Antibacterial effectiveness of several irrigating solutions and the Endox Plus system - an ex vivo study

Aim To compare the ex vivo antibacterial effectiveness of the Endox Plus system and sodium hypochlorite (NaOCl) in combination with BioPure MTAD (Tulsa Dental, Tulsa, OK, USA) or with EDTA in Enterococcus faecalis-contaminated root canals.Methodology After initial preparation, the root canals of 70 single-rooted human teeth were inoculated with E. faecalis (ATCC 29212) and incubated for 21 days. Specimens were divided into five groups: Endox Plus/saline; 2.5% NaOCl/MTAD; 2.5% NaOCl/EDTA; saline (positive control); negative control (root canals not prepared, nor irrigated). Samples were collected using paper points. Microbiological analysis evaluated the number of CFUs. Data were analysed by anova and Tukey tests at 0.05 significance.Results All specimens had bacterial growth after the incubation period, with similar CFU per mL counts (P > 0.05). After chemo-mechanical preparation, the number of bacteria in all groups reduced, except for the negative control. No significant differences were observed between 2.5% NaOCl/MTAD and 2.5% NaOCl/EDTA, but these groups had lower CFU counts than the other groups (P < 0.05). In the final samples, an increase in the bacterial counts was observed for Endox Plus/saline, 2.5% NaOCl/MTAD, 2.5% NaOCl/EDTA and saline (P < 0.05) with no significant differences between these groups.Conclusions This ex vivo study revealed that the Endox Plus system was associated with a reduced antibacterial effectiveness compared with conventional irrigation using 2.5% NaOCl/MTAD and 2.5% NaOCl/EDTA. All irrigation procedures allowed recovery of bacteria 7 days after treatment, demonstrating persistence of contamination within the root canal system.

Persistence of endodontic methacrylate-based cement residues on dentin adhesive surface treated with different chemical removal protocols

The aim of this study was to evaluate the persistence of methacrylate-based cement residues on the dentin, after dentin surface cleaning with ethanol or acetone, with or without previous application of a dentin adhesive. Forty bovine crown fragments were obtained and the dentin surface was washed with 1.0 mL of 2.5% sodium hypochlorite (NaOCl), followed by 0.1 mL of 17% ethylenediaminetetraacetic acid application for 3 min, and final irrigation with 2.5% NaOCl. The specimens were air dried and resin-based cement was rubbed onto the dentine surface with a microbrush applicator. In 20 specimens, previously to cement, a dentin adhesive was applied in all surfaces. After 15 min, the surface was scrubbed with a cotton pellet and moistened with ethanol or acetone, compounding the following groups: G199.5% ethanol and G2acetone, without previous use of dentin adhesive; G399.5% ethanol and G4acetone, with previous use of dentin adhesive. The dentin surface was scrubbed until the cement residues could not be visually detected. Sections were then processed for scanning electron microscopy and evaluated at 500x magnification and scores were attributed to each image according to the area covered by residual sealer, and data were subjected to KruskalWallis at 5% significance. The lower residue presence was observed in G3 (P = 0.005). All surface presented cement residues when acetone was used as cleaning solution (P = 0.0005). The cleaning solutions were unable to completely remove the cement residues from both surfaces. The ethanol used after previous application of the dentin adhesive promoted the lower presence of residues.

In vitro evaluation of the action of irrigating solutions associated with intracanal medications on Escherichia coli and its endotoxin in root canals

Objective: The purpose of this study was to evaluate the efficacy of auxiliary chemical substances and intracanal medications on Escherichia coli and its endotoxin in root canals. Material and Methods: Teeth were contaminated with a suspension of E. coli for 14 days and divided into 3 groups according to the auxiliary chemical substance used: G1) 2.5% sodium hypochlorite (NaOCl); G2) 2% chlorhexidine gel (CLX); G3) pyrogen-free solution. After, these groups were subdivided according to the intracanal medication (ICM): A) Calcium hydroxide paste (Calen (R)), B) polymyxin B, and C) Calcium hydroxide paste+2% CLX gel. For the control group (G4), pyrogen-free saline solution was used without application of intracanal medication. Samples of the root canal content were collected immediately after biomechanical preparation (BMP), at 7 days after BMP, after 14 days of intracanal medication activity, and 7 days after removal of intracanal medication. The following aspects were evaluated for all collections: a) antimicrobial activity; b) quantification of endotoxin by the limulus Amebocyte lysate test (LAL). Results were analyzed by the kruskal-wallis and Dunn's tests at 5% significance level. Results: The 2.5% NaOCl and CLX were able to eliminate E. coli from root canal lumen and reduced the amount of endotoxin compared to saline. Conclusions: It was concluded that 2.5% NaOCl and CLX were effective in eliminating E. coli. Only the studied intracanal medications were to reduce the amount of endotoxin present in the root canals, regardless of the irrigant used.

