Lysozyme antimicrobial activity against Enterococcus Faecalis - a pilot study / Atividade antimicrobiana da lisozima contra Enterococcus Faecalis - um estudo piloto

O preparo químico-mecânico (PQM) do sistema de canais radiculares é essencial para eliminar tecidos infectados e garantir uma desinfecção adequada. O Hidróxido de Cálcio (HC) combinado com o propilenoglicol é frequentemente utilizado como uma pasta intracanal para desinfecção e medicação intraoperatória. No entanto, algumas bactérias, como o Enterococcus faecalis (E. faecalis), podem resistir aos efeitos do hidróxido de cálcio. O Ultracal® é uma medicação de hidróxido de cálcio de alta qualidade e radiopaco usado em procedimentos endodônticos. Já a lisozima é uma substância com propriedades antimicrobianas encontrada em várias partes do corpo humano e tem sido estudada como uma opção promissora para o tratamento de infecções endodônticas. O objetivo do presente estudo foi avaliar e comparar a atividade antimicrobiana do HC com propilenoglicol, Ultracal® e Lisozima contra E. faecalis. Foram realizadas escavações em placas de petri contaminadas com E. faecalis. Após, foi adicionado as medicações intracanais e as placas foram levadas a estufa a 37°C em aerobiose. Os halos de inibição formados foram medidos em 2, 4 e 7 dias. HC apresentou halos de inibição maiores quando comparado as outras medicações e com maior crescimento com o passar dos dias. A lisozima apresentou apenas ação nas primeiras 48 horas, perdendo seu efeito após esse período. Ambas as medicações com hidróxido de cálcio apresentaram valores crescentes. Baseado nos resultados obtidos, conclui-se que as medicações a base de hidróxido de cálcio demonstraram melhor ação contra E. faecalis em ação direta.

The chemical-mechanical preparation (CMP) of root canals system is essential to eliminate infected tissues and ensure adequate disinfection. Calcium hydroxide (CH) combined with propylene glycol is often used as an intracanal medication for intraoperative disinfection and medication. However, some bacteria, such as Enterococcus faecalis (E. faecalis), may resist the effects of calcium hydroxide. Ultracal® is a high-quality radiopaque calcium hydroxide medication used in endodontic procedures. Lysozyme, on the other hand, is a substance with antimicrobial properties found in various parts of the human body and has been studied as a promising option for the treatment of endodontic infections. The aim of this study was to evaluate and compare the antimicrobial activity of CH with propylene glycol, Ultracal®, and Lysozyme against E. faecalis. Petri plates contaminated with E. faecalis were excavated, intracanal medications were added, and the plates were incubated at 37°C in aerobic conditions. The inhibition halos formed were measured at 2, 4, and 7 days. CH showed larger inhibition halos compared to the other medications and exhibited increased growth over the days. Lysozyme showed activity only in the first 48 hours, losing its effect after this period. Both medications with calcium hydroxide showed increasing values. Based on the results obtained, it is concluded that calcium hydroxide-based medications demonstrated better action against E. faecalis in direct action.

In-vitro and In-silico evaluation of antimicrobial and antibiofilm effect of Neem oil and Calcium hydroxide nanoparticles against Mutans Streptococci and Enterococcus faecalis isolated from endodontic infections.

