Antimicrobial potential of new diclofenac hydrogels for disinfection in regenerative endodontics: An in vitro and ex vivo study.

AIM: There is a need to explore new alternatives for root canal disinfection in regenerative endodontics, since the current strategies are far from ideal. Currently, the potential use of diclofenac (DC) is being investigated for controlling root canal infections. The objective was to evaluate the antimicrobial efficacy of novel DC-based hydrogels (DCHs) against polymicrobial biofilms grown in radicular dentine and root canals and to compare results with triantibiotic (TAH) and diantibiotic (DAH) hydrogels, and calcium hydroxide (Ca[OH]2 ). METHODOLOGY: The in vitro antimicrobial activity of intracanal medicaments was evaluated against 3-week-old polymicrobial root canal biofilms grown on human radicular dentine. Dentine samples were obtained and randomly divided into the study groups (n = 4/group): (1) 1 mg/ml TAH; (2) 1 mg/ml DAH; (3) 5% diclofenac (DCH); (4) 2.5% DCH; (5) 1.25% DCH; (6) 1 mg/ml DAH + 5% DCH; (7) Ca(OH)2 paste; (8) positive control. The microbial viability, in terms of percentage of intact cell membranes, was assessed after 7 days by confocal scanning laser microscopy (CSLM). The ex vivo efficacy of intracanal medications was evaluated in root canals infected with a polymicrobial suspension. Intracanal microbiological samples at baseline (S1) and 7 days post-treatment (S2) were taken; microbial quantification and cell viability were assessed by quantitative polymerase chain reaction (qPCR) and flow cytometry (FC). The mean Log10 of bacterial DNA copies in root canal samples before (S1) and the Log10 reduction of DNA copies S1-S2 in qPCR were recorded. The absolute value of total cells stained, and the percentage reduction of intact membrane cells after treatment (S1-S2), were analysed by FC. Global comparison was done using the Kruskal-Wallis test, whilst the Mann-Whitney U test was used for pair-by-pair comparison. RESULTS: Confocal scanning laser microscopy analysis indicated that the greatest effectiveness was obtained with 5% DCH, showing significant differences with respect to the other groups (p < .001). In root canals, the highest Log10 DNA reduction S1-S2 was obtained with 5% DCH and TAH, with no differences between them. The results of FC showed that only 5% DCH proved significantly superior to the other treatments. CONCLUSIONS: Sodium DC hydrogels demonstrate antimicrobial efficacy against endodontic biofilms.

Effectiveness of conservative instrumentation in root canal disinfection.

OBJECTIVES: The impact of conservative instrumentation on the disinfection of root canals with different curvatures has not yet been determined. This ex vivo study aimed to evaluate and compare the effect of conservative instrumentation with TruNatomy (TN) and Rotate and a conventional rotary system, ProTaper Gold (PTG), on root canal disinfection during chemomechanical preparation of straight and curved canals. MATERIALS AND METHODS: Ninety mandibular molars with straight (n = 45) and curved (n = 45) mesiobuccal root canals were contaminated with polymicrobial clinical samples. Teeth were divided into three subgroups (n = 14) according to the file systems and the curvature. Canals were instrumented with TN, Rotate, and PTG, respectively. Sodium hypochlorite and EDTA were used as irrigants. Intracanal samples were taken before (S1) and after (S2) instrumentation. Six uninfected teeth were used as negative controls. The bacterial reduction between S1 and S2 was measured by ATP assay, flow cytometry, and culture methods. Kruskal-Wallis and ANOVA tests were followed by the Duncan post hoc test (p < 0.05). RESULTS: Bacterial reduction percentages were similar for the three file systems in straight canals (p > 0.05). However, PTG showed a lower reduction percentage of intact membrane cells in flow cytometry than TN and Rotate (p = 0.036). For the curved canals, no significant differences were obtained (p > 0.05). CONCLUSION: Conservative instrumentation of straight and curved canals using TN and Rotate files resulted in similar bacterial reduction compared to PTG. CLINICAL RELEVANCE: The disinfection efficacy of conservative instrumentation is similar to conventional instrumentation in straight and curved root canals.

