Endodontic retreatment: clinical comparison of reciprocating systems versus rotary system in disinfecting root canals.

INTRODUCTION: This clinical study was conducted to compare the effectiveness of single-file reciprocating systems and rotary systems in removing endotoxins and cultivable bacteria in endodontic retreatment. METHODS: Thirty endodontically treated teeth with post-treatment apical periodontitis were selected. The specimens were divided into three groups according to the system used: WaveOne (n = 10), Reciproc instrument (n = 10), and ProTaper Universal Retreatment system (n = 10). Samples were collected before and after chemomechanical preparation. The irrigation was performed by using 2.5% sodium hypochlorite. A chromogenic limulus amebocyte lysate assay test was used to quantify endotoxins. Culture techniques were used to determine bacterial colony-forming unit counts. RESULTS: At baseline, endotoxins and cultivable bacteria were recovered from 100% of the root canal samples in a median value of 5.84 EU/mL and 4.98 × 10(3) CFU/mL, respectively. After CMP, no differences were found in the median percentage values of endotoxin reduction achieved with reciprocating systems-WaveOne [94.11%] and Reciproc [93.29%] and with rotary systems-ProTaper [94.98%] (P > 0.05). Both single-file reciprocating systems [WaveOne (98.27%) and Reciproc (99.54%)] and rotary system [ProTaper (98.73%)] were effective in reducing bacterial load (P > 0.05). Moreover, no differences were found among the systems tested. CONCLUSIONS: The Reciproc and WaveOne reciprocating systems were as effective as the ProTaper system for removal of endotoxins and bacteria in endodontic retreatment. CLINICAL RELEVANCE: All systems tested were effective to remove cultivable bacteria and endotoxin in endodontic retreatment. As no differences among systems were observed, it is possible to suggest that clinicians should choose the preferred technique to perform endodontic.

Clinical influence of different intracanal medications on Th1-type and Th2-type cytokine responses in apical periodontitis.

INTRODUCTION: This clinical study assessed the influence of different intracanal medications on Th1-type and Th2-type cytokine responses in apical periodontitis and monitored the levels of bacteria from primarily infection during endodontic procedures. METHODS: Thirty primarily infected teeth were randomly divided into 3 groups according to the medication selected: chlorhexidine (CHX), 2% CHX gel; Ca(OH)2/SSL, Ca(OH)2 + SSL; and Ca(OH)2/CHX, Ca(OH)2 + 2% CHX gel (all, n = 10). Bacterial sample was collected from root canals, and the interstitial fluid was sampled from lesions. Culture techniques were used to determine bacterial counts (colony-forming units/mL). Th1 (tumor necrosis factor-α, interferon-γ, and interleukin [IL]-2) and Th2 cytokines (IL-4, IL-5, and IL-13) were measured by enzyme-linked immunosorbent assay. RESULTS: All intracanal medication protocols were effective in reducing the bacterial load from root canals (all P < .05) and lowering the levels of Th1-type cytokines in apical lesions (all P < .05), with no differences between them (P > .05). Both Ca(OH)2 treatment protocols significantly increased the levels of Th2-type cytokines (P < .05), with no differences between them (P > .05). Thus, chlorhexidine medication showed the lowest effectiveness in increasing the levels of Th2-type cytokine. After treatment, regardless of the type of medication, the linear regression analysis indicated the down-regulation of Th2-type cytokines by Th1-type cytokines. CONCLUSIONS: All intracanal medication protocols were effective in reducing bacterial load and lowering the levels of Th1-type cytokines. Thus, the use of Ca(OH)2 medications contributed to the increase in the Th2-type cytokine response in apical periodontitis.

Clinical comparison of the effectiveness of single-file reciprocating systems and rotary systems for removal of endotoxins and cultivable bacteria from primarily infected root canals.

INTRODUCTION: This clinical study was conducted to compare the effectiveness of single-file reciprocating systems and rotary systems in removing endotoxins and cultivable bacteria from primarily infected root canals. METHODS: Forty-eight primarily infected root canals were selected and randomly divided into 4 groups: WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) (n = 12); Reciproc (VDW, Munich, Germany) (n = 12), ProTaper (Dentsply Maillefer) (n = 12), and Mtwo (VDW) (n = 12). Samples were collected before and after chemomechanical preparation. The irrigation was performed by using 2.5% sodium hypochlorite. A chromogenic limulus amebocyte lysate assay test was used to quantify endotoxins. Culture techniques were used to determine bacterial colony-forming unit counts. RESULTS: In the baseline samples (ie, samples collected before chemomechanical preparation), endotoxins and cultivable bacteria were recovered from 100% of the root canal samples. No differences were found in the median percentage values of endotoxin reduction achieved with reciprocating systems (ie, WaveOne [95.15%] and Reciproc [96.21%]) and with rotary systems (ie, ProTaper [97.98%] and Mtwo [96.34%]) (P < .05). Both single-file reciprocating systems (ie, WaveOne [99.45%] and Reciproc [99.93%]) and rotary systems (ProTaper [99.85%] and Mtwo [99.41%]) were effective in reducing the cultivable bacteria (all P < .05). Moreover, the culture analysis revealed no differences in bacterial load reduction (P > .05). CONCLUSIONS: Both single-file reciprocating systems (ie, WaveOne and Reciproc instruments) and rotary systems (ie, ProTaper and Mtwo instruments) showed similar effectiveness in reducing endotoxins and cultivable bacteria from primarily infected root canals, but they were not able to eliminate them from all root canals analyzed.

