Effectiveness of XP-Endo Finisher in the reduction of bacterial load in oval-shaped root canals

Abstract: This study investigated the effectiveness of XP-Endo Finisher (XPF) associated with XP-Endo Shaper (XPS) or Reciproc Blue (RB) files in reducing bacterial load in oval-shaped root canals (RC) during chemomechanical preparation (CMP) using 0.9% saline solution (NaCl) or 2.5% sodium hypochlorite (NaOCl). Eighty mandibular incisors with single oval-shaped RC were contaminated with Enterococcus faecalis. The teeth were randomly assigned to eight experimental groups (n = 10) according to the CMP, as follows: G1: XPS, G2: XPS + XPF, G3: RB, and G4: RB + XPF. CMP was performed with NaCl or NaOCl. The reduction of bacterial load was assessed by colony-forming unit count before (S1) and after (S2) CMP. Data normality was verified by using Shapiro-Wilk test. ANOVA, Tukey's test, and Bonferroni post-hoc test were used at a 5% significance level. Culturable bacteria were present in all S1 samples (p>0.05). All instrumentation techniques were effective in reducing bacterial load, irrespective of the irrigating solution (p < 0.05). With the use of NaCl, RB was more effective than XPS (p = 0.035). With the use of NaOCl, XPS and RB presented similar effectiveness (p = 0.779). XPF enhanced the bacterial reduction of both systems tested (p < 0.05). The use of NaOCl improved the CMP, irrespective of the instrumentation technique used (p < 0.05). In conclusion, XPS and RB files are effective in reducing bacterial levels in oval-shaped RC. The use of XPF as a method of agitation of the irrigating solution improved the cleaning efficiency of both file systems tested. Mechanical preparation performed with saline solution decreased culturable bacteria from the root canal, but antimicrobial substances such as NaOCl should be used to achieve a significantly better disinfection.

Investigation in vivo of Enterococcus faecalis in endodontic retreatment by phenotypic and genotypic methods / Investigação in vivo de Enterococcus faecalis em retratamento endodôntico por meio de métodos fenotípicos e genotípicos

This study aimed to investigate the prevalence of E. faecalis in root-filled canals using culture and molecular approaches. It was evaluated the antimicrobial susceptibility to different antibiotics and the virulence factors of E. faecalis isolates. Microbial samples were taken from thirty root-filled canals. Culture methods and 16S rDNA assay were used to identify E. faecalis. The antimicrobial susceptibility of E. faecalis was determined by MIC values using the E test. Cultivable strains of E. faecalis were investigated for virulence factors by PCR technique. E. faecalis were detected by culture (7/30), traditional PCR assay (13/30) and nested PCR (23/30). Both PCR were significantly more effective than culture in detecting E. faecalis (p < 0.05). All tested E. faecalis were highly sensitive to amoxicillin. Some strains of E. faecalis were resistant to antibiotics such as rifampicin (4/12), erythromycin (3/12) and azythromycin (8/12). The genes efaA and ace were detected in all isolates. The other virulence genes were found in 91.6 (gelE), 83.3 (asa), 25 (esp) and 16.6% (cylA). Strains of E. faecalis isolated from root-filled canals showed virulence factors related to adherence. They also showed resistance to some antibiotics commonly used in dentistry.

O objetivo deste estudo foi investigar a prevalência de E. faecalis em dentes tratados endodonticamente utilizando as técnicas de cultura e molecular. Foram avaliados a suscetibilidade antimicrobiana frente a diferentes antibióticos e os fatores de virulência de E. faecalis isolados. As amostras foram coletadas de 30 dentes tratados endodonticamente. Métodos de cultura e 16S rDNA foram utilizados para identificar E. faecalis. A suscetibilidade antimicrobiana de E. faecalis foi determinada por valores de MIC, utilizando o E test. Os fatores de virulência de cepas de E. faecalis cultiváveis foram investigados pela técnica de PCR. E. faecalis foram detectados por cultura (7/30), PCR tradicional (13/30) e nested PCR (23/30). Ambas as técnicas de PCR foram significativamente mais eficazes do que a cultura na detecção de E. faecalis (p < 0,05). Todos os E. faecalis testados foram altamente sensíveis à amoxicilina. Algumas cepas de E. faecalis foram resistentes a antibióticos, como a rifampicina (4/12), eritromicina (3/12) e azitromicina (8/12). Os fatores de virulência efaA e ace foram detectados em todos os isolados. Os outros genes de virulência foram encontrados em 91,6 (gelE), 83,3 (asa), 25 (esp) e 16,6% (cylA). As cepas de E. faecalis isoladas em dentes tratados endodonticamente mostraram fatores de virulência relacionados à adesão. Eles também apresentaram resistência a alguns antibióticos comumente utilizados na odontologia.

