The impact of methylene blue photosensitizer, aPDT and a calcium hydroxide-based paste on the physicochemical and mechanical characteristics of root canal dentin and the bonding interface of fiberglass posts

PURPOSE

To investigate the influence of methylene blue (MB)-mediated antimicrobial photodynamic therapy (aPDT) and calcium hydroxide (CH) medication on the mechanical characteristics, degree of conversion (DC), quantification, and volume of gaps at the adhesive interface of glass fiber posts (GFPs) luted to distinct thirds of root canal dentin. Additionally, the microhardness (MH), elastic modulus (Eit), morphology, and chemical structure of the intraradicular dentin were assessed.

MATERIALS AND METHODS

6 experimental groups were formed by sorting 102 bovine incisors. Canals receiving deionized water irrigation as a negative control; canals receiving deionized water irrigation and filled with CH as a positive control; groups treated with CH + MB at 50 and 100 mg/L without irradiation; and groups treated with CH + MB at 50 and 100 mg/L irradiated by red laser for 60 s (660 nm; 100 mW; 6.5 J; 72 J/cm2). MH, Eit, and DC properties were evaluated for both the resin cement layer and root dentin substrate (n = 8). Volume and quantification of gaps at the bonding interface (n = 6), and dentin morphology and chemical content were investigated (n = 3). Data were analyzed using a repeated-measures 2-way ANOVA followed by Tukey post hoc analysis (α = 0.05).

RESULTS

The distinct intraradicular thirds and treatment with MB-mediated aPDT, whether activated or not, in combination with CH, had a significant impact on the mechanical characteristics of the root dentin. This effect was also observed in the MH, Eit, DC, quantification, and volume of gaps at the luting interface (P < .05). In general, a higher concentration of MB, whether activated by a red laser or not, led to lower values in the mechanical properties of the root dentin, as well as in MH, Eit, and DC at the adhesive interface (P < .05). Additionally, these groups exhibited higher values for quantification and volume of gaps at the luting substrate (P < .05). Scanning electron micrographs and energy dispersive X-ray spectra showed qualitative similarity among all groups, except for the negative experimental control group.

CONCLUSIONS

MB-mediated aPDT at 50 mg/L, in combination with CH, demonstrated favorable physico-chemical and mechanical characteristics in intraradicular dentin, along with satisfactory mechanical features and the adhesive interface integrity for GFPs at all intraradicular depths.

CLINICAL SIGNIFICANCE

MB-mediated aPDT at a concentration of 50 mg/L combined to CH medication represents a suitable choice for photosensitization in the context of intracanal disinfection following the biomechanical procedure and prior to luting of intraradicular restorations.

Efficacy of calcium hydroxide-loaded poly(lactic-co-glycolic acid) biodegradable nanoparticles as an intracanal medicament against endodontopathogenic microorganisms in a multi-species biofilm model

This study aimed to evaluate the antimicrobial activity of calcium hydroxide-loaded poly(lactic-co-glycolic acid) nanoparticles (CH-loaded PLGA NPs) on multi-species biofilms. Human root blocks were prepared (n = 40), and multi-species suspensions of Candida albicans, Enterococcus faecalis and Streptococcus gordonii were incubated within the root canals for 21 days. Canals (n = 10/group) were then medicated with saline solution (negative control), chlorhexidine (positive control), calcium hydroxide and CH-loaded PLGA NPs for 7 days. Samples taken from the 0.1 mm root canal dentin were collected, and cell growth was detected by culture on BHI agar. The viable cell count of the Ca(OH)2, chlorhexidine gel and CH-loaded PLGA NPs group was significantly lower than the normal saline group (p < 0.001). CH-loaded PLGA NPs demonstrated a significant lower viable cell than Ca(OH)2 (p < 0.001); it has potential as a medicament for endodontic therapy.

Antibacterial biofilm efficacy of calcium hydroxide loaded on Gum Arabic nanocarrier: an in-vitro study

BACKGROUND

An innovative intracanal medication formulation was introduced in the current study to improve the calcium hydroxide (Ca(OH)2) therapeutic capability against resistant Enterococcus faecalis (E. faecalis) biofilm. This in-vitro study aimed to prepare, characterize, and evaluate the antibacterial efficiency of Ca(OH)2 loaded on Gum Arabic (GA) nanocarrier (Ca(OH)2-GA NPs) and to compare this efficiency with conventional Ca(OH)2, Ca(OH)2 nanoparticles (NPs), GA, and GA NPs.

MATERIALS AND METHODS

The prepared nanoparticle formulations for the tested medications were characterized using Transmission Electron Microscope (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). 141 human mandibular premolars were selected, and their root canals were prepared. Twenty-one roots were then sectioned into 42 tooth slices. All prepared root canals (n = 120) and teeth slices (n = 42) were divided into six groups according to the intracanal medication used. E. faecalis was inoculated in the samples for 21 days to form biofilms, and then the corresponding medications were applied for 7 days. After medication application, the residual E. faecalis bacteria were assessed using CFU, Q-PCR, and SEM. Additionally, the effect of Ca(OH)2-GA NPs on E. faecalis biofilm genes (agg, ace, and efaA) was investigated using RT-PCR. Data were statistically analyzed at a 0.05 level of significance.

RESULTS

The synthesis of NPs was confirmed using TEM. The results of the FTIR proved that the Ca(OH)2 was successfully encapsulated in the GA NPs. Ca(OH)2-GA NPs caused a significant reduction in the E. faecalis biofilm gene expression when compared to the control (p < 0.001). There were significant differences in the E. faecalis CFU mean count and CT mean values between the tested groups (p < 0.001) except between the Ca(OH)2 and GA CFU mean count. Ca(OH)2-GA NPs showed the least statistical E. faecalis mean count among other groups. SEM observation showed that E. faecalis biofilm was diminished in all treatment groups, especially in the Ca(OH)2-GA NPS group when compared to the control group.

CONCLUSIONS

Ca(OH)2 and GA nanoparticles demonstrate superior anti-E. faecalis activity when compared to their conventional counterparts. Ca(OH)2-GA NPs showed the best antibacterial efficacy in treating E. faecalis biofilm. The tested NP formulations could be considered as promising intracanal medications.

Examining the Effects of Asiaticoside on Dental Pulp Stem Cell Viability and Proliferation: A Promising Approach to Root Canal Treatment

AIM

This study aims to evaluate the impact of asiaticoside (AC) on the viability and proliferation of dental pulp stem cells (DPSCs), considering the known negative effects of routinely used intracanal medicaments. This evaluation will be compared with the outcomes from using traditional intracanal medicaments, specifically triple antibiotic paste (TAP) and calcium hydroxide [Ca(OH)2].

MATERIALS AND METHODS

The DPSCs were obtained from the third molars of an adult donor. The application of flow cytometry was employed to do a phenotypic analysis on DPSCs using CD90, CD73, CD105, CD34, CD14, and CD45 antibodies. The methylthiazol tetrazolium (MTT) assay was employed to assess cellular viability. The cells were treated with different concentrations of TAP and Ca(OH)2 (5, 2.5, 1, 0.5, and 0.25 mg/mL), along with AC (100, 50, 25, 12.5, and 6.25 µM). A cell proliferation rate was performed at 3, 5, and 7 days.

RESULTS

The characterization of DPSCs was conducted by flow cytometry analysis, which verified the presence of mesenchymal cell surface antigen molecules (CD105, CD73, and CD90) and demonstrated the absence of hematopoietic markers (CD34, CD45, and CD14). Cells treated with concentrations over 0.5 mg/mL of TAP and Ca(OH)2 showed a notable reduction in cell viability in comparison to the untreated cells (p < 0.05). Additionally, the cells treated with different concentrations of AC 12.5, 6.25, 25, and 50 µM did not differ significantly from the untreated cells (p > 0.05). Nevertheless, cells treated with concentrations of 100 µM showed a significant reduction in viability compared to the untreated cells (p < 0.05). After a period of 7 days, it was noted that cells exposed to three different concentrations of AC (50, 25, and 12.5 µM) had a notable rise in cell density in comparison to TAP and Ca(OH)2 (p < 0.05). Furthermore, cells that were exposed to a concentration of 12.5 µM exhibited the highest cell density.

CONCLUSION

The cellular viability of the AC-treated cells was superior to that of the TAP and Ca(OH)2-treated cells. Moreover, the AC with a concentration of 12.5 µM had the highest degree of proliferation.

CLINICAL SIGNIFICANCE

This study underscores the importance of evaluating alternative root canal medicaments and their effects on DPSCs' growth and vitality. The findings on AC, particularly its influence on the survival and proliferation of DPSCs, offer valuable insights for its probable use as an intracanal medication. This research contributes to the ongoing efforts to identify safer and more effective intracanal treatments, which are crucial for enhancing patient outcomes in endodontic procedures. How to cite this article: Alazemi MJ, Badawi MF, Elbeltagy MG, et al. Examining the Effects of Asiaticoside on Dental Pulp Stem Cell Viability and Proliferation: A Promising Approach to Root Canal Treatment. J Contemp Dent Pract 2024;25(2):118-127.

Phage PEf771 for the Treatment of Periapical Periodontitis Induced by Enterococcus faecalis YN771

Enterococcus faecalis was the main causative bacteria of refractory periapical periodontitis (PP), there is a pressing need to explore effective methods for eradicating E. faecalis in patients with refractory PP. This study aimed to assess the anti-infective effectiveness of phage PEf771 in treating periapical inflammation in rats. We developed a rat model of PP through E. faecalis YN771 induction. Micro-computed tomography and hematoxylin-eosin staining were utilized to evaluate bone destruction and inflammation in experimental teeth for seven consecutive weeks. Subsequently, rats with PP caused by E. faecalis YN771 were treated with phage PEf771, calcium hydroxide preparation, and 2% chlorhexidine gel. The healing progress of bone defects and inflammation in the apical region was monitored over three consecutive weeks using imaging and histopathology assessments. The PP rat model was successfully developed, and bone destruction and inflammatory cell infiltration in the apical region of the experimental tooth peaked at 4 weeks. The area of bone destruction in rats treated with phage PEf771, calcium hydroxide preparation, and 2% chlorhexidine gel was significantly smaller than that in the untreated group. Phage PEf771, calcium hydroxide preparation, and 2% chlorhexi-dine gel all have the effect of promoting the healing of apical lesions. Therapeutic effects of phage PEf771 on periapical inflammation infected by E. faecalis YN771 enhanced with time. Phage PEf771 promoted the healing of apical lesions, presenting a promising new approach for the treatment of refractory PP using bacteriophages.