Evaluation of final irrigation regimens with maleic acid for smear layer removal and wettability of root canal sealer.

OBJECTIVE: To evaluate the smear layer removal and wettability of AH Plus sealer on root canal dentin treated with MA (maleic acid), MA + CTR (cetrimide) and MA + CTR + CHX (chlorhexidine) as final irrigating regimens. MATERIAL AND METHODS: For smear layer removal, 40 teeth were instrumented to size F4 and divided into four groups: (1) 7% MA, (2) 7% MA + 0.2% CTR, (3) 7% MA + 0.2% CTR + 2% CHX, (4) distilled water (control). After irrigation, teeth were subjected to SEM analysis. For contact angle analysis, 20 teeth were split longitudinally and divided into four groups similar to smear layer analysis. AH plus sealer was placed on each specimen and contact angle was analysed. RESULTS: In both smear layer (p = .393) and contact angle analysis (p = .961), there was no significant difference between the groups MA and MA + CTR. However, MA + CTR + CHX removed smear layer less effectively (p = .023) and increased the contact angle of the sealer (p = .005). In smear layer analysis, specimens in negative control group were heavily smeared. In case of contact angle analysis, samples in the control group had least contact angle. CONCLUSION: MA alone or in combination with CTR removed smear layer effectively and increased the wettability of AH plus sealer to root canal dentin.

Antimicrobial activity of alexidine, chlorhexidine and cetrimide against Streptococcus mutans biofilm.

BACKGROUND: The use of antimicrobial solutions has been recommended to disinfect demineralized dentin prior to placing the filling material. The aim of this study was to evaluate the ability of several antimicrobials in controlling Streptococcus mutans (SM) biofilm formed in dentin. METHODS: Antimicrobial activity of 0.2% and 2% chlorhexidine (CHX), 0.2% cetrimide (CTR) and 0.2%, 0.5%, 1% and 2% alexidine (ALX) was assayed on 1-week SM biofilm formed on standardized coronal dentin blocks. Results of SM biofilm antimicrobial activity by different protocols were expressed as the kill percentage of biofilm and the term "eradication" was used to denote the kill of 100% of the bacterial population. To compare the efficacies of the different protocols the Student t test was used, previously subjecting data to the Anscombe transformation. RESULTS: All ALX concentrations tested and 0.2% CTR achieved a kill percentage higher than 99%, followed by 2% CHX with percentages above 96% (no statistically significant difference among them). Whereas 2% ALX and 0.2% CTR respectively showed eradication in 10 and 9 of the twelve specimens, 0.2% CHX did not produce eradication in any case. CONCLUSIONS: The present study shows that, when used for one minute, 2% and 1% alexidine, and 0.2% cetrimide, achieve eradication of Streptococcus mutans biofilm in most specimens when applied to a dentin-volumetric model.

Bacterial leakage in root canals filled with AH Plus and dentine bonding agents.

OBJECTIVE: The aim of this study was to compare the efficacy of different dentine adhesives in delaying the coronal bacterial leakage of Enterococcus faecalis in filled root canals. Materials and methods. Ninety-five lower incisors of patients >65 years of age were instrumented using the ProTaper system and were irrigated with 1 mL of 2.5% sodium hypochlorite (NaOCl) alternated with 1 mL 17% EDTA between each file change. Final irrigation was performed with 5 mL of 17% EDTA and then flushed with 5 mL of distilled water. The teeth were randomly divided into five experimental groups (n = 15/group) and one of the following dentine adhesives was applied: (1) AdheSE; (2) Excite DSC; (3) Clearfil Protect Bond; (4) One Coat 7.0; or (5) Control group without adhesive. After filling the root canals, the samples were mounted on a double chamber device to evaluate the bacterial filtration of E. faecalis during a period of 240 days. The results underwent non-parametric Kaplan-Meier survival analysis and comparisons among groups were done using the Log-Rank test. RESULTS: At 240 days, E. faecalis was detected in samples of all groups in the lower chamber. The highest survival value was obtained by One Coat 7.0, giving statistically significant differences from the other groups, whereas Clearfil Protect Bond, AdheSE and Excite DSC showed similar behaviours, likewise similar to the Control group. CONCLUSIONS: One Coat 7.0 adhesive system provides the longest survival value to delay E. faecalis coronal leakage in filled root canals.

