Is there bacterial infection in the intact crowns of teeth with pulp necrosis of sickle cell anaemia patients? A case series study nested in a cohort.

AIM: To evaluate the presence of bacteria in permanent teeth with intact crowns (without caries, periodontal disease or dental trauma) in patients with sickle cell anaemia (HbSS genotype) by analysing their clinical, imaging and microbiological parameters. METHODOLOGY: This is a case series study nested in a cohort. In the first follow-up of this cohort study (Journal of Endodontics, 2013, 39, 177), 10 HbSS patients with at least one tooth with an intact crown and clinically diagnosed with pulp necrosis by pulse oximetry adapted for dentistry and a cold pulp sensitivity test (n = 27 teeth) were selected. Changes in the pulp chamber, root and periodontal ligament were identified in the tomographic analysis. Bacterial culture, staining for live and dead bacteria, and real-time polymerase chain reaction with 16S rRNA primers were used to identify the presence of bacteria. Culture sample collection was performed immediately after access to the pulp chamber. The microbiome was analysed with a MiSeq sequencer (Illumina, San Diego, CA). RESULTS: The diagnosis of pulp necrosis was confirmed clinically in 82% (22/27) of the teeth. The amount of bacterial load identified was less than 100 copies µL-1 in 23% (5/22) of the teeth with intact crowns and pulp necrosis. Thirteen bacterial species were identified that are commonly found in urinary tract infections, septicaemia and infective endocarditis. Only one of these species, Granulicatella adjacens, has also be found in primary endodontic infections. CONCLUSION: Prospective clinical, imaging and microbiological analyses suggest that pulp necrosis of teeth with intact crowns in HbSS patients is not associated with the presence of bacteria.

Is there association between chronic kidney disease and dental caries? A case-controlled study.

BACKGROUND: The purpose of this study was to assess the association between chronic kidney diseases (CKD) and dental caries. MATERIAL AND METHODS: 107 patients with CKD and 107 with no systemic alteration were randomly included. DMFT (decayed, missing, and filled teeth), plaque index, colony-forming units (CFU) of Streptococcus mutans and salivary composition (IgA total, IgA anti- Streptococcus mutans, calcium and urea) were evaluated. McNemar and Wilcoxon tests were used to compare test and control groups. Spearman test was used to correlate time of hemodialysis and variables studied. Associations between variables were evaluated by logistic regression analysis. RESULTS: The number of filled teeth, the amount of IgA anti-Streptococcus mutans, salivary urea, education level, monthly income and the amount of CFU of Streptococcus mutans were statistically different between groups. There was a positive correlation between the duration of hemodialysis (Hd) and the amount of IgA anti-Streptococcus mutans, urea in saliva, and the number of CFU of Streptococcus mutans. In the adjusted model, a higher incidence of CFU mutans streptococci, elevated salivary urea, smaller number of filled teeth, lower DMFT, and less calcium salivary were associated with CKD. CONCLUSIONS: Programs to prevent and treat oral problems and regular follow-up at the beginning of dialysis are necessary to increase patients' awareness of their condition.

Partial caries removal in primary teeth: association of clinical parameters with microbiological status.

The relationship between clinical characteristics of carious dentin and bacterial colonization after partial caries removal is not completely understood. The aim of this study was to compare microbial counts between categories of carious dentin color, consistency and humidity, and to evaluate the correlation between these characteristics and the presence of cariogenic microorganisms in deep cavities (2/3 or more of the dentin thickness) submitted to partial caries removal. Sixteen primary teeth were submitted to the removal of all carious tissue from the lateral walls of the cavity, whereas carious tissue of the pulp wall was removed superficially. Dentin in the pulp wall was classified according to color, consistency and humidity immediately after cavity preparation and 3-6 months after cavity sealing and a tissue sample was collected on the same occasion for microbiological evaluation. Before sealing, Streptococcus mutans (p = 0.033) and Lactobacillus spp. (p = 0.048) counts were higher in cavities with humid dentin compared to cavities with dry dentin. A negative correlation was observed between carious dentin consistency and S. mutans count during this phase (r(s) = -0.571; p = 0.020). Arrest of dentinal caries lesions was observed after sealing, which was characterized by a reduction of bacterial counts and changes in dentin color, consistency and humidity, irrespectively of baseline dentin characteristics. The clinical characteristics of carious dentin change after the period of cavity sealing and cannot be applied as absolute indicators to limit the excavation of carious dentin when minimally invasive techniques are used.

Microbiological analysis after complete or partial removal of carious dentin in primary teeth: a randomized clinical trial.

Since viable bacteria can persist in tooth cavities regardless of the technique used for caries removal, the objective of the present randomized clinical trial was to examine the microflora of primary teeth treated by complete or partial removal of carious dentin. Deciduous molars with acute carious lesions in the inner half of dentin and vital pulp were randomly divided into two groups of 16: complete removal, in which the carious dentin was completely removed with the help of a caries detector dye, and partial removal, in which the carious dentin was completely removed from the dentinoenamel junction and lateral walls, while the necrotic carious dentin from the cavity floor was only removed superficially. Dentin samples were obtained with a sterile No. 3 bur after caries removal and 3-6 months after protection with calcium hydroxide cement and restoration of the cavities with resin composite. The samples were stored in thioglycolate. Decimal dilutions were then prepared and seeded for the enumeration of Streptococcus spp., mutans streptococci, Lactobacillus spp. and total microorganisms. Before sealing, a larger number of microorganisms was detected in teeth submitted to partial caries removal compared to the complete removal group. However, after sealing the level of colonization was similar in the two groups for all microorganisms studied. The results suggest that persistence of bacteria does not seem to be a reason for reopening of cavities in deciduous teeth after partial caries removal.

Diffusely adhering Escherichia coli (DAEC) strains of fecal origin rarely express F1845 adhesin.

A total of 398 diffusely adhering Escherichia coli (DAEC) strains of fecal origin were analyzed for the presence of sequences homologous to the structural subunit gene (daaE) of the F1845 fimbria. For that purpose, a DNA fragment homologous to daaE, obtained by PCR, was used as a probe in colony hybridization assays. Only two strains carried daaE and expressed F1845, suggesting that this fimbria is rare among DAEC strains.

Virulence properties of Escherichia coli O111:H12 strains.

Seventeen Escherichia coli O111:H12 strains isolated from the feces of children with acute diarrhea were studied with regard to their adherence properties and other virulence characteristics. All strains showed an aggregative adherence pattern to HEp-2 cells and agglutinated bovine and sheep red cells in the presence of mannose. These strains did not have gene sequences homologous to the aggregative adherence fimbria I gene and did not react with any of the DNA probes used to detect other virulence genes in enteropathogens. With one exception, the O111:H12 strains did not induce fluid accumulation in the rabbit ileal loop assay, although 16 of the strains had the enteroaggregative E. coli heat-stable enterotoxin 1 (EAST) gene sequences. A 60-70 MDa plasmid was present in 16 of the strains studied. We conclude that the O111:H12 serotype, one of the first E. coli identified in infantile diarrhea, belongs to the enteroaggregative E. coli category but the genes encoding its adherence phenotype are distinct from those previously described.