distinctly indicated that strain CPCC 204076T represents a novel species of the genus Jatrophihabitans, for which the name Jatrophihabitans huperziae sp. nov. is proposed. The type strain is CPCC 204076T (I13A-01604) (=DSM 46866T=NBRC 110718T).


Assuntos
Actinobacteria/classificação , Huperzia/microbiologia , Filogenia , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , China , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Glicolipídeos/química , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , Plantas Medicinais/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
6.
Front Microbiol ; 6: 1059, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26483778

RESUMO

The goal of this study was to gain insight into the diversity of culturable actinobacteria in desert soil crusts and to determine the physiological characteristics of the predominant actinobacterial group in these crusts. Culture-dependent method was employed to obtain actinobacterial strains from desert soil samples collected from Shapotou National Desert Ecological Reserve (NDER) located in Tengger Desert, China. A total of 376 actinobacterial strains were isolated and 16S rRNA gene sequences analysis indicated that these isolates belonged to 29 genera within 18 families, among which the members of the family Geodermatophilaceae were predominant. The combination of 16S rRNA gene information and the phenotypic data allowed these newly-isolated Geodermatophilaceae members to be classified into 33 "species clusters," 11 of which represented hitherto unrecognized species. Fermentation broths from 19.7% of the isolated strains showed activity in at least one of the six screens for antibiotic activity. These isolates exhibited bio-diversity in enzymatic characteristics and carbon utilization profiles. The physiological characteristics of the isolates from different types of crusts or bare sand samples were specific to their respective micro-ecological environments. Our study revealed that members of the family Geodermatophilaceae were ubiquitous, abundant, and diverse in Shapotou NDER, and these strains may represent a new major group of potential functional actinobacteria in desert soil.

7.
Int J Syst Evol Microbiol ; 65(10): 3359-3364, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26297147

RESUMO

A novel aerobic actinomycete, designated strain I12A-02601T, was isolated from a desert soil crusts sample collected from the Shapotou region of Tengger Desert, north-west China. The substrate mycelia of this isolate were well-developed and branched, but not fragmented. The maturity aerial mycelia formed short chains of small, rod-shaped spores. The strain contained ll-diaminopimelic acid, dd-diaminopimelic acid, galactose, glucose, ribose and xylose in its whole-cell hydrolysates. The polar lipids consisted of diphosphatidylglycerol, N-acetylglucosamine-containing phospholipids, phosphatidylinositolmannoside and glycolipids. The predominant menaquinones were MK-10(H6) and MK-10(H8). The major fatty acids were iso-C15 : 0, anteiso-C15 : 0, C16 : 0, anteiso-C17 : 0 and iso-C16 : 0. The G+C content of the genomic DNA was 72.2 mol%. The 16S rRNA gene sequences comparison showed that strain I12A-02601T was most closely related to members of the family Nocardioidaceae, such as Actinopolymorpha alba YIM 48868T (93.3 % sequence similarity), Actinopolymorpha pittospori PIP 143T (93.2 %), and Flindersiella endophytica EUM 378T (93.2 %). In the phylogenetic tree based on 16S rRNA gene sequences, strain I12A-02601T formed a clade with the members of the genera Flindersiella, Thermasporomyces, and Actinopolymorpha in the family Nocardioidaceae. Combined data from this taxonomic study using a polyphasic approach, led to the conclusion that strain I12A-02601T represents a novel species of a new genus in the family Nocardioidaceae, for which the name Tenggerimyces mesophilus gen. nov., sp. nov. is proposed. The type strain of the type species is I12A-02601T ( = CPCC 203544T = DSM 45829T = NBRC 109454T).


Assuntos
Actinomycetales/classificação , Filogenia , Microbiologia do Solo , Actinomycetales/genética , Actinomycetales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Clima Desértico , Ácido Diaminopimélico/química , Ácidos Graxos/química , Dados de Sequência Molecular , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/química
8.
Int J Syst Evol Microbiol ; 64(Pt 9): 3120-3125, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24944338

RESUMO

An actinomycete strain, designated I12A-02593(T), was isolated from a desert soil crust sample collected in the Shapotou region of Tengger Desert, north-west China. The isolate grew well on International Streptomyces Project (ISP) media 2, 3, 5 and 7, YS and Bennett's agar; it produced spherical bodies and formed clumps on the aerial mycelia on ISP 5 agar plates. Chemotaxonomically, the strain contained meso-diaminopimelic acid as the diagnostic diamino acid, arabinose and galactose as the diagnostic sugars in whole-cell hydrolysates, MK-9(H4) as the sole isoprenoid quinone, and iso-C16 : 0, iso-C16 : 0 2-OH and iso-C16 : 1 H as the major cellular fatty acids, without mycolic acids. The profile of the phospholipids mainly comprised diphosphatidylglycerol, phosphatidylethanolamine and hydroxyphosphatidylethanolamine. The genomic DNA G+C content was 70.1 mol%. The 16S rRNA gene sequence of strain I12A-02593(T) exhibited 96.4-97.4 % similarities with members of the genus Actinophytocola. In the phylogenetic tree based on 16S rRNA gene sequences, the isolate formed a robust cluster with Actinophytocola oryzae NBRC 105245(T), Aactinophytocola timorensis NBRC 105524(T), Actinophytocola corallina NBRC 105525(T), Actinophytocola burenkhanensis NBRC 105883(T)and Actinophytocola xinjiangensis NBRC 106673(T). DNA-DNA hybridization values between strain I12A-02593(T) and the five species of the genus Actinophytocola were all less than 70 %. On the basis of the polyphasic taxonomy evidence, a novel species of the genus Actinophytocola is proposed, with the name Actinophytocola gilvus sp. nov. The type strain is I12A-02593(T) ( = CPCC 203543(T) = DSM 45828(T) = NBRC 109453(T) = KCTC 29165(T)). An emended description of the genus Actinophytocola is also provided.


