Article
Dentistry, Oral Surgery & Medicine
Sang Won Kwak, Jung-Hong Ha, Ya Shen, Markus Haapasalo, Hyeon-Cheol Kim
Summary: The study observed a significant correlation between the curvature angle and the type of file system, with an increase in total and maximum torque generated as the degree of canal curvature increased. NiTi files with reciprocating motion showed higher torque values at 15 degrees and 25 degrees compared to files with continuous rotation, with ProTaper Universal exhibiting the steepest increase in torque with increasing curvature angle. ProTaper Next files had the lowest torque values at higher canal angles of 35 degrees and 45 degrees.
JOURNAL OF ENDODONTICS
(2021)
Article
Chemistry, Multidisciplinary
Hoang-Lan-Anh Le, Thuan-Loc Tran, Thu-Thuy Nguyen, Tran-Lan-Khue Pham, Van-Khoa Pham
Summary: The study aimed to measure the number of cycles leading to fracture (NCF) in stainless steel double-curved canals under static and dynamic cyclic fatigue situations at body temperature. Different groups of ProTaper Universal and ProTaper Next instruments were tested using proprietary programs and the rotations before fracture were recorded. The results showed that ProTaper Next had the highest NCF in dynamic cycles, while ProTaper Universal had the lowest NCF in static condition. The study suggests that factors such as rotation modes, materials, and design influence the cyclic fatigue resistance of the instruments.
APPLIED SCIENCES-BASEL
(2023)
Review
Dentistry, Oral Surgery & Medicine
Jorge N. R. Martins, Rui F. Martins, Francisco Manuel Braz Fernandes, Emmanuel J. N. L. Silva
Summary: The mechanical strength and flexibility of instruments are traditionally evaluated through various tests, including cyclic fatigue, torsional, bending, buckling, and microhardness tests. Cyclic fatigue testing, in particular, can provide valuable information on the factors that may affect fatigue strength outcomes. Despite their importance, these tests are associated with limitations such as artificiality, simplicity, inconsistency, and low external validity. Efforts have been made to improve the reliability of the outcomes by incorporating settings that mimic clinical conditions.
JOURNAL OF ENDODONTICS
(2022)
Article
Chemistry, Multidisciplinary
Alessio Zanza, Rodolfo Reda, Giuseppe Familiari, Stefania Annarita Nottola, Dario Di Nardo, Luca Testarelli, Orlando Donfrancesco
Summary: This study assessed surface alterations of four reciprocating instruments before and after shaping resin-simulated root canals, showing significant differences in cutting edges for one instrument and higher presence of debris for another after simulated use.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Sen Tang, Xinyu Wang, Beihai Huang, Dongtong Yang, Lang Li, Chao He, Bo Xu, Yongjie Liu, Chong Wang, Qingyuan Wang
Summary: This paper proposes an accelerated fatigue test method based on ultrasonic loading technology to investigate the bending fatigue characteristics of thin-plate structures in the very high cycle fatigue (VHCF) regime. A new bending fatigue specimen with a frequency of 20 kHz was designed and verified by axial load tests. The results showed that the method effectively transferred dangerous cross-sections and demonstrated a linear relationship between vibration amplitude and maximum stress. The S-N curves and fracture morphology were consistent with conventional studies, indicating the reasonability of the bending test model design.
Article
Chemistry, Physical
Michal Bumbalek, Zdenek Joska, Zdenek Pokorny, Josef Sedlak, Jozef Majerik, Vlastimil Neumann, Karel Klima
Summary: This study investigated the possibility of using low-temperature plasma nitriding technology to improve the properties and fatigue life of NiTi dental instruments. The results showed that nitriding process can significantly increase the fatigue life of NiTi instruments in some cases. Nitrided files have promising possibilities for enhancing the surface properties and quality.