Different Streptococcal species including Streptococcus mutans, Streptococcus sobrinus and Enterococcus faecalis are commonly isolated in root canal infections including refractory, recurrent, and persistent cases. Calcium hydroxide (Ca (OH)2) has been widely used in endodontics as an intracanal medicament. However, using new antimicrobial herbal alternatives offers promising potentials which can be additionally enhanced by using nanoparticles (NPs). In this study, we evaluate the antimicrobial efficacy and antibiofilm effect of Neem oil including its NPs preparations and we compare the effect of conventional Ca (OH)2 to Ca (OH)2 NPs using standard disc diffusion method and quantitative microtitre dish biofilm formation assay against common pathogens isolated from root canal samples. Molecular docking was used to test the binding of 10 Streptococcal macromolecules to 5 candidate neem active constituents. Neem NPs 0.125 mg/ml showed better antibacterial effect than both Neem 15 mg/ml and Neem 0.15 mg/ml. Ca (OH)2 NPs 0.125 mg/ml also showed better antibacterial effect than each of Ca (OH)2 10 mg/ml and Ca (OH)2 0.1 mg/ml. Best biofilm mass inhibition was achieved by Neem oil 0.15 mg/ml at 74.55% ( IQ: 67.36-87.65) and Neem NPs 0.0125 mg/ml at 59.33% (IQ: 51--75.27). For Ca (OH)2, the best biofilm mass inhibition was observed with Ca (OH)2 NPs 0.125 mg/ml at 54.7% (IQ: 42.37- 77.25). Both neem oil and neem NPs show promising antibacterial and antibiofilm potential against Mutans Streptococci group at low concentrations and hence are good candidates for use as endodontic medications. In silico analysis shows that both Sitosterol and Gedunin appear to be important active constituents of neem and possible drug candidates. Additionally, Ca (OH)2 NPs showed significantly higher antimicrobial effect against Mutans streptococci group than conventional Ca (OH)2 preparations.

Antibiofilm efficacy of a calcium silicate-based intracanal medicament against Fusobacterium nucleatum strains.

This study evaluated the antibiofilm efficacy of a calcium silicate-based intracanal medicament (Bio-C Temp) against Fusobacterium nucleatum (F. nucleatum). Dentin slices (n = 88) were inoculated with F. nucleatum biofilms and divided into experimental groups (n = 24 each) treated with Bio-C Temp, triple antibiotic paste (TAP), or Ca(OH)2 for 1 or 2 weeks. Untreated dentin slices exposed to saline served as a positive control, while sterile dentin slices incubated anaerobically served as a negative control. Bacterial viability was assessed using confocal laser scanning microscopy after staining with LIVE/DEAD® BacLight™ dye. Samples treated with TAP demonstrated the highest percentage of dead bacteria (95%). The antibiofilm effect of TAP and Bio-C Temp significantly increased from Week 1 to Week 2. At Week 2, samples treated with Bio-C Temp showed a significantly higher percentage of dead bacteria (75.25%) than those treated with Ca(OH)2 (58.65%). TAP showed superior efficacy against F. nucleatum biofilms. After an application time of 2 weeks, the antibiofilm efficacy of Bio-C Temp was superior to that of Ca(OH)2.

Potential application of a combined extract of Channa striata and calcium hydroxide for inhibiting lymphocytes and interleukin-1ß cells in the asymptomatic irreversible pulpitis of Wistar rats (Rattus norvegicus).

Aim: This study aimed to evaluate the effectiveness of combining Channa striata extract with calcium hydroxide (Ca(OH)2) in reducing lymphocyte counts and interleukin (IL)-1ß levels in inflamed pulp teeth. Materials and Methods: A laboratory experimental setup with a posttest control group (CG) design was employed. Thirty-two rat incisor teeth were divided into four groups: a positive CG (100% Ca(OH)2), treatment 1 (25% C. striata extract + 75% Ca(OH)2), treatment 2 (50% C. striata extract + 50% Ca(OH)2), and treatment 3 (75% C. striata extract + 25% Ca(OH)2). These test materials were applied to Class 1 cavities extending to the pulp roof, with samples collected on days 1, 3, 5, and 7. Data were analyzed using analysis of variance and post hoc least significant difference tests. Results: In all the groups, the highest levels of lymphocytes and IL-1ß were observed on day 3, followed by a decline on days 5 and 7. The combination of C. striata extract with Ca(OH)2 significantly reduced inflammatory markers, particularly lymphocyte and IL-1ß levels. Conclusion: The extract of C. striata holds significant potential as an innovative therapeutic approach for managing inflamed dental pulp.

The Efficacy of Aloe vera Against Enterococcus faecalis as an Intracanal Medicament: A Systematic Review and Meta-Analysis.