Monitoring the effectiveness of root canal procedures on endotoxin levels found in teeth with chronic apical periodontitis

Objective: The aim of this study was to monitor the effectiveness of root canal procedures by using different irrigants and intracanal medication on endotoxin levels found in root canals of teeth with chronic apical periodontitis. Material and Methods: Thirty root canals of teeth with pulpal necrosis associated with periapical lesions were selected and randomly divided into groups according to the irrigants used: GI - 2.5% NaOCl, GII - 2% chlorhexidine (CHX) gel, and GIII - saline solution (SS) (all, n=10). Samples were collected with sterile/apyrogenic paper points before (S1) and after root canal instrumentation (S2), after use of 17% ethylenediaminetetraacetic acid (EDTA) (S3), and after 30 days of intracanal medication (Ca(OH)2+SS) (S4). A turbidimetric kinetic Limulus Amebocyte Lysate assay was used for endotoxin measurement. Results: Endotoxins were detected in 100% of the root canals investigated (30/30), with a median value of 18.70 EU/mL. After S2, significant median percentage reduction was observed in all groups, irrespective of the irrigant tested: 2.5% NaOCl (99.65%) (GI), 2% CHX (94.27%) (GII), and SS (96.79%) (GIII) (all p<0.05). Root canal rinse with 17% EDTA (S3) for a 3-minute period failed to decrease endotoxin levels in GI and a slight decrease was observed in GII (59%) and GIII (61.1%) (all p>0.05). Intracanal medication for 30 days was able to significantly reduce residual endotoxins: 2.5% NaOCl (90%) (GI), 2% CHX (88.8%) (GII), and SS (85.7%) (GIII, p<0.05). No differences were found in the endotoxin reduction when comparing s2 and s4 treatment groups. Conclusion: Our findings demonstrated the effectiveness of the mechanical action of the instruments along with the flow and backflow of irrigant enduring root canal instrumentation for the endotoxin removal from root canals of teeth with chronic apical periodontitis. Moreover, the use of intracanal medication for 30 days contributed for an improvement ...

Culture and molecular detection of Enterococcus faecalis from patients with failure endodontic treatment and antimicrobial susceptibility of clinical isolates / Cultura e detecção molecular de Enterococcus faecalis de pacientes com insucesso no tratamento endodôntico e suscetibilidade antimicrobiana dos isolados clínicos

Objective: The aim of this study was to evaluate the minimal inhibitory concentrations (MIC) of different antibiotic agents against to the most prevalent microorganism found in root-filled canals by culture and molecular approaches. Material and Methods: The microbial samples were taken either from thirty root-filled canals after removal of gutta-percha. Culture methods and 16s rDNA assay were used to identify the E faecails present in the samples. The antimicrobial susceptibilities of the isolates of E faecalis were determined by MIC values using the E test System and interpreted according to the Clinical and Laboratory Standards Institute guidelines. The following antibiotics were used: benzylpenicillin, amoxicillin, amoxicillin-clavulanic acid, erythromycin, azithromycin, vancomycin, chloramphenicol, tetracycline, doxycycline, ciprofloxacin, rifampicin and moxifloxacin. Results: E faecalis were isolated (7/30) and detected (13/30) by culture and PCR assay, respectively. All tested E faecalis (n = 12) were highly sensitive to amoxicillin, moxifloxacin, vancomycin, benzylpenicillin and amoxicillin-clavulanic acid. Isolated E faecalis strains were resistant to some antibiotics such as rifampicin (4/12), tetracycline (2/12), doxycycline (1/12), erythromycin (3/12) and azythromycin (8/12). Conclusion: Amoxicillin, amoxicillin-clavulanic acid, benzylpenicillin, vancomycin and moxifloxacin were the most active antibiotics, in vitro, against E faecalis clinical strains, with all the isolates being susceptible Azithromycin and erythromycin were least effective, with none percentage of isolates being susceptible, during laboratory testing. Moreover, E faecalis were identified more frequently by PCR assay than by culture technique.