Article
Engineering, Mechanical
Binwen Wang, Chengcheng Qian, Chunyu Bai, Weiping Hu, Zhixin Zhan, Qiang Yang, Yupei Guo, Biao Wang
Summary: This study aims to investigate the impact fatigue properties of TC18 titanium alloy and propose a new damage model for predicting the impact fatigue life of materials. By designing the impact fatigue test method and measurement scheme, the fatigue lives and impact responses of the tested specimens were obtained under different impact conditions. A new impact damage model considering the effect of strain rate was proposed based on the theory of continuum damage mechanics. The model parameters were calibrated using the test data of TC18. The numerical implementation of impact damage calculation was established, and a user-defined subroutine in ABAQUS was used for finite element numerical simulation. The simulation results of the damage evolution and fatigue life prediction of TC18 under tensile impact fatigue loading showed errors within 25% compared to experimental results, demonstrating the good validity and applicability of the proposed damage model and numerical method.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Medicine, Research & Experimental
Mohammad Daher Altufayli, Basem Salem, Imad Katbeh, Pierre Georges, Roua Kamel Moualla
Summary: The anatomy of the root canal system is complex and variable, requiring a flexible system for minimal preparation. NiTi instruments are advantageous for preparing curved root canals due to their properties of memory shape, super elasticity, and resistance to fatigue.
Article
Engineering, Mechanical
John A. Moore, Jacob P. Rusch, Parisa Shabani Nezhad, Sivom Manchiraju, Dinc Erdeniz
Summary: Fatigue indicator parameters play a crucial role in materials design by evaluating the potential of various microstructures to initiate fatigue cracks in metal alloys. This study explores the impact of reversible phase transformation on the predicted values of fatigue indicator parameters for Nitinol, a alloy with solid-state phase transformations. The crystal mechanics of both plasticity and phase transformations are modeled using the finite element method. The findings show that a crystal-mechanics-based phase transformation model influences the values of fatigue indicator parameters, the shape of strain-life curves, the distribution of fatigue indicator parameter values, and the ranking of deleterious microstructural features.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Engineering, Mechanical
Abdul Khadar Syed, Rob Plaskitt, Michelle Hill, Zsolt Pinter, Jialuo Ding, Robert Zboray, Stewart Williams, Xiang Zhang
Summary: This paper investigates the cyclic deformation behavior and fatigue properties of a wire + arc additive manufactured Ti-6Al-4V alloy. Compared to Ti-6Al-4V alloys produced by other additive manufacturing processes, the material used in this study has a coarser primary columnar beta grain structure and alpha microstructure. Fatigue tests were conducted on specimens with horizontal and vertical orientations. The vertical samples, where the loading axis was parallel with the primary columnar beta grains, showed slightly higher fatigue life and a higher cyclic softening rate compared to the horizontal samples. No porosity defects were found, and cracks initiated from either the alpha laths or alpha/beta interface due to cyclic slip localization.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Anatomy & Morphology
Ekim Onur Orhan, Ihsan Furkan Ertugrul, Samet Tosun
Summary: The study evaluated the torsional and fatigue resistance of the novel SCOPE RS instruments and compared them with other instruments. It was found that SCOPE RS had higher torsional resistance but did not show significant improvement in cyclic fatigue resistance compared to its counterparts.
MICROSCOPY RESEARCH AND TECHNIQUE
(2021)
Article
Chemistry, Physical
Hayate Unno, Arata Ebihara, Keiko Hirano, Yuka Kasuga, Satoshi Omori, Taro Nakatsukasa, Shunsuke Kimura, Keiichiro Maki, Takashi Okiji
Summary: This study compared the mechanical properties and root canal shaping abilities of TruNatomy (TRN) with existing instruments. The results showed that TRN performed better in terms of load values, cycles to fracture, torque, and vertical force.
Article
Dentistry, Oral Surgery & Medicine
Thais Kauana Magalhaes Sobral, Lucila Piasecki, Flavia Sens Fagundes Tomazinho, Alison Luis Kirchhoff, Marilisa Carneiro Leao Gabardo, Natanael Henrique Ribeiro Mattos, Flares Baratto Filho, Luiz Fernando Fariniuk
Summary: The objective of this study was to compare the fatigue resistance of different heat-treated reciprocating instruments in a dynamic cyclic fatigue model. The results showed that Pro-R and Reciproc Blue instruments had the highest fatigue resistance, significantly different from the other tested files. Reciproc instruments had intermediate results, significantly different from X1 Blue. These findings have important implications for the selection and optimization of reciprocating instruments.
