Marginal adaptation of three root-end filling materials in cavities prepared with laser and ultrasonic tips: an in vitro comparative study

Zengin Busra,Aydemir Seda,Chandler Nicholas Paul 대한치과보존학회 2025 Restorative Dentistry & Endodontics Vol.50 No.4

Objectives: This study evaluated the marginal adaptation of ProRoot MTA (Dentsply Tulsa Dental), Biodentine (Septodont), and TotalFill BC RRM (FKG) placed in root-end cavities prepared with ultrasonic or Er,Cr:YSGG laser tips, using scanning electron microscopy.Methods: The canals of 90 extracted maxillary central incisors were prepared and obturated and their roots resected. Six groups of 15 specimens were allocated as follows: ultrasonic + ProRoot MTA, ultrasonic + Biodentine, ultrasonic + TotalFill, laser + ProRoot MTA, laser + Biodentine, and laser + TotalFill. Roots were sectioned longitudinally to expose the filling material. Apical and coronal micrographs were taken, and the greatest distance between dentin and filling material was measured. The total gap area was also calculated using further micrographs.Results: Cavities prepared with the ultrasonic tips and filled with Biodentine showed significantly greater gap dimensions compared with TotalFill (p < 0.001) and ProRoot MTA (p = 0.007) in the apical region. The ultrasonic group showed significantly higher void values compared to the laser group for ProRoot MTA (p = 0.026), when comparing the total values of void. The Biodentine group was significantly higher than the TotalFill group in root-end cavities prepared with ultrasonic tips (p < 0.001). The Biodentine group was significantly higher than the ProRoot MTA group in root-end cavities prepared with the laser tip (p = 0.002).Conclusions: Under the conditions of this study, it was determined that the root-end cavity preparation technique had an effect on the amount of gaps formed between the dentin and the three filling materials.

The effect of mortar type and joint thickness on mechanical properties of conventional masonry walls

Zengin, Basak,Toydemir, Burak,Ulukaya, Serhan,Oktay, Didem,Yuzer, Nabi,Kocak, Ali Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.6

Masonry walls are of a complex (anisotropic) structure in terms of their mechanical properties. The mechanical properties of the walls are affected by the properties of the materials used in wall construction, joint thickness and the type of masonry bond. The carried-out studies, particularly in the seismic zones, have revealed that the most of the conventional masonry walls were constructed without considering any engineering approach. Along with that, large-scale damages were detected on such structural elements after major earthquake(s), and such damages were commonly occurred at the brick-joint interfaces. The aim of this study was to investigate the effect of joint thickness and also type of mortar on the mechanical behavior of the masonry walls. For this aim, the brick masonry walls were constructed through examination of both the literature and the conventional masonry walls. In the construction process, a single-type of brick was combined with two different types of mortar: cement mortar and hydraulic lime mortar. Three different joint thicknesses were used for each mortar type; thus, a total of six masonry walls were constructed in the laboratory. The mechanical properties of brick and mortars, and also of the constructed walls were determined. As a conclusion, it can be stated that the failure mechanism of the brick masonry walls differed due to the mechanical properties of the mortars. The use of bed joint thickness not less than 20 mm is recommended in construction of conventional masonry walls in order to maintain the act of brick in conjunction with mortar under load.

Large-Scale Integrated Network System Simulation with DEVS-Suite

( Ahmet Zengin ) 한국인터넷정보학회 2010 KSII Transactions on Internet and Information Syst Vol.4 No.4

Formidable growth of Internet technologies has revealed challenging issues about its scale and performance evaluation. Modeling and simulation play a central role in the evaluation of the behavior and performance of the large-scale network systems. Large numbers of nodes affect simulation performance, simulation execution time and scalability in a weighty manner. Most of the existing simulators have numerous problems such as size, lack of system theoretic approach and complexity of modeled network. In this work, a scalable discrete-event modeling approach is described for studying networks` scalability and performance traits. Key fundamental attributes of Internet and its protocols are incorporated into a set of simulation models developed using the Discrete Event System Specification (DEVS) approach. Large-scale network models are simulated and evaluated to show the benefits of the developed network models and approaches.