In vitro evaluation of the effectiveness of irrigants and intracanal medicaments on microorganisms within root canals

Aim To evaluate in vitro the effectiveness of sodium hypochlorite (NaOCl). chlorhexidine (CHX) and live intracanal medicaments on microorganisms within root canals.Methodology Ninety-six human single-rooted extracted teeth were used. After removing the crowns, canal preparation was completed and the external root Surfaces were coated with epoxy resin. Following sterilization. The teeth were contaminated with Candida albicans and enterococcus faecalis. and were incubated at 37 +/- 1 degreesC for 7 days. The teeth were divided according to the irrigant solution or intracanal medicament: group 1. sterile physiologic solution (SPS) and calcium hydroxide (Ca(OH)(2)) paste: group 2. SPS and camphorated paramonochlorophenol (CPMC): group 3.SPS and tricresol formalin: group 4, SPS and CaOH2 + CPMC paste: group 5, SPS and PMC furacin; group 6.2.5%, NaOCl without intracanal medication: group 7, 2.0% CHX without intracanal medication and group 8, SPS Without intracanal medication (control group). Microbiological samples were collected with sterile paper points, and bacterial growth was determined. The data were submitted to the analysis of variance (ANOVA. P = 0.05).Results For C. albicans, groups 3 and S were statistically less effective than groups 1, 2. 4 and 5 (Kruskal-Wallis (K-W) = 65.241; gl = 7; P = 0.001). For E. faecalis, groups 6 and 8 were statistically less effective than groups 1-4 and 7 (K-W = 61.048; gl = 7; P = 0.001).Conclusions Ca(OH)(2) + CPMC paste was the most effective intracanal medicament for the elimination of the two microorganisms; 2.0% CHX solution was more effective than 2.5% NaOCl against E. faecalis.

Conservação de uvas Crimson Seedless e Itália, submetidas a diferentes tipos de embalagens e dióxido de enxofre (SO2)

Estudaram-se o efeito de diferentes tipos de embalagens e a ação do dióxido de enxofre (SO2) na conservação pós-colheita de uvas finas de mesa var. Crimson Seedless e Itália. Os frutos, colhidos em propriedade agrícola situada no município de Boa Vista-RR (Lat. 2º 50' 06 N e Long. 60º 40' 28 W), apresentavam, no momento da colheita, sólidos solúveis (SS) médios de 16,50 e 14,80°Brix, para as variedades Crimson Seedless e Itália, respectivamente. Antes da confecção dos tratamentos, os cachos foram higienizados em solução de hipoclorito de sódio (NaOCl) a 100 mg.L-1, previamente acidificada, por dez minutos. Utilizaram-se, para a atmosfera modificada passiva, sacolas de polietileno de baixa densidade (PEBD), sem perfuração, com 0,010; 0,015 e 0,020mm de espessura,e acondicionadas em embalagens secundárias de papelão (4kg) e de madeira (7,5kg). Para a geração do SO2, foram utilizados papéis Kraft de liberação rápida, com 3 e 8g de metabissulfito de sódio (Na2S2O5). Após a confecção dos tratamentos, os frutos foram armazenados em câmara frigorífica a 4 ± 1°C e 95 ± 3% de umidade relativa (U.R.). As avaliações foram realizadas no momento da colheita e, 7; 21; 35; 42 e 56 dias de armazenamento refrigerado, quanto à porcentagem de perda de massa fresca, taxa de desgrana e de bagas deterioradas, qualidade do engaço e teor de SS dos frutos. Após oito semanas, foi realizado teste de preferência para as duas variedades. Verificou-se, em ambas as variedades, que as uvas submetidas à ação do gerador de SO2 , contendo 3g de metabissulfito de sódio e acondicionamento em embalagens de PEBD de 0,020mm de espessura, independentemente do tipo de embalagem secundária, apresentaram a menor perda de massa fresca, menor taxa de desgrana e de bagas deterioradas, e melhor qualidade do engaço. Os resultados da análise sensorial concordaram com os resultados das análises físico-químicas. Não foram detectadas diferenças nos teores de SS entre os tratamentos, em ambas as variedades. (Apoio: Roraima Agrofrutas).

