Synthesis and characterization of two novel antibacterial dendritic methacrylate-based dental monomers

This study explores the synthesis and characterization of two novel antibacterial dendritic methacrylate-based dental monomers. For this purpose, two dendritic esters have been synthesized via condensation reaction and then reacted with methacryloyl chloride to afford methacrylate-end caped dendritic esters. These compounds are subsequently converted to quaternary ammonium fluoride monomers (QAFMs) with decyl substituted side chain to produce two novel antibacterial dendreticdental monomers. The chemical structures of synthesized samples have been characterized using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopies.The obtained monomers can be used to replace 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropyl)-phenyl]propane (Bis-GMA) as the base monomer of universal resin-based dental composites in the presence of a diluting monomer (e.g.,triethyleneglycoldimethacrylate; TEGDMA), mainly due to their superior characteristics such as multifunctionalities as well as antibacterial activities

Synthesis and characterization of two novel antibacterial dendritic methacrylate-based dental monomers

504-513This study explores the synthesis and characterization of two novel antibacterial dendritic methacrylate-based dental monomers. For this purpose, two dendritic esters have been synthesized via condensation reaction and then reacted with methacryloyl chloride to afford methacrylate-end caped dendritic esters. These compounds are subsequently converted to quaternary ammonium fluoride monomers (QAFMs) with decyl substituted side chain to produce two novel antibacterial dendreticdental monomers. The chemical structures of synthesized samples have been characterized using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopies.The obtained monomers can be used to replace 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropyl)-phenyl]propane (Bis-GMA) as the base monomer of universal resin-based dental composites in the presence of a diluting monomer (e.g.,triethyleneglycoldimethacrylate; TEGDMA), mainly due to their superior characteristics such as multifunctionalities as well as antibacterial activities

The effect of Morinda Citrifolia juice as an endodontic irrigant on smear layer and microhardness of root canal dentin

AbstractPurposeThe purpose of this study was to evaluate the effect of Morinda Citrifolia Juice (MCJ) on smear layer removal and microhardness value of root canal dentin in compared with various endodontic irrigants.Material and methodsEighty-four single-rooted human teeth were prepared to apical size of #35. Since decoronation, samples were divided into seven groups of 12 in each (n=12). Specimens were finally irrigated by either 1: 2.5% NaOCl, 2: 6% MCJ, followed by a final flush of 17% ethylene diaminetetraacetic acid (EDTA), 3: 6% MCJ, 4: 2.5% NaOCl then17% EDTA, 5: MTAD, 6: 2% chlorhexidine (CHX), and 7: saline. After irrigation, all samples were subjected to Vickers microhardness test at 100 and 500-μm depths and then were examined under scanning electron microscopy (SEM) and ImageJ program was used to calculate open dentinal tubules. One way ANOVA and post hoc Tukey tests were used to reveal any significant differences among and between groups respectively.ResultsThe microhardness values at 100μm and 500μm for MTAD were significantly lower than for NaOCl+EDTA and MCJ+EDTA groups (p<0.05). MCJ+EDTA, NaOCl+EDTA, and MTAD protocol significantly removed smear layer in compared with control group (p<0.05), with no significant differences among these three groups.ConclusionsIt was concluded that 6% MCJ followed by a final flush of 17% EDTA can be regarded as an effective solution on smear layer removal without any adverse influence on microhardness property of root canal dentin

Comparison of Manual and Rotary Instrumentation on Postoperative Pain in Teeth with Asymptomatic Irreversible Pulpitis: A Randomized Clinical Trial

Introduction: One of the most common complications of root canal treatment is postoperative pain. The aim of the present clinical trial was to compare the severity of postoperative pain after root canal preparation with RaCe rotary system and hand K-Flexofile. Methods and Materials: A total of 96 mandibular first and second molars were divided into two groups (n=48) based on root canal preparation technique. The teeth in both groups underwent one-session root canal treatment and the severity of postoperative pain was evaluated using visual analog scale (VAS) at 4-, 8-, 12-, 24- and 48-h and 1-week intervals. In addition, the type and dosage of analgesics were recorded. Data were analyzed with repeated-measures ANOVA. Statistical significance was set at 0.05. Results: The difference between the two groups during this period and at subsequent intervals were not significant (P&gt;0.05). There were no significant differences between the two groups in type and the number of analgesics in pain-free subjects (P=0.12 and P=0.61, respectively). Conclusion: There were no statistically significant differences in pain severity between the two groups at any intervals.Keywords: Manual Instrumentation; Postoperative Pain; Root Canal Preparation; Rotary Instrumentatio

