Fracture resistance of endodontically treated maxillary premolars restored by silorane-based composite with or without fiber or nano-ionomer

Shafiei, Fereshteh,Tavangar, Maryam Sadat,Ghahramani, Yasamin,Fattah, Zahra The Korean Academy of Prosthodonitics 2014 The Journal of Advanced Prosthodontics Vol.6 No.3

PURPOSE. This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane-or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS. Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate-and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (${\alpha}$=0.05). RESULTS. Mean fracture resistance for the eight groups (in Newton) were G1: $1200{\pm}169^a$, G2: $360{\pm}93^b$, G3: $632{\pm}196^c$, G4: $692{\pm}195^c$, G5: $917{\pm}159^d$, G6: $1013{\pm}125^{ad}$, G7: $959{\pm}148^d$, G8: $947{\pm}105^d$ (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION. Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.

The impact of arbuscular mycorrhizal fungi on tomato plant resistance against Tuta absoluta (Meyrick) in greenhouse conditions

Shafiei Fateme,Shahidi-Noghabi Shahnaz,Sedaghati Ebrahim 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.3

The symbiotic relationship between plants and arbuscular mycorrhizal fungi (AMF) improves plant growth and increases its resistance to pests and diseases. Mycorrhizal fungi are among the specialized fungi associated with the rhizosphere and are completely dependent on plant organic carbon. In this research tomato, Solanum lyco persicum L. was used as the host plant to evaluate the interaction effects between inoculation of tomato plant with AMF and feeding of tomato leaf miner, Tuta absoluta (Meyrick). In addition, plant growth parameters and growth rate of insect were assessed. The mycorrhizal treatment included a mixture of four fungal species (Funneliformis mosseae, Rhizophagus intraradices, R. irregularis and Glomus iranicus). The results of the experiment showed that tomato plant roots were well colonized (66.29%) by AMF and there was a significant mutual relationship be tween the insects feeding on the plants and the fungi. Feeding by the insects on plants inoculated with the fungus increased percentage of colonization by AMF in plants infested with the insect as compared to the control plants. The results also indicated that growth parameters and phosphorus content of the plants inoculated with fungi significantly increased compared to the control group. Moreover, significantly lower growth rate and con sumption index observed in the T. absoluta larvae were fed on the leaves of plants treated with AMF compared to leaves of plants not inoculated with AMF.

Effect of dimethyl sulfoxide on bond durability of fiber posts cemented with etch-and-rinse adhesives

Shafiei, Fereshteh,Memarpour, Mahtab,Sarafraz, Zahra The Korean Academy of Prosthodonitics 2016 The Journal of Advanced Prosthodontics Vol.8 No.4

PURPOSE. This study was undertaken to investigate whether use of an adhesive penetration enhancer, dimethyl sulfoxide (DMSO), improves bond stability of fiber posts to root dentin using two two-step etch-and-rinse resin cements. MATERIALS AND METHODS. Forty human maxillary central incisor roots were randomly divided into 4 groups after endodontic treatment and post space preparation, based on the fiber post/cement used with and without DMSO pretreatment. Acid-etched root dentin was treated with 5% DMSO aqueous solution for 60 seconds or with distilled water (control) prior to the application of Excite DSC/Variolink II or One-Step Plus/Duolink for post cementation. After micro-slicing the bonded root dentin, push-out bond strength (P-OBS) test was performed immediately or after 1-year of water storage in each group. Data were analyzed using three-way ANOVA and Student's t-test (${\alpha}$=.05). RESULTS. A significant effect of time, DMSO treatment, and treatment${\times}$time interaction were observed (P<.001). DMSO did not affect immediate bonding of the two cements. Aging significantly reduced P-OBS in control groups (P<.001), while in DMSO-treated groups, no difference in P-OBS was observed after aging (P>.05). CONCLUSION. DMSO-wet bonding might be a beneficial method in preserving the stability of resin-dentin bond strength over time when fiber post is cemented with the tested etch-and-rinse adhesive cements.