Ion release, biocompatibility, and bioactivity of resin-modified calcium hydroxide cavity liners

BACKGROUND

The placement of liners near the pulp area is essential for therapeutic effects and maintaining pulp health while stimulating the formation of tertiary dentin. This in vitro study aimed to evaluate the calcium release, pH, biocompatibility, solubility, and bioactivity of three resin-modified calcium hydroxide cavity liners.

METHODS

The disc specimens of each cavity liner were prepared using polyethylene molds of 7 mm in diameter and 2 mm in height (n = 10). Three light-cure liners evaluated include Ultra-Blend Plus (UB), Base-it (BI), and Master Dent (MD). The samples were then immersed in flasks containing 10 mL of distilled water. Calcium ion release, pH, and solubility were evaluated in two weeks of incubation. The cytotoxicity of extracts adjacent to the specimens was evaluated by MTT assay using NIH/3T3 cells after 1, 3, and 7 days of incubation. The ability to induce the nucleation of calcium phosphates (CaPs) after 28-day immersion in a simulated body fluid was investigated by SEM-EDX analysis. Statistical analysis was performed using ANOVA, Kruskal-Wallis, and repeated measures tests at the significant level of 0.05.

RESULTS

There was a significant difference in the release of calcium ions among the three liners investigated on days 1, 7, and 14 (p < 0.05). UB liners exhibited a significantly higher amount of calcium release than the other two liners, followed by BI, and MD. On day 1, there was no significant difference in the average pH among the three liners. However, after day 7, the MD liner showed a significant decrease in pH compared to the other two liners. BI liner demonstrated the highest level of biocompatibility, followed by the MD and UB liners. UB showed a high calcium release, solubility with no alkalizing activity, and the formation of more mature Ca-rich apatite deposits than the other two liners.

CONCLUSION

Based on the results of this study, the cavity liner material's performance is material dependent. It can impact ion release, biocompatibility, and bioactivity which are important factors to consider in clinical practice. Further studies are needed to investigate the long-term effects of different liner materials on oral tissues.

Novel strategies enhancing endodontic disinfection: Antibacterial biodegradable calcium hydroxide nanoparticles in an ex vivo model

Due to the high failure rates associated to endodontic disinfection, this study aimed to investigate the antibacterial properties of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with Ca(OH)2 for endodontic disinfection procedures. Ca(OH)2 NPs production and physicochemical characterization were carried out as well as multiple antibacterial tests using three bacterial strains and an ex vivo model of endodontic infection with extracted human teeth. Agar diffusion test and broth dilution determined the inhibition growth zones (n = 5) and the minimal inhibitory concentration (MIC, n = 5), respectively. Cell viability was assessed using Live/Dead staining with confocal microscopy (n = 5). Data was analysed using ANOVA followed by post-hoc analysis. After 24 h of incubation, Ca(OH)₂ NPs demonstrated a MIC of 10 µg/mL for Porphyromonas gingivalis (p < 0.001) and Enterococcus faecalis and 5 µg/mL for Fusobacterium nucleatum (p < 0.001). Although the agar diffusion test did not exhibit any inhibition area for Ca(OH)2 nor for Ca(OH)₂ NPs, this was probably due to the buffering effect of the agar medium. However, the antibacterial capacity was confirmed in an ex vivo model, where instrumentalized teeth were infected with Enterococcus Faecalis and treated after 28 days of culture. A significant reduction in bacterial metabolic activity was confirmed for Ca(OH)2 NPs (40 % reduction with a single dose) and confirmed by Live/Dead staining. In conclusion, Ca(OH)₂-loaded PLGA NPs present promising antibacterial efficacy for endodontic disinfection procedures.

The Effects of Calcium Silicate- and Calcium Hydroxide-based Root Canal Sealers on Postoperative Pain: A Randomized Clinical Trial

INTRODUCTION

This study aimed to compare the postoperative pain level changes resulting from using calcium silicate- (EndoSeal MTA) and calcium hydroxide-based (Sealapex) root canal sealers in mandibular first and second molar teeth with symptomatic apical periodontitis.

METHODS

A total of 60 patients with symptomatic apical periodontitis in their lower molar teeth were randomly allocated into 2 groups according to sealer type (n = 30). Demographic data, including gender, age, and smoking habit, and preoperative pain measures were recorded. Root canal treatments were performed in a single visit. Postoperative pain measurements and analgesic intake were measured at 6, 12, 24, and 48 hours and after 3, 5, and 7 days using the visual analog scale. The data were statistically analyzed using a chi-squared test (to compare gender, age, smoking habit, analgesic intake, and sealer extrusion), the Mann-Whitney U test (to compare pain levels), Friedman tests (for the evaluations of the reduction in pain levels over time), and Spearman's correlation test (to analyze the relationships of age, gender, smoking habit factors with postoperative pain) (P = .05).

RESULTS

The statistical analysis showed no significant differences between the groups in postoperative pain and analgesic intake at any of the time intervals evaluated (P > .05).

CONCLUSIONS

Patients treated with calcium silicate- and calcium hydroxide-based root canal sealers experienced similar postoperative pain and no statistically significant differences were observed in analgesic intake.

Effect of Boswellic Acid on Viability of Dental Pulp Stem Cells Compared to the Commonly Used Intracanal Medications: An In Vitro Study

AIM

This study was aimed at evaluating the effect of acetyl-11-keto-β-boswellic acid (AKBA) on dental pulp stem cells (DPSCs) viability and proliferation to be used as a potential root canal medicament.

MATERIALS AND METHODS

Dental pulp stem cells were isolated from human third molars. The phenotypic characterization of DPSCs was verified by flow cytometry analysis. The viability assay was performed using the methyl-thiazoltetrazolium (MTT) assay. Cells were treated with different concentration of triple antibiotic paste (TAP) and calcium hydroxide Ca(OH2) (5, 2.5, 1, 0.5, and 0.25 mg/mL), AKBA (10, 5, 1, 0.1, and 0.01 µM). All experiments were done in separate triplicate experiments. Results: Dental pulp stem cells were characterized by flow cytometry. Cells treated with Ca(OH)2 (1, 2.5, and 5 mg/mL) showed significantly reduced viability compared with the control cells (p < 0.05). Dental pulp stem cells treated with 1, 2.5, and 5 mg/mL TAP resulted in a significant decrease in viability (p < 0.05). Cells treated with AKBA in concentrations (1, 0.1, and 0.01 µM) demonstrated higher viability than the control group (p < 0.05), while AKBA in concentrations (5 and 10 µM) showed equal or decreased viability than the control group. (p > 0.05). Regarding cell density assay, AKBA showed significant increase in cell density after 5 and 7 days compared with cells medicated with TAP and Ca(OH)2 while TAP revealed marked reduction in cell density in all the tested intervals.

CONCLUSION

Acetyl-11-keto-β-boswellic acid in lower concentrations (0.01, 0.1, and 1 µM) demonstrated superior cell viability than TAP and Ca(OH)2, and it may possess the potential to be an intracanal medicament in regenerative endodontics.

CLINICAL SIGNIFICANCE

Studying the effect of different potential root canal medicaments and their capability to induce DPSCs proliferation might be of value. The influence of AKBA on the viability and proliferation of DPSCs tested in this study sheds light on its use as a potential intracanal medication especially in regenerative endodontics. How to cite this article: Amer NA, Badawi MF, Elbeltagi MG, et al. Effect of Boswellic Acid on Viability of Dental Pulp Stem Cells Compared to the Commonly Used Intracanal Medications: An In Vitro Study. J Contemp Dent Pract 2023;24(12):957-966.

Comparative evaluation of antimicrobial efficacy of different combinations of calcium hydroxide against Enterococcus faecalis

BACKGROUND

The study aims to compare the synergistic antibacterial efficacy of different combinations of calcium hydroxide as an intracanal medicament against E. faecalis.

MATERIAL AND METHODS

The current study included four hundred extracted human permanent mandibular premolar teeth. After complete chemo-mechanical preparation, the middle third of the root was sectioned using a rotary diamond disc and a total of 400 samples were obtained. The specimens were inoculated with E. faecalis for 21 days. After that, specimens were divided into five groups (n = 80) based on materials used for the disinfection of samples: Group I, calcium hydroxide alone; Group II, calcium hydroxide + 2% chlorhexidine gel; Group III, calcium hydroxide + 2% chitosan gel; Group IV, calcium hydroxide + 0.02% silver nanoparticle gel; Group V, calcium hydroxide + Bioactive glass S53P4. Dentin shavings from the apical third were obtained from the inner third of dentin were obtained using gates glidden no.1 to the apical depth, followed by no.2, 3, 4 and 5 analyzed for E. faecalis using the culture method. One-way analysis of variance (ANOVA) was used for data analysis, followed by post-hoc Tukey's test for multiple comparisons of means to check the difference in bacterial inhibition between the groups.

RESULTS

ANOVA results revealed a significant reduction of bacterial counts in all the groups compared (p < 0.001). Intergroup comparison showed maximum bacterial reduction (p < 0.001) with calcium hydroxide + bioactive glass S53P4 compared with other groups.

CONCLUSION

Synergistic effect of calcium hydroxide showed better bacterial reduction compared to calcium hydroxide alone. Among the combinations evaluated, calcium hydroxide with bioactive glass, found to be most effective compared to other groups.

The Effect of Calcium hydroxide, Glass Ionomer and light cured resin modified calcium silicate on viability, proliferation and differentiation of stem cells from human exfoliated deciduous teeth

BACKGROUND

Vital pulp therapy, based on the use of stem cells, has promising research and therapeutic applications in dentistry. It is essential to understand the direct effect of capping materials on the dental pulp stem cells of primary teeth, which contribute to the healing powers of the tooth. The aim of this study is to evaluate the effect of different capping materials (Calcium Hydroxide (DyCal®) - Glass Ionomer (Fuji IX®) and light-cured resin modified calcium silicate (TheraCal LC®)) on the viability, proliferation, and differentiation of stem cells from human exfoliated deciduous teeth (SHEDs).

METHODS

SHEDs were isolated from extracted primary teeth, then divided into four groups and each of the capping materials were applied to the stem cells as follows: group I the controls, group II with Ca(OH)2, group III with the GIC, and group IV with the Theracal LC. For all groups assessment of viability and proliferation rate was done using the MTT cell proliferation assay. Also, Differentiation was evaluated by measuring the gene expression of Alkaline phosphatase enzyme activity (ALP) and Dentin matrix protein-1 (DMP1) through quantitative real-time PCR. Morphological assessment was conducted using Alizarin Red S staining. All evaluations were performed after 7 and 14 days of culture.