Escala diagramática para avaliação de mofo cinzento (Amphobotrys ricini) da mamoneira (Ricinus communis L.)

O objetivo do trabalho foi a elaboração de uma escala diagramática para avaliação de mofo cinzento causado por Amphobotrys ricini (Buchw.) em mamoneira (Ricinus communis L.). Utilizaram 59 cachos, que foram desinfestados em solução de hipoclorito de sódio a 2% por 30 segundos e em água destilada e esterilizada. Depois foram acondicionados em bandejas com espuma umedecida, onde receberam discos de micélio de 5mm do patógeno, permanecendo em câmara climática a 25ºC e UR de 80%. Observou-se a evolução da doença e foram obtidos fotos dos cachos doentes diariamente. Para a determinação da porcentagem de severidade dos cachos, os frutos infectados e sadios foram contados, estimando-se dessa forma a porcentagem da área lesionada e elaborando uma escala diagramática com seis níveis de severidade. A adoção da escala proposta, melhorou a acurácia (R²=0,94), com valores de a não significativamente diferentes de zero (0) e os valores de b não diferentes de um (1).

Histological study of the effect of some irrigating solutions on bacterial endotoxin in dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Scanning electron microscopic study of the cleaning ability of chlorhexidine as a root-canal irrigant

Aim To evaluate in vitro the cleaning of root-canal walls after irrigation with different irrigants.Methodology A total of 36 recently extracted human teeth were divided into four experimental groups according to the irrigating solution used: saline; 2% chlorhexidine; 2.5% sodium hypochlorite; and 2.5% sodium hypochlorite + EDTA. The cleaning of the apical, middle and coronal thirds of the root canals was evaluated by scanning electron microscope examination using a 4-point scoring system.Results the best cleaning was obtained using 2.5% sodium hypochlorite and EDTA, followed by 2.5% sodium hypochlorite only (P < 0.05), whose cleaning was similar to chlorhexidine only in the cervical third. Cleaning by saline and 2% chlorhexidine was worse than the other two groups and was similar in all thirds. Better cleaning was found in the cervical and middle thirds for all groups with the worst results in the apical third.Conclusions the apical third of the root canals was not cleaned as well as the middle and coronal thirds. Cleaning by chlorhexidine and saline was inferior compared to the cleaning by sodium hypochlorite with and without EDTA.

Effect of different irrigation solutions and calcium hydroxide on bacterial LPS

Aim To evaluate the effect of biomechanical preparation with different irrigating solutions and calcium hydroxide dressing in dog root canals containing bacterial endotoxin (lipopolysaccharides; LPS).Methodology One hundred and forty premolar roots from seven dogs were filled with Escherichia coli LPS for 10 days (three roots were lost during histological processing). The following irrigating solutions were used for biomechanical preparation: 1% (group I, n = 20), 2.5% (group II, n = 19) and 5% sodium hypochlorite (group III, n = 19), 2% chlorhexidine digluconate (group IV, n = 20) and physiological saline solution (group V, n = 19). In group VI (n = 20), the LPS solution was maintained in the root canal during the entire experiment and in group VII (n = 20), after biomechanical preparation with saline solution, the root canals were filled with a calcium hydroxide dressing (Calen; control). After 60 days, the animals were sacrificed and the following parameters of periapical disease were evaluated: (a) inflammatory infiltrate, (b) periodontal ligament thickness, (c) cementum resorption and (d) bone resorption. Scores were given and data were analysed statistically with the Kruskal-Wallis and Dunn tests (P < 0.05).Results Histopathological evaluation showed that groups I-VI had more inflammatory infiltrate, greater periodontal ligament thickening and greater cementum and bone resorption (P < 0.05) compared to group VII, which received the calcium hydroxide intracanal dressing.Conclusions Biomechanical preparation with the irrigating solutions did not inactivate the effects of the endotoxin but the calcium hydroxide intracanal dressing did appear to inactivate the effects induced by the endotoxin in vivo.

