Antimicrobial action and cytotoxicity of hypochlorous acid obtained from an innovative electrolytic device - An in vitro study.

OBJECTIVE: This study evaluated the antimicrobial effect and cytotoxicity of hypochlorous acid(HClO) obtained from an innovative electrolytic device. DESIGN: The root canals of fifty extracted human teeth were inoculated with Enterococcus faecalis and divided into 5 groups (n = 10): DW (control); 2% chlorhexidine gel(CHX); 2.5% sodium hypochlorite(NaOCl); 250 ppm HClO and 500 ppm HClO. The counting of colony forming units evaluated the decontamination potential of each group. Cytotoxicity was evaluated after inoculation of tested protocols in fibroblastic cells for 3 min, calculating the cell viability. Specific statistical analysis was performed (α = 5%). RESULTS: The highest bacterial reduction was observed in experimental groups, with no statistical differences from each other (p > 0.05). The highest number of viable cells was observed in control group, followed by 250 ppm HClO and 500 ppm HClO groups, with statistical differences from each other (p < 0.05). CONCLUSIONS: It could be concluded that HClO presented high antimicrobial activity and low cytotoxicity at both tested concentrations.

Effectiveness of ultrasonic activation associated to glycolic acid on smear layer removal, dentin structure and bond strength to root dentin

This study evaluated the effects of ultrasonic activation (US) associated to glycolic acid (GA) on smear layer, dentin structure and bond strength (BS) of filling/restorative material to root dentin. The roots were used for antimicrobial activity, dentin structure and BS evaluation, being distributed into seven groups, according to irrigation protocols: G1:DW+US; G2:17% EDTA; G3:QMix; G4:17% GA; G5:17% EDTA+US; G6:QMix+US; G7:17% GA+US. Scanning electronic microscopy, transmission electronic microscopy and push-out were performed, with specific statistical analysis for each evaluation. The highest smear layer removal occured in Groups 6 and 7 (p<0.05), and the largest collagen dispersion in Group 7, being similar to Group 2 and 5 (p>0.05). The highest BS of filling and restorative material occurred in Groups 6 and 7, and Groups 5, 6 and 7, respectively, being similars between them (p>0.05). The use of GA+US promoted effective smear layer removal and dentin structure preservation, improving the BS of filling/restorative material to root dentin.

Influence of photodynamic therapy, different final irrigants, and ultrasonic activation on the bond strength of glass fiber posts to root dentin.

OBJECTIVE: To evaluate the influence of photodynamic therapy (PDT), different final irrigants, and ultrasonic activation (US) on the bond strength of glass fiber posts (GFP) to root dentin. METHODS: One hundred twenty bovine roots were divided into 12 groups according to PDT application, the type of final endodontic irrigant, and US. The samples were divided into 12 groups (n = 10): G1-DW(distilled water); G2-DW+US; G3-17% EDTA; G4-17% EDTA+US; G5-17% GA (glycolic acid); G6-17% GA+US; G7-PDT+DW; G8-PDT+DW+US; G9-PDT+17% EDTA; G10-PDT+17% EDTA+US; G11-PDT+17% GA; G12-PDT+17% GA+US. After cementing the glass fiber posts with resin cement, roots were sectioned into 2-mm-thick slices. One slice from the cervical third and another from the middle third were used for the push out test (PO), and the other two for the diametral compression test (DC). Thus, 10 samples were obtained per third for each mechanical test (n = 10). Kruskal-Wallis and Student-Newman-Keuls tests were used to analyze PO and DC data, and Pearson's correlation test was used to verify the relationship between the variables. Failure patterns were analyzed with chi-square test. RESULTS: Significant differences were found in the PO test among the experimental groups (p < 0.001; power=1.00). PDT improved bond strength when using EDTA. PDT and US increased bond strength when using GA. Favorable failure patterns occurred more frequently in Group GA+US. There was no correlation between data obtained with PO and DC tests (r = 0.112; p = 0.729). CONCLUSION: PDT provided the highest bond strength values of GFP to root dentin when associated with GA and US or when associated only with EDTA.

Influence of ultrasonic activation on antimicrobial activity of a new final irrigant containing glycolic acid: An in vitro study.