RESULTS

TheraCal LC showed the highest values of proliferation, which was significant only compared to the control group after 2 weeks (p = 0.012). After one week, TheraCal LC showed the highest significant values of ALP and DMP1 compared to all other groups (p < 0.001).

CONCLUSION

The three materials under study are biocompatible, maintain viability, and stimulate the proliferation and differentiation of SHEDs. However, TheraCal LC allows better proliferation of SHEDs than Dycal Ca(OH)2 and Fuji IX GIC.

Effect of different final irrigation agitation techniques on root canal dentin tubule penetration of nanoparticle calcium hydroxide dressing

This study is aimed to assess the efficacy of different final irrigation agitation techniques on dentin tubule penetration of nanoparticle calcium hydroxide (NCH) dressing. Ninety-six extracted upper incisors were shaped up to #40file. Then, Four experimental groups were formed according to the final irrigation procedure: conventional needle irrigation (CNI), manual dynamic agitation (MDA), sonic agitation (SA) and ultrasonic irrigant agitation (UIA). According to the intracanal drug used, these groups were divided into two subgroups: calcium hydroxide (CH) and NCH. Prepared CH preparations were labelled with Rhodamine B, and CH or NCH were placed in root canals. In the UIA group, both CH and NCH had the highest penetration depth and percentage compared to the other groups (p < 0.05). The penetration depth and percentage of NCH in the UIA and SA groups were significantly higher than in the CH groups (p < 0.05). UIA is more effective than other groups in increasing dentinal tubule penetration of CH and NCH.

Evaluation of the biological effect of mineral trioxide aggregate in inflamed pulp-in vivo analysis

The health of dental pulp tissue is critical to maintaining normal tooth function from the eruption of permanent teeth to the formation of the apex. The study evaluated the inflamed pulp response to the mineral trioxide aggregate (MTA) after direct pulp capping with the mechanical pulp exposure in rats' incisor. Forty-eight mandibular central incisors of twenty-four Sprague-Dawley rats which were prepared with the cavities of one mm diameter, and the pulp exposures were randomly assigned into two groups: MTA group and calcium hydroxide (Ca(OH)2) group. The direct pulp capping was performed after three days and samples histological observations conduction within eight weeks. In both MTA and Ca(OH)2 groups, dentin -like structures were observed in the pulp tissues of some teeth. The number of teeth with reparative tissue in MTA group was statistically significantly higher than that in Ca(OH)2 group (p = 0.041). Inflammatory cell infiltration was found in the crown pulp tissues in two groups, and no statistical difference was observed between the two groups (p = 0.243). Pulp necrosis occurred in both groups, and there was no statistical difference between the two groups (p = 0.622). The results in this paper suggest that MTA promotes direct pulp capping and hence has certain potential clinical applications value in the treatments for the preservation of inflamed pulp.

A comparison of hydroxyl ion diffusion through root dentine from various calcium hydroxide preparations

Different calcium hydroxide [Ca(OH)2 ] formulations are available. The aim was to assess differences in hydroxyl ion release with different formulations. Sixty-six teeth were divided one control (n = 6) and four experimental (n = 15) groups: (i) Pulpdent Paste; (ii): DT Temporary Dressing; (iii): Ca(OH)2 powder/saline; (iv): Ca(OH)2 points; (v): no medicament. pH was measured in inner dentine and outer dentine cavities over 12 weeks. Inner dentine pH rose rapidly for all groups except the points and controls. Peak pH was reached by day 2 before dropping and stabilising (8.0-9.2). Outer dentine pH rose steadily until day 21 for aqueous solutions and then stabilised (8.0-8.5). The points had minimal pH increase for the entire period. There were no significant differences in hydroxyl ion release between the aqueous solutions. Type of paste base did not affect release and diffusion of hydroxyl ions which continued for 84 days.

Nano eggshell-based slurry as a direct pulp-capping material: In vitro characterization and histopathological assessment in an experimental animal model

AIM

Pulp vitality is essential for tooth integrity. Following pulp exposure, choosing a suitable pulp-capping material is crucial to maintain pulp vitality. However, the reparative dentine bridge created by calcium hydroxide (Ca(OH)2 ) is generally porous and incomplete. The aim of the current study is to assess the in vitro and in vivo bioactivities of nano eggshell-based slurry (NES), using NES as a direct pulp-capping material, compared with Ca(OH)2 in rabbit animal model.

METHODOLOGY

Nano eggshell powder (NE) was characterized for particle morphology, chemical composition and ion release. In vitro bioactivity was tested by immersion in simulated body fluid (SBF) for 7 days. For histopathological evaluation, 36 adult New Zealand rabbits (72 pulp exposures) were divided into nine groups (n = 8) according to the pulp-capping material (NES, Ca(OH)2 and no capping as negative control group) and the animals were sacrificed after 7, 14 or 28 days. The pulps of the two lower central incisors were exposed and then directly capped by Ca(OH)2 or NES or left untreated. The cavities were then sealed with glass ionomer cement. Teeth were collected for histopathological evaluation using an optical microscope. Pulp haemorrhage, inflammation, fibrosis and calcific bridge formation were assessed. Results were statistically analysed using anova and Tukey's tests.

RESULTS

Nano eggshell particles were spherical with a 20 nm diameter and were composed mainly of calcite. Statistical analysis showed that there was a significant increase in the release of all investigated ions between days 1 and 28, except for copper. NES group showed a significantly higher release of all elements as compared to Ca(OH)2 . Environmental scanning electron microscope micrographs of NES incubated for 7 days in SBF showed the formation of HAp with a Ca/P ratio (1.686). For histopathological evaluation, the difference between groups was statistically significant. At day 28, 75% of the pulps of the Ca(OH)2 group showed mild calcific bridge in comparison with 100% moderate calcific bridge in the NES group. The NES group showed significantly less inflammation at days 7 and 28, and higher fibrosis at day 7 compared with Ca(OH)2 .

CONCLUSIONS

Nano eggshell-based slurry represents a promising novel direct pulp-capping material with favourable pulp tissue response.

Direct and residual antimicrobial effect of 2% chlorhexidine gel, double antibiotic paste and chitosan- chlorhexidine nanoparticles as intracanal medicaments against Enterococcus faecalis and Candida albicans in primary molars: an in-vitro study

BACKGROUND

Thorough disinfection of root canals in primary molars may be complicated by the complex root canal morphology. This in-vitro study aimed to compare direct and residual antimicrobial effect of 2% chlorhexidine (CHX) gel, 500 mg/ml double antibiotic paste (DAP) and chitosan-chlorhexidine nanoparticles (CS-CHX NPs) as intracanal medicaments against Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans) in primary molars.

METHODS

Mesial roots of 63 mandibular second primary molars were infected with E. faecalis and C. albicans. Teeth were divided into 9 groups: Ia: (CS-CHX NPs), IIa: (CHX), IIIa: (DAP), IVa: chitosan nanoparticles (CSNPs) in which medicaments were placed for 3 days, groups Ib: (CS-CHX NPs), IIb: CHX, IIIb: (DAP), IVb: (CSNPs) in which medicaments were placed for 7 days, and Group V (control): teeth were infected, irrigated with saline, and sampled 3- and 7-days post-infection. Microbiological samples were obtained after infection, 3, and 7 days after medicament placement and 7 days after medicament removal for both time points. One-way ANOVA, Tukey's post hoc test and paired t-test were used at p < 0.05.

RESULTS

CS-CHX NPs had the highest anticandidal effect which was comparable to CHX and significantly higher than other medicaments (p < 0.001) at both time points. CS-CHX NPs had the highest effect against E. faecalis which was comparable to DAP and significantly higher than other medicaments (p < 0.001) at 3 days. All medicaments showed similar effect against E. faecalis after 7 days. The 7-days placement significantly increased the antimicrobial effect against both micro-organisms in all groups, except CS-CHX NPs which showed an insignificant increase. CS-CHX NPs showed the highest residual effect against both micro-organisms that increased with 7-days placement.

CONCLUSION

CSNPs and CHX combination showed a synergistic effect against both micro-organisms. CS-CHX NPs displayed a higher effect at a shorter period compared to other medicaments, yet its residual effect was higher with 7-days placement.

Efficacy of disinfection procedures performed prior to regenerative endodontic therapy: An integrative review

The aim of this integrative review was to identify whether the disinfection procedures performed prior to regenerative endodontic treatment were effective on biofilm removal from the root canals. The research was based on PubMed, Latin American and Caribbean Health Sciences Literature (Lilacs) and Scientific Electronic Library Online (SciELO) databases. Four articles were selected; one of the studies was in vivo and the others ex vivo. Different disinfection procedures were studied, characterised mainly by the use of intracanal medication, highlighting the double antibiotic paste, triple antibiotic paste and calcium hydroxide paste. Disinfection ability was evaluated against Enterococcus faecalis and multispecies biofilms by using the fluorescence technique and colony forming unit counting, for 7 to 21 days. Double antibiotic paste and triple antibiotic paste demonstrated excellent antibiofilm activity, unlike CH paste that showed limited disinfection, even when associated with different antimicrobial agents. Triple antibiotic paste was the most effective medication against biofilm.

Assessment of depth of penetration and antibiofilm properties of Boswellia sacra compared with calcium hydroxide intracanal medicament (in vitro study)

Successful endodontic treatment requires advanced materials to eliminate biofilm This study aims to assess the penetration depth and the effectiveness of Boswellia sacra as a novel intracanal medicament compared with calcium hydroxide against Enterococcus faecalis biofilm. 60 single-rooted teeth were decoronated, prepared and sterilised. Fifty teeth were contaminated with a culture of E. faecalis (ATCC 19433) for 21 days. Two teeth were used to confirm the biofilm using scanning electron microscope. For colony-forming unit (CFU), 40 samples were divided into one control group (calcium hydroxide) and the other experimental group (B. sacra). Each group was divided into two subgroups to be tested at 3 and 7 days. The minimum inhibitory concentration (MIC) of B. sacra was determined, and the B. sacra's ethanolic extract medicament was prepared. Eight discs divided into groups similar to CFU were used to evaluate live/dead bacteria using confocal laser scanning microscopy (CLSM). Ten teeth were selected for penetration depth using CLSM. The intracanal medicaments were mixed with 0.1% rhodamine B. were inserted into the root canals 0.2 slices were dissected and viewed under CLSM. The MIC of B. sacra was 1.25 mg/ml. The CFU evaluation proved that B. sacra are more effective than calcium hydroxide in the 3 days groups. However, it was statistically insignificant compared with calcium hydroxide after 7 days. The depth of penetration of B. sacra exceeds that of calcium hydroxide. B. sacra is an effective intracanal medicament.