Compressive Strength of Mineral Trioxide Aggregate with and without Disodium Hydrogen Phosphate at Different Mixing Ratios

Introduction: Mineral Trioxide Aggregate (MTA) is a substance with favorable physical-mechanical properties. Disodium hydrogen phosphate(DHP) is sometimes added to MTA to reduce its setting time. Therefore, this study was conducted to evaluate the effect of various ratios of liquid to powder of white MTA (WMTA) and addition of DHP on its compressive strength. Methods and Materials: One hundred and twenty samples were prepared with a two-piece stainless steel mold with a height of 6 mm and a diameter of 4 mm in order to evaluate the compressive strength where WMTA was used in 60 samples and DHP in white MTA composition (DHPWMTA) was used in other 60 samples. The compressive strength of WMTA and DHPWMTA was measured in various ratios of liquid to powder including 50, 60 and 70% and at 24 h and 21 days (n=10). Univariate Analysis of Variance test with SPSS 16 software were used to determine the difference between groups. The level of significance was set at 0.05. Results: The maximum and minimum compressive strength of WMTA groups were 63.25±1.96 (50% ratio and 21 days) and 37.79±1.28 (70% ratio and 24 h), respectively. The maximum and minimum compressive strength of DHPWMTA groups were 63.96±1.40 (60% ratio and 21 days) and 37.37±1.62 (70% ratio and 24 h), respectively. The effect of each of factors (type of material, powder to liquid ratio and time) alone were significant on the compressive strength (P&lt;0.05). However, the interactive effect of three factors (type of material, powder to liquid ratio and time) were not statistically significant on compressive strength (P&gt;0.05). Conclusion: Adding 2.5 wt% of DHP to white MTA increased samples compressive strength. Compressive strength in liquid to powder ratios of 50 and 60% compare to 70% and at 21 days compared to 24 h was high.Keywords: Compressive Strength; Disodium Hydrogen Phosphate; Mineral Trioxide Aggregat

A Comparative Analysis of Spatial Configuration in Designing Residential Houses Using Space Syntax Method (Case Studies: Houses of Isfahan and Modern Architecture Styles)

In the traditional Persian architecture, the design of different spaces of houses was based on the needs of their inhabitants, and these needs affected even the arrangement and the mode of spatial relationships. In contemporary architecture, housing patterns do not usually meet the needs of their inhabitants. This research investigates spatial configuration in a sample of houses of the first modern and Isfahan style architecture; in order to find the functional space and the most important factor affecting the space syntax. Selected samples were analyzed using "E-Graph" software, and by calculating the average and the Pearson coefficients of three variables of depth, integration and connectivity, and the correlation of these variables on space syntax was studied. The results show that in traditional houses, the yard and the porch, had the role of connection in the system; and Majlesi (chamber) was located at the lowest depth. In modern houses, the living room and the hall are functionally used and perform as space divider while other spaces connect to this space with direct access. Finally, the variables of integration and connectivity had the greatest impact on the space syntax, both in traditional and modern houses

Cyclic fatigue resistance and fractographic analysis of RaCe and ProTaper rotary NiTi instruments

INTRODUCTION: This study investigated the fatigue and fracture modes of RaCe and ProTaper rotary instruments. MATERIALS & METHODS: Fatigue resistance was evaluated by rotating the files 30° or 60° and with 2 or 5mm radius of curvature. RaCe taper 06 size 25 and ProTaper F1 files (n=40) were used. The number of rotations to failure was analyzed by two-way ANOVA and independent sample    t-test. Fracture surfaces were examined under a scanning electron microscope.RESULTS: Both files exhibited significantly more resistance to fracture when angle severity was reduced and increase in curvature radius (P=0.000). ProTaper demonstrated higher number of cycle of failure (P=0.0029) in one group (r=5mm, 60º). SEM observation revealed fatigue mark/features in 17 specimens, shear characteristics in 37 samples, and tensile overload in 26 samples.CONCLUSION: Radius of curvature was the main factor in torsional and fatigue failures

Antibacterial Efficacy of Different Concentrations of Sodium Hypochlorite Gel and Solution on Enterococcus faecalis Biofilm

