Antimicrobial action of calcium hydroxide-based endodontic sealers after setting, against E. faecalis biofilm

Biological investigation of resinous endodontic sealers containing calcium hydroxide

The purpose of this study was to evaluate, in vivo, the biocompatibility, biomineralization, collagen maturation and the in vitro antibacterial and cytotoxicity of resinous endodontic sealers containing calcium hydroxide. Forty rats were implanted with polyethylene tubes containing Sealer 26, Sealer Plus, Dia-ProSeal and an empty tube, examined after 7, 15, 30 and 60 days. Antimicrobial activity was evaluated against Enterococcus faecalis by Agar Diffusion Test (ADT) through inhibition zones. For cytotoxicity, undifferentiated pulp cells (OD-21) were cultured and assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, exposed to dilution of serial extracts at 6, 24, 48h. Cytotoxicity was analyzed by two-way ANOVA and Bonferroni correction. Kruskal-Wallis test followed by Dunn test was performed for nonparametric data (p<0.05). MTT assay revealed cell proliferation affected by sealers extract in all periods (p<0.0001), except for Dia-Proseal and Sealer Plus ⅛ dilution. Subcutaneous analysis showed at day 7th moderate inflammatory infiltration. After 30 days, Sealer 26 still showed moderate inflammatory infiltrate compared to mild inflammation from control and Dia-ProSeal (p = 0.006). At day 60th, all groups showed similar mild inflammatory infiltrate (p>0.05). Sealer 26 induced more biomineralization than other sealers in all periods. At 7 and 15 days, all sealers had significant percentage of immature collagen fibers. After 60 days Sealer 26 showed more mature fibers compared to other sealers (p<0.001). All sealers had a smaller zone of inhibition than chlorhexidine, but with no significant difference among any group (p>0.05). All sealers showed satisfactory biological responses with in vitro/in vivo biocompatibility and antimicrobial activity against planktonic bacteria. Sealer 26 induced more biomineralization than Sealer Plus and Dia-ProSeal.

Laboratory study of tissue repair of resin-based endodontic sealers in critical surgical defects

Filling materials should be restricted to the root canal space. However, sometimes it is impossible to control the apical extrusion, in this case, the fate of the filling material and the result of the treatment will depend on its physicochemical properties and biocompatibility.

Antimicrobial Activity of Calcium Silicate-Based Dental Materials: A Literature Review

Endodontic biomaterials have significantly improved dental treatment techniques in several aspects now that they can be used for vital pulp treatments, as temporary intracanal medication, in definitive fillings, in apical surgeries, and for regenerative procedures. Calcium silicate-based cement is a class of dental material that is used in endodontics in direct contact with the dental structures, connective tissue, and bone. Because the material interacts with biological tissues and stimulates biomineralization processes, its properties are of major importance. The main challenge in endodontic treatments is the elimination of biofilms that are present in the root canal system anatomical complexities, as it remains even after chemical-mechanical preparation and disinfection procedures. Thus, an additional challenge for these biomaterials is to exert antimicrobial activity while maintaining their biological properties in parallel. This article reviews the literature for studies considering the antimicrobial properties of calcium silicate-based dental biomaterials used in endodontic practice. Considering the reviewed studies, it can be affirmed that the reduced antimicrobial effect exhibited by calcium silicate-based endodontic materials clearly emphasizes that all clinical procedures prior to their use must be carefully performed. Future studies for the evaluation of these materials, and especially newly proposed materials, under poly-microbial biofilms associated with endodontic diseases will be necessary.

Short-Term Antibacterial Efficacy of Three Bioceramic Root Canal Sealers Against Enterococcus Faecalis Biofilms

Objectives

The aim of the study was to evaluate the antimicrobial efficacy of three bioceramic root canal sealers against Enterococcus faecalis (E. faecalis) biofilm.

Material and methods

E. faecalis bacterial suspension was grown on filter paper discs on agar plates. After the incubation period, the discs were covered with four different root canal sealers: 1) Premixing bioceramic root canal sealer (TotalFill BC Sealer); 2) Dual component bioceramic sealer (BioRoot RCS); 3) Mineral trioxide agreggate based sealer (MTA Fillapex); 4) Epoxy resin-based selar (AH Plus). After contact time of 60 minutes, the sealers were removed, and the discs were transferred into sterile tubes containing phosphate buffered saline. After serial dilutions, the aliquots of the suspension were cultivated for 24 hours. After the incubation period, the colony forming units (CFUs) were counted.