Antibiofilm Efficacy of Calcium Silicate-Based Endodontic Sealers.

BACKGROUND: Using endodontic sealers with long-term antimicrobial properties can increase the success of endodontic treatment. This study aimed to assess the antimicrobial activity over time of two calcium silicate (CS)-based sealers, AH Plus Bioceramic and BioRoot RCS, and to compare them with an epoxy resin-based sealer, AH Plus Jet, against mature polymicrobial biofilms grown on human radicular dentin. METHODS: The antimicrobial activity of the sealers was tested using a direct contact test after 1 and 6 weeks of contact with the biofilms. Cell viability was determined by the adenosine triphosphate (ATP) method and flow cytometry (FC). The results of the ATP test were analyzed using an ANOVA with Welch's correction, followed by the Games-Howell test. The number of cells with damaged membranes obtained by FC in each period was compared by means of an ANOVA and Duncan's test. For the comparison between times, a Student's t-test was used. RESULTS: Globally, after a week of contact, the epoxy resin-based sealer obtained the best results. However, at 6 weeks, the two CSs showed the highest antimicrobial efficacy, with a significant increase in this activity over time. CONCLUSIONS: Calcium silicate-based sealers exert long-term antimicrobial activity against endodontic biofilms.

Decalcifying effects of antimicrobial irrigating solutions on root canal dentin.

OBJECTIVE: The aim of this study was to determine the decalcifying efficacy of 7% maleic acid (MA), 2% chlorhexidine (CHX), and combinations of 7% MA + 0.2% cetrimide (CTR) and 2% CHX + 0.2% CTR, in four time periods. STUDY DESIGN: Four specimens per tooth were obtained from a 2-mm thick slice of the cervical third of the root of ten human incisors. At 1, 2, 3 and 5 minutes of immersion, the concentrations of Ca2+ were measured by atomic absorption spectrophotometry. The results were analyzed using the Mann-Whitney U-test. RESULTS: Statistically significant differences were seen for the extracted calcium in all time periods. The amount of calcium extracted by 7% MA was the highest at all four immersion times, followed by 7% MA + 0.2% CTR. Two percent CHX and its combination with 0.2% CTR extracted virtually no calcium. CONCLUSIONS: The decalcifying capacity of 7% MA and 2% CHX diminished when combined with 0.2% CTR.

Ex vivo study of bacterial coronal leakage in indirect pulp treatment.

OBJECTIVE: The aim of this study was to evaluate, ex vivo, bacterial coronal leakage with different antimicrobial agents applied to the dentine for indirect pulp treatment (IPT). STUDY DESIGN: Sixty extracted teeth were prepared and randomly distributed into 5 groups (n=10): Group 1: no antimicrobial dentine treatment; group 2: 1% chlorhexidine (CHX)+1% thymol varnish (Cervitec); group 3: 2 % CHX solution; group 4: 40% CHX varnish (EC40) and group 5: Clearfil Protect Bond (CPB). Ten teeth served as controls. The teeth were restored using a resin-modified glass ionomer cement (GIC) and then mounted in a two-chamber device. The coronal access was exposed to Streptococcus mutans for 45 days. The appearance of turbidity in the BHI broth of the lower chamber was considered as specimen leakage. RESULTS: Survival analysis, determined by non parametric Kaplan-Meier and log-rank tests, showed that the best results were for groups EC40+GIC and GIC alone; yet there were not statistically significant differences between them. All specimens of CPB+GIC and 2% CHX+GIC, leaked at 45 days. CONCLUSIONS: In IPT the use of GIC without pretreatment of the dentine and pretreatment with 40% CHX varnish resulted in a significant delay of bacterial coronal leakage.