Introduction: This in vitro study compared the antibacterial efficacy of 2.5% sodium hypochlorite gel and 2.5% and 5.25% sodium hypochlorite solutions on Enterococcus faecalis (E. faecalis) biofilm. Methods and Materials: The root canals of 60 extracted human single-rooted teeth were contaminated with E. faecalis and incubated for 6 weeks. The samples were randomly assigned to three experimental groups and one control group (n=15). The study protocol in the experimental groups consisted of injection of 5 mL of each irrigant into the root canals. Samples were collected from the root canal walls and 1:10 serial dilutions were prepared and added to Muller Hinton Agar (MHA) plates and incubated at 37°C for 48 h. A classic colony counting technique was used for determining vital E. faecalis bacterial counts in MHA plates. The Kruskal-Wallis test was used for statistical analysis of the data. The level of significance was set at 0.05. Results: The antibacterial effect of the irrigants in all three experimental groups was significantly greater than the control group (P&lt;0.05), with no significant difference between 2.5% and 5.25% NaOCl solutions (P&gt;0.05). The effect of 2.5% and 5.25% NaOCl solutions were significantly superior to 2.5% NaOCl gel (P&lt;0.05). Conclusion: Under the limitations of this study, 2.5% NaOCl gel was effective in reducing E. faecalis counts; however this effect was less than that of NaOCl solutions.Keywords: Antibacterial; Biofilm; Enterococcus Faecalis; Sodium Hypochlorit

Antimicrobial Efficacy of Mineral Trioxide Aggregate with and without Silver Nanoparticles

Introduction: Most current root-end filling materials do not provide a perfect seal. Thus, a microscopic space is likely to exist in the interface between walls of the root-end cavity and filling material, which allows microorganisms and their products to penetrate. In addition to good sealing ability and biocompatibility, root-end filling materials should ideally have some antimicrobial activity. Therefore, this in vitro study aimed to evaluate the antimicrobial properties of Angelus white mineral trioxide aggregate (MTA) and the mixture of MTA with silver nanoparticles (1% weight; MTA/SN). Materials and Methods: Antimicrobial properties of MTA and MTA/SN were tested by agar diffusion technique against Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans. The microbial inhibition zones around the materials were measured by a caliper with 0.1-mm accuracy. Student’s t-test was used for comparison between the two groups in normal data distribution and Man-Whitney U test for non-normal distribution. Results: Student’s t-test revealed that for E. faecalis, C. albicans, and P. aeruginosa, microbial inhibition zone of MTA/SN was significantly greater than that of MTA (P=0.000). Mann-Whitney U test indicated no significant difference between the effect of MTA and MTA/SN on S. aureus (P&gt;0.05). Conclusion: Based on the results of this study, adding silver nanoparticles to MTA improved its antimicrobial efficacy

Effect of pH on compressive strength of some modification of mineral trioxide aggregate

Objectives: Recently, it was shown that NanoMTA improved the setting time and promoted a better hydration process which prevents washout and the dislodgment of this novel biomaterial in comparison with WTMA. This study analyzed the compressive strength of ProRoot WMTA (Dentsply), a NanoWMTA (Kamal Asgar Research Center), and Bioaggregate (Innovative Bioceramix) after its exposure to a range of environmental pH conditions during hydration. Study Design: After mixing the cements under aseptic condition and based on the manufacturers' recommendations, the cements were condensed with moderate force using plugger into 9 × 6 mm split molds. Each type of cement was then randomly divided into three groups (n=10). Specimens were exposed to environments with pH values of 4.4, 7.4, or 10.4 for 3 days. Cement pellets were compressed by using an Instron testing machine. Values were recorded and compared. Data were analyzed by using one-way analysis of variance and a post hoc Tukey's test. Results: After 3 days, the samples were solid when probed with an explorer before removing them from the molds. The greatest mean compressive strength 133.19±11.14 MPa was observed after exposure to a pH value of 10.4 for NanoWMTA. The values decreased to 111.41±8.26 MPa after exposure to a pH value of 4.4. Increasing of pH had a significant effect on the compressive strength of the groups (p<0.001). The mean compressive strength for the NanoWMTA was statistically higher than for ProRoot WMTA and Bioaggregate (p<0.001). Moreover, increasing of pH values had a significant effect on compressive strength of the experimental groups (p<0.001). Conclusion: The compressive strength of NanoWMTA was significantly higher than WMTA and Bioaggregate; the more acidic the environmental pH, the lower was the compressive strength