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.

Synthesis and characterization of calcium-releasing elastomeric resin-based endodontic sealers

OBJECTIVES

To evaluate the incorporation of halloysite nanotubes (HNTs) loaded with one of two calcium sources (i.e., calcium hydroxide/CaOH2 or beta-tricalcium phosphate/β-TCP) on the physicochemical and biological properties of an experimental resin-based dual-cured endodontic sealer.

MATERIALS AND METHODS

HNTs were encapsulated with CaOH2 or β-TCP at 10 wt.%. HNTs containing CaOH2 or β-TCP were added into the experimental sealers at 50 wt.%. The control sealers were the calcium-free HNT-modified resin-based experimental sealer and AH Plus™, a commercially available endodontic sealer. Degree of conversion, setting time, flow, film thickness, radiopacity, dimensional stability, and calcium ions release were determined. Antibiofilm properties and cytocompatibility of the formulated sealers and commercial control were also evaluated. One and two-way ANOVA analysis followed by Tukey's post hoc test was conducted to evaluate the effect of the independent variable on the evaluated properties.

RESULTS

FTIR confirmed the encapsulation of calcium sources into HNTs. Regarding flow and film thickness, the values obtained from these sealers were in accordance with the specifications provided by ISO 6876. For radiopacity, AH Plus™ achieved the highest radiopacity (p<0.05). Among the experimental formulations, all experimental HNT-containing compositions exhibited values below 3 mm Al. The experimental sealers showed greater dimensional changes when compared to the commercial (AH Plus™) control. The release of calcium ions was observed for the HNT_CaOH2 and HNT_β-TCP sealers without statistical differences. Experimental sealers containing HNT_CaOH2 and HNT_β-TCP significantly reduced the CFU/mL count and showed cell compatibility.

CONCLUSIONS

The findings of this study demonstrate that the incorporation of HNT_CaOH2 or HNT_β-TCP into resin-based experimental sealers promoted antimicrobial effects and gradual calcium release without impairing cytocompatibility or physicochemical properties of the sealers. Still, an adjustment to reach the minimal radiopacity established by ISO 6876 is needed.

CLINICAL RELEVANCE

The experimental resin-based sealers seemed to be an alternative for endodontics. The incorporation of calcium sources exerts promising antimicrobial effects while displaying low cell toxicity.

Evaluation of antimicrobial efficacy of ethanolic extract of Cuminium Cyminium as intracanal medicament on common bacteria of endodontic infections: An in vitro study

Context

Antimicrobial intracanal medicaments play a vital role in successful outcome of any endodontic procedure. One such plant extract Cuminium cyminium, as intracanal medicaments needs to be researched.

Aims

The purpose of this study was in vitro assessment of the antibacterial activity of ethanol extract of C. Cyminium in comparison to Calcium hydroxide (Ca[OH]2) as intracanal medicament against the pathogens of endodontic infection, at an interval 1 h, 24 h, 48 h, and 72 h.

Settings and Design

The study was conducted in the central research laboratory of our institute. Freshly prepared C. cyminium extract was procured from AYUSH approved laboratory and direct contact test (DCT) was utilized, which is based on turbidometric determination of microbial growth in a 96-well microplate, carrying 6 times for each bacteria.

Methodology

Three groups were assigned for each material in a 96 microwell plate for DCT. Bacterial growth kinetics was monitored at intervals of 1 h, 24 h, 48 h, and 72 h using spectrophotometer at 595 nm. The optical density of T2 (Test group), P2 (Positive control), and N2 (Negative control) was considered.

Statistical Analysis Used

After compiling the data, based on the normality of data, further statistical analysis was conducted using Kolmogorov-Smirnov test, Paired t-test, and pairwise comparisons by Turkey's multiple post hoc procedures. The level of statistical significance was set at P = 0.05.

Results

The comparison of mean optical density values of C. cyminium in comparison with Ca(OH)2 against the microorganisms of endodontic origin showed a statically significant decrease in bacterial viability at the end of 24 h, 48 h, and 72 h.

Conclusion

Based on the results of the study, it can be concluded that C. cyminium has significant antibacterial action against endodontic origin, at interval of 24 h, 48 h, and 72 h.

Evaluation of antibacterial effects of different intracanal medicaments on Enterococcus faecalis in primary teeth: An in vitro study

OBJECTIVES

Successful endodontic therapy is based on the reduction of infecting bacteria by cleaning, shaping, and disinfecting of the root canal system, thus the use of intracanal dressing is necessary for optimal success of root canal treatment. This study was designed to evaluate the effect of chitosan and propolis as intracanal medicaments against Enterococcus faecalis compared to calcium hydroxide in primary root canals.

MATERIAL AND METHODS

Ninety-six extracted primary second molars were collected. Teeth preparation was completed to size 30 K-file. They were randomly divided into four groups; (A): chitosan, (B): propolis, (C): calcium hydroxide, and (D): control group (saline). The tooth specimens were inoculated with E. faecalis. Then, tested materials were applied for all groups in accordance to the groups each tooth belonged to. Following this, the bacterial colonies were counted after 24 h, 72 h, and 1 week of applying dressing materials and incubation. Finally, one-way analysis of variance and Fisher's least significant difference tests were used for statistical comparisons between the groups at a significance level of .05.

RESULTS

No statistically significant difference was found between groups A, B, and C for both 24 h and a week (p ≥ .05). Yet, a statistical difference between groups A, B, C, and D after 72 h and 1 week were seen (p ≤ .05).

CONCLUSIONS

Chitosan and propolis medicaments were as effective as calcium hydroxide against E. faecalis in primary root canal treatment and might be considered as an alternative dressing material between treatment sessions.

Impact of N-acetylcysteine (NAC) and calcium hydroxide intracanal medications in primary endodontic infection: a randomized clinical trial

OBJECTIVES

This RCT investigated the impact of N-acetylcysteine (NAC) and calcium hydroxide [Ca(OH)₂] intracanal medications (ICMs) in primary endodontic infection with apical periodontitis (PEIAP).

MATERIALS AND METHODS

Thirty-six teeth with PEIAP were randomly divided into groups according to the ICM: NAC, Ca(OH)₂ + saline solution (SSL), and Ca(OH)₂ + 2% chlorhexidine-gel (2% CHX-gel) (all, n = 12). Root canal samples (RCSs) were collected before (s1) and after instrumentation (s2) and after 14 days of ICM (s3). Chemomechanical preparation (CMP) was performed with a Reciproc file and 2.5% NaOCl. Checkerboard DNA-DNA hybridization was used to assess 40 target bacteria species.

RESULTS

At s1, bacterial DNA was detected in 100% of RCSs (36/36). All 40 bacterial species were found in PEIAP. The mean number of species per RCS was 17.92 ± 13.18. The most frequent bacteria were S. mitis (65%), E. nodatum (63%), E. faecalis (63%), F. nucl sp vicentii (58%), T. forsythia (58%), and F. periodonticum (56%). CMP reduced the mean number of species per RCS to 6.8 ± 2.36 (p < 0.05). At s3, the intragroup analysis revealed a broader antimicrobial activity for Ca (OH)₂ + 2% CHX-gel and NAC than Ca(OH)₂ + SSL (p < 0.05). NAC eliminated 8/12 bacteria species resistant to both Ca (OH)₂ ICMs, including P. micra, P. nigrescens, T. denticola, A. israelii, P. endodontalis, P. acnes, C. ochracea, and E. corrodens.

CONCLUSIONS

Ca (OH)2 + 2% chlorhexidine gel (2% CHX gel) showed a greater bacterial elimination over the number of bacterial species; however, NAC eliminated 8/12 bacteria species resistant to both Ca (OH)2 ICMs (RBR-3xbnnn).

CLINICAL RELEVANCE

The use of intracanal medication with a broad antimicrobial activity can optimize root canal disinfection. Ca(OH)₂ + 2% CHX gel and NAC showed a broader antimicrobial activity than Ca(OH)₂ + SSL against endodontic pathogens in primary root canal infection.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (REBEC), No. RBR-3xbnnn.

Mechanism of action of Bioactive Endodontic Materials

A continuous search for bioactive materials capable of supporting the replacement of damaged pulp tissue, with effective sealing potential and biocompatibility, has represented the attention of studies over the last decades. This study involves a narrative review of the literature developed by searching representative research in PUBMED/MEDLINE and searches in textbooks associated with the mechanism of action of bioactive materials (calcium hydroxide, mineral trioxide aggregate (MTA), and calcium silicate cements). The reflective analysis of the particularities of the chemical elements of these materials, considering the tissue and antibacterial mechanism of action, allows a better understanding of the characteristics and similarities in their tissue responses. Calcium hydroxide paste remains the antibacterial substance of choice as intracanal dressing for the treatment of root canal system infections. Calcium silicate cements, including MTA, show a favorable biological response with the stimulation of mineralized tissue deposition in sealed areas when in contact with connective tissue. This is due to the similarity between the chemical elements, especially ionic dissociation, the potential stimulation of enzymes in tissues, and the contribution towards an alkaline environment due to the pH of these materials. The behavior of bioactive materials, especially MTA and the new calcium silicate cements in the biological sealing activity, has been shown to be effective. Contemporary endodontics has access to bioactive materials with similar properties, which can stimulate a biological seal in lateral and furcation root perforations, root-end fillings and root fillings, pulp capping, pulpotomy, apexification, and regenerative endodontic procedures, in addition to other clinical conditions.

Ferric sulfate pulpotomy in primary teeth with different base materials: a 2-year randomized controlled trial

OBJECTIVE

To evaluate the effects of zinc oxide-eugenol, calcium hydroxide, and mineral trioxide aggregate as base materials on the clinical and radiographic success of ferric sulfate pulpotomies in primary molars.

METHOD AND MATERIALS

Following hemostasis with 15.5% ferric sulfate, 105 teeth were randomly allocated to three groups: Group 1, zinc oxide-eugenol; Group 2, calcium hydroxide; and Group 3, mineral trioxide aggregate. All teeth were restored with stainless-steel crowns. Clinical and radiographic examinations were conducted at 6, 12, 18, and 24 months.