This study evaluated the influence of ultrasonic activation (US) on the antimicrobial activity of a new final irrigant containing glycolic acid (GA). Extracted teeth were used, being 70 to counting of colony-forming units (CFUs) and 35 to confocal laser scanning microscopy. Samples were inoculated with Enterococcus faecalis and divided into 7 groups: distilled water + US; 17% EDTA; Qmix; 17% GA; 17% EDTA + US; QMix + US; and 17% GA + US and kept in contact with test solution for 1 min in the groups with or no US. In the CFUs, the highest bacterial reduction was observed in QMix + US group, followed by QMix and GA + US. In the confocal evaluation, the lowest number of viable cells was observed in EDTA + US, with no statistical difference from QMix, QMix + US and GA + US (P > 0.05). The use of US improves the antimicrobial activity of EDTA and GA, being statistically different from the isolated use of these final irrigants in both evaluation tests.

Effectiveness of grape seed extract-based intracanal dressings against Enterococcus Faecalis and its influence on dentin microhardness and bond strength of filling material / Eficácia de medicamentos intracanais à base de extrato de semente de uva contra o Enterococcus Faecalis e sua influência na micro-dureza da dentina e na resistência de união do material obturador

The aim of this study was to evaluate the effectiveness of grape seed extract (GSE)-based intracanal dressings against Enterococcus faecalis (E. faecalis) and its influence on dentin microhardness and bond strength of the filling material. The root canals of 126 human teeth were distributed into three test groups: antimicrobial activity (60 teeth), dentin microhardness (30 teeth) and bond strength (36 teeth). In all three groups, specimens were subdivided into six groups, according to intracanal dressing protocols: G1 ­ distilled water (DW); G2 ­ 2% chlorhexidine gel (CHX); G3 ­ calcium hydroxide (Ca[OH]2)+DW; G4 ­ GSE+DW; G5 ­ Ca(OH)2+CHX; G6 ­ GSE+CHX. The counting of colony-forming units (CFUs), the Vickers microhardness tester and the push-out test were performed to evaluate the antimicrobial activity, dentin microhardness and bond strength, respectively. Specific statistical analysis was performed for each evaluation (α=5%). The greatest bacterial reduction was observed in G5 (Ca[OH]2+CHX) and G6 (GSE+CHX) (p<0.05). There was no statistically significant difference among groups in the dentin microhardness evaluation (p<0.05). The highest bond strength in the immediate evaluation was observed in G4 (GSE+DW) and G6 (GSE+CHX), whereas the highest bond strength after 12 months of storage was observed in G2 (CHX), G3 (Ca[OH]2+DW), G4 (GSE+DW), and G6 (GSE+CHX) (p<0.05). After the storage period, bond strength was increased in G2 (CHX) and G3 (Ca[OH]2+DW), and remained unchanged in G4 (GSE+DW) and G6 (GSE+CHX) (p<0.05). GSE-based intracanal dressings have antimicrobial potential against E. faecalis, have no influence in dentin microhardness and preserve the high bond strength of filling materials for root dentin over time.

O objetivo deste estudo foi avaliar a eficácia de medicamentos intracanal à base de extrato de semente de uva (GSE) contra Enterococcus faecalis (E. faecalis) e sua influência na microdureza da dentina e na resistência de união do material de obturação. Os canais radiculares de 126 dentes humanos foram distribuídos em três grupos de teste: atividade antimicrobiana (60 dentes), microdureza da dentina (30 dentes) e resistência adesiva (36 dentes). Nos três grupos, as amostras foram subdivididas em seis grupos, de acordo com os protocolos de curativos intracanal: G1 ­ água destilada (DW); G2 ­ gel de clorexidina a 2% (CHX); G3 ­ hidróxido de cálcio (Ca[OH]2) +DW; G4 ­ GSE+DW; G5 ­ Ca(OH)2+CHX; G6 ­ GSE+CHX. A contagem de unidades formadoras de colônias (UFCs), o testador de microdureza Vickers e o teste push-out foram realizados para avaliar a atividade antimicrobiana, a microdureza da dentina e a resistência adesiva, respectivamente. Análise estatística específica foi realizada para cada avaliação (α=5%). A maior redução bacteriana foi observada no G5 (Ca[OH]2+CHX) e G6 (GSE+CHX) (p<0,05). Não houve diferença estatisticamente significativa entre os grupos na avaliação da microdureza da dentina (p<0,05). A maior resistência adesiva na avaliação imediata foi observada no G4 (GSE+DW) e G6 (GSE+CHX), enquanto a maior resistência adesiva após 12 meses de armazenamento foi observada no G2 (CHX), G3 (Ca[OH]2+DW), G4 (GSE+DW) e G6 (GSE+CHX) (p<0,05). Após o período de armazenamento, a resistência de união aumentou no G2 (CHX) e G3 (Ca[OH]2+DW), permanecendo inalterada no G4 (GSE+DW) e G6 (GSE+CHX) (p<0,05). Os medicamentos intracanal à base de GSE têm potencial antimicrobiano contra E. faecalis, não influenciam na microdureza da dentina e preservam a alta resistência adesiva dos materiais de obturação da dentina radicular ao longo do tempo.