Assuntos
Actinomycetales/classificação , Filogenia , Microbiologia do Solo , Actinomycetales/genética , Actinomycetales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Clima Desértico , Ácido Diaminopimélico/química , Ácidos Graxos/química , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Vitamina K 2/análogos & derivados , Vitamina K 2/química
9.
Asian Pac J Cancer Prev ; 15(5): 2075-81, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24716937

RESUMO

The association between glutathione-S-transferase polymorphisms (GSTM1, GSTT1 and GSTP1) and risk of acute leukemia in Asians remains controversial. This study was therefore designed to evaluate the precise association in 23 studies identified by a search of PubMed and several other databases, up to December 2013. Using random or fixed effects models odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated. Heterogeneity across studies was assessed, and funnel plots were constructed to test for publication bias. The meta-analysis showed positive associations between GST polymorphisms (GSTM1 and GSTT1 but not GSTP1) and acute leukemia risk [(OR=1.47, 95% CI 1.18-1.83); (OR=1.32, 95% CI 1.07-1.62); (OR=1.01, 95% CI 0.84-1.23), respectively] and heterogeneity between the studies. The results suggested that the GSTM1 null genotype and GSTT1null genotype, but not the GSTP1 polymorphism, might be a potential risk factors for acute leukemia. Further well-designed studies are needed to confirm our findings.


Assuntos
Povo Asiático/genética , Predisposição Genética para Doença/genética , Glutationa S-Transferase pi/genética , Glutationa Transferase/genética , Polimorfismo Genético/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Genótipo , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-Idade , Risco , Fatores de Risco , Adulto Jovem
10.
Gene ; 527(1): 26-32, 2013 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-23791657

RESUMO

MicroRNA-183 (miR-183) family is proposed as promising biomarkers for early cancer detection and accurate prognosis as well as targets for more efficient treatment. The results of their expression feature in cancer tissues are inconsistent and controversy still exists in identifying them as new biomarkers of cancers. Therefore, to systemically evaluate the most frequently reported cancers in which miR-183 family members were up- or down-regulated is critical for further investigation on physiological impact of its aberrant regulation in specific cancers. The published studies that compared the level of miR-183 family expression in cancer tissues with those in noncancerous tissues were reviewed by the meta-analysis with a vote-counting strategy. Among the 49 included studies, a total of 18 cancers were reported, with 11 cancers reported in at least two studies. In the panel of miR-183 family members' expression analysis, colorectal cancer and prostate cancer ranked at the top among consistently reported cancer types with up-regulated feature. Bladder cancer, lung cancer and hepatocellular carcinoma were the third most frequently reported cancer types with significant over-expression of miR-96, miR-182 and miR-183 respectively. Breast cancer and gastric cancer were presented with inconsistent regulations and the members of this family had their own distinct regulated features in other different cancers. MiR-183 family, either individually or as a cluster, may be useful prognostic markers and/or therapeutic targets in several cancers. Further studies and repeat efforts are still required to determine the role of miR-183 family in various cancer progressions.


Assuntos
MicroRNAs/genética , Neoplasias/genética , Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , MicroRNAs/metabolismo , Neoplasias/metabolismo
12.
Artigo em Coreano | WPRIM (Pacífico Ocidental) | ID: wpr-58043

RESUMO

Since the introduction of restorative dental composites, their physical properties have been significantly improved. However, polymerization shrinkage is still a major drawback. Many efforts have been made to develop a low shrinking composite, and silorane-based composites have recently been introduced into the market. In addition, many different methods have been developed to measure the polymerization shrinkage. In this study, we developed a new method to measure the linear polymerization shrinkage of composites without direct contact to a specimen using a particle tracking method with computer vision. The shrinkage kinetics of a commercial silorane-based composite (P90) and two conventional methacrylate-based composites (Z250 and Z350) were investigated and compared. The results were as follows: 1. The linear shrinkage of composites was 0.33-1.41%. Shrinkage was lowest for the silorane-based (P90) composite, and highest for the flowable Z350 composite. 2. The new instrument was able to measure the true linear shrinkage of composites in real time without sensitivity to the specimen preparation and geometry.


