RESUMEN
INTRODUCTION: The infectious content of root canals, including bacteria and lipoteichoic acid (LTA), cause injuries to the periapical tissues. The purpose of this clinical study was to quantify the levels of both LTA and cultivable bacteria at the different phases of endodontic retreatment (ER) of teeth with post-treatment apical periodontitis. It also aimed to investigate the presence of gram-positive microorganisms before and after chemomechanical preparation (CMP) and intracanal medication (ICM). METHODS: Twenty infected root canals of single-rooted teeth were randomly assigned into 2 groups according to the chemical substance used for CMP (n = 10 per group): chlorhexidine (CHX) group, 2% CHX gel, and the sodium hypochlorite (NaOCl) group, 6% NaOCl. Root canal samples were taken using paper points before (S1) and after CMP (S2) and after 30 days of ICM with calcium hydroxide + 2% CHX gel (S3). Microorganisms were identified by the culture technique using biochemical tests. Cultivable bacteria were determined by counting the colony-forming unit. LTA levels were measured using the enzyme-linked immunosorbent assay (pg/mL). RESULTS: A total of 70 gram-positive species, out of 102 species isolated, were found in the root canals (54 in S1, 4 in S2, and 12 in S3). Enterococcus faecalis was the most frequent isolated taxon in all phases of the ER. LTA (574.0 ± 94.7) and cultivable bacteria (101.2 ± 79.2) were present in all S1 samples. CMP decreased the overall levels of cultivable bacteria by 99.4% and LTA by 24.8% (P < .05), whereas the total overall reduction level of ICM on viable bacteria was 99.5% and on LTA it was 38.6% (P < .05). CMP with 2% CHX gel (CHX group, 99.3%) was more effective (P < .05) than 6% NaOCl (NaOCl group, 92.1%) on bacterial reduction. Likewise, ICM showed a 100% reduction in the CHX group and 98.5% in the NaOCl group. Regarding the reduction of LTA, CMP with 2% CHX gel (CHX group, 26.9%) was more effective (P < .05) than 6% NaOCl (NaOCl group, 22.6%). In addition, ICM showed a 43.2% reduction in the CHX group and 36.2% in the NaOCl group (P > .05). CONCLUSIONS: The reduction rates of bacteria were higher than the LTA. Moreover, gram-positive microorganisms were present in all phases of the endodontic retreatment.
Asunto(s)
Bacterias/crecimiento & desarrollo , Cavidad Pulpar/metabolismo , Cavidad Pulpar/microbiología , Lipopolisacáridos/metabolismo , Periodontitis Periapical/metabolismo , Periodontitis Periapical/microbiología , Tratamiento del Conducto Radicular/métodos , Ácidos Teicoicos/metabolismo , Adulto , Bacterias/efectos de los fármacos , Clorhexidina/uso terapéutico , Cavidad Pulpar/química , Enterococcus faecalis/efectos de los fármacos , Enterococcus faecalis/crecimiento & desarrollo , Enterococcus faecalis/aislamiento & purificación , Bacterias Grampositivas/clasificación , Bacterias Grampositivas/crecimiento & desarrollo , Bacterias Grampositivas/aislamiento & purificación , Humanos , Lipopolisacáridos/análisis , Persona de Mediana Edad , Distribución Aleatoria , Retratamiento , Irrigantes del Conducto Radicular/uso terapéutico , Preparación del Conducto Radicular/métodos , Hipoclorito de Sodio/uso terapéutico , Ácidos Teicoicos/análisisRESUMEN
This research evaluates the effects of the lipopolysaccharides (LPS) from Escherichia coli and lipoteichoic acid (LTA) from Enterococcus faecalis on dental pulp. These molecules are components of the Gram-negative and Gram-positive bacteria cell wall, respectively. Ten dogs were used in the experiment. Inoculation in surgically opened pulp and coronal restoration with glass ionomer was the method chosen. The evaluation times were 1, 7, 15, 30 and 60 days. The results showed that the LPS and LTA, at 150 icg/ml, produced a negative interference in the pulp leading to destruction. LTA caused less damage than LPS.
Asunto(s)
Animales , Masculino , Perros , Ácidos Teicoicos/farmacología , Enterococcus faecalis , Escherichia coli , Lipopolisacáridos/farmacología , Pulpa Dental , Pulpa Dental/microbiología , Ácidos Teicoicos/análisis , Endotoxinas , Lipopolisacáridos/análisis , Pulpa Dental/patologíaRESUMEN
Outbreaks of food-borne listeriosis have often involved strains of serotype 4b. Examination of multiple isolates from three different outbreaks revealed that ca. 11 to 29% of each epidemic population consisted of strains which were negative with the serotype-specific monoclonal antibody c74.22, lacked galactose from the teichoic acid of the cell wall, and were resistant to the serotype 4b-specific phage 2671.