Calcium hydroxide (CaOH) is commonly used as an intracanal medicament due to its antimicrobial properties; its antibacterial property depends on the release of hydroxyl ions. By analyzing experimental in vitro studies related to the research question, many studies carried out bacterial inoculation on extracted human teeth or laboratory Petri dishes. This review article seeks to assess the antimicrobial efficacy of Aloe vera (AV) against Enterococcus faecalis in comparison to CaOH as an intracanal medicament. After being retrieved from databases such as PubMed, Scopus, the Cochrane Library, and EBSCOhost, publications from 2013 to 2024 were screened against our inclusion criteria. As a result, seven papers were included in the systematic review and four in the meta-analysis. Using a meta-analysis (Stata software version 16.0, StataCorp LLC, College Station, TX) to compare colony-forming units (CFUs) formed by CaOH and AV, forest plots were created to record the specimen size, mean, and standard deviation value of the outcome in CFU, at 95% confidence intervals. AV exhibits bactericidal qualities that are equal to or comparable to those of CaOH. AV displayed a nonsignificantly reduced CFU count than CaOH in a meta-analysis (p > 0.05). In summary, AV exhibits antibacterial/antimicrobial capabilities against E. faecalis that are equal to or comparable to CaOH.

Rheological properties and handling characteristics of four injectable calcium hydroxide pastes.

The aim of this study was to investigate the rheological properties and handling characteristics of four brands of injectable calcium hydroxide pastes (Calcipex II, CleaniCal, DiaPaste, Well-Paste). Shear viscosity was measured with a rotational rheometer. A universal mechanics analyzer assembled in the laboratory was used to quantify the force for extrusion and extruded weight of the materials. The apical pressure during injection into an artificial root canal was measured using a pressure sensor. All materials exhibited pseudoplastic behavior. The force for extrusion was highest for DiaPaste, and lowest for CleaniCal, while the extruded weight was lowest for DiaPaste and highest for CleaniCal (p<0.05), indicating a need for caution when using CleaniCal. However, the pressure generated at the apex may vary depending on the shape, and taper of the needle tip, as well as the viscosity of the materials.

Effectiveness of mechanical vs. chemomechanical methods in removing intracanal calcium hydroxide medication: a randomised trial.

OBJECTIVE: To compare the mechanical and chemomechanical methods for removing calcium hydroxide medication from the root canal system. METHODS: The triple-blind, randomised clinical trial was conducted at the Department of Operative Dentistry and Endodontics, School of Dentistry, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan, from December 16, 2022, to June 15, 2023, and comprised patients having necrotic teeth and chronic apical pathosis. They were randomised into groups A and B. On the initial visit, after access opening and chemomechanical preparation, calcium hydroxide paste was placed as an intracanal medication in both groups. the patients were recalled after two weeks. In Group A, calcium hydroxide was removed from the canals using a rotary master apical file, while in Group B, an endoactivator was used to sonically agitate the endodontic irrigant. Verification of placement was done by using a periapical radiograph. Data was analysed using SPSS 26. RESULTS: Of the 98 individuals assessed initially, 60(61.22%) were included; 34(57%) females and 26(43%) males with age ranging from 19 to 57 years. There were 27(45%) incisors, 22(36.7%) premolars and 11(18.3%) canines. There were 30(50%) patients in each of the 2 groups. The intergroup difference was not statistically significant (p=0.43). Tooth arch did not significantly correlate with the removal method (p=0.79). CONCLUSIONS: Both methods were found to be equally effective in removing water-based calcium hydroxide medication from the endodontic system. Clinical Trial Number: NCT05744661.

Investigating the potential of waste oyster shell as a sustainable bio-mordant in natural dyeing.

The use of natural bioresources in textile dyeing has attracted significant research interest due to their environmentally friendly and low-toxic nature. This study investigated the utilization of waste oyster shell (WOS) as a bio-mordant combined with sappan wood extract to dye silk fabrics using pre-, meta-, and post-mordanting method. The crystal structure of CaCO3 derived from WOS and their impact on color properties, color strength and color fastness were analyzed. The dyed fabrics displayed a range of shades from light pink to deep red and brown. FTIR analysis confirmed chemical interactions among dye, silk, and WOS mordants. Notably, silk treated with WOS at 800 °C as a pre-mordant showed color strength approximately 2.6 times higher than that of un-mordanted samples. Additionally, bio-mordanted samples exhibited improved color fastness compared to untreated ones (rating 2), with pre-mordanting offering the highest resistance to washing (rating 4-5). These findings shed light on the potential of waste oyster shell as an effective, sustainable alternative to conventional metal mordants in textile dyeing. This study not only support the utilization of waste but also enhances environmental and resource efficiency of the dyeing process.