Antimicrobial Activity and Cytotoxicity of Nonsteroidal Anti-Inflammatory Drugs against Endodontic Biofilms.

Persistent infections have become a challenge in dentistry because of growing antibiotic resistance. Nonsteroidal anti-inflammatory drugs (NSAIDs) appear to be a therapeutic alternative to control biofilm infection. The objective of this work is to evaluate the antimicrobial activity and cytotoxicity of sodium diclofenac (DCS), ibuprofen (IBP) and ibuprofen arginine (IBP-arginine) solutions against endodontic polymicrobial biofilms. Sterile radicular dentin blocks of 4 mm × 4 mm × 0.7 mm were used as substrate to grow biofilm. The dentin blocks were submerged into solutions for 5 min. The antimicrobial activity was evaluated by means of the adenosine triphosphate (ATP) assay and confocal laser scanning microscopy (CLSM). Fibroblasts 3T3-L1 (ECACC 86052701) were used to test the cytotoxicity of irrigating solutions. The antibiofilm effects determined by the ATP assay showed that 4% IBP-arginine solution exerted the highest antibiofilm activity, followed by 4% DCS and 4% IBP, with statistical differences among groups (p < 0.001). As for CLSM, 4% DCS and 4% IBP-arginine solutions gave the lowest viable cell percentages, without significant differences between them. Cytotoxicity results at 1/10 dilution were similar for all solutions. At 1/100 dilution, a 4% DCS solution obtained the lowest cell viability for both time periods assayed, 1 h and 24 h. The IBP-arginine group showed the highest cell viability at 24 h. In this preliminary study, in terms of antibiofilm activity and cytotoxicity, a mixed 4% IBP-arginine solution gave the most promising results. NSAID solutions could be recommendable drugs for endodontic disinfection procedures.

Efficacy of mixed diclofenac solutions against root canal biofilms.

The objective of this research was to evaluate the efficacy of diclofenac sodium solutions, with or without cetrimide (CTR) added, against polymicrobial root canal biofilms grown in dentin specimens. The study groups were: (1) 5% diclofenac sodium (DCS); (2) 2.5% DCS; (3) 2.5% DCS + 0. 2% CTR; (4) 2.5% DCS + 0.4% CTR and (5) 0.9% saline solution (SS) as the control. After 5 min of solution contact with the biofilms, the antimicrobial activity was evaluated by means of the adenosine triphosphate (ATP) assay as well as confocal laser scanning microscopy (CLSM). Microbial quantification was indicated as the percentage reduction of relative light units (RLUs) for the ATP assay, the Log10 total biovolume and the viability percentage (green cells) for CLSM. Solutions of 2.5% DCS + 0.4% CTR and 5% DCS showed the highest antimicrobial efficacy. Cetrimide increased the antibiofilm activity of diclofenac sodium against endodontic biofilms.

Eradication of enterococci biofilms by lactic acid alone and combined with chlorhexidine and cetrimide.

OBJECTIVE: The antimicrobial activity of lactic acid (LA) alone or in combination with chlorhexidine (CHX) and cetrimide (CTR) against three Enterococcus faecalis strains, E. faecalis ATCC 29212, E. faecalis EF-D1 and E. faecalis U-1765, one Enterococcus durans strain and one dual-species biofilm was investigated. STUDY DESIGN: The irrigating solutions tested were 20%, 15%, 10%, 5% and 2.5% LA, alone and in combination with 2% CHX and with 0.2% CTR. The biofilms were grown in the MBECTM high-throughput device for 24 hours and exposed to the solutions for 30 seconds and 1 minute. "Eradication" was defined as 100% bacterial kill. RESULTS: Twenty percent LA eradicated all enterococci biofilms after 30 seconds contact time. The association of LA+0.2% CTR achieved better results than LA alone, in contrast with the results obtained using LA+2% CHX. E. durans was eradicated by all the tested solutions at 1 minute. The dual-species biofilm, E. faecalis ATCC 29212+E. durans, gave intermediate values of the pure cultures. CONCLUSIONS: LA is capable of eradicating enterococci biofilm at a concentration of 20%. The combination of lower concentrations with 0.2% CTR achieved eradication after 1 minute.