Results

There were no significant differences in antibacterial efficacy between the Total Fill BC Sealer and the AH Plus sealer (p=0.386). Both sealers showed better antibacterial efficacy compared to the BioRoot RCS and the MTA Fillapex (p<0.001).

Conclusion

The Total Fill BC Sealer and AH Plus had better antibacterial efficacy than the BioRoot RCS and the MTA Fillapex sealers.

Physico-chemical and antimicrobial properties and the shelf life of experimental endodontic sealers containing metal methacrylates

The objective of this study was to evaluate the physico-chemical and antimicrobial properties of a dual polymerization experimental endodontic sealer (E) and experimental sealers containing dibutyltin methacrylate (Sn²⁺) (ETs) or calcium methacrylate (Ca²⁺) (ECs). The pH and ion release levels of the sealers were measured. The dimensional stability was evaluated in accordance with ISO 6876. Biofilm growth inhibition was evaluated using confocal laser scanning microscopy (CLSM). Biofilm viability analysis was performed using the SYTO 9 technique. The shelf life was evaluated through the degree of conversion and film thickness tests after the sealers had been stored for different periods of time. For statistical analysis, ANOVA and Tukey's post hoc test were used, with a significance level of 5%. ETs revealed better anti-biofilm potential after 15 days than that of the controls. The degree of conversion was reduced after the shelf-life period. The addition of calcium and dibutyltin methacrylate improved the anti-biofilm properties of the experimental endodontic sealer without impairing their physico-chemical properties.

Physical Properties, Antimicrobial Activity and In Vivo Tissue Response to Apexit Plus

We investigated the physical properties, antimicrobial activity, and tissue reaction to Apexit Plus in comparison to Sealapex. Flow, radiopacity, setting time, and solubility were evaluated in each material. The antimicrobial activity against Enterococcus faecalis was performed. Polyethylene tubes containing Apexit Plus or Sealapex, and without material (control group) were implanted into the subcutaneous tissue of rats. At 7, 15, 30, and 60 days of implantation, the specimens were paraffin-embedded and the number of inflammatory cells (ICs) and the amount of birefringent collagen (BC) were quantified. The von Kossa reaction followed by immunohistochemistry for detection of alkaline phosphatase (ALP) was also performed. Statistical analysis was performed with ANOVA and Tukey test (p ≤ 0.05). The flow value of Apexit Plus was greater than Sealapex, whereas the radiopacity (3.44 mm Al) was lower than Sealapex (6.82 mm Al). Apexit Plus showed lower solubility and shorter initial and final setting (p < 0.0001), whereas the antimicrobial activity was significantly greater than Sealapex. Although the number of ICs was higher in Apexit Plus (p = 0.0009) at 7 days, no significant difference was detected between Apexit Plus and Sealapex at 15, 30, and 60 days. All groups showed higher values for BC in the capsules over time. ALP-immunolabelled cells were observed, mainly around von Kossa-positive structures, either in the capsules of Apexit Plus or Sealapex. Therefore, our results revealed that Apexit Plus exhibited a greater effectiveness against Enterococcus faecalis and better physical properties than Sealapex, except for the radiopacity. In vivo findings indicate that Apexit Plus is biocompatible and presents potential bioactivity in the subcutaneous tissue.

Antimicrobial Efficacy of Different Endodontic Sealers against Enterococcus faecalis: An In vitro Study

Objective

The aim of this in vitro study is to compare the antimicrobial efficacy of four different endodontic sealers against Enterococcus faecalis.

Material and Method:

Four different endodontic sealers, namely, resin based (AH Plus), zinc oxide-eugenol based (Tubliseal), calcium hydroxide based (Sealapex), and mineral trioxide aggregate (MTA Fillapex) based were tested for their antimicrobial efficacy against E. faecalis using agar diffusion method. Four wells were made by the removal of agar at equidistant points and filled with freshly mixed respective root canal sealers and were inoculated with E. faecalis. All the three plates were incubated for a period of 72 h at 37°C under aerobic conditions. The diameter of inhibition zones was measured at 24, 48, and 72 h time intervals. Data obtained were statistically analyzed using one-way analysis of variance and unpaired t-test.