Antimicrobial activity of intracanal dressings composed by natural products associated to chlorhexidine and its influence on dentinal colour change / Avaliação da ação antimicrobiana de medicações intracanais à base de produtos fitoterápicos associados à clorexidina e sua influência na alteração de cor da estrutura dentinária

Purpose: evaluate the antimicrobial activity of intracanal dressings and their influence on dentinal colour changes. Material and methods: eighty single-rooted human extracted teeth were decoronated and divided into eight groups (n=10) according to intracanal dressing protocols inserted into the root canals: G1­distilled water (DW); G2­2% chlorhexidine gel (CHX); G3­calcium hydroxide (Ca[OH]2)+DW; G4­grape seed extract (GSE)+DW; G5­ginger extract (GE)+DW; G6­Ca(OH)2+CHX; G7­GSE+CHX; and G8­GE+CHX. The antimicrobial activity was evaluated by colony-forming units (CFUs) counting and dentinal colour changes was evaluated by digital spectrophotometry. Data were statistically analysed by One-way ANOVA followed by Tukey´s post hoc test (antimicrobial evaluation) and non-parametric Wilcoxon followed by the Mann- Whitney-U test (colour change evaluation) (α=0.05). Results: the highest bacterial reduction was observed in groups 4, 6, 7 and 8, with no significant difference between them (p<0.05). Groups 4 and 7 showed the highest medians of dentinal colour change (p<0.05). Conclusion: the addition of CHX improved the antimicrobial activity of GE-based intracanal dressing, with no effect in GSE-based intracanal dressing; moreover, these protocols induced significant dentinal colour changes. (AU)

Objetivo: avaliar a atividade antimicrobiana de medicações intracanais e sua influência na alteração da cor dentinária. Materiais e métodos: oitenta dentes humanos extraídos unirradiculares foram seccionados e divididos em oito grupos (n = 10), de acordo com os protocolos de medicação intracanal inseridos nos canais radiculares: água destilada G1 (DW); G2-2% de gel de clorexidina (CHX); hidróxido de cálcio G3 ­ (Ca [OH] 2) + DW; extrato de semente de uva G4 (GSE) + DW; extrato de gengibre G5 (GE) + DW; G6- Ca (OH) 2 + CHX; G7 ­ GSE + CHX; e G8-GE + CHX. A atividade antimicrobiana foi avaliada por contagem de unidades formadoras de colônias (UFCs) e as alterações de cor dentinária foram avaliadas por espectrofotometria digital. Os dados foram analisados estatisticamente por ANOVA one-way, seguida pelo teste post hoc de Tukey (avaliação antimicrobiana) e Wilcoxon não paramétrico, seguido pelo teste de Mann- Whitney-U (avaliação da mudança de cor) (α = 0,05). Resultados: a maior redução bacteriana foi observada nos grupos 4, 6, 7 e 8, sem diferença significativa entre eles (p < 0,05). Os grupos 4 e 7 apresentaram as maiores medianas da alteração da cor dentinária (p < 0,05). Conclusão: a adição de CHX melhorou a atividade antimicrobiana da medicação intracanal baseado em GE, sem efeito na medicação intracanal baseado em GSE; além disso, esses protocolos induziram alterações significativas na cor dentinária.(AU)

Association of calcium hypochlorite, reciprocating instrumentation and photodynamic therapy: Antimicrobial analysis and effects on root dentin structure.