RESULTS

After 24 months, clinical success rates for Groups 1 to 3 were 97.1% (34/35 teeth), 94.2% (33/35 teeth), and 97.1% (34/35 teeth), respectively (P > .05). Radiographic success rates were 65.7% (23/35 teeth), 65.7% (23/35 teeth), and 77.1% (27/35 teeth), respectively (P > .05). Internal resorption was the most observed radiographic finding (15/105 teeth).

CONCLUSIONS

The choice of zinc oxide-eugenol, calcium hydroxide, and mineral trioxide aggregate, as base materials, did not affect the clinical and radiographic success of ferric sulfate pulpotomies in primary teeth.

Human root dentin microhardness and degradation by triple antibiotic paste and calcium hydroxide

PURPOSE

To investigate and compare the effects of the two widely used regenerative endodontics medicaments: Triple antibiotic paste (ciprofloxacine-metronidazole-clindamycin) and calcium hydroxide on the microhardness and degradation of human root dentin.

METHODS

Following ethical approval and subject consent to use teeth in this research study, 60 singled-rooted permanent human teeth were randomly divided into six groups:(1) Tri-antibiotic paste with distilled water, or with (2) propylene glycol, (3) calcium hydroxide with distilled water, (4) calcium hydroxide propylene glycol, (5) untreated extracted teeth as negative controls, or (6) teeth instrumented and filled with calcium hydroxide or tri-antibiotic paste as positive controls. The microhardness tests were conducted after 1 and 2 months of exposure to the medicaments using a Vickers microhardness tester. Raman spectroscopy and energy dispersive x-ray spectroscopy were used to evaluate the chemistry and structure of the root dentin.

RESULTS

There were differences in the dentin microhardness following treatment with the medicaments or controls (P< 0.05). The time of root dentin exposure to the medicaments was similar (P> 0.05). The root dentin microhardness was lower in the teeth treated with the triple antibiotic paste or calcium hydroxide when combined with propylene glycol. The root dentin collagen in these treated teeth were also significantly degraded when viewed with Raman spectroscopy and energy dispersive x-ray spectroscopy, whereas the inorganic phase (dentin) remained unaltered. Samples exposed to the antimicrobial agents with water as a vehicle exhibited stronger microhardness and less degradation.

CLINICAL SIGNIFICANCE

These ex vivo results suggest that the triple antibiotic paste and calcium hydroxide should be used with propylene glycol if a fast diffusion is desired or with water to avoid degrading the collagen and weakening the microhardness of the teeth. Clinical trials are needed of new formulations of medicaments with propylene glycol to disinfect teeth for regenerative endodontic procedures, to help strengthen the teeth to prevent the loss of children's permanent immature teeth by fracture following caries or trauma.

Effect of calcium hydroxide on morphology and physicochemical properties of Enterococcus faecalis biofilm

Calcium hydroxide Ca(OH)2 has been used as an intracanal medicament to targets microbial biofilms and avert secondary infection in the root canal system. This study evaluated the effects of this material on the morphology and physicochemical properties of an established in-vitro biofilm of Enterococcus faecalis. A biofilm of E. faecalis was grown in multichannel plates. The chemicals including Ca2+, OH-, and saturated Ca(OH)2 (ie 21.6 mM) were prepared in order to evaluate which component eradicated or amplified biofilm structure. Various biochemical and microscopic methods were used to investigate the properties of the biofilm. Biofilms treated with Ca(OH)2 absorbed more Ca2+ because of the alkaline pH of the environment and the ions affected the physicochemical properties of the E. faecalis biofilm. A denser biofilm with more cavities and a granular surface was observed in the presence of Ca2+ ions. This resulted in a decrease in the surface-to-biofilm ratio with increases in its biomass, thickness, colony size, and volume. Calcium hydroxide did not destroy E. faecalis biofilms but rather contributed to the biofilm structure. This in-vitro study sheds light on a missing link in the formation of E. faecalis biofilm in which the Ca2+ in Ca(OH)2.

Comparative Evaluation of Ozonoid Olive Oil and Calcium Hydroxide as an Indirect Pulp Capping Agent in Primary Mandibular Second Molar: A Randomized Controlled Trial

AIM

The aim of this study was to evaluate clinical and radiographical success of ozonoid olive oil as an indirect pulp capping (IPC) agent in primary mandibular second molar when compared to calcium hydroxide and to evaluate the antimicrobial efficacy of ozonoid olive oil on Streptococcus mutans and Lactobacilli.

MATERIALS AND METHODS

A split-mouth randomized controlled trial was conducted on 30 primary mandibular second molars in 15 children of age 5-9 years with deep dentinal carious lesion. Teeth were randomly allocated to two groups of 15 each. After achieving local anesthesia and rubber dam isolation, an IPC procedure was performed using ozonoid olive oil in group I and calcium hydroxide in group II. Teeth were evaluated clinically and radiographically at 6 and 12 months of follow-up for success or failure of IPC. The bacterial counts of S. mutans and Lactobacilli were measured before and after application of ozonoid olive oil for 60 seconds on dentinal tissue in group I and recorded as colony-forming units per mL (CFU/mL).

RESULTS

There were no statistically significant differences found between the materials used for IPC (p >0.05). About 93.33% and 100% clinical and radiographical success rates were seen in group I and group II, respectively. Statistically significant differences were observed for bacterial reduction after the application of ozonoid olive oil (p <0.05) for both the microorganisms.

CONCLUSION

The results of this study showed that the success of IPC is independent of capping material. Ozonoid olive oil, an antimicrobial agent, can also be used for IPC. The success of the IPC procedure depends on a reduction in the bacterial count and sealing of the tooth with hermetic restoration. More clinical studies with a larger sample size and longer follow-up duration are required for understanding the efficacy of this material.

CLINICAL SIGNIFICANCE

Ozonoid olive oil can be used as an IPC agent in primary molars and also for a bacterial reduction in dentinal caries.

Cytocompatibility and bioactivity of calcium hydroxide-containing nanofiber scaffolds loaded with fibronectin for dentin tissue engineering

OBJECTIVES

The aim of this study was to characterize polycaprolactone-based nanofiber scaffolds (PCL) incorporated with calcium hydroxide (CH) and evaluate their bioactivity on human dental pulp cells (HDPCs) when loaded with fibronectin (FN).

MATERIALS AND METHODS

CH (0.1%; 0.2%; 0.4% w/v; or 0%) was incorporated into PCL (10% w/v) scaffolds prepared by electrospinning. Morphology and composition were characterized using SEM/EDS. HDPCs were seeded on the scaffolds and evaluated for viability (alamarBlue; Live/Dead), and adhesion/spreading (F-actin). Next, scaffolds containing 0.4% CH were loaded with FN (20 µg/mL). HDPCs were evaluated for viability, adhesion/spreading, migration (Trans-well), gene expression (RT-qPCR), alkaline phosphatase activity (ALP), and mineralization nodules (Alizarin Red). Data were submitted to ANOVA and post-hoc tests (α = 5%).

RESULTS

Nanofibers with larger diameter were seen as CH concentration increased, while there was no effect on interfibrillar spaces. An increase in cell viability was seen for 0.4% CH, in all periods. Incorporation of CH and FN into the scaffolds increased cellular migration, spread, and viability, all intensified when CH and FN were combined. ALPL and DSPP expression, and ALP activity were not affected by CH and FN. COL1A1 was downregulated in all groups, while DMP1 was upregulated in the presence of CH, with no differences for the groups loaded with FN. CH increased the formation of mineralized matrix, which was not influenced by FN.

CONCLUSIONS

In conclusion, the incorporation of CH enhanced the odontogenic potential of HDPCs, irrespective of the presence of FN. The PCL + 0.4% CH formulation may be a useful strategy for use in dentin tissue engineering.

CLINICAL RELEVANCE

A change in the form of presentation of calcium hydroxide-based materials used for direct pulp capping can increase biocompatibility and prolong the vitality of dental pulp.

Ultrasonic agitation reduces the time of calcium hydroxide antimicrobial effect and enhances its penetrability

OBJECTIVES

The objective of the present work was to evaluate the ultrasonic agitation, time and vehicle (propylene glycol or distilled water) on the antimicrobial potential and penetrability of calcium hydroxide pastes on infected dentin by means of Confocal Laser Scanning Microscopy (CLSM) and microbiological culture (MC).

MATERIALS AND METHODS

Dentin specimens were infected with Enterococcus faecalis using a new contamination protocol of 5 days. The specimens were divided into eight groups and dressed with the pastes for 7 or 15 days: G1) calcium hydroxide (CH) + propylene glycol (prop)/7 days (d), G2) CH + prop/7d + ultrasonic agitation (U), G3) CH + distilled water (dw)/7d, G4) CH + dw/7d + U, G5) CH + prop/15d, G6) CH + prop/15d + U, G7) CH + dw/15d, G8) CH + dw/15d + U. The ultrasonic activation was made for 1 min in both directions with a plain point insert. After medications removal, the images obtained by CLSM showed the viable (green) and dead (red) bacteria with Live and Dead dye. By the MC, the dentinal wall debris obtained by burs were collected for colony counts. For the penetration test, the Rodamine B dye was added to the CH pastes and analyzed by CLSM.

RESULTS

The 7 and 15-days CH + prop+U pastes performed better antimicrobial efficacy, followed by the CH + dw+U/15d paste.

CONCLUSIONS

All pastes demonstrated better penetration and antimicrobial activity against E. faecalis when agitated with ultrasound, even in periods of up to seven days. The propylene glycol vehicle showed better results.

CLINICAL RELEVANCE

Agitation of the dressing that remains for less time inside the root canal can optimize the decontamination of endodontic treatment.

Comparative Evaluation of Antibacterial Efficacy of Silver and Cadmium Nanoparticles and Calcium Hydroxide against Enterococcus faecalis Biofilm

AIM

The purpose of this study was to evaluate and compare the antibacterial efficacy of calcium hydroxide medicament, silver (AgNPs) and cadmium nanoparticles (CdSNPs) as medicament against the biofilms of Enterococcus faecalis on dentin sections. E. faecalis is commonly detected in asymptomatic and persistent endodontic infections.

