Navegando por Autor "Siqueira Junior, José F."

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Antimicrobial activity and flow rate of newer and established root canal sealers
(2000) Siqueira Junior, José F.; Favieri, Amauri; Gahyva, Sérgio M. M.; Moraes, Saulo R.; Lima, Kenio Costa de; Lopes, Hélio P.
Endodontic sealers that possess both optimum flow ability and antimicrobial properties may theoretically assist in the elimination of microorganisms located in confined areas of the root canal system. The antimicrobial effects and the flow rate of the following sealers were investigated and compared: Kerr Pulp Canal Sealer EWT, Grossman's Sealer, ThermaSeal, Sealer 26, AH Plus, and Sealer Plus. The agar diffusion test was used to assess the antimicrobial activity of the sealers. In the flow assay, the sealers were placed between two glass slabs and a weight of 500 g was placed on the top of the glass. The diameters of the formed discs were recorded. All root canal sealers tested showed some antimicrobial activity against most of the microorganisms. There were no significant differences between the materials tested (p > 0.05). All root canal sealers also flowed under the conditions of this study. Statistical analysis of the results revealed that AH Plus and Kerr Pulp Canal Sealer EWT had flow values significantly superior to the other sealers tested (p > 0.05). Taken together, these findings suggest that these sealers have the potential to help in the microbial control in the root canal system.
Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis
(2007) Siqueira Junior, José F.; Roças, Isabela N.; Paiva, Simone S. M.; Guimarães-Pinto, Tatiana; Magalhães, Karen M.; Lima, Kenio Costa de
Objective This clinical study was undertaken to compare the effectiveness of 2.5% sodium hypochlorite (NaOCl) and 0.12% chlorhexidine digluconate as irrigants in reducing the cultivable bacterial populations in infected root canals of teeth with apical periodontitis. Study design According to stringent inclusion/exclusion criteria, 32 teeth with primary intraradicular infections and chronic apical periodontitis were selected and followed in the study. Bacterial samples were taken at the baseline (S1) and after chemomechanical preparation using either NaOCl (n = 16) or chlorhexidine (n = 16) as irrigants (S2). Cultivable bacteria recovered from infected root canals at the 2 stages were counted. Isolates from S2 samples were identified by means of 16S rRNA gene sequencing analysis. Results At S1, all canals were positive for bacteria, and the median number of bacteria per canal was 7.32 × 105 for the NaOCl group and 8.5 × 105 for the chlorhexidine group. At S2, the median number of bacteria in canals irrigated with NaOCl and chlorhexidine was 2.35 × 103 and 2 × 102, respectively. Six of 16 (37.5%) canals from the NaOCl group and 8 of 16 (50%) canals from the chlorhexidine group yielded negative cultures. Chemomechanical preparation using either solution substantially reduced the number of cultivable bacteria in the canals. No significant difference was observed between the NaOCl and chlorhexidine groups with regard to the number of cases yielding negative cultures (P = .72) or quantitative bacterial reduction (P = .609). The groups irrigated with NaOCl or chlorhexidine showed a mean number of 1.3 and 1.9 cultivable species per canal, respectively. The great majority of isolates in S2 were from gram-positive bacteria, with streptococci as the most prevalent taxa. Conclusions The present findings revealed no significant difference when comparing the antibacterial effects of 2.5% NaOCl and 0.12% chlorhexidine used as irrigants during the treatment of infected canals.
Chemomechanical reduction of the bacterial population in the root canal after instrumentation and irrigation with 1%, 2.5%, and 5.25% sodium hypochlorite
(2000) Siqueira Junior, José F.; Rôças, Isabela N.; Favieri, Amauri; Lima, Kenio Costa de
Given the importance of bacteria in the development of periradicular lesions, the eradication of the root canal infection is paramount in endodontic treatment. This study evaluated the in vitro intracanal bacterial reduction produced by instrumentation and irrigation with 1%, 2.5%, and 5.25% sodium hypochlorite (NaOCl) or saline solution. Root canals inoculated with Enterococcus faecalis were instrumented and irrigated with the solutions tested. Canals were sampled before and after preparation. After serial dilution, samples were plated onto Mitis salivarius agar, and the colony-forming units grown were counted. Inhibitory effects of the three NaOCl solutions on E. faecalis were also evaluated by means of the agar diffusion test. All test solutions significantly reduced the number of bacterial cells in the root canal (p < 0.05). There was no significant difference between the three NaOCl solutions tested (p > 0.05). Nonetheless, all NaOCl solutions were significantly more effective than saline solution in reducing the number of bacterial cells within the root canal (p < 0.05). The three NaOCl concentrations showed large zones of inhibition against E. faecalis. The results of this study suggest that regular exchange and the use of large amounts of irrigant should maintain the antibacterial effectiveness of the NaOCl solution, compensating for the effects of concentration.