Exploring topological indices and entropy measure via rational curve fitting models for calcium hydroxide network.

This work uses rational curve fitting models to investigate the complex link between topological indices and entropy metrics in calcium hydroxide ( C a ( O H ) 2 ) networks. Entropy measurements shed light on the complexity and disorder of these networks, whereas topological indices are essential instruments for comprehending the structural characteristics of chemical substances. Our goal is to find new patterns and connections by merging these two fields, improving materials science's prediction capacity. We calculate many topological indices, such as the Randic, Balaban, and Zagreb indices, and examine the relationship between them and entropy measurements obtained from ( C a ( O H ) 2 ) structural arrangement.

Antimicrobial Effects of Formulations of Various Nanoparticles and Calcium Hydroxide as Intra-canal Medications Against Enterococcus faecalis: A Systematic Review.

The combination of calcium hydroxide (Ca(OH)2) and nanoparticles (NPs) offers a promising approach to improving the efficacy of intra-canal treatments. Their synergistic effects can enhance antimicrobial action, improve penetration, and promote better healing outcomes in endodontic therapy. This review article examines the antimicrobial efficacy of various nanoparticles combined with Ca(OH)2 against Enterococcus faecalis (E. faecalis) compared to Ca(OH)2 alone as an intra-canal medicament. The analysis is based on in vitro studies involving bacterial inoculation on human-extracted teeth. Publications from 2013 to 2024 were retrieved from databases such as PubMed, Scopus, the Cochrane Library, and EBSCOhost and were screened according to specific inclusion criteria. Ultimately, 11 studies met these criteria for inclusion in the systematic review. A meta-analysis was not conducted due to the heterogeneity of the studies regarding the duration of medicament application, analytical methods, and result interpretations. The results indicate that NPs combined with calcium hydroxide exhibit superior bactericidal effects compared to Ca(OH)2 alone, suggesting their potential as effective intra-canal medicaments. Thus, a systematic review concluded that nanoparticle-based Ca(OH)2 intra-canal medicaments exhibit superior antibacterial/antimicrobial capabilities against E. faecalis when compared to Ca(OH)2individually.

Management Strategies for Immature Teeth with Pulp Necrosis: An Umbrella Review of Systematic Reviews.

Introduction: This review evaluates the effectiveness of treatment modalities for immature teeth with pulp necrosis, focusing on calcium hydroxide (CH) and mineral trioxide aggregate (MTA) apexification, as well as regenerative endodontic treatments (RETs). Recent advancements and clinical outcomes are highlighted. Materials and Methods: A comprehensive search of MEDLINE (PubMed), Embase, Cochrane Library, Scopus, and grey literature was conducted from inception to July 2024. Systematic reviews and meta-analyses (SR/MAs) assessing apexification and RET outcomes in immature teeth with pulp necrosis were included. Studies were selected based on predefined criteria, and data on study design, interventions, and outcomes were extracted. Methodological quality was evaluated using the AMSTAR-2 tool. Results: 31 SR/MAs were included. The quality ranged from critically low to low, except one rated as high. MTA apexification was more effective than CH for faster apical barrier formation, though overall success rates were similar. MTA is preferred for its efficiency, but standardized protocols are needed, and tooth discoloration was noted as a potential complication. RET generally outperforms apexification in root maturation, with platelet concentrates like platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) showing promising results; PRP was associated with greater root length, while PRF showed superior apical healing. Variability in RET outcomes was noted due to the lack of standardized protocols. Comparative studies of RET versus apexification showed no significant differences in survival or overall success rates. RET often provides better apical closure and root development, though results vary. Both approaches are viable, but more research with standardized protocols and larger samples is needed to establish definitive clinical advantages. Conclusions: MTA apexification and RET are viable alternatives to CH apexification, with RET showing greater potential for root development and apical healing. Future research should focus on developing standardized protocols and uniform RET guidelines, and evaluating long-term outcomes to establish efficacy and safety.