METHODS

Twenty standard size dentin sections were prepared. E. faecalis was inoculated on these dentin sections for four weeks to form the bacterial biofilm. Twenty dentin sections were segregated into four different groups with five specimens in each group. Group I was kept as control group, and antibacterial efficacy was tested by treating biofilms with Ca(OH) ₂ medicament, 0.02% AgNP and CdSNP gels for 7 days. The ultrastructure of biofilms from each group was examined under scanning electron microscope and was visually evaluated and compared for different groups.

RESULTS

Ca(OH)₂ exhibited a slight disruption of E. faecalis biofilm. Both AgNP and CdSNP medicaments disrupted E. faecalis biofilm effectively after 7 days of inoculation. AgNPs disrupted the biofilm more effectively than CdSNPs. Biofilms in control group, which was irrigated with saline, did not show any disruption of biofilm, which could be seen as homogenous layer over most of dentin sections.

CONCLUSIONS

This study suggests that both AgNP and CdNP gels are effective against E. faecalis and can be used as a medicament to eliminate residual bacterial biofilms during root canal disinfection. AgNP medicament is more effective than CdNP, whereas Ca(OH) ₂ is not effective against E. faecalis biofilms.

CLINICAL SIGNIFICANCE

Incomplete clearance and the development of antibiotic resistance in E. faecalis are the important factors for failure of root canal treatment. When cationic nanoparticles are introduced for the treatment of biofilms, it can interact with both extracellular polymeric substances and bacterial cells. The initial electrostatic attraction between positively charged nanoparticles and negatively charged bacterial surface leads to bacterial killing via the production of reactive oxygen species. Metal nanoparticles that are effective against E. faecalis have a significant potential role in the prevention and treatment of such cases, as bacteria do not develop resistance against metal nanoparticles.

Evaluation of the effect of various endodontic irrigants and medicaments on dentine fluorescence

This study examined the effect of various root canal irrigants and medicaments on dentin fluorescence elicited by 655 nm visible red laser light. To replicate clinical use, irrigants were applied onto dentin samples for 2 min, while medicaments were applied for 2 weeks. Fluorescence values tracked from baseline across the following to 24 h, starting 5 min after exposure. Sodium hypochlorite, hydrogen peroxide, and articaine local anaesthetic (4% articaine with 1:1000,000 adrenaline) all significantly quenched fluorescence (p < 0.0001), which then returned to baseline levels after 20 min. Conversely, elevated fluorescence readings were recorded after 3% mepivacaine (p < 0.05), 0.2% chlorhexidine (p < 0.01) and chloroform (p <0.05). A 2 week application of Ledermix™ paste containing 3% demeclocycline caused an irreversible increase in fluorescence (p < 0.0001). Other tested endodontic materials (15% EDTA, eucalyptus oil, calcium hydroxide, Odontopaste™ clindamycin paste, and distilled water) had no impact on dentine fluorescence. The influences of endodontic materials on dentin fluorescence need to considered when using fluorescence endpoints to guide the progress of root canal treatment.

Comparative Evaluation of Efficacy of Calcium Hydroxide, Propolis, and Glycyrrhiza glabra as Intracanal Medicaments in Root Canal Treatment

AIM

To evaluate and compare the antimicrobial efficacy of Ca(OH)₂, 25% propolis, and 25% Glycyrrhiza glabra as intracanal medicaments in root canal treatment.

MATERIALS AND METHODS

Total 60 freshly extracted permanent incisors were decoronated and chemomechanical preparation of root canal was performed. Samples were inoculated with a pure culture of Enterococcus faecalis and incubated for 21 days. Colony-forming units (CFUs) were recorded before medication. Incubated samples were randomly categorized into three groups, namely, Ca(OH)₂, propolis, and G. glabra, with 20 samples in each group. Antibacterial activity was assessed by evaluating the variance in the CFUs on Day 7. Paired "t" test and Post-hoc Tukey's test were applied to analyze the data.

RESULTS

Reduction of CFUs was noticed in all the groups (p <0.001), however the reduction was more predominant in the propolis group.

CONCLUSION

Propolis is more effective against E. faecalis, when compared to G. glabra and Ca(OH)₂.

CLINICAL SIGNIFICANCE

Propolis could be used as an effective medicament in root canal treatment.

Antibacterial Effect and Bioactivity of Innovative and Currently Used Intracanal Medicaments in Regenerative Endodontics

INTRODUCTION

The purpose of this study was to determine the antibacterial effect and bioactivity of triple antibiotic paste (TAP), calcium hydroxide (Ca[OH]₂), and calcium hypochlorite (Ca[OCl]₂).

METHODS

Root canals were infected with 3-week-old Enterococcus faecalis biofilm and then medicated for 7 days with TAP, Ca(OH)₂, or Ca(OCl)₂ (n = 10/group). Untreated and uninfected canals were used as positive and negative controls. The antibacterial effect was determined using colony-forming units and a Live/Dead bacterial viability kit. Dental pulp stem cells were seeded on medicated dentin surfaces for 7 days. Sodium thiosulfate and various concentrations of ascorbic acid (1%, 5%, and 10%) were also used to neutralize the samples treated with Ca(OCl)₂ before cell seeding (n = 3 in triplicate). Cell viability and morphology were evaluated using a viability assay and Live/Dead cell analysis. Alkaline phosphatase (ALP) activity was also measured to determine the cells' mineralization activity.

RESULTS

All medicaments decreased the initial bacterial load (P < .05). The highest bacterial reduction in the main canal and dentinal tubules was observed in the Ca(OCl)₂ group (P < .05). TAP- or Ca(OH)₂-treated dentin surface improved cell viability and ALP activity compared with the untreated dentin surface (P < .05), whereas Ca(OCl)₂ decreased cell viability and ALP activity (P < .05). Ten percent ascorbic acid neutralized the effect of Ca(OCl)₂ on the treated dentin surface, showing higher cell viability (P < .05) and similar ALP activity with the untreated dentin surface and the other groups (P > .05).

CONCLUSIONS

Ca(OCl)₂ medication improved root canal disinfection against E. faecalis biofilm compared with TAP and Ca(OH)₂. The adverse effects caused by Ca(OCl)₂ on cell viability and mineralization activity can be neutralized with 10% ascorbic acid.

Evaluation of the Antibacterial Efficacy of Daptomycin, Gentamicin, and Calcium Hydroxide-Antibiotic Combinations on Enterococcus faecalis Dentinal Biofilm: An In Vitro Study

AIM

To evaluate the antibacterial efficacy of calcium hydroxide (CH) with antibiotic combinations: daptomycin and gentamicin against Enterococcus faecalis (E. faecalis) dentinal biofilm.

MATERIALS AND METHODS

Sixty freshly extracted single-rooted mandibular premolars were inoculated with E. faecalis(ATCC 29212) (n = 30) (group A) and clinical isolates (n = 30) (group B) for 3 weeks to form a biofilm. The tooth samples of groups A and B were randomly divided into three subgroups of 10 each, groups 1A and 1B (CH), groups 2A and 2B (CH+G), groups 3A and 3B (CH+D), depending on the medicaments to be placed for one week. The difference between initial and final CFU was calculated and statistically analyzed.

RESULTS

Among the clinical isolates, CH-antibiotic combinations were more effective than CH alone, which was statistically significant (p = 0.006).

CONCLUSION

The dentinal biofilm of clinical isolates of E. faecalis strains exhibited more reduction in bacterial colonies with CH in combination with antibiotics (D and G).

CLINICAL SIGNIFICANCE

Daptomycin and gentamicin when used as an intra-canal medicament in combination with CH are effective in eliminating E. faecalis. Keywords: Calcium hydroxide, Daptomycin, Dentinal biofilm, E. faecalis, Gentamicin.

Osteoclast formation, inflammation, and matrix metalloproteinase-9 are downregulated in bone repair following root canal treatment in dogs teeth

OBJECTIVES

The aim of this study was to investigate the inflammatory infiltrate, osteoclast formation, and expression of MMP-9 during the healing phase following root canal treatment in teeth with apical periodontitis.

MATERIALS AND METHODS

Apical periodontitis was induced in dogs teeth, and root canal treatment was performed in a single visit or using calcium hydroxide as intracanal medication. One hundred and eighty days following treatment the presence of inflammation was examined, and the tissues were stained to detect osteoclasts by means of a tartrate resistant alkaline phosphatase (TRAP) assay. Synthesis of MMP-9 was detected using Western blotting and immunohistochemistry.

RESULTS

Teeth with apical periodontitis that had root canal therapy performed in a single visit presented a higher synthesis of MMP-9 compared with root canal treatment using calcium hydroxide. Treatment with calcium hydroxide resulted in a reduced amount of inflammatory cells and MMP-9 positive cells. Osteoclast formation, the number of MMP-9 positive osteoclasts and cementocytes, was reduced following root canal treatment, regardless of the root canal treatment protocol used.

CONCLUSION

Root canal treatment reduced the amount of inflammatory cells and osteoclasts in periapical area. The use of calcium hydroxide as intracanal medication resulted in a lower synthesis of MMP-9, though the number of osteoclasts and MMP-9 positive osteoclasts were similar between the groups.

CLINICAL RELEVANCE

Periapical bone repair following root canal treatment is impacted by therapy performed either in single visit or using calcium hydroxide dressing measured by inflammatory cell recruitment, osteoclast formation, and MMP-9 synthesis.

Effect of Calcium Hydroxide Combinations with Green Tea Extract and Cocoa Pod Husk Extract on p38 MAPK and Reparative Dentine

AIM AND OBJECTIVE

The aim of this research is to analyze the effect of calcium hydroxide combinations with green tea extract and the combination of calcium hydroxide with cocoa pod husk extract on the activation of p38 MAPK and wide area of reparative dentin in mice dental.

MATERIALS AND METHODS

This study used 36 rats that were randomly divided into three treatment groups: positive control group was applied calcium hydroxide and aquades (group I), the test group was applied calcium hydroxide combined with cocoa pod husk extract (group II), and the next test group was applied using calcium hydroxide combined with green tea extract (group III); all the cavities were restored with RMGIC. On day 7 and 28, experimental animals from each treatment group were killed by peritoneal injection to see the activation of p38 MAPK, while reparative dentin was only seen on day 28.

RESULTS

The result of data analysis using Multiple Comparison Tukey HSD test showed significant difference between the positive control group and the test groups for the average p38 MAPK activation value on day 7 and 28. But there was no significant difference between two test groups. The same thing was obtained in the calculation of the average area of reparative dentin, where group I had the lowest value compared to groups II and III on day 28 with a significant difference. There was no significant difference between groups II and III.