Efficacy of instrumentation techniques and irrigation regimens in reducing the bacterial population within root canals
(2002) Siqueira Junior, José F.; Roças, Isabela N.; Santos, Sandra R. L. D.; Lima, Kenio Costa de; Magalhães, Fernando A. C.; Uzeda, Milton de
The purpose of this study was to compare the in vitro intracanal bacterial reduction produced by using two instrumentation techniques and different irrigation methods. Root canals inoculated with Enterococcus faecalis were prepared by using the following techniques and irrigants: alternated rotary motions (ARM) technique, hand nickel-titanium files and 2.5% sodium hypochlorite (NaOCl) as irrigant; ARM technique and combined irrigation with 2.5% NaOCl and citric acid; ARM technique and combined irrigation with 2.5% NaOCl and 2% chlorhexidine gluconate; and Greater Taper rotary files, using 2.5% NaOCl as irrigant. Controls were instrumented by using the ARM technique and irrigated with sterile saline. Canals were sampled before and after preparation. After serial dilution, samples were plated onto Mitis-Salivarius agar, and the colony forming units that were grown were counted. All test techniques and solutions significantly reduced the number of bacterial cells within the root canal (p < 0.05). There was no significant difference between the experimental groups (p > 0.05). Nonetheless, all of them were significantly more effective than the control group (p < 0.05). These findings support the importance of using antimicrobial irrigants during the chemomechanical preparation, regardless of the solutions or instrumentation techniques used.
Microbiome of Deep Dentinal Caries Lesions in Teeth with Symptomatic Irreversible Pulpitis
(2016) Rôças, Isabela N.; Alves, Flávio R. F.; Rachid, Caio T. C. C.; Lima, Kenio Costa de; Assunção, Isauremi Vieira de; Gomes, Patrícia N.; Siqueira Junior, José F.
This study used a next-generation sequencing approach to identify the bacterial taxa occurring in the advanced front of caries biofilms associated with pulp exposure and irreversible pulpitis. Samples were taken from the deepest layer of dentinal caries lesions associated with pulp exposure in 10 teeth diagnosed with symptomatic irreversible pulpitis. DNA was extracted and the microbiome was characterized on the basis of the V4 hypervariable region of the 16S rRNA gene by using paired-end sequencing on Illumina MiSeq device. Bacterial taxa were mapped to 14 phyla and 101 genera composed by 706 different OTUs. Three phyla accounted for approximately 98% of the sequences: Firmicutes, Actinobacteria and Proteobacteria. These phyla were also the ones with most representatives at the species level. Firmicutes was the most abundant phylum in 9/10 samples. As for genera, Lactobacillus accounted for 42.3% of the sequences, followed by Olsenella (13.7%), Pseudoramibacter (10.7%) and Streptococcus (5.5%). Half of the samples were heavily dominated by Lactobacillus, while in the other half lactobacilli were in very low abundance and the most dominant genera were Pseudoramibacter, Olsenella, Streptococcus, and Stenotrophomonas. High bacterial diversity occurred in deep dentinal caries lesions associated with symptomatic irreversible pulpitis. The microbiome could be classified according to the relative abundance of Lactobacillus. Except for Lactobacillus species, most of the highly prevalent and abundant bacterial taxa identified in this study have been commonly detected in infected root canals. The detected taxa can be regarded as candidate pathogens for irreversible pulpitis and possibly the pioneers in pulp invasion to initiate endodontic infection.
Relationship between FcY receptor and interleukin-1 gene polymorphisms and post-treatment apical periodontitis
(2009) Siqueira Junior, José F.; Roças, Isabela N.; Provenzano, José C.; Daibert, Frederico K.; Silva, Marlei G.; Lima, Kenio Costa de
Introduction Genetic polymorphisms have been reported to act as modifiers of diverse diseases and, as such, might theoretically influence the severity and response to treatment of apical periodontitis. The purpose of this study was to investigate the association of Fcγ receptor and interleukin (IL)-1 gene polymorphisms with post-treatment apical periodontitis in Brazilian individuals. Methods The study population consisted of 18 patients with post-treatment apical periodontitis and 44 individuals with root canal–treated teeth exhibiting healthy/healing periradicular tissues (controls). Patients were typed for the following genes (alleles): FcγRIIA (R131 or H131), FcγRIIIB (NA1 or NA2), IL-1A (1 or 2), and IL-1B (1 or 2). Results No significant statistical differences were observed for all specific genotypes and almost all allele carriage rates of the test genes as well as combinations thereof with regard to association with disease (P > .05). Actually, only 2 genetic conditions were found to be associated with post-treatment apical periodontitis: carriage of allele H131 of the FcγRIIa gene (P = .04) and a combination of this allele with allele NA2 of the FcγRIIIb gene (P < .01). Conclusions Data from the present study suggest that some conditions associated with polymorphism of Fcγ receptor genes might influence the patient's response to endodontic treatment of teeth with apical periodontitis.
Susceptibilities of enterococcus faecalis biofilms to some antimicrobial medications
(2001) Lima, Kenio Costa de; Fava, Luis R. G.; Siqueira Junior, José F.
Enterococcus faecalis has bEnterococcus faecalis has been suggested to be an important etiological agent in endodontic failures. The purpose of this study was to evaluate the effectiveness of chlorhexidine- or antibiotics-based medications in eliminating E. faecalis biofilms. One-day and three-day biofilms of E. faecalis were induced on cellulose nitrate membrane filters. Each biofilm-containing membrane was thoroughly covered with 1 ml of the test medications and incubated for 1 day at 37°C. Treated biofilms were then aseptically transferred to vials containing a neutralizing agent in saline solution and vortexed. Suspensions were 10-fold diluted, seeded onto Mitis salivarius agar plates, and the colony-forming units counted after 48 h of incubation. There were significant differences between the formulations tested. The association of clindamycin with metronidazole significantly reduced the number of cells in 1-day biofilms. However of all medications tested, only 2% chlorhexidine-containing medications were able to thoroughly eliminate most of both 1-day and 3-day E. faecalis biofilms.

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Navegando por Autor "Siqueira Junior, José F."