Controlled enzymatic stability and release characteristics of supramolecular chiral peptide amphiphile nanofiber gels

Aygul Zengin,Goksu Cinar,Mustafa O. Guler 한국물리학회 2017 Current Applied Physics Vol.17 No.5

Supramolecular bioarchitectures formed by assembly of achiral or chiral building blocks play important roles in various biochemical processes. Stereochemistry of amino acids is important for structural organization of peptide and protein assemblies and structure-microenvironment interactions. In this study, oppositely charged peptide amphiphile (PA) molecules with L-, D- and mixture of L- and D-amino acid conformations are coassembled into supramolecular nanofibers and formed self-supporting gels at pH 7.4 in water. The enzymatic stability of the PA nanofiber gels was studied in the presence of proteinase K enzyme, which digest a broad spectrum of proteins and peptides. The structural changes on the chiral PA nanofibers were also analyzed at different time periods in the presence of enzymatic activity. Controlled release of a model cargo molecule through the chiral PA nanofiber gels was monitored. The diffusivity parameters were measured for all gel systems. Release characteristics and the enzymatic stability of the peptide nanofiber gels were modulated depending on organization of the chiral PA molecules within the supramolecular assemblies.

New Banach spaces defined by the domain of Riesz-Fibonacci matrix

Pinar Zengin Alp,Emrah Evren Kara 강원경기수학회 2021 한국수학논문집 Vol.29 No.4

The main object of this study is to introduce the spaces $c_0(\widehat{F}^q)$ and $c(\widehat{F}^q)$ derived by the matrix $\widehat{F}^q$ which is the multiplication of Riesz matrix and Fibonacci matrix. Moreover, we find the $\alpha$-, $\beta$-, $\gamma$- duals of these spaces and give the characterization of matrix classes $(\Lambda(\widehat{F}^q),\Omega)$ and $(\Omega,\Lambda(\widehat{F}^q))$ for $\Lambda\in\{c_0,c\}$ and $\Omega\in\{\ell_1,c_0,c,\ell_\infty\}$.

Fracture strength and marginal gap comparisons of monolayered and multilayered monolithic zirconia crowns with various milling depths

Gökçe Zengin,Burcu Kanat-Ertürk,Mine Dündar-Çömlekoğlu 대한치과보철학회 2025 The Journal of Advanced Prosthodontics Vol.17 No.5

Purpose. This study aimed to compare the marginal adaptation and fracture strength of monolayered and multilayered monolithic zirconia crowns fabricated at three distinct milling depths. Materials and methods. Eighty-four epoxy resin dies of prepared premolars were fabricated. Crowns were designed in software and milled from two monolayered zirconia materials [3Y-TZP (VITA YZ HT)(3-VYZ) and 4Y-TZP (Priti®multidisc ZrO2 Extra Translucent)(4-ET)], three multilayered zirconia materials [3/5Y-TZP (IPS e.max ZirCAD Prime)(3/5-ZP), 4/5Y-TZP (IPS e.max ZirCAD Prime Esthetic)(4/5-ZPE), and 4/5Y-TZP (Priti®multidisc ZrO2 Multi Translucent Plus)(4/5-MTP)], at three milling depths [above (A), center (C), below (B)], and a zirconia-reinforced lithium silicate glass ceramic block (VITA Suprinity)(VS) (n = 7). After sintering and glazing, marginal gaps (MG) were measured using silicone replica technique. Crowns were cemented with dual-cure resin (SpeedCEM Plus, Ivoclar Vivadent), subjected to 5000 thermal cycles. Fracture strength (FS) test was performed perpendicularly to occlusal surface at 1 mm/min. Data were analyzed (SPSS 26, one-way ANOVA, Tukey post-hoc tests, P = .05), and fracture types were classified. SEM analysis was performed on representative specimens. Results. MG differences among groups were insignificant (P > .05). The highest FS values were observed in 3-VYZ (1587.14 ± 228.26 N), 3/5ZP-B (1537.28 ± 268.81 N), and 4-ET (1364.86 ± 196.98 N) (P < .05). The lowest FS values were found in VS (483.86 ± 47.10 N)(P < .05). B-positioned multilayered crowns exhibited numerically higher FS than A or C positions. Conclusion. Monolayered (3Y-TZP and 4Y-TZP) or multilayered 3/5Y-TZP zirconia milled from below layer may be preferred for posterior region, whereas multilayered 3/5Y-TZP milled from upper layer and all configurations of multilayered 4/5Y-TZP may be more suitable for anterior.