INTRODUCTION: This study aimed to evaluate the antimicrobial action of calcium hypochlorite(Ca[OCl]2) and sodium hypochlorite (NaOCl) with reciprocating instrumentation and photodynamic therapy(PDT), and its influence on root dentin structure. METHODS: One hundred and ten human teeth were used to antimicrobial evaluation, inoculated with Enterococcus faecalis and divided into 11 groups (n = 10): G1 - distilled water(control); G2-1 % NaOCl; G3-5.25 % NaOCl; G4-1 % Ca(OCl)2; G5-5.25 % Ca(OCl)2; G6-PDT; G7-distilled water + PDT; G8-1 % NaOCl + PDT; G9-5.25 % NaOCl + PDT; G10-1 % Ca(OCl)2+PDT; G11-5.25 % Ca(OCl)2+PDT. In all groups, except G6, the root canals were instrumented with #R50 Reciproc file in the working length in association with tested chemical auxiliary substance. The counting of colony forming units (CFUs) was performed to calculate the bacterial percentage reduction of each group. Following, 55 bovine teeth were used to microhardness evaluation and divided into the same 11 groups (n = 5), with no instrumentation and immersion in the tested protocols. The modification of root dentin microhardness was evaluated by using the Vicker tester. Finally, 33 bovine teeth were used to organic components evaluation and divided into the same 11 groups (n = 3), with no instrumentation and immersion in the tested protocols. The modification of organic components of root dentin was evaluated by light microscopy. Specific statistical analysis was performed for each evaluation. RESULTS: The higher bacterial reduction was observed in groups 3,4,5,8,9,10 and 11, with no statistical difference between them (p > 0.05). The higher microhardness reduction was observed in groups 8,9,10 e 11, with no statistical difference between them (p > 0.05). The highest modification on organic components was observed in groups 3,5,9 and 11, with no statistical difference between them (p > 0.05). CONCLUSIONS: The association of Ca(OCl)2, reciprocating instrumentation and PDT promotes effective antimicrobial action. Moreover, lower modification was induced in microhardness and organic components of root dentin, by using Ca(OCl)2 in low concentration associated to PDT.

Influence of final irrigation protocols and type of resin cement on bond strength of glass fiber posts in root dentin previously treated with photodynamic therapy.

INTRODUCTION: This study aimed to evaluate the influence of final irrigation protocols and type of resin cement on the bond strength of glass fiber posts (GFPs) in root dentin previously treated with photodynamic therapy (PDT). METHODS: One hundred root canals were prepared up to #4 Gates Glidden drill to receive the GFPs. All samples were subjected to PDT, and randomly divided into five groups (n = 20) according to final irrigation protocol: distilled water + ultrasonic activation [US]; 17% EDTA; QMix; 17% EDTA + US; and QMix + US. Each group was randomly divided into 2 subgroups (n = 10) according to the type of resin cement used for cementation of GFPs: Rely-X ARC dual-resin; or Rely-X U200 (#M, St Paul, MN, USA) self-adhesive resin cement. Bond strength was evaluated using the push-out test. Failure patterns were observed under an optical microscope. Bond strengths were compared using two-way ANOVA, followed by the Tukey post-hoc test; failure modes were compared using the chi-squared test (α = 5%). RESULTS: The use of US over final irrigants improved the bond strength of GFPs, regardless of resin cement used (p < 0.05). The type of resin cement did not influence the bond strength of GFPs (p < 0.05). There was a higher predominance of cohesive failure in all groups, regardless of resin cement tested (p < 0.05). CONCLUSIONS: The use of US on final irrigation improved the bond strength of GFPs, while the type of resin cement (dual or self-adhesive) did not influence the bond strength of GFPs in root dentin previously treated with PDT.

Influence of final irrigation protocols and endodontic sealer on bond strength of root filling material with root dentin previously treated with photodynamic therapy.