CONCLUSION

The use of combination calcium hydroxide with green tea extract and combination calcium hydroxide with cocoa pod husk extract have significant effect on p38 MAPK activation and wide area of reparative dentin in mice dental.

CLINICAL SIGNIFICANCE

The use of combination calcium hydroxide with green tea extract and combination calcium hydroxide with cocoa pod husk extract have been proven to activate more p38 and form a wider reparative dentin.

Selenium intracanal dressing: effects on the periapical immune response

OBJECTIVES

To evaluate the selenium (Se) behavior when used as an endodontic dressing in teeth with pulp necrosis. Additionally, its effects was also compared with the calcium hydroxide (C.H.), which is used globally as a root canal dressing, and the combination of the C.H. with Se (C.H. + Se).

MATERIALS AND METHODS

The sample consisted of 60 patients requiring endodontic treatment who were divided into groups, i.e., without intracanal medication (empty) and with medications as follows: selenium (Se), calcium hydroxide (C.H.), and calcium hydroxide + selenium (C.H. + Se) (n = 15). After the coronary opening, three absorbent paper points were placed in the RCS and maintained for 2 min for microbial evaluation. Following the cleaning and shaping procedures, new paper points were introduced into the root canal system, passing passively through the root apex (2 mm) into the periapical tissues for 2 min, for immune evaluation. The collections were performed again 15 days later. Real-time PCR quantified the expression of the prokaryotic 16S ribosomal RNA. The 16S mRNA was evaluated before the cleaning and shaping procedures and 15 days later in the groups treated with or without medication.

RESULTS

A significant reduction in the microbial load was observed only in the groups that received endodontic dressing (p < 0.05). The cytokines IFN-γ, TNF-α, IL-1α, IL-17A, IL-10, IL-6 and MCP-1, were also quantified by real-time PCR. There was an increase in the gene expression level of the cytokines (T15) TNF-α and IL-10 in the C.H. group compared to the other groups (p < 0.05). The IFN-γ mRNA expression was reduced in the groups treated with the medications (Se, C.H., and C.H. + Se).

CONCLUSIONS

The findings of the present study indicate that in the case of treatment over multiple sessions, the use of root canal dressing is essential to avoid the root canal system (RCS) microbial recolonization. Selenium potentiated the effects of calcium hydroxide inducing an anti-inflammatory response in periapical tissues.

CLINICAL RELEVANCE

Se is a mineral essential for the formation of the amino acid selenocysteine, which is directly involved in the maintenance of the immune response. Selenium has been widely used in the medical field in the treatment of cancer, as an activator of bone metabolism, and as a stimulator of the immune system. In this study, it was shown that the incorporation of Se, whether as intracanal medication alone or in conjunction with other medications, may potentiate periapical tissue repair after RCS cleaning and shaping procedures.

Antifungal Effectiveness of Various Intracanal Medicaments against Candida albicans: An In Vitro Study

AIM AND OBJECTIVE

To evaluate the antifungal efficiency of various intracanal medicaments against Candida albicans.

MATERIALS AND METHODS

One-hundred and forty extracted human mandibular premolar teeth were decoronated, and the biomechanical preparation was done in crown-down technique. 10 μL culture suspension of C. albicans was placed into the prepared root canal space of all the teeth. After 21 days of incubation, all the teeth were randomly divided into 7 groups with 20 teeth per each group. Group I: triple antibiotic powder (TAP) mixed with 3% chitosan solution; group II: TAP mixed with macrogol-propylene (MP) glycol; group III: chlorhexidine-guttapercha (CHX-GP); group IV: Vitapex; group V: 2% chlorhexidine gel; group VI: calcium hydroxide paste; group VII: normal saline with cotton (positive control) were used as intracanal medicaments, and the samples were incubated for 14 days. Intracanal medicaments were then completely removed using the canal brush. Dentinal chips were harvested from the walls of the root canal space in all samples using Gates-Glidden drills, were transferred into test tubes containing saline, and were serially diluted and placed in 140 Sabouraud dextrose agar plates, incubated at 37°C for 48 hours. Colony forming units (CFUs) of C. albicans were then counted using the digital colony counter.

RESULTS

One-way ANOVA test showed statistically significant difference among the seven groups, as the p value was < 0.001. Tukey's post hoc test showed intergroup comparison between group I and group V; group II and group III were statistically nonsignificant as p value was >0.05.

CONCLUSION

2% chlorhexidine gel and TAP mixed with 3% chitosan solution showed superior antifungal efficiency against C. albicans.

CLINICAL SIGNIFICANCE

Chitosan solution's inherent antifungal efficiency and slow and controlled drug release make it as an effective alternate carrier in mixing it with TAP instead of mixing TAP with MP.

Evaluation of Resin-Based Material Containing Copaiba Oleoresin (Copaifera Reticulata Ducke): Biological Effects on the Human Dental Pulp Stem Cells

The purpose of this study was to analyze in vitro the biological effects on human dental pulp stem cells triggered in response to substances leached or dissolved from two experimental cements for dental pulp capping. The experimental materials, based on extracts from Copaifera reticulata Ducke (COP), were compared to calcium hydroxide [Ca(OH)₂] and mineral trioxide aggregate (MTA), materials commonly used for direct dental pulp capping in restorative dentistry. For this, human dental pulp stem cells were exposed to COP associated or not with Ca(OH)₂ or MTA. Cell cytocompatibility, migration, and differentiation (mineralized nodule formation (Alizarin red assay) and gene expression (RT-qPCR) of OCN, DSPP, and HSP-27 (genes regulated in biomineralization events)) were evaluated. The results showed that the association of COP reduced the cytotoxicity of Ca(OH)₂. Upregulations of the OCN, DSPP, and HSP-27 genes were observed in response to the association of COP to MTA, and the DSPP and HSP-27 genes were upregulated in the Ca(OH)₂ + COP group. In up to 24 h, cell migration was significantly enhanced in the MTA + COP and Ca(OH)₂ + COP groups. In conclusion, the combination of COP with the currently used materials for dental pulp capping [Ca(OH₎₂ and MTA] improved the cell activities related to pulp repair (i.e., cytocompatibility, differentiation, mineralization, and migration) including a protective effect against the cytotoxicity of Ca(OH)₂.

Endodontic Sealers Modified with Silver Vanadate: Antibacterial, Compositional, and Setting Time Evaluation

The incorporation of nanoparticles into endodontic sealers aims at increasing antimicrobial activity of the original material. Aim. The aim of this study is to incorporate the nanostructured silver vanadate decorated with silver nanoparticles (AgVO3, at 2.5%, 5%, and 10%) into three endodontic sealers and evaluate the antibacterial activity of freshly sealers, surface topography and chemical composition, and setting time. Material and Methods. The AgVO3 was incorporated into AH Plus, Sealer 26, and Endomethasone N at concentrations 0%, 2.5%, 5%, and 10% (in mass). The antibacterial activity of freshly sealers was assessed by direct contact with Enterococcus faecalis and CFU/mL count (n=10), surface topography, and chemical composition were measured by SEM/EDS, and the setting time was measured by Gillmore needle (n=10). The Kruskal-Wallis and Dunn statistical tests were applied (α=0.05). Results. All groups of sealers evaluated inhibited E. faecalis (p>0.05). The incorporation of AgVO3 altered the atomic proportions between components of the endodontic sealers, and the percentage of silver (Ag) and vanadium (V) increased proportionally to the concentrations of AgVO3. Topography analysis showed differences in components distribution on the surface of the specimens. The sealers incorporated with AgVO3 of AH Plus presented a lower setting time than the control group (p<0.05). For Sealer 26 and Endomethasone N, the incorporation of AgVO3 increased the setting time in relation to control group (p<0.05). Conclusions. The modification of endodontic sealers by AgVO3 increased the atomic percentage of Ag and V proportionally to the concentration of the nanomaterial and changed the atomic percentage of the sealer components and setting times. It cannot be affirmed that the AgVO3 promote differences in the antimicrobial activity of freshly sealers, and further investigations of the antimicrobial activity of the set sealers should be carried out.

Alkaline fermentation of waste activated sludge with calcium hydroxide to improve short-chain fatty acids production and extraction efficiency via layered double hydroxides

Ca(OH)₂ addition was proposed to improve short chain fatty acids (SCFAs) production via alkaline fermentation of waste activated sludge (WAS), with CO₃^2- and PO₄^3- being removed simultaneously, so that the SCFAs extraction efficiency could be improved. Alkaline fermentation of WAS with Ca(OH)₂ and NaOH addition were performed respectively, and the efficiencies of SCFAs extraction from the fermentation liquids via in situ layered double hydroxides (LDHs) were investigated. The results showed that, the SCFAs production was much more improved with NaOH addition than that with Ca(OH)₂ addition. However, the SCFAs contents in the synthesized SCFAs-LDH were 6.7 ± 0.4 mg COD/L (control), 12.4 ± 0.5 mg COD/L (with NaOH addition) and 17.4 ± 0.4 mg COD/L (with Ca(OH)₂ addition), respectively. This means that Ca(OH)₂ addition is an effective way to improve SCFAs extraction from fermentation liquid of WAS.

The effectiveness of endodontic sealers and endodontic medicaments on the elimination of enterococcus faecalis: an in vitro study

The aim of this study was to investigate the efficacy of endodontic sealers and endodontic medicaments: Aureoseal (OGNA), MTA (DENTSPLY), calcium hydroxide (CH) (Endoidrox OGNA) and iodoformic paste (OGNA) against Enterococcus faecalis. Thirty-six Biomeraux plates (18 MH and 18 DCO) were inoculated with the experimental suspensions. The E. faecalis broth culture suspensions were prepared and adjusted to no. 0.5-0.7 McFarland standard. In each agar plate, three cavities were created, each measuring 4mm in depth and 7mm in diameter, and then completely filled with the product to be tested. To investigate the root canal sealers' antimicrobial activity, the agar diffusion method is used. The diameters of the zones of microbial inhibition were measured in millimeters around the plate. The results showed that the antimicrobial activity of Aureoseal was superior to those of MTA, iodoformic paste and calcium hydroxide for the microorganisms tested. The study confirmed the resistance of Enterococcus faecalis to endodontic sealers. Aureoseal and Calcium hydroxide showed the best results in inhibition test suggesting to employ them in clinical cases.