Effect of Microstructure and Texture Evolution During Variable Gauge Rolling on Mechanical Properties of Tailor Rolled Blanks

E. Shafiei,K. Dehghani,F. Ostovan,Meysam Toozandehjani 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.5

In this study, anisotropic elastic and plastic mechanical properties of a tailor rolled blank (TRB) with thickness ratio of0.52 (1 mm/1.9 mm), have been fully studied. To gain a deeper insight into anisotropic mechanical behavior of the studiedTRB, continuous changes in microstructure and crystallographic texture of a dual phase steel caused by variable gaugerolling (VGR) were investigated on several points (on RD–ND plane) along longitudinal direction with the aid of EBSDobservations. Analysis of grain boundary (GB) maps revealed that ferrite grain refinement is occurred during VGR so thatthe average ferrite grain size decreases from 4.1 μm for the thicker side to 2.2 μm for the thinner side. Furthermore, it wasfound out that substructure density is more intense within smaller ferrite grains. Evaluation of inverse pole figures as well asorientation distribution function maps showed that texture of thicker side comprises {001}⟨110⟩ and {112}⟨110⟩ componentsalong -fiber. In addition, it was revealed that orientations of {111}⟨110⟩ and {111}⟨112⟩ along -fiber strengthen alongVGR direction by further increase in thickness reduction near thinner side. Accordingly, unprecedented gradual changes inmechanical properties with respect to these changes in microstructure and texture, were obtained. Finally, the correlationbetween in-plane anisotropic mechanical properties [Young’s modulus (E), yield stress (YS), ultimate tensile stress (UTS)and total elongation] of the studied tailor rolled blank with microstructure and deformation texture was interpreted.

Investigation and optimization of the internal cylindrical surface lapping process of 440c steel

Mohammad Shafiei Alavijeh,Hossein Amirabadi 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.8

A new lapping method is proposed for internal cylindrical surfaces finishing. Regression analysis and artificial neural network (ANN) were used for modeling this lapping process and predicting the effects of parameters of rotational speed of the lapping tool (ω), the length of the lapping tool (L) and difference in external diameter of the lapping tool and internal diameter of the workpiece (D) on the material removal rate (MRR), out-of-cylindricity (C) and surface roughness (Ra) of the lapped holes. Comparison of the results of the regression and ANN models with the values obtained from the experiments indicates that the MRR, Ra and C are more accurately predicted using ANN models. MRR, Ra and C of the lapped holes have been optimized using genetic algorithm (GA) and particle swarm optimization (PSO) algorithm. The results show that the highest MRR, which is equal to 2029 μg/min, has been achieved at ω of 400 rpm, D of 0.1 mm and L of 45 mm. The lowest Ra of the lapped hole is 64 nm which has been obtained at ω of 100 rpm, D of 0.1 mm and L of 20.82 mm. The minimum C of the lapped hole is 3 μm, which was obtained at ω of 212 rpm, D of 0.1 mm and L of 28.3 mm. The most important problem in the lapping process is the low MRR which causes increased cost and production time. Therefore, in the lapping process, the selection of conditions, that in addition to the production of pieces with geometric accuracy and surface roughness needing a high MRR, is very important. In this study, MRR, Ra and cylindricity of the lapped holes was optimized using multi-objective PSO (MOPSO) algorithm and non-dominated sorting genetic algorithm II (NSGA II), and the Pareto optimal solutions were obtained. Comparison of the results obtained from NSGA II and MOPSO shows that both of these algorithms can achieve optimal Pareto front with the same accuracy, but the time required to reach the MOPSO algorithm to the optimal Pareto front is 25 % less than the NSGA II.

Study on Iranian Maritime Law System

Fereydoon Shafiei Karaji,Yeong Seok Cheong 韓國海法學會 2009 韓國海法學會誌 Vol.31 No.1

This study focuses on foundation of Iranian maritime law code. The research first provides a background to the topic, with brief introduction to history of Iran starting from 500BC on time of Persian Empire, review the present government and judicial legal system of Iran. Discussing the history of maritime law and its developments from a global perspective, and also will study in general the procedural method of compiling and codification of present enforced Iranian Maritime Code, and its involvements in marine activities. it will briefly analysis the weak and strong points of the law with recommendation for appropriate further action which may requires to be taken by government for revision or amendment of present law to comply with vast number of respective conventions which Islamic Republic of Iran already ratified many of them in order of keep the international legal standard for judgments. It will be concluded with short conclusion.