EUROPEAN ENDODONTIC JOURNAL
(2023)
Article
Engineering, Mechanical
I. Lecinana, J. Zurbitu, J. Renart, A. Turon
Summary: In this study, a robust method based on surrogate modelling and multi objective optimization is presented for determining the input fatigue parameters of a fatigue cohesive zone model. The parameter determination is conducted using experimental data from delamination tests, emphasizing the phenomenological nature of the model. The capability to simulate both fatigue onset and propagation is validated for two different monotonic cohesive laws. The methodology's predictive capability is further validated against experimental results of a partially reinforced double cantilever beam specimen (R-DCB) with non-self-similar crack propagation.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Materials Science, Characterization & Testing
D. A. Bozkurt, M. Akman, H. B. Karadag, Z. Ovalioglu, O. Kucuk Keles
Summary: This study focused on investigating the effects of sodium-hypochlorite and hypochlorous-acid solutions on the cyclic fatigue resistance of three nickel-titanium instruments. It was found that the use of 2.5% sodium-hypochlorite and hypochlorous-acid solutions reduced the fracture resistance of one of the instruments, but had no significant effect on the other two. Hypochlorous-acid solution can be considered as an alternative irrigation solution due to its lower corrosiveness compared to sodium-hypochlorite solution.
STRENGTH OF MATERIALS
(2023)
Article
Dentistry, Oral Surgery & Medicine
Ali Keles, Cangul Keskin, Marco Aurelio Versiani
Summary: This study used micro-computed tomography to evaluate the frequency, position, and length of radicular pulp calcifications in three-rooted maxillary first molars. Results showed that MB2 and MB3 canals had the highest frequency and length of calcifications, mainly occurring at the orifice level and along the canal path. In contrast, calcifications in MB1, DB, and P canals were mainly found at the apical third.
CLINICAL ORAL INVESTIGATIONS
(2022)
Article
Dentistry, Oral Surgery & Medicine
Elif Ciftcioglu, Ozgun Yucel, Vasfiye Isik, Ali Keles, Mehmet Baybora Kayahan
Summary: This study evaluated the irrigation dynamics of syringe irrigation with different needle designs and ultrasonic irrigation in root canals with internal root resorption using a computational fluid dynamics model. The results showed that the insertion depth and irrigation model had an influence on shear stress and irrigant extension, with the irrigant extending more towards 2-5mm from the working length. Ultrasonic irrigation had the highest shear stress values regardless of the insertion depth.
Article
Dentistry, Oral Surgery & Medicine
Orkun Uslu, Faruk Haznedaroglu, Cangul Keskin
Summary: This study compared the differences between original and replica-like endodontic systems in terms of various factors. The replica-like files showed significant differences in size and taper compared to the original files. There were also differences in phase-transformation behavior and the precision of measurement lines between the replica-like and original systems. Only One File exhibited significantly lower cyclic fatigue and torsional resistance compared to Reciproc, while there were no significant differences between X File and ProTaper Next in these aspects. Although the replica files have acceptable mechanical properties, they lack consistency in terms of standardization and design.
AUSTRALIAN ENDODONTIC JOURNAL
(2023)
Article
Multidisciplinary Sciences
Elif Seher Boke, Ali Keles, Cangul Keskin, Yeliz Tanriverdi Cayci, Tugba Turk
Summary: This study compared the ability of different aerosol reduction systems to reduce Enterococcus faecalis contaminated aerosol in a simulated dental office set-up. The study found that although these devices reduced the spread of aerosols to some extent, they could not completely eliminate the contaminated aerosol load in the cabin environment.
Article
Dentistry, Oral Surgery & Medicine
Canguel Keskin, Defne Toplu, Ali Keles
Summary: This study used micro-CT to determine and compare the dentine thickness around root canals in fused maxillary molars. Results showed that the dentine thickness significantly decreased 2 mm apical to the orifice level regardless of fusion type. The minimum dentine thickness was found around the second mesiobuccal canal. The fusion type influenced the dentine thickness, with type 1 fusion having greater thickness around the mesiobuccal canal compared to types 2 and 3, while type 3 fusion had thinner dentine around the distobuccal and palatal canals.
INTERNATIONAL ENDODONTIC JOURNAL
(2023)
Article
Dentistry, Oral Surgery & Medicine
Elif Kalyoncuoglu, Canguurol Keskin, Ali Keles, Kubra Bozsoy, Rawan Alqawasmi
Summary: This study aimed to evaluate the efficacy of examinations by endoscope of root canals to determine residual root canal filling materials. The endoscope detected residual root canal filling material as efficiently as periapical radiography.