Influence of root canal dressings and sealers on repair of apical periodontitis after endodontic treatment

Objective. The objective of this study was to evaluate the histopathologic response of periapical tissues after root canal treatment of necrotic dog teeth with chronic apical periodontitis by using 2 calcium hydroxide-based root canal dressings and 2 root canal sealers.Study design. Seventy-eight root canals were instrumented by using 5.25% sodium hypochlorite as the irrigating solution, after which a calcium hydroxide paste (Calen/PMCC or Calasept) was placed for 30 days as a dressing. The root canals were then filled by using cold lateral gutta-percha condensation and an enclodontic sealer (Sealapex or AH Plus). After 360 days, the animals were killed by anesthetic overdose; then, the teeth were histologically prepared, sectioned, and stained with hematoxylin and eosin for optical microscopic analysis of apical and periapical tissue repair.Results. Statistical analysis showed that the poorest histopathologic results were observed in the Calasept/AH Plus group and that the Sealapex sealer overall resulted in better apical repair than the AH Plus sealer. The histopathologic results of Calen/PMCC paste with both AH Plus and Sealapex and Calasept paste with only Sealapex were statistically similar but were different from the results of Calasept with AH Plus.Conclusions. The results of this study in the dog showed differences in apical and periapical tissue repair of teeth with chronic apical periodontitis by using 2 calcium hydroxide root canal dressings and 2 sealers. More research is necessary to determine the best combination of dressings and sealers.

In vitro effects of endodontic irrigants on endotoxins in root canals

Objective. The objective of this study was to evaluate the effects of endodontic irrigants on endotoxins in root canals.Study design. Ninety-eight single-root human teeth were used. Escherichia coli endotoxin was inoculated into 84 root canals. All root canals were enlarged and assigned to 7 groups (n = 14), according to solution used. Group 1 (G1): 2.5% NaOCl; G2: 5.25% NaOCl; G3: 2% chlorhexidine; G4: 0.14% calcium hydroxide; G5: polymyxin B; G6: positive control, saline solution; G7: negative control (no endotoxin). Two samplings of root canal were accomplished: immediate and after 7 days. Detoxification of endotoxin was evaluated by Limulus assay and antibody production in B-lymphocyte culture. Results were analyzed by Kruskal-Wallis/Dunn and ANOVA/Tukey.Results. At the immediate and second samplings, groups G4, G5, and G7 presented the best results, significantly different from groups G1, G2, G3, and G6 (P = .05).Conclusions. Calcium hydroxide and polymyxin B detoxified endotoxin in root canals and altered properties of LPS to stimulate the antibody production by B-lymphocytes. Sodium hypochlorite and chlorhexidine did not detoxify endotoxin.

In vitro antibacterial efficacy of endodontic irrigants against Enterococcus faecalis

Objective. The objective of this study was to compare the in vitro antimicrobial activity of 2% chlorhexidine gel against Enterococcus faecalis with sodium hypochlorite in 2 different concentrations (1.5% and 5.25%).Study design. Eighty human lower premolars with single root canals were prepared, autoclaved, and infected for 7 days with E. faecalis monocultures. The roots were then separated into 5 experimental groups according to the irrigant solution used during the standardized preparation. To assess the antimicrobial action of the irrigant solutions, 3 microbial samples were taken: S1-initial (before the biomechanical preparation), S2-posttreatment (immediately after the biomechanical preparation), and S3-final (7 days after the biomechanical preparation). The microbiological samples were plated to count the colony-forming units (CFU).Results. The 2% chlorhexidine gel and 5.25% sodium hypochlorite significantly reduced the E. faecalis CFU in the posttreatment and final microbiological samples. The 1.5% sodium hypochlorite also reduced the E. faecalis CFU immediately after the root canal instrumentation, but the E. faecalis CFU increased in the final sample showing no statistical difference from the control group.Conclusion. The 2% chlorhexidine gluconate gel and 5.25% sodium hypochlorite were effective in eliminating E. faecalis even 7 days after the instrumentation; moreover, the higher the concentration of sodium hypochlorite the better its antimicrobial action.