INTRODUCTION: The aim of this study was to evaluate the influence of final irrigation protocols and endodontic sealer on bond strength of root filling material on root dentin previously treated with photodynamic therapy (PDT). METHODS: One hundred root canals were prepared up to #F3 file of Pro-Taper system to receive the root filling material. All samples were submitted to PDT and randomly divided into five groups (n = 20) according to final irrigation protocols: Group 1-distilled water + ultrasonic activation (US); Group 2-17% EDTA; Group 3-QMix; Group 4-17% EDTA + US; Group 5-QMix + US. Each group was randomly divided into two subgroups (n = 10), according to the endodontic sealer used for cementation of gutta-percha points: AH Plus or MTA Fillapex. The bond strength was evaluated by a push-out test. The patterns of failure were observed under optical microscopy. The bond strength was evaluated using a two-way Anova followed by the Tukey post-hoc test, and the failure mode was evaluated using the chi-square test (α = 5%). RESULTS: The use of 17% EDTA and QMix associated or not to US improved the bond strength of root filling material with either endodontic sealer (p < 0.05). AH Plus showed higher bond strength than MTA Fillapex (p < 0.05). There was a higher predominance of cohesive failure in all groups, regardless of the tested final irrigation protocols and endodontic sealer (p < 0.05). CONCLUSIONS: The use of 17% EDTA and QMix, regardless of association with US, and the use of AH Plus improve the bond strength of the root filling material on root dentin previously treated with PDT.

Influence of ultrasonic activation using different final irrigants on antimicrobial activity, smear layer removal and bond strength of filling material.

The aim of this study was to evaluate the influence of ultrasonic activation (US) over final irrigants on antimicrobial activity, smear layer removal and bond strength. The root canals of 180 extracted human teeth were distributed into three experimental tests (n = 60). In each test, the samples were subdivided into six groups (n = 10) according to final irrigation protocols: G1:distilled water (DW); G2:DW + US; G3:17% EDTA; G4:QMix; G5:17% EDTA + US; and G6:QMix + US. The antimicrobial activity was evaluated by counting of colony-forming units (CFUs), the smear layer removal by scanning electron microscopy and the bond strength by push-out test. Statistical analysis was performed for each evaluation (α = 5%). Groups 4 and 6 provided higher bacterial reduction, groups 5 and 6 provided higher smear layer removal, groups 3, 4, 5 and 6 provided the higher bond strength (P < 0.05). US activation did not improve the antimicrobial activity and the bond strength, whereas it improved the smear layer removal.

Antimicrobial activity of hypochlorite solutions and reciprocating instrumentation associated with photodynamic therapy on root canals infected with Enterococcus faecalis - An in vitro study.

INTRODUCTION: The aim of this study is to evaluate the antimicrobial activity of hypochlorite solutions and reciprocating instrumentation associated with photodynamic therapy (PDT). METHODS: One hundred and thirty two root canals were enlarged up to #35 K-file and inoculated with E.faecalis for 14 days. The 132 samples were randomly divided into eleven groups (n = 12) and subjected to the following protocols: G1-distilled water + Reciproc R40 (control), G2-1% sodium hypochlorite (NaOCl) + Reciproc R40, G3-2.5% NaOCl + Reciproc R40; G4-1% calcium hypochlorite (Ca[OCl]2) + Reciproc R40, G5-2.5% Ca(OCl)2 + Reciproc R40; G6-PDT; G7-distilled water + Reciproc R40 + PDT, G8-1% NaOCl + Reciproc R40 + PDT, G9-2.5% NaOCl + Reciproc R40 + PDT; G10-1% Ca(OCl)2 + Reciproc R40 + PDT, G11-2.5% Ca(OCl)2 + Reciproc R40 + PDT. The percentage bacterial reduction was checked by counting the colony-forming units (CFUs) in 10 samples of each group. The remaining 2 samples of each group were submitted to scanning electronic microscopy (SEM) to illustrate the effectiveness of the proposed treatments. Data were subjected to one-way ANOVA followed by Tukey's post hoc test (α = 0.05). RESULTS: The greatest ability to promote bacterial reduction was observed in groups 8 (1% NaOCl + R40 + PDT), 9 (2.5% NaOCl + R40 + PDT), 10 (1% Ca[OCl]2 + R40 + PDT), and 11 (2.5% Ca[OCl]2 + R40 + PDT), with no significant difference between them (p < 0.05). CONCLUSIONS: The association of PDT with hypochlorite solutions and reciprocating instrumentation provides effective elimination of E.faecalis.