Bactericidal efficacy of a quaternary ammonium compound with food additive grade calcium hydroxide toward Salmonella Infantis and Escherichia coli on abiotic carriers

The bactericidal efficacies of 0.2% food additive grade calcium hydroxide (FdCa(OH)2) solution, a quaternary ammonium compound (QAC) diluted at 1:500 (QACx500) and their mixture-Mix500 (FdCa(OH)2 powder added at final concentration 0.2% to QACx500)-were investigated at two different temperatures (room temperature (RT) (25 ± 2°C) and 2°C), using varying contact time, with or without presence of organic materials (5% fetal bovine serum: FBS), either in suspension or on abiotic carrier (steel, rubber and plastic). In the suspension test, QACx500 could inactivate Salmonella Infantis at effective level (≥3 log reductions), within 30 sec and 5 sec, respectively, with or without 5% FBS at RT; however, at 2°C it required 30 min and 1 min, respectively. Mix500 revealed the same efficacy as QACx500 at RT, but, at 2°C it required 1 min and 30 sec, respectively with or without FBS. Whereas, 0.2% FdCa(OH)2 solution alone could inactivate S. Infantis within 1 min and 3 min, respectively at RT and 2°C, even with 5% FBS. In the carrier test, single disinfectant required bit more (3 or 5 min) contact time to reduce bacterial load (S. Infantis or Escherichia coli) down to the effective level on rubber surface than that on steel and plastic surface. However, Mix500 could inactivate both bacteria on carrier surfaces within 1 min, even at 2°C. Thus, synergistic effects were observed in the suspension test and the carrier test at both temperatures toward both bacteria.

Effects of a Chimeric Lysin against Planktonic and Sessile Enterococcus faecalis Hint at Potential Application in Endodontic Therapy

Enterococcus faecalis is a commensal opportunistic pathogen found in the intestine, mouth, and vaginal tract of humans. As an invasive pathogen in the oral cavity, E. faecalis is one of the leading causes of periapical endodontic lesions. However, due to the strong biofilm-forming capacity and tolerance of E. faecalis to conventional antibiotics and treatments, limited therapeutic options are available. In the present study, we investigated the activity of ClyR, a chimeric lysin with extended streptococcal lytic spectrum, against planktonic and sessile E. faecalis cells in vitro and in an ex vivo dental model. Our results showed that ClyR has robust and rapid lytic activity against multiple E. faecalis strains, killing >90% planktonic cells within 1 min at a concentration of 50 μg/mL. The biochemical experiments combined with microscopy analysis revealed that ClyR degrades E. faecalis biofilm with high efficacy in a dose-dependent manner, reducing the survival rate to <40% within biofilms after treatment with 50 μg/mL ClyR for 1 h. In the ex vivo dental model, ClyR showed a significant biofilm removal efficacy, killing >90% viable bacteria within biofilms at a low dose of 50 μg/mL, which is much better than ampicillin and similar to calcium hydroxide, the extensively used routine intracanal medicament in the treatment of endodontics and dental traumatology. The robust activity of ClyR against both planktonic and sessile E. faecalis suggests the potential of ClyR in treating endodontic infections caused by E. faecalis.

Hydrogel Arrays and Choroidal Neovascularization Models for Evaluation of Angiogenic Activity of Vital Pulp Therapy Biomaterials

INTRODUCTION

This study intended to evaluate the angiogenic properties of vital pulp therapy materials including white mineral trioxide aggregate (WMTA), calcium hydroxide (Ca[OH]2), Geristore (Den-Mat, Santa Maria, CA), and nano WMTA biomaterials.

METHODS

WMTA, Ca(OH)2, Geristore, and nano WMTA disks were prepared, dispersed into 2 mL Milli-Q (Millipore, ThermoFisher, Hanover Park, IL) distilled water, and centrifuged to obtain 2 mL supernatant elution. Thirty-five wells of polyethylene glycol hydrogel arrays were prepared and divided into 5 groups of 7 (n = 7). Mice molar endothelial cells (ECs) were placed on hydrogel arrays. The elution prepared from each sample was diluted in growth medium (1:3) and added to the hydrogel arrays. The EC medium alone was used for the control. For the choroidal neovascularization (CNV) model, thirty-five 6-week-old female mice were lasered and divided into 5 groups, and elution from each sample (2 μL) or saline (control) was delivered by intravitreal injection on the day of the laser treatment and 1 week later. The mean number of nodes, the total length of the branches in the hydrogel arrays, and the mean area of CNV were calculated using ImageJ software (National Institutes of Health, Bethesda, MD) and analyzed by 1-way analysis of variance and post hoc Tukey honest significant difference tests.

RESULTS

The comparison of results regarding the number of nodes showed the values of control > Geristore > nano WMTA > WMTA > Ca(OH)2. Regarding the total branch length and the CNV area, the comparison of results showed values of Geristore > control > nano WMTA > WMTA > Ca(OH)2.

CONCLUSIONS

All tested materials showed minimal antiangiogenic activity, whereas Geristore and nano WMTA showed a higher proangiogenic activity than WMTA and Ca(OH)2.

Removal of calcium hydroxide intracanal medicament by different irrigants and irrigating techniques: a cone beam computed tomography analysis

The aim of this study was to use cone beam computed tomography (CBCT) to evaluate the removal of calcium hydroxide (Ca[OH]2) from root canals after using different irrigation and activation protocols. Root canals (n = 128) were filled with Ca(OH)2 and scanned using CBCT. The Ca(OH)2 was removed after 1 week using 1 of 12 groups (G1-G12) according to the final irrigating solution: G1, 6% sodium hypochlorite (NaOCl) + 18% etidronic acid (EA) with no activation; G2, NaOCL + EA + passive ultrasonic irrigation (PUI); G3, NaOCl + EA + Finishing File (FF); G4, NaOCl + EA + NaviTip FX irrigation needle (NTFX); G5, 3% NaOCl + 17% ethylenediaminetetraacetic acid (EDTA) with no activation; G6, NaOCl + EDTA + PUI; G7, NaOCl + EDTA + FF; G8, NaOCl + EDTA + NTFX; G9, 3% NaOCl with no activation; G10, NaOCl + PUI; G11, NaOCl + FF; G12, NaOCL + NTFX. The amount of residual Ca(OH)2 was assessed by CBCT. Group comparisons were performed using 1-way analysis of variance and Student-Newman-Keuls post hoc test (P = 0.05). Group 7 showed the least residual Ca(OH)2 (10.83%), which was not significantly different from G6 (13.79%) (P > 0.05). The percentage of residual Ca(OH)2 found in these 2 groups was significantly less than that found in the other groups (P < 0.05). None of the protocols could completely remove Ca(OH)2 from the root canal system, but the plastic rotary FF and PUI, in conjunction with NaOCl and EDTA, removed significantly more Ca(OH)2 than the other irrigation activation protocols tested.

Effects of alkali types on waste activated sludge (WAS) fermentation and microbial communities

The effects of two alkali agents, NaOH and Ca(OH)₂, on enhancing waste activated sludge (WAS) fermentation and short chain fatty acids (SCFAs) accumulation were studied in semi-continuous stirred tank reactors (semi-CSTR) at different sludge retention time (SRT) (2-10 d). The optimum SRT for SCFAs accumulation of NaOH and Ca(OH)₂ adding system was 8 d and 10 d, respectively. Results showed that the average organics yields including soluble chemical oxygen demand (SCOD), protein, and carbohydrate in the NaOH system were as almost twice as that in the Ca(OH)₂ system. For Ca(OH)₂ system, sludge hydrolysis and protein acidification efficiencies were negatively affected by Ca²⁺ precipitation, which was revealed by the decrease of Ca²⁺ concentration, the rise of zeta potential and better sludge dewaterability in Ca(OH)₂ system. In addition, Firmicutes, Proteobacteria and Actinobacteria were the main microbial functional groups in both types of alkali systems. NaOH system obtained higher microbial quantities which led to better acidification. For application, however, Ca(OH)₂ was more economically feasible owning to its lower price and better dewaterability of residual sludge.

Clinical and radiographic evaluation of pulpectomy in primary teeth: a 18-months clinical randomized controlled trial

BACKGROUND

To avoid untoward changes when primary teeth are replaced by permanent teeth, resorption of the material used in primary teeth root canal filling should occur at the same rate as root resorption. The Aim of this study was to compare the success rates of a mixed primary root canal filling (MPRCF, ingredients: zinc oxide-eugenol [ZOE], iodoform, calcium hydroxide) to those of ZOE and Vitapex in pulpectomised primary molars.

METHODS

One hundred and sixty primary molars from 155 children (average age 5.88 ± 1.27 years) underwent two-visit pulpectomy using one of the three materials. The clinical and radiographic findings at 6, 12 and 18 months were assessed.

RESULTS

At 6 and 12 months, the MPRCF and ZOE success rates were 100%. The Vitapex group showed clinical success rate and radiographic success rate of 100 and 94.5% at 6 months, and 80.4 and 60.7% at 12 months. The 18-month clinical success rates of the MPRCF, ZOE and Vitapex were 96.2, 92.2 and 71.4% and radiographic success rates were 92.5, 88.2 and 53.6%, respectively. There was a statistically significant difference in the success rates between MPRCF and Vitapex and no significant differences between MPRCF and ZOE. More MPRCF were resorbed at same rate with roots than ZOE and Vitapex. Early resorption of root filling resulted in more failure.

CONCLUSIONS

The mixture of ZOE, iodoform and calcium hydroxide can be considered an effective root canal filling material in pulp involved primary teeth and had no adverse effect on tooth replacement.

TRIAL REGISTRATION

ChiCTR-TRC-14004938 . Registered 13 July 2014.

NOS Evaluations in Human Dental Pulp-Capping with MTA and Calcium-Hydroxide

The aim of this study is to compare mineral trioxide aggregate (MTA) with calcium hydroxide when used as pulp-capping material in human teeth. 40 teeth were divided into groups based on clinical diagnosis: healthy and hyperaemic. The teeth were pulp capped with MTA and calcium hydroxide. We localized the eNOS and iNOS by immunohistochemistry, tested their mRNA expression by RT-PCR and protein levels by western blots. The evaluation of the samples was based on the cell inflammatory response and on the pulp tissue organization. In particular, evaluation of eNOS and iNOS differences between the various groups and the cellular evolution after the first 7 days from the treatment, and at a distance of 28 days. Our results suggest that there are differences in localization and expression between eNOS and iNOS in dental pulp. Our study has helped us to better understand the effects that calcium hydroxide and MTA have on pulp tissue.