Antimicrobial and anti-endotoxin activity of N-acetylcysteine, calcium hydroxide and their combination against Enterococcus faecalis, Escherichia coli and lipopolysaccharides.

Background: The management of endodontic infections is a complex challenge, mainly due to the involvement of diverse microorganisms and their by-products. This study aimed to evaluate the efficacy of N-acetylcysteine (NAC), calcium hydroxide (Ca(OH)2), and their combined application as intracanal medications in combating Enterococcus faecalis, Escherichia coli, and lipopolysaccharides (LPS) from E. coli. Methods: A total of 60 single-rooted human teeth were carefully selected and divided into six groups. These tooth canals were deliberately exposed to E. faecalis (ATCC 29212) and E. coli (ATCC 25922) to induce biofilm formation. Subsequently, the specimens were treated with NAC, Ca(OH)2, or a combination of both substances. Three samples of the root canals were collected at three moments: the first sample (S1) was to confirm the initial contamination, the second sample (S2) was immediately post-instrumentation, and the third sample (S3) was collected after the use of the intracanal medication. The antimicrobial efficacy of these intracanal medications was assessed by enumerating colony-forming units per milliliter (CFU/mL). In addition to this, the kinetic chromogenic Limulus Amebocyte Lysate (LAL) assay by Lonza was used to quantify LPS from E. coli. Data tested for normality; then, Kruskal-Wallis and Friedman tests were used, and Dunn's for multiple comparisons. Results: The findings of this study showed significant reductions in the microbial load of E. faecalis and E. coli by S3. Notably, there were no statistically significant differences among the treatment groups concerning these microorganisms. However, it was observed that only the combination of NAC and Ca(OH)2 led to a noteworthy decrease in the quantity of E. coli's LPS after 7-days, demonstrating a statistically significant difference from the other treatment groups. NAC + Ca(OH)2 combination, applied for a duration of 7-days, proved to be more suitable in reducing the presence of E. faecalis, E. coli, and LPS from E. coli within the context of endodontic infections.

In Vitro Evaluation of Sodium Hypochlorite, Chlorhexidine, Propolis, and Calcium Hydroxide Effect on Lipoteichoic-Acid-Induced Proinflammatory Cytokines Production.

This study aimed to evaluate the effects of sodium hypochlorite (NaOCl), chlorhexidine (CHX), and the glycolic extract of propolis (GEP) as endodontic irrigants and of calcium hydroxide [Ca(OH)2], CHX, or Ca(OH)2 + CHX as intracanal medications on the capacity of the lipoteichoic acid (LTA) of Enterococcus faecalis in macrophages' proinflammatory cytokines production. Freshly extracted 108 human single-rooted teeth were used in this study. The LTA of E. faecalis was standardized in double-distilled pyrogen-free water (250 µg/mL) and inoculated into the specimens subdivided into nine subgroups (n = 12). Cultures of murine macrophages (RAW 264.7) were treated with 30 µL of each sample collected from root canals and incubated (37 °C, 5% CO2) for 24 h. Lastly, anti-TNF-α, anti-IL-6, anti-IP-10, anti-MIP-1α, anti-G-CSF, and anti-IL-1ß DuoSet kits were used to perform an ELISA assay. Data were analyzed using one-way ANOVA and Tukey test (p ≥ 0.05). It was found that 1% NaOCl was the most effective irrigant in reducing the capacity of LTA in cytokines production, followed by 12% GEP and 2% CHX, respectively. Ca(OH)2 + CHX presented the best results when associated with NaOCl or GEP. Thus, NaOCl or GEP associated with Ca(OH)2 + CHX were effective in reducing the capacity of LTA in different macrophages pro-inflammatory cytokines production.

The Impact of Silver Nanoparticles' Size on Biofilm Eradication.