Objetivo: O objetivo deste estudo foi avaliar as concentrações inibitórias mínimas (CIM) de diferentes antibióticos contra micro-organismos mais prevalentes em canais radiculares pelos métodos moleculares e de cultura. Material e Métodos: As amostras microbianas foram obtidas de trinta canais radiculares após a remoção da gutapercha. Os métodos de cultura e ensaio 16s rDNA foram utilizados para identificar E. faecalis presente nas amostras. As susceptibilidades antimicrobianas dos isolados de E. faecalis foram determinadas pelos valores de CIM utilizando o sistema E teste e interpretados de acordo com as diretrizes CLSI(Clinical and Laboratory Standards Institute). Foram utilizados os seguintes antibióticos: benzilpenicilina, amoxicilina, amoxicilina com ácido clavulânico, eritromicina, azitromicina, vancomicina, cloranfenicol, tetraciclina, doxiciclina, ciprofloxacina, moxifloxacina e rifampicina. Resultados: E. faecalis foram isolados (7/30) e detectados (13/30) por cultura e pelo método PCR, respectivamente. Todos E. faecalis (n = 12) foram altamente sensíveis à amoxicilina,moxifloxacina,vancomicina, benzilpenicilina e amoxicilina com ácido clavulânico. Cepas isoladas de E. faecalis foram resistentes a alguns antibióticos como a rifampicina (4/12), tetraciclina (2/12), doxiciclina (1/12), eritromicina (3/12) e azitromicina (8/12). Conclusão: Amoxicilina, amoxicilina com ácido clavulânico, benzilpenicilina, vancomicina e moxifloxacina foram os antibióticos mais ativos, in vitro, contra cepas clínicas de E. faecalis, com todos os isolados sendo suscetíveis. Azitromicina e eritromicina foram menos eficazes, com nenhuma porcentagem de isolados suscetível durante os testes laboratoriais. E ainda, E. faecalis foram identificados mais frequentemente pela técnica PCR do que pela técnica de cultura.

Influence of the apical enlargement size on the endotoxin level reduction of dental root canals

Gram-negative bacteria play an essential role in endodontic infections because they have virulence factors such as endotoxin. Due to its potential cytotoxic activity, special attention has been given to the removal/neutralization of this endotoxin in the root canal system. OBJECTIVE: The aim of this study was to evaluate the influence of the apical enlargement size (AES) by using rotary instruments on the endotoxin level reduction of dental root canals. MATERIAL AND METHODS: Forty root canals of the mandibular premolar teeth were used. Escherichia coli endotoxin (055: B55) was inoculated into thirty root canals. Ten teeth served as the negative control group. After the incubation period, the first endotoxin samples were collected from the root canals with a sterile/apyrogenic paper point for the analysis of the endotoxin units (EU/mL) present before instrumentation (S1). Specimen instrumentation was performed with the Mtwo® rotary system in the sequence 10/.04, 15/.05, 20/.06, 25/.06, 30/.05, 35/.04 and 40/.04. To monitor the effectiveness of increasing apical enlargement on endotoxin removal, the second endotoxin samples were collected from all the root canals after instrumentation with the following instruments: #25/.06- (S2); #30/.05- (S3); # 35/.04- (S4); and #40/.04- (S5). Limulus amebocyte lysate (LAL) was used to quantify the levels of endotoxin. The results were statistically compared by using repeated measures of ANOVA with post hoc Tukey testing. RESULTS: Increasing levels of endotoxin removal was achieved by large sized apical enlargement: S2 (AES #25/.06)- 89.2%, S3 (AES #30/.05)- 95.9%, S4 (AES #35/.04)- 97.8% and S5 (AES #40/.04)- 98.2%. Substantial reduction of endotoxin content was obtained in S4 and S5 compared to S2 (p<0.05), however, the root canal preparation was not able to eliminate the endotoxin. CONCLUSIONS: Under the conditions of this study, it was concluded that the reduction of endotoxin levels of the dental root canals could be predicted by increasing the apical enlargement size.