Effects of chemical disinfectants on the transverse strength of denture base acrylic resins

The disinfection of dental prostheses by immersion in a chemical solution should be capable of rapid inactivation of pathogenic microorganisms, without causing any adverse effect on the denture base resins. This study evaluated the effect of disinfection immersion on the transverse strength of two heat-cured resins. The denture base resins (Lucitone 550 and QC 20) were polymerized according to the manufacturers' instructions. After polymerization, the specimens were polished, and then stored in water at 37 degreesC for 50 +/- 2 h prior immersion in one of the following solutions for 10 min: 4% chlorhexidine, 1% sodium hypochlorite and 3.78% sodium perborate. The specimens were submitted to disinfection twice, simulating when dentures come from the patient and before being returned to the patient. Ten specimens were made for each group. The transverse strength was evaluated by a 3-point bend test. The flexural strength of the two denture base acrylic resins evaluated remained unaffected after immersion in the three solutions evaluated. In general, the QC 20 resin specimens exhibited lower transverse strength than the Lucitone 550 resin specimens, regardless of immersion solutions.

Cytotoxic effects of cleansing solutions recommended for chemical lavage of pulp exposures

Purpose: To evaluate the in vitro cytotoxic effects of three cleansing solutions used for chemical lavage of pulp exposures. Materials and Methods: the immortalized odontoblast cell line (MDPC-23) was plated (30,000 cells/cm(2)) and incubated for 72 hrs in 24-well dishes. After counting the cell number under inverted light microscopy, 20 mul of the experimental and control solutions were added to 980 mul of fresh culture medium. Then, hydrogen peroxide (3%, H2O2), sodium hypochlorite (6%, NaOCl) or calcium hydroxide-saline solution (5g of Ca(OH)(2) in 10 mi of sterile distilled water) were added to wells for experimental Groups 1, 2 and 3, respectively. The positive and negative control groups received Syntac Sprint bonding agent (SS) and phosphate buffered saline (PBS), respectively. Following incubation for 120 min the cell number was counted again, the cell morphology was evaluated by scanning electron microscopy (SEM) and the cell metabolism was determined by the methyltetrazolium (MTT) assay. The scores obtained from cell counting and MTT assay were analyzed with an ANOVA followed by Fisher's PLSD tests. Results: H2O2 NaOCl solutions, and SS bonding agent were more cytotoxic than Ca(OH)2 or PBS. In the groups with H2O2 Or SS, only a few cells remained attached to the bottom of wells. The difference between these two groups was not statistically significant. H2O2, NaOCl and SS depressed the mitochondrial enzyme response by 97.7%, 97.3%, and 95.0%, respectively. on the other hand, Ca(OH)2 depressed the metabolic activity of cells by only 5%. While H2O2, NaOCl and SS caused extreme changes on the cell morphology, neither Ca(OH)2 nor PBS promoted dramatic changes in the cell morphology.

Produção de polpas de mangas Tommy Atkins, na Amazônia setentrional, através da aplicação de preservativos e da pasteurização

The present work had evaluated the efficiency of the pasteurization and the use of preservatives in mangos pulps (Mangifera indica L.) refrigerated. Before carrying out the treatments, the fruits had been cleaned in solution of sodium hypochlorite (NaOCl) at 100 mg. L(-1), for 10 minutes. After the processing, it was carried out through the adjustment of pH of pulps for 3.0 and the adjustment of the water activity (W(a)) at 0.95. The used variable had been the branching (hot water at 95 +/- 5 degrees C, for 0 and I minute), the addition of sodium benzoate in the concentrations of 0; 200 and 500 mL.L(-1) and, sulfite dioxide (SO(2)) in 0, 100 and 200 mL.L(-1). Then the pulps had been packed in low density polyethylene (LDPE) bags of 0,060 mm (0.10 x 0.12 m - without free space and content of 500g of pulp) and, conditioned in at 20 +/- 1 degrees C e 80 +/- 3% of R.H, for 28 days. At the end of the experiment, the treatments not submitted to the branching had shown the biggest ascorbic acid levels. However, in these same treatments had been noticed intense microbiological activity and raised levels of pH. There aren't significant differences between the tested treatments in the titratable acidity (TA) and soluble solids (SS) analyses. Due to the absence of black spot in the pulps used during all the experimental period, it couldn't be detected the differences between the application of the SO(2) and the use of the branching. The lower index of microbiological contamination and the preference of the judges in the sensorial panel had been attributed to the submitted treatments to the branching, addition of 500mL.L(-1) of sodium benzoate and addition of 200mL.L(-1) of sulfite dioxide.