The effect of mortar type and joint thickness on mechanical properties of conventional masonry walls

Başak Zengin,Burak Toydemir,Serhan Ulukaya,Didem Oktay,Nabi Yüzer,Ali Kocak 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.6

Masonry walls are of a complex (anisotropic) structure in terms of their mechanical properties. The mechanical properties of the walls are affected by the properties of the materials used in wall construction, joint thickness and the type of masonry bond. The carried-out studies, particularly in the seismic zones, have revealed that the most of the conventional masonry walls were constructed without considering any engineering approach. Along with that, large-scale damages were detected on such structural elements after major earthquake(s), and such damages were commonly occurred at the brick-joint interfaces. The aim of this study was to investigate the effect of joint thickness and also type of mortar on the mechanical behavior of the masonry walls. For this aim, the brick masonry walls were constructed through examination of both the literature and the conventional masonry walls. In the construction process, a single-type of brick was combined with two different types of mortar: cement mortar and hydraulic lime mortar. Three different joint thicknesses were used for each mortar type; thus, a total of six masonry walls were constructed in the laboratory. The mechanical properties of brick and mortars, and also of the constructed walls were determined. As a conclusion, it can be stated that the failure mechanism of the brick masonry walls differed due to the mechanical properties of the mortars. The use of bed joint thickness not less than 20 mm is recommended in construction of conventional masonry walls in order to maintain the act of brick in conjunction with mortar under load.

On Vibration Feedback Method for Pain Emulation and its Feedback to Human

Aydin Tarik Zengin,Hiroshi Okajima,Nobutomo Matsunaga 제어로봇시스템학회 2011 제어로봇시스템학회 국제학술대회 논문집 Vol.2011 No.10

Considering human and robot cooperation and interaction, sensory and emotional feelings can be assumed as the most important point of being safe and secure for human and environment. In our previous study that is focused on imitating human pain sensing system, we designed a multi-layer pain sensing unit to mimic human behaviors in the case of superficial stimulation. Translating data acquired by pain sensing system to human is remained another important issue. In this study, we implemented a translation method from pain signal to subject, providing a vibratory feedback that has the ability to adjust vibration frequency due to actual stimulation. After an overview of pain sensing system and multiple sensor unit structure, we discuss the feedback system providing information about the stimulation applied onto sensor units. Results confirmed that the proposed feedback system translates sufficient information about the stimulation in a human readable format.

Slope Driving Experiment of Front Drive Type Electric Wheelchair with Casters using Yaw-rate Compensation

Aydin Tarik Zengin,Yutaro Maruno,Hiroshi Okajima,Nobutomo Matsunaga 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

Electric-powered wheelchairs have been used as a convenient transport device for elderly and disabled. Recently, a front drive type electric wheelchair that is easy for a disabled person to climb on from a bed has been focused on. However, front-drive-type wheelchairs are hard to run straight and difficult to operate because their over-steering characteristic is strong owing to free casters. If the wheelchair can be driven by an easy control stick operation, it will be a comfortable function for disabled persons. In our previous study, we proposed a front-drive-type wheelchair control method which realizes comfortable functions, i.e. driving with easy stick operation like the traditional rear-drive-type wheelchair. The proposed control system uses ideal model of electric wheelchairs. By using our proposed method, the maneuverability can be improved for realizing easy stick operation. In this paper, we evaluate the effectiveness of our proposed method by simulations and experiments on a slope with electric-powered front-drive-type wheelchair. In particular, straight-ahead stability on slope is analyzed by human driving.

Red Cell Distribution Width as a Predictor of Prostate Cancer Progression

Albayrak, Sebahattin,Zengin, Kursad,Tanik, Serhat,Bakirtas, Hasan,Imamoglu, Abdurrahim,Gurdal, Mesut Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18

Background: The aims of this study were to investigate the utility of red blood cell distribution width (RDW) as a simple and readily available marker in prostate cancer, as well as to evaluate RDW as a predictor of progression in prostate cancer patients. Materials and Methods: We evaluated 62 newly diagnosed prostate cancer patients who underwent transrectal ultrasound (TRUS)-guided biopsy and 62 healthy controls of mean age 64 (range, 45-75) years at the Urology Clinic of Bozok University Hospital. Data collection was performed using our laboratory information system database to retrieve findings regarding RDW, hemoglobin, prostatespecific antigen (PSA), and age. The RDW values were compared between the healthy control group and prostate cancer patients. A high risk of progression as defined as a Gleason score (GS) >6, total number of cores positive for cancer >33%, each core containing >50% cancer cells, and a prostate-specific antigen (PSA) level >10 ng/mL. Patients were classified according to risk of progression, as well as divided into subgroups according to the RDW quartile. Results: The mean RDW value of prostate cancer patients was 14.6, compared with 13.7 in the healthy control group (p=0.001). A higher RDW was associated with an increased risk of progression, whereas a lower RDW value was correlated with a low risk of progression. Conclusions: RDW is an easily derived measure that might, in combination with other markers, help predict prostate cancer risk and progression. We suggest that RDW may be used in combination with other parameters in the assessment of prostate cancer.