Navegando por Autor "Rôças, Isabela N."

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Advanced caries microbiota in teeth with irreversible pulpitis
(2015) Rôças, Isabela N.; Lima, Kenio Costa de; Assunção, Isauremi Vieira de; Gomes, Patrícia N.; Bracks, Igor V.; Siqueira, José F.
INTRODUCTION: Bacterial taxa in the forefront of caries biofilms are candidate pathogens for irreversible pulpitis and are possibly the first ones to invade the pulp and initiate endodontic infection. This study examined the microbiota of the most advanced layers of dentinal caries in teeth with irreversible pulpitis. METHODS: DNA extracted from samples taken from deep dentinal caries associated with pulp exposures was analyzed for the presence and relative levels of 33 oral bacterial taxa by using reverse-capture checkerboard hybridization assay. Quantification of total bacteria, streptococci, and lactobacilli was also performed by using real-time quantitative polymerase chain reaction. Associations between the target bacterial taxa and clinical signs/symptoms were also evaluated. RESULTS: The most frequently detected taxa in the checkerboard assay were Atopobium genomospecies C1 (53%), Pseudoramibacter alactolyticus (37%), Streptococcus species (33%), Streptococcus mutans (33%), Parvimonas micra (13%), Fusobacterium nucleatum (13%), and Veillonella species (13%). Streptococcus species, Dialister invisus, and P. micra were significantly associated with throbbing pain, S. mutans with pain to percussion, and Lactobacillus with continuous pain (P < .05). Quantitative polymerase chain reaction revealed a mean total bacterial load of 1 × 10(8) (range, 2.05 × 10(5) to 4.5 × 10(8)) cell equivalents per milligram (wet weight) of dentin. Streptococci and lactobacilli were very prevalent but comprised only 0.09% and 2% of the whole bacterial population, respectively. CONCLUSIONS: Several bacterial taxa were found in advanced caries lesions in teeth with exposed pulps, and some of them were significantly associated with symptoms. A role for these taxa in the etiology of irreversible pulpitis is suspected.
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.
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.
Type 2 diabetes mellitus and the prevalence of apical periodontitis and endodontic treatment in an adult Brazilian population
(2011) Marotta, Patrícia S.; Fontes, Tatiana V.; Armada, Luciana; Lima, Kenio Costa de; Rôças, Isabela N.; Siqueira Jr, José F.
Introduction This cross-sectional study evaluated the prevalence of apical periodontitis (AP) and endodontic treatment in type 2 diabetic individuals as compared with nondiabetics from an adult Brazilian population. Methods Full-mouth radiographs from 30 type 2 diabetic and 60 age- and sex-matched nondiabetic individuals were examined, and the presence of AP lesions in untreated and root canal-treated teeth was recorded. The number of teeth and the prevalence of root canal treatment were also evaluated. Results AP was significantly more present in teeth from diabetic individuals (98/652, 15%) than in nondiabetic controls (162/1,368, 12%) (P = .05). A separate analysis of untreated and treated teeth revealed that significance was mostly because of the prevalence of AP in untreated teeth, which was 10% in diabetics and 7% in nondiabetics (P = .03). No significant difference between diabetics and nondiabetics was observed for the other parameters under study, including the prevalence of AP in root canal–treated teeth, the number of teeth in the oral cavity, the number of treated teeth per individual, the number of individuals with at least 1 AP lesion or 1 root canal treatment, and the number of teeth with AP per individual (P > .05). Conclusions AP was significantly more prevalent in untreated teeth from type 2 diabetics. This suggests that diabetes may serve as a disease modifier of AP in the sense that individuals with diabetes can be more prone to develop primary disease. However, findings do not confirm that diabetes may influence the response to root canal treatment because treated teeth had no increased prevalence of AP when compared with controls.

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Navegando por Autor "Rôças, Isabela N."