Results:

All the tested sealers showed some bacterial growth inhibition of E. faecalis. Their efficacy in descending order of antibacterial activity was as follows: Sealapex > AH Plus > Tubliseal > MTA Fillapex. The efficacy of the root canal sealers decreased marginally with increase in their duration of action.

Conclusion:

Antimicrobial efficacy of calcium hydroxide-based sealer was highest followed by resin-based sealer and was the least with MTA based sealer.

Avaliação da dissociação iônica do hidróxido de cálcio associado ao Aloe vera como veículo

Resumo Introdução O hidróxido de cálcio é considerado uma medicação intracanal padrão ouro e diferentes substâncias podem ser empregadas como veículo para melhorar suas propriedades. O Aloe vera é um fitoterápico popularmente conhecido por babosa e que se destaca pela sua capacidade imunorreguladora, antimicrobiana, cicatrizante e pela biocompatibilidade celular. Objetivo Avaliar a dissociação iônica do hidróxido de cálcio, tendo o Aloe vera como veículo. Material e método O extrato de Aloe vera foi obtido diretamente da folha, submetido à filtração e armazenado em tubo Falcon estéril. Foram preparados dois grupos de medicação intracanal: o grupo controle, com hidróxido de cálcio e soro fisiológico, e o grupo experimental, com hidróxido de cálcio e Aloe vera como veículo. Resultado Não foi verificada uma diferença estatisticamente significativa entre as médias de liberação de cálcio dos grupos (p=0,944). Quando comparados os valores de forma pareada, considerando as diferentes avaliações ao longo do tempo, foi identificada uma diferença estatisticamente significativa (p=0,015) para o grupo experimental, de modo que os valores médios da liberação de cálcio foram superiores até o 21º dia do estudo. Conclusão O hidróxido de cálcio, quando associado ao Aloe vera, apresentou maior dissociação iônica que quando utilizado com água destilada. Tal resultado, associado às propriedades inerentes deste fitoterápico, sugerem que a pasta de hidróxido de cálcio e Aloe vera pode ser uma alternativa viável e promissora como medicação intracanal, e melhorar o reparo apical e periapical.

Sub-lethal doses of photodynamic therapy affect biofilm formation ability and metabolic activity of Enterococcus faecalis

BACKGROUND

During photodynamic therapy (PDT) in the treatment of a primary endodontic infection, it is extremely likely that microorganisms would be exposed to sub-lethal doses of PDT (sPDT). Although sPDT cannot kill microorganisms, it can considerably influence microbial virulence. This study was conducted to characterize the effect of sPDT using toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) on biofilm formation ability and metabolic activity of Enterococcus faecalis.

METHODS

The antimetabolic and antibiofilm potential of ICG-, TBO-, and MB-sPDT against E. faecalis was analyzed at sub-lethal doses (1/2-1/64 minimum inhibitory concentration) using the XTT reduction assay, crystal violet assay, and scanning electron microscopy.

RESULTS

Higher doses of sPDT adversely affected biofilm formation ability and metabolic activity. ICG-, TBO-, and MB-PDT at a maximum sub-lethal dose markedly reduced the formation of biofilm up to 42.8%, 22.6%, and 19.5%, respectively. ICG-, TBO-, and MB-sPDT showed a marked reduction in bacterial metabolic activity by 98%, 94%, and 82%, respectively. ICG-PDT showed a stronger inhibitory effect on biofilm formation in E. faecalis than MB- and TBO-PDT at sub-lethal levels. Interestingly, a gradual increase in metabolic activity and biofilm formation upon exposure to a lower dose of test sPDT were observed.

CONCLUSION

sPDT showed dual effect on biofilm formation ability and metabolic activity of E. faecalis. High doses revealed antimetabolic and antibiofilm potential activity, whereas lower doses had conflicting results. Hence, when PDT is prescribed in clinical settings, the dose of PDT used in vivo should be taken into consideration.