Antimicrobial activity and enterococcus faecalis biofilm formation on chlorhexidine varnishes.

OBJECTIVE: To evaluate, in vitro, the antimicrobial activity and biofilm formation of three chlorhexidine varnishes in four E. faecalis strains: E. faecalis ATCC 29212, E. faecalis EF-D1 (from failed endodontic treatment), E. faecalis 072 (cheese) and E. faecalis U-1765 (nosocomial infection), and one E. durans strain (failed endodontic treatment). STUDY DESIGN: The direct contact test was used to study the antimicrobial activity. Bacterial suspensions were exposed for one hour to EC40, Cervitec (CE) and Cervitec Plus (CEP) varnishes. "Eradication " was defined as 100% bacterial kill. The formation of enterococci biofilms was tested on the surface of the varnishes after 24 hours of incubation and expressed as percentage of biofilm reduction. RESULTS: EC40 eradicated all strains except E. faecalis ATCC 29212, where 98.78% kill was achieved. CE and CEP showed antimicrobial activity against all the strains, but most clearly against E. durans and E. faecalis 072. EC40 completely inhibited the formation of biofilm of E. faecalis ATCC 29212, E. faecalis 072 and E. durans. CE and CEP led to over 92% of biofilm reduction, except in the case of E. faecalis U-1765 on CEP (76.42%). CONCLUSION: The three varnishes studied were seen to be effective in killing the tested strains of enterococci and in inhibiting the formation of biofilm, the best results being observed with EC40.

In vitro Enterococcus faecalis biofilm formation on five adhesive systems.

OBJECTIVE: To determine the E. faecalis biofilm formation on the surface of five adhesive systems (AS) and its relationship with roughness. STUDY DESIGN: The formation of E. faecalis biofilms was tested on the surface of four dual-cure AS: AdheSE DC, Clearfil DC Bond, Futurabond DC and Excite DSC and one light-cure antimicrobial AS, Clearfil Protect Bond, after 24 hours of incubation, using the MBEC high-throughput device. RESULTS: E. faecalis biofilms grew on all the adhesives. The least growth of biofilm was on Excite DSC, Clearfil Protect Bond, and the control. Futurabond DC resulted in the greatest roughness and biofilm amount. There was a close relationship between the quantity of biofilm and roughness, except for Clearfil Protect Bond, which showed little biofilm but high roughness. CONCLUSION: None of the tested AS prevented E. faecalis biofilm formation, although the least quantity was found on the surface of Clearfil Protect Bond.

An in vitro evaluation of two dentine adhesive systems to seal the pulp chamber using a glucose penetration model.

OBJECTIVES: To evaluate the sealing capability of Cavit™ G with or without Clearfil™ S3 Bond and Prime & Bond NT placed in the pulp chamber. STUDY DESIGN: Forty single rooted premolars, extracted for orthodontic and periodontal reasons, with intact coronal surface and mature apices, were standardized to a length of 15 mm. The teeth were instrumented, filled with a gutta-percha master cone and divided into three groups to obturate the pulp chambers: Cavit™ G; Clearfil™ S3 Bond plus Cavit™ G and Prime & Bond® NT plus Cavit™ G. A glucose leakage model was used for evaluating the coronal microleakage. The Mann-Whitney test was used to evaluate the differences in the means of the glucose leakage. RESULTS: An increase in glucose penetration was observed during the first week in groups Cavit™ G and Cavit™ G+PBNT. The glucose penetration values of all groups were similar at 30 and 45 days, and there were no significant differences among them in both time periods (p=0.736 and p=0.581, respectively). CONCLUSIONS: The adhesive systems did not improve the capability of Cavit™ G to seal the pulp chamber over time.