Effect of chemical and natural irrigant solutions on microhardness of root dentin­ an in vitro study

Aim: Modifications in the mechanical properties of dentin may reduce the fracture resistance of tooth, especially after endodontic treatment. The aim of present study was to evaluate the effect of the irrigation with different root canal irrigants on the microhardness of root dentin. Methods: The coronal portion of 60 single-rooted bovine incisors was sectioned and the pulpal tissue removed using endodontic K-files. The roots were cut transversely to obtain 2 fragments, which were embedded in acrylic resin and randomly distributed into six groups (n=20) according to the irrigation protocol: distilled water (DW) (control); 2% chlorhexidine solution (CHX); 6% sodium hypochlorite (NaOCl); 6% calcium hypochlorite (Ca[OCl]2); QMix; and 6.5% grape seed extract solution (GSE). The solutions were kept in contact with the root dentin specimens for 30 min. After that, irrigation with 5 mL of DW was performed. The Vickers microhardness was determined by performing three indentations in all specimens, using 300-g load and 20-second dwell time. The first indentation was made 1.000 µm from the root canal entrance, and two other indentations were made at a distance of 200 µm from each other. The microhardness value for each specimen was obtained as the average of the results for the three indentations. Data were statistically analyzed using one-way ANOVA with 5% significance level. Results: All the tested irrigant solutions maintained the same microhardness level of the root dentin when compared to the control group, with no statistically significant differences between them (p<0.05) Conclusion: The tested irrigant solutions did not present ability to modify the microhardness of root dentin

Evaluation of antimicrobial activity of association of chlorhexidine to photosensitizer used in photodynamic therapy in root canals infected by Enterococcus faecalis.

INTRODUCTION: The aim of the present study was to evaluate, in vitro, the influence of the addition of chlorhexidine to photosensitiser in the antimicrobial activity of photodynamic therapy in root canals infected by Enterococcus faecalis. METHODS: The root canals of 50 single-rooted human extracted teeth were enlarged up to a file F3 of Pro-Taper system, autoclaved, inoculated with Enterococcus faecalis and incubated for 14days. The samples were divided into five groups (n=10) according to the protocol of decontamination: G1 (control group) - no procedure was performed; G2-photosensitiser (0.01% methylene blue); G3-2% chlorhexidine gel; G4-photodynamic therapy; and G5-photodynamic therapy with photosensitiser modified by chlorhexidine. Microbiological test (CFU counting) was performed to evaluate the effectiveness of proposed treatments. Data were subjected to one-way ANOVA followed by post-hoc Tukey test (α=0.05). RESULTS: Group 3 (CHX) showed the lowest mean contamination (2.03 log10 CFU/mL), being statistically different from all other all groups (p<0.05). There was no statistically significant difference between groups 4 (PDT) and 5 (PDT+CHX) (p<0.05), being more effectives against E. faecalis when compared to groups 1 (NT) and 2 (MB), and less effective when compared to group 2 (CHX). CONCLUSIONS: The addition of chlorhexidine to photosensitiser did not result in a better decontamination potential of photodynamic therapy alone over root canals infected by E. faecalis.

Influence of ultrasonic activation over final irrigants in the removal of photosensitizer from root canal walls after photodynamic therapy.

INTRODUCTION: The aim of the present study was to evaluate the influence of ultrasonic activation (US) of the final irrigant in the removal of the photosensitizer from root canal walls after photodynamic therapy. METHODS: The root canals of 60 single-rooted bovine extracted teeth were filled with 0.01% methylene blue and submitted to photodynamic therapy for 90s. After that, the roots were divided into six groups (n=10) according to the final irrigation protocol: distilled water (DW), DW+US, 17% EDTA, QMix, EDTA+US, and QMix+US. Then, the samples were submitted to scanning electron microscopy where a scoring system was used to evaluate the images and effectiveness of proposed treatments in the cervical, middle and apical regions of the root canals. The data were statistically analyzed by the Kruskal-Wallis and Mann-Whitney U tests for intergroup comparisons as well as the Wilcoxon and Friedman tests for intragroup comparisons at 5% of significance. RESULTS: The 17% EDTA+US and QMix+US treatments were most effective in the removal of the photosensitizer in all regions of the root canal; the difference was statistically significant when compared to all other groups (p<0.05). There were no significant differences in the intragroup analysis comparing the effectiveness in the different regions of the same group (p<0.05). CONCLUSIONS: US can aid 17% EDTA and QMix in removing the photosensitizer after photodynamic therapy and contributes to cleaning root canal walls.