Assuntos
Cinética , Polimerização , Polímeros , Resinas de Silorano , Atletismo , Visão Ocular
13.
Artigo em Coreano | WPRIM (Pacífico Ocidental) | ID: wpr-164695

RESUMO

The purpose of this study was to evaluate the effect of instrument compliance on the polymerization shrinkage stress measurements of dental composites. The contraction strain and stress of composites during light curing were measured by a custom made stress-strain analyzer, which consisted of a displacement sensor, a cantilever load cell and a negative feedback mechanism. The instrument can measure the polymerization stress by two modes: with compliance mode in which the instrument compliance is allowed, or without compliance mode in which the instrument compliance is not allowed. A flowable (Filtek Flow: FF) and two universal hybrid (Z100: Z1 and Z250: Z2) composites were studied. A silane treated metal rod with a diameter of 3.0 mm was fixed at free end of the load cell, and other metal rod was fixed on the base plate. Composite of 1.0 mm thickness was placed between the two rods and light cured. The axial shrinkage strain and stress of the composite were recorded for 10 minutes during polymerization, and the tensile modulus of the materials was also determined with the instrument. The statistical analysis was conducted by ANOVA, paired t-test and Tukey's test (alpha<0.05). There were significant differences between the two measurement modes and among materials. With compliance mode, the contraction stress of FF was the highest: 3.11 (0.13), followed by Z1: 2.91 (0.10) and Z2: 1.94 (0.09) MPa. When the instrument compliance is not allowed, the contraction stress of Z1 was the highest: 17.08 (0.89), followed by FF: 10.11 (0.29) and Z2: 9.46 (1.63) MPa. The tensile modulus for Z1, Z2 and FF was 2.31 (0.18), 2.05 (0.20), 1.41 (0.11) GPa, respectively. With compliance mode, the measured stress correlated with the axial shrinkage strain of composite; while without compliance the elastic modulus of materials played a significant role in the stress measurement.


Assuntos
Quimera , Colódio , Complacência (Medida de Distensibilidade) , Contratos , Deslocamento Psicológico , Módulo de Elasticidade , Luz , Polimerização , Polímeros , Resinas Sintéticas , Entorses e Distensões
14.
Artigo em Coreano | WPRIM (Pacífico Ocidental) | ID: wpr-164694

RESUMO

This clinical study evaluated the whitening effect and safety of polymer based-pen type BlancTis Forte (NIBEC) containing 8.3% carbamide peroxide. Twenty volunteers used the BlancTis Forte whitening agent for 2 hours twice a day for 4 weeks. As a control, Whitening Effect Pen (LG) containing 3% hydrogen peroxide was used by 20 volunteers using the same protocol. The change in shade (DeltaE*, color difference) was measured using Shadepilot(TM) (DeguDent) before, during, and after bleaching (2 weeks, 4 weeks, and post-bleaching 4 weeks). A clinical examination for any side effects (tooth hypersensitivity or soft tissue complications) was also performed at each check-up. The following results were obtained. 1. Both the experimental and control groups displayed a noticeable change in shade (DeltaE) of over 2. No significant differences were found between the two groups (p > 0.05), implying that the two agents have a similar whitening effect. 2. The whitening effect was mainly due to changes in a and b values rather than in L value (brightness). The experimental group showed a significantly higher change in b value, thus yellow shade, than the control (p < 0.05). 3. None of the participants complained of tooth hypersensitivity or soft tissue complications, confirming the safety of both whitening agents.


Assuntos
Clareadores , Peróxido de Hidrogênio , Hipersensibilidade , Peróxidos , Polímeros , Dente , Ureia
15.
Artigo em Coreano | WPRIM (Pacífico Ocidental) | ID: wpr-40936

RESUMO

The aim of this study was to develop a method for measuring the slumping resistance of flowable resin composites and to evaluate the efficacy using rheological methodology. Five commercial flowable composites (Aelitefil flow:AF, Filtek flow:FF, DenFil flow:DF, Tetric flow:TF and Revolution:RV) were used. Same volume of composites in a syringe was extruded on a glass slide using a custom-made loading device. The resin composites were allowed to slump for 10 seconds at 25degrees C and light cured. The aspect ratio (height/diameter) of cone or dome shaped specimen was measured for estimating the slumping tendency of composites. The complex viscosity of each composite was measured by a dynamic oscillatory shear test as a function of angular frequency using a rheometer. To compare the slumping tendency of composites, one way-ANOVA and Turkey's post hoc test was performed for the aspect ratio at 95% confidence level. Regression analysis was performed to investigate the relationship between the complex viscosity and the aspect ratio. The results were as follows. 1. Slumping tendency based on the aspect ratio varied among the five materials (AF < FF < DF < TF < RV). 2. Flowable composites exhibited pseudoplasticity in which the complex viscosity decreased with increasing frequency (shear rate). AF was the most significant, RV the least. 3. The slumping tendency was strongly related with the complex viscosity. Slumping resistance increased with increasing the complex viscosity. The slumping tendency could be quantified by measuring the aspect ratio of slumped flowable composites. This method may be applicable to evaluate the clinical handling characteristics of flowable composites.


Assuntos
Resinas Compostas , Vidro , Manobra Psicológica , Luz , Seringas , Viscosidade
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