Intraorifice sealing ability of different materials in endodontically treated teeth.

OBJECTIVES: To evaluate Cavit TM G, ProRoot TM MTA and Tetric® EvoFlow as intraorifice barriers to prevent coronal microleakage in root canal treatment. STUDY DESIGN: Forty-two human single rooted teeth were divided randomly in three experimental groups of 10 specimens each and two control groups. The experimental groups were prepared with hand instrumentation and cold lateral condensed technique of the gutta-percha. Four millimetres of coronal gutta-percha were removed and replaced by one of the following filling materials: Cavit TM G, Tetric® EvoFlow or ProRoot TM MTA. In the experimental groups, leakage was measured by the concentration of leaked glucose in the apical reservoir at 1, 7, 30, and 45 days, using the enzymatic glucose oxidase method. Data were analyzed by means of Mann-Whitney U and Kruskal-Wallis tests at α=0.05. RESULTS: The glucose penetration results of three experimental groups increased gradually over time. No significant differences were found among groups at 24 hours and 1 week. At thirty and forty-five days, Cavit TM and Tetric® EvoFlow values were significantly different (p=0.007 and p=0.023, respectively). CONCLUSIONS: The sealing ability of the Cavit TM G, ProRoot TM MTA and Tetric® EvoFlow used as intraorifice materials tends to be similar over time.

Root Canal Disinfection Articles with the Highest Relative Citation Ratios. A Bibliometric Analysis from 1990 to 2019.

The relative citation rate (RCR) is a normalized article-level metric useful to assess the impact of research articles. The objective of this bibliometric study is to identify and analyze, in root canal disinfection, the 100 articles having the highest RCRs in the period 1990-2019, then compare them with the top 100 articles most cited. A cross-sectional study was performed, and the search strategy ((Disinfection AND root canal) AND (("1990/01/01"[Date-Publication]: "2019/12/31"[Date-Publication]))) relied on PubMed (n = 4294 documents), and article data were downloaded from the iCite database. The 100 articles with the highest RCRs and the top 100 cited were selected and evaluated in bibliometric terms. Among the 100 articles with the highest RCRs, there were no differences in the three decades for RCRs values, but there were in citations, being 2000-2009 the most cited. The USA was the predominant country (n = 30), followed by Brazil (n = 14). The most frequent study designs were reviews (n = 27) and in vitro (n = 25) and ex vivo (n = 24) studies. All subfields were well represented, although they varied over time. In 2010-2019, regenerative procedures and irrigation/disinfection techniques were predominant. Considering the RCR's top 100 articles, 76 were common with the 100 most cited articles. Using the RCR metric allowed us to identify influential articles in root canal disinfection, a research field with topics of significance that fluctuate over time. Compared to citations, RCR reduces the time from publication to detection of its importance for the readership and could be a valid alternative to citation counts.

Antibiofilm Activity of Diclofenac and Antibiotic Solutions in Endodontic Therapy.