INTRODUCTION: Efficient intracanal disinfection is required for a successful regenerative endodontic treatment. Thus, this study aimed to identify the silver nanoparticles' (NPs) size (AgNPs) with the highest antibiofilm efficacy when mixed with calcium hydroxide [Ca(OH)2] to eradicate an in vitro endodontic biofilm. METHODS: The various sizes of AgNPs and mixtures were characterized by scanning electron microscopy, transmission electron microscopy, and ultraviolet-visible spectroscopy. A total of 168 dentin root segments were prepared, sterilized, and inoculated for 3 weeks with Actinomyces naeslundii and Fusobacterium nucleatum. Samples were randomly allocated to 4 experimental groups (n = 28/group): 2 nm AgNPs + 35% Ca(OH)2, 5 nm AgNPs + 35% Ca(OH)2, 10 nm AgNPs + 35% Ca(OH)2, and 35% Ca(OH)2 alone. Samples exposed to saline and triple antibiotic paste (TAP) acted as negative and positive control groups, respectively. After 1 and 2 weeks, samples were stained with LIVE/DEAD BacLight dye and examined under a confocal laser scanning microscope to determine the proportion of dead bacteria. RESULTS: The characterization procedure revealed a spherical NP's structure with minor aggregations. Except for Ca(OH)2 group, all groups had significantly higher antibiofilm efficacy at 2 weeks. Both the 10 nm mixture (99.5%) and TAP (99.2%) exhibited the highest antibiofilm efficacy at 2 weeks and were not significantly different from one another (P > .05). No significant difference was noted between the 2 and 5 nm mixtures at 1 week (81% and 84%) and 2 weeks (89% and 91%). CONCLUSION: The 10 nm AgNPs (0.02%) + 35% Ca(OH)2 mixture exhibited the highest antibiofilm efficacy at 2 weeks compared to all other mixtures at both observation periods. Interestingly, the 10 nm mixture performed similarly to TAP at 2 weeks. Excluding Ca(OH)2 group, longer application significantly improved the antibiofilm efficacy of all tested medicaments. CLINICAL RELEVANCE: The 10 nm AgNPs + 35% Ca(OH)2 mixture revealed promising results as an intracanal medicament in the regenerative endodontic treatment protocol.

Removal mechanism of phosphorus in water by calcium hydroxide modified copper tailings.

With the development of industry and agriculture, eutrophication caused by increasing amounts of phosphorus in the environment has attracted people's attention. On the other hand, copper tailings (CT) is a kind of solid waste with large quantity, large area, and easy to cause groundwater and soil pollution. CT is also a potential resource because of its large specific surface area. CT is intended to be used as an adsorbent for removal phosphate in water, but trace heavy metals and a small amount of phosphate in CT may bring negative effects. Calcium hydroxide (Ca(OH)2) was used to modify CT (CCT), hoping to fix the heavy metals and phosphate in CT at the same time. It was found that the removal capacity of CCT was significantly higher than that of CT. The process of phosphate removal by CCT involves electrostatic sorption and surface precipitation, and there is a synergistic effect between CT and Ca(OH)2. The phosphate removal rate of CCT-0.4 increased with the increase of pH value under alkaline conditions. The XRD patterns of phosphate sorption by CCT mean that Ca3(PO4)2, Ca5(PO4)3(OH) and AlPO4 exist in CCT after phosphate removal, indicating that surface precipitation occurs during the removal process. In summary, the removal mechanism of phosphate by CCT is mainly electrostatic attraction and surface precipitation.

The Effect of Intracanal Medicaments on the Healing of Apical Periodontitis.