Relationship between the size of patency file and apical extrusion of sodium hypochlorite.

BACKGROUND: Sodium hypochlorite (NaOCl) is the most widely used endodontic irrigant because of its excellent antimicrobial, organic tissue dissolving, and lubricating properties. However, it is highly cytotoxic to the periapical tissues. AIM: This study evaluated in vitro the extrusion of 5.25% NaOCl through the apical foramina of mesiobuccal (MB) root canals of maxillary first molars in two experimental conditions: Before apical debridement and after apical debridement with different instrument sizes to ensure direct access to the apical foramen (apical patency). MATERIALS AND METHODS: Coronal accesses were prepared in 17 teeth and the apical foramina of the distobuccal and palatal root canals were sealed. The teeth were held in acrylic receptacles with the roots turned upwards to reproduce their position in the maxillary dental arch. The receptacles were filled with a starch/KI solution (a reagent that changes its color to blue after contacting NaOCl) covering the roots. The experiment had two phases: P1: Irrigation of the MB canals with 5.25% NaOCl without previous establishment of apical patency; P2: Canal irrigation after use of size 10 K-file and size 15 Flexofile as patency files. Only specimens with no NaOCl extrusion in P1 were assigned to P2. NaOCl was delivered pressureless at the canal entrance. The moment that the starch/KI solution contacted NaOCl was captured on digital photographs. RESULTS AND CONCLUSIONS: There was no NaOCl extrusion in nine specimens in P1, but all of these teeth had irrigant extrusion in P2. The 5.25% NaOCl used as an endodontic irrigant showed great capacity to extrude beyond both intact and small-sized apical foramina of MB root canals of maxillary first molars.

Investigation of virulence factors of Enterococcus faecalis strains isolated in secondary/ persistent infections / Investigação de fatores de virulência de estirpes de Enterococcus faecalis isoladas em infecções secundárias persistentes

More virulent strains may result from the acquisition of genes by genetic exchange, pathogenicity islands in several species encoding toxins, adhesion factors and other factors associated with virulence. The aim of this study was to investigate the prevalence of E. faecalis strains in secondary endodontic/ persistent using endodontic infection by culture and PCR technqiues; and to investigate for the presence of virulence factor genes of gelatinase (gelE), cytolysin activator (Cyla), surface adhesion of Enterococcus (ESP) and collagen adhesin of Enterococcus (ACE). Material and methods: Microbial samples were obtained from 12 teeth with secondary/ persistent endodontic infection showing apical periodontitis. Culture techniques were used including serial dilution, plating, incubation, and biochemical identification. For PCR detection, samples were analyzed using a species-specific primer of the 16S rDNA and the downstream intergenic spacer region. Results: Culture and PCR detected the test species in 3/12 (25%) and 5/12 (41.6%) of teeth,respectively. A total of 38 Enterococcus faecalis strains were isolated and submitted to the virulence factor genes analysis. PCR products consistent with genes encoding surface adhesion (ESP), gelatinase (gelE) and collagen binding antigen (ACE) were found in 26/38 (68%), 31/38 (81%) and 38/38 (100%) of the isolates. The Cytolysin activator (Cyla) gene was not recovered from E. faecalis isolates. Conclusions: In conclusion, the present study revealed by culture and molecular methods revealed a high prevalence of E. faecalis in teeth with secondary/ persistent endodontic infection. Moreover, of a clinical relevance, we found different E. faecalis strains carrying different virulence determinants.

Objetivos: O objetivo deste estudo foi investigar a prevalência de cepas de E. faecalis em canais com infecções endodônticas secundárias/persistentes por meio de cultura e PCR, além de analisar a presença de fatores de virulência genéticos como: gelatinase (gelE), ativador de citolisina (Cyla), adesina de superfície (ESP) e adesina de colágeno (ACE). Material e métodos: Foram coletadas amostras de 12 canais radiculares com infecção endodôntica secundária/persistente e presença de lesão periapical. Para a cultura microbiológica foi realizada diluição em série, incubação e identificação bioquímica dos microrganismos, enquanto que no PCR as amostras foram analisadas através de primers específicos 16S rDNA. Os casos com presença de Enterococcus faecalis foram selecionadas para realização de análise quanto aos fatores de virulência: gelE, Cyla, ESP e ACE. Resultados: Enterococcus faecalis foi detectado através de cultura e PCR em 3/12 (25%) e 5/12 (41,6%) dos casos, respectivamente. No total, foram isoladas 38 amostras com presença de E. faecalis. Os produtos de PCR consistentes com os genes ESP, gelE e ACE foram encontrados em 26 /38 (68%), 31 /38 (81%) e 38/38 (100%) dos isolados. Cyla não foi recuperado a partir de E. faecalis em nenhum dos isolados. Conclusões: O presente estudo revelou alta prevalência de E. faecalis em dentes com infecção endodôntica secundária/ persistente. Estes microrganismos apresentaram elevado índice de diferentes fatores de virulência.