INTRODUCTION: The aim of this study was to compare the antibiofilm effects of a triple antibiotic solution (TAS); a double antibiotic solution (DAS); and 5%, 2.5%, and 1.25% diclofenac solutions (DCSs) against Enteroccocus faecalis biofilm. METHODS: Eighty-four sterile radicular dentin blocks were used as biofilm substrate for 3 weeks. The study groups were as follows: (1) 1 mg/mL TAS (minocycline, metronidazole, and ciprofloxacin), (2) 1 mg/mL DAS (metronidazole and ciprofloxacin), (3) 5% DCS, (4) 2.5% DCS, (5) 1.25% DCS, and (6) 0.9% saline solution. The antimicrobial activity was evaluated by bacterial count determinations and confocal laser scanning microscopy. The contact time for the antimicrobial tests was 5 minutes. Bacterial counts were expressed as the reduction percentage of colony-forming units; for the confocal laser scanning microscopic evaluation, the log10 total biovolume and percentage of green population (live cells) were calculated. RESULTS: The colony-forming unit reduction percentage ranged between 62.98 and 98.62, respectively, for TAS and 5% DCS. The DCS showed a concentration-dependent effect.For the confocal laser scanning microscopy, the log10 total biovolume in all groups was very similar and showed a scarce (1.39-1.02) but significant reduction with respect to the control; 5% and 2.5% DCSs gave the lowest viable cell percentage. The TAS and DAS groups showed intermediate values without significant differences between them. CONCLUSIONS: DCSs at 5% and 2.5% have greater antimicrobial effects than TAS and DAS and may be considered a valid alternative for controlling the infection of teeth with apical periodontitis.

Long-term sealing ability of GuttaFlow versus Ah Plus using different obturation techniques.

OBJECTIVE: To compare the long-term sealing ability of GuttaFlow® using different obturation techniques. STUDY DESIGN: Three hundred teeth, prepared with a crown-down technique, were divided into thirty experimental groups (n=10) to evaluate the apical and coronal leakage, at 3, 30 and 120 days, of lateral compaction gutta-percha+AH Plus TM, lateral compaction gutta-percha+GuttaFlow®, single cone+AH Plus TM, single cone+GuttaFlow®, and GuttaFlow® only. RESULTS: Both coronal and apical leakage, at the three times of measurement, no significant differences were found among GuttaFlow®+lateral compaction gutta-percha and GuttaFlow®+single cone groups, whereas the only GuttaFlow® reached the highest leakage values at 30 and 120 days. AH Plus TM, using both techniques, showed high levels of leakage after 120 days to the coronal leakage and after 30 days to the apical leakage when compared silicon based sealer. CONCLUSION: GuttaFlow®, using with lateral compaction and single cone techniques, shows a greater apical and coronal sealing ability than AH Plus TM over time. GuttaFlow® when used as only creates a poorer sealing when used with lateral compaction gutta-percha or single cone techniques.

Cytotoxic effects of two acid solutions and 2.5% sodium hypochlorite used in endodontic therapy.

AIM: To evaluate the cytotoxicity of 15% citric acid, 5% phosphoric acid and 2.5% NaOCl on cultured fibroblasts using MTT colorimetric assay. METHODOLOGY: Irrigating solutions of 5% phosphoric acid, 15% citric acid, and 2.5% NaOCl, diluted at 0.1% and 0.5%, were applied to cell cultures of 3T3L1 fibroblasts. The cell viability was determined by means of MTT colorimetric assay after a period of 1, 6 and 24 hours. Percentages of cell viability were analyzed using the Kruskal-Wallis test for global comparisons and the Mann-Whitney U-test for pairwise comparisons. RESULTS: The percentage of cell viability diminished progressively over a 24 hour period in all solutions at both dilutions. At 0.1% dilution, 2.5% NaOCl (63.39%) and 15% citric acid (53.91%) showed the highest percentage of cell viability (p=0.083). At 0.5% dilution, 2.5% NaOCl again showed the highest cell viability value (48.51%). CONCLUSIONS: The irrigating solution with the highest percentage of cell viability was 2.5% NaOCl at both 0.1% and 0.5% dilutions. A very low percentage of cell viability was obtained with 15% citric acid and 5% phosphoric acid at 0.5% dilution.

Clinical importance of the presence of lateral canals in endodontics.

This article presents a clinical case in which the diagnosis and treatment of a lateral canal was instrumental in the successful completion of endodontic therapy. Endodontic treatment was performed by crown-down shaping and copious irrigation (using 2.5% sodium hypochlorite associated with 17% ethylenediaminetetracetic acid (EDTA)). After 10 months, there were no clinical symptoms of inflammation and radiographs showed periradicular healing.