BACKGROUND: Apical periodontitis is a prevalent inflammatory condition affecting the tissues surrounding the root apex of a tooth. The selection of appropriate intracanal medicaments for its management remains a topic of ongoing research. This study aimed to investigate the effect of calcium hydroxide and triple antibiotic paste on the healing of apical periodontitis. METHODS: A total of 304 teeth from 215 patients with apical periodontitis were included in this observational study. Patients were randomly assigned to three groups: Group A (calcium hydroxide), Group B (triple antibiotic paste), and Group C (control). Baseline characteristics were recorded, and follow-up assessments were conducted at three, six, and 12 months. Parameters such as reduction in apical radiolucency, presence of periapical healing, bleeding on probing (BOP) percentage, clinical attachment level (CAL), and periodontal depth were evaluated. RESULTS: At baseline, the three groups exhibited similar distributions of apical periodontitis parameters. Over the 12-month follow-up, Group A and Group B demonstrated a significant reduction in apical radiolucency compared to Group C (p < 0.05). The presence of periapical healing was more frequent in Group A (85%) and Group B (80%) compared to Group C (60%). Group A showed the lowest mean BOP percentage (15.2 ± 3.5), followed by Group B (18.6 ± 4.2) and Group C (22.1 ± 4.8). Similarly, Group A demonstrated the highest mean CAL (5.8 ± 0.9 mm) and the lowest mean periodontal depth (3.2 ± 0.6 mm). Group B exhibited intermediate values for CAL (5.2 ± 1.1 mm) and periodontal depth (3.6 ± 0.8 mm). CONCLUSION: In this study, both calcium hydroxide and triple antibiotic paste demonstrated potential therapeutic effects in promoting healing and reducing apical radiolucency compared to the control group. Calcium hydroxide exhibited the most favorable outcomes, with a higher presence of periapical healing, lower BOP percentage, and superior CAL and periodontal depth measurements. These findings contribute to the understanding of intracanal medicaments' effectiveness in apical periodontitis management.

Effect of non-thermal acidic and alkaline modifications on the structural, pasting, rheological, and functional properties of cassava (Manihot esculenta) starch.

This study aimed to investigate the effects of acid or alkali modification of isolated cassava starch (ICS) on its physicochemical properties. Acetic acid concentrations of 5%, 10%, and 20% v/v (0.87, 1.73, and 3.46 M, respectively) and calcium hydroxide concentrations of 0.15%, 0.20%, and 0.30% w/w (0.02, 0.025, and 0.04 M, respectively) were tested independently and compared with untreated isolated starch. The scanning electron microscope (SEM) shows starches with polyhedral and semispherical shapes; these modifications do not change the surface of the starch granules. Nanocrystals with orthorhombic crystal structure were extracted from ICS. Transmission electron microscopy (TEM) shows crystallites with a size (two-dimensional) of 20 ± 5 nm in length and 10 ± 2 nm in width and reveals that this starch contains nanocrystals with orthorhombic crystal structure. The X-ray patterns show that these nanocrystals are unaffected by acidic or alkaline treatments. The Ca+2 and CH3COO- ions do not interact with these nanocrystals. The alkaline treatment only affects the gelatinization temperature at a Ca(OH)2 concentration of 0.30%. Low concentrations of acidic and alkaline treatments affect the ability of cassava starch to absorb water and reduce the peak and final viscosity. The infrared spectra show that the modifications lead to C-H and C═C bond formations. ICS-B 0.30 can modify the amorphous regions of the starch, and the acid treatment leads to acetylation, which was confirmed by the presence of an IR band at 1740 cm-1.

Metformin reduced the alkaline resistance of Enterococcus faecalis against calcium hydroxide via Man-PTS EII: in vitro and in vivo studies.

OBJECTIVES: The mannose phosphotransferase system (Man-PTS) plays crucial roles in the adaptive metabolic activity of Enterococcus faecalis (E. faecalis) in adverse environments. The aim of this study was to evaluate the role of Man-PTS in the alkaline resistance of E. faecalis against calcium hydroxide (CH) and the effect of metformin (Met) on the alkaline resistance of E. faecalis to CH. MATERIALS AND METHODS: The regulatory role of Man-PTS EII in the alkaline resistance of E. faecalis was firstly investigated using a wild-type highly alkaline-resistant E. faecalis XS 003, standard ATCC 29212 and Man-PTS EIID gene deficient (△mptD) and overexpressing (+mptD) strains of E. faecalis. RNA sequencing of Met-treated E. faecalis was performed to further validate the effect of Met on Man-PTS. The effect of Met on CH resistance of E. faecalis was verified by evaluating the survival, membrane potential and permeability, intracellular pH and ATP, and the expression of Man-PTS EII and membrane transporter-related genes of E. faecalis. The effect of Met on the ability of CH to remove E. faecalis biofilm on the dentin surface was also tested. The in vivo therapeutic effect of Met plus CH (CHM) was further investigated in a rat apical periodontitis model induced by E. faecalis XS 003. RESULTS: Man-PTS EII significantly promoted the survival ability of E. faecalis in CH and enhanced its resistance to CH. The inhibition of Man-PTS EII by Met resulted in reduced alkaline resistance of E. faecalis in the presence of CH, while also enhancing the antimicrobial properties of CH against E. faecalis biofilm on dentin. Additionally, Met plus CH showed the synergistically promoted intra-canal E. faecalis infection control and healing of periapical lesion in rats. CONCLUSIONS: Met could significantly reduce the alkaline resistance of E. faecalis against CH through the modulation of Man-PTS EII, and improved the antibacterial effect of CH against E. faecalis infection both in vitro and in vivo. CLINICAL RELEVANCE: Met could significantly enhance the ability of CH to control E. faecalis infection through reducing the alkaline resistance of E. faecalis.