Basilar Skull Fractures and Their Complications in Patients With Traumatic Brain Injury

Mehdi Shafiei,Bahram Aminmansour,Mehdi Mahmoodkhani,Mohammadamin Seyedmoalemi,Donya Sheibani Tehrani 대한신경손상학회 2023 Korean Journal of Neurotrauma Vol.19 No.1

Since traumatic brain injury is more common in young people, who are the main workforce and builders of society, it is important to consider the effects caused by brain injury on them. In this study, we investigated the clinical manifestations, complications, and prognosis of patients with basilar skull fractures.

Fracture resistance of endodontically treated maxillary premolars restored by silorane-based composite with or without fiber or nano-ionomer

Fereshteh Shafiei,Maryam Sadat Tavangar,Yasamin Ghahramani,Zahra Fattah 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.3

PURPOSE This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane- or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate- and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (α=0.05). RESULTS Mean fracture resistance for the eight groups (in Newton) were G1: 1200 ± 169a, G2: 360 ± 93b, G3: 632 ± 196c, G4: 692 ± 195c, G5: 917 ± 159d, G6: 1013 ± 125ad, G7: 959 ± 148d, G8: 947 ± 105d (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.

Effect of dimethyl sulfoxide on bond durability of fiber posts cemented with etch-and-rinse adhesives

Fereshteh Shafiei,Mahtab Memarpour,Zahra Sarafraz 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.4

PURPOSE This study was undertaken to investigate whether use of an adhesive penetration enhancer, dimethyl sulfoxide (DMSO), improves bond stability of fiber posts to root dentin using two two-step etch-and-rinse resin cements. MATERIALS AND METHODS Forty human maxillary central incisor roots were randomly divided into 4 groups after endodontic treatment and post space preparation, based on the fiber post/cement used with and without DMSO pretreatment. Acid-etched root dentin was treated with 5% DMSO aqueous solution for 60 seconds or with distilled water (control) prior to the application of Excite DSC/Variolink II or One-Step Plus/Duo-link for post cementation. After micro-slicing the bonded root dentin, push-out bond strength (P-OBS) test was performed immediately or after 1-year of water storage in each group. Data were analyzed using three-way ANOVA and Student's t-test (α=.05). RESULTS A significant effect of time, DMSO treatment, and treatment × time interaction were observed (P<.001). DMSO did not affect immediate bonding of the two cements. Aging significantly reduced P-OBS in control groups (P<.001), while in DMSO-treated groups, no difference in P-OBS was observed after aging (P>.05). CONCLUSION DMSO-wet bonding might be a beneficial method in preserving the stability of resin-dentin bond strength over time when fiber post is cemented with the tested etch-and-rinse adhesive cements.

Design of Eutectic High Entropy Alloys in Al–Co–Cr–Fe–Ni System

Ali Shafiei 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.1

In the present work, a simple approach is proposed for predicting the compositions of eutectic high entropy alloys (EHEAs)in Al–Co–Cr–Fe–Ni system. It is proposed that eutectic lines exist between certain eutectic alloys in this system and, asa result, new eutectic or near-eutectic compositions can be obtained by mixing the alloys which are located on the sameeutectic line. The approach is applied for a series of experimentally verified eutectic alloys and new eutectic or near-eutecticalloys are designed for Al–Co–Cr–Fe–Ni system. Furthermore, by investigating the compositions of verified eutectic alloysin Al–Co–Cr–Fe–Ni system, compositional maps are proposed which show the relations between the concentrations ofconstituent elements in eutectic alloys. The compositional maps suggest that EHEAs are derived from binary and ternaryeutectic alloys. Moreover, the proposed diagrams can be considered as convenient methods for evaluating the compositionof EHEAs in Al–Co–Cr–Fe–Ni system.