JOURNAL OF ENDODONTICS
(2023)
Article
Dentistry, Oral Surgery & Medicine
C. Keskin, A. Aksoy, E. Kalyoncuoglu, A. Keles, A. Arkan Ilik, O. Komec, E. Yuzgulec, H. Akgun, S. G. Alak, O. Tokur
Summary: This study aimed to investigate the changes in biomarker levels related to inflammation and tissue destruction in the periapical exudate of mandibular premolar teeth with asymptomatic apical periodontitis after receiving intracanal cryotherapy. The study compared the cryotherapy group and control group in terms of analgesic intake, interappointment, and post-operative pain, and evaluated the correlation between biomarker levels and interappointment pain.
INTERNATIONAL ENDODONTIC JOURNAL
(2023)
Article
Dentistry, Oral Surgery & Medicine
Jorge N. R. Martins, Marco A. Worldwide Anatomy Res Grp, Marco A. Versiani
Summary: This cross-sectional study examined the global prevalence of a lingual canal in mandibular incisors and its association with patient demographics. The study analyzed 26,400 mandibular incisors from 44 countries using cone-beam computed tomography imaging. The results showed significant variations in the prevalence of lingual canals based on geographic location, ethnicity, age, and gender. The overall prevalence was 21.9% for central incisors and 26.0% for lateral incisors.
JOURNAL OF ENDODONTICS
(2023)
Article
Dentistry, Oral Surgery & Medicine
Sibel Akkuc, Gulsum Duruk, Ali Keles
Summary: This study investigated the remineralization efficiency of Sensodyne Promine, GC Tooth Mousse, and Agarta herbal toothpaste on initial caries and erosion. Results showed that all three products significantly increased mineral density and reduced surface area and lesion volume and depth. There was no significant difference between the products in terms of remineralization efficiency.
Article
Multidisciplinary Sciences
Elif Ciftcioglu, Ali Keles, Gozde Akbal Dincer, Melis Oya Ates, Enver Sedat Kucukay
Summary: This study aimed to compare the shaping abilities of OneReci and WOG systems and evaluate the effect of increased apical enlargement on preparation quality. The results showed that both systems performed similarly and safely in the size 25 instrument preparation stage, but using a size 35 instrument in the WOG system resulted in significantly higher dentin removal, volume increase, and prepared surface area. The differences in canal transportation and centering ratio were not significant.
Article
Dentistry, Oral Surgery & Medicine
Merve Yeniceri Ozata, Seda Falakaloglu, Ali Keles, Oezkan Adiguzel, Mustafa Gundogar
Summary: This study compared the shaping ability of different instruments using micro-CT scanning and found that glide path instruments can effectively shape moderately curved canals with minimal apical transportation and better centering ability. TruNatomy Glider showed greater transportation in the mesiodistal direction, while WaveOne Gold Glider had the best centering ability in the buccolingual direction. Canal distinction (MB vs. ML) did not significantly affect centering or transportation.
Article
Dentistry, Oral Surgery & Medicine
Sabiha Gulcin Alak, Ali Keles, Cangul Keskin, Jorge N. R. Martins, Marco Aurelio Versiani
Summary: This study used micro-CT technology to evaluate changes in root canal morphology in patients of different ages. The results showed significant variations in canal configuration, with canal volume decreasing and surface area increasing with age in patients aged 30 and below. The internal morphology of the mesial roots was more affected by aging than distal canals, and the most significant change was a reduction in the volume of the root canal systems.
CLINICAL ORAL INVESTIGATIONS
(2023)
Article
Dentistry, Oral Surgery & Medicine
Cangul Keskin, Burcu Pirimoglu, Elif Ciftcioglu, Esma Dinger, Onur Komec, Ali Keles
Summary: This study assessed the outcome of shaping the mesial roots of mandibular first molars containing band-shaped isthmuses with an isthmus floor located at the apical third with Reciproc Blue and Rotate instruments in terms of canal transportation, canal aberrations and unprepared apical canals.
CLINICAL ORAL INVESTIGATIONS
(2023)
Article
Dentistry, Oral Surgery & Medicine
Ali Keles, Cangul Keskin, Elif Ciftcioglu, Gulcin Alak
Summary: In this study, micro-computed tomography was used to analyze band-shaped isthmuses in the apical third of the mesiobuccal roots of maxillary molars. The results showed that the frequency of band-shaped isthmuses was 13.5% with a length of up to 5.5 mm. There was no significant difference in the distance between the isthmus floor and apical foramina of the mesiobuccal canals.
CLINICAL ORAL INVESTIGATIONS
(2022)