Comparative evaluation of antimicrobial efficacy of chitosan nanoparticles and calcium hydroxide against endodontic biofilm of Enterococcus faecalis: An in vitro study.

Aim: The aim of the study was to assess and evaluate the antimicrobial effectiveness of chitosan nanoparticles (CSNPs) with calcium hydroxide in the elimination of Enterococcus faecalis. Materials and Methods: Using the broth microdilution method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of calcium hydroxide and CSNPs were measured. The antibiofilm effect of calcium hydroxide and CSNPs against E. faecalis biofilm was qualitatively analyzed using a crystal violet assay. A 7-day-old biofilms of E. faecalis grown on dentine discs were assigned to the following three groups (n = 11 dentine discs), normal saline (group I), calcium hydroxide (group II), and CSNPs (group III). Quantification of live and dead cells using confocal microscopy was done to evaluate the antibiofilm efficacy of the medicaments included in the study. Results: MIC of calcium hydroxide and CSNPs against E. faecalis was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. MBC of calcium hydroxide and CSNPs was observed at 2.5 mg/mL and 0.31 mg/mL, respectively. Using Crystal Violet (CV) assay, calcium hydroxide and CSNPs showed biofilm inhibition at concentrations of 2.5 mg/mL and 0.625 mg/mL, respectively. Confocal laser scanning microscopy analysis found that both calcium hydroxide and CSNPs showed a significant decrease in viable cells at their MBC values compared to the control group's normal saline. CSNPs showed a significantly lower percentage of live cells than calcium hydroxide (P < 0.05). Conclusion: The study results reveal that the antimicrobial efficacy of CSNPs is better than calcium hydroxide and normal saline against E. faecalis biofilm.

Cellulose nano-dispersions enhanced by ultrasound assisted chemical modification drive osteoblast proliferation and differentiation in PVA/HA bone tissue engineering scaffolds.

To develop a biological bone tissue scaffold with uniform pore size and good cell adhesion was both challenging and imperative. We prepared modified cellulose nanocrystals (CNCs) dispersants (K-PCNCs) by ultrasound-assisted alkylation modification. Subsequently, nano-hydroxyapatite (HC-K) was synthesized using K-PCNCs as a dispersant and composited with polyvinyl alcohol (PVA) to prepare the scaffold using the ice template method. The results showed that the water contact angle and degree of substitution (135°, 1.53) of the K-PCNCs were highest when the ultrasound power was 450 W and the time was 2 h. The dispersion of K-PCNCs prepared under this condition was optimal. SEM showed that the pore distribution of the composite scaffolds was more homogeneous than the PVA scaffold. The porosity, equilibrium swelling rate, and mechanical properties of the composite scaffolds increased and then decreased with the increase of HC-K content, and reached the maximum values (56.1 %, 807.7 %, and 0.085 ± 0.004 MPa) at 9 % (w/w) of HC-K content. Cell experiments confirmed scaffold has good cytocompatibility and mineralization capacity. The ALP activity reached 1.71 ± 0.25 (ALP activity/mg protein). In conclusion, the scaffolds we developed have good biocompatibility and mechanical properties and have great potential in promoting bone defect repair.