Analysis of Torque Maintenance and Fracture Resistance after Fatigue in Retention Screws Made of Different Metals for Screw-Retained Implant-Borne Prosthesis Joints

Purpose. The aim was to evaluate the effect of different metallic alloys used in the manufacture of retention screws for universal cast to long abutment (UCLA) abutments for external hexagon (HE) and Morse taper (MT) connection implants, as well as of mechanical cycling on torque maintenance and fracture resistance through electromechanical fatigue testing by mastication followed by compression testing. Methods. Sixty implants were used, 30 MT and 30 HE, with their respective titanium UCLA abutments and retention screws of 5 different materials (n = 6): Ti cp grade 2, Ti cp grade 4, Ti cp grade 4 hard, Ti grade 5—Ti6Al4V and surgical steel (DSP® Biomedical). The assemblies were positioned in an electromechanical masticatory fatigue testing machine. The fracture strength test was performed by compression testing in a universal testing machine EMICDL-200. Results. The cycled screws and new screws of each alloy group for each connection type were evaluated, obtaining the maximum force (FM), in order to verify the effect of mechanical cycling. The data were tabulated and submitted to appropriate statistical analysis (α = 0.05). Conclusion. It was concluded that for the MT, the alloy with the best performance was steel, both in the maintenance of torque and in the compression test, and cycling negatively influenced the maintenance of preload for this connection. The alloy material did not influence torque maintenance for HE. The new screws that were subjected to EMIC showed higher strength. The alloy with the lowest strength was Ti grade 2.

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Impacts of Thermal and Mechanical Cycles on Electro-Thermal Anti-Icing System of CFRP Laminates Embedding Sprayable Metal Film

Materials ◽

10.3390/ma14071589 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1589

Author(s):

Rongjia Li ◽

Wang Xu ◽

Dalin Zhang

Keyword(s):

Fatigue Life ◽

Metal Film ◽

Fatigue Testing ◽

Aerodynamic Force ◽

Testing Machine ◽

Laminated Composite ◽

Heating Element ◽

Electric Resistance ◽

Potential Threat ◽

Mechanical Cycling

The aircraft electro-thermal anti-icing system that can guarantee flight safety may be affected by periodic heating and cyclic aerodynamic force during long-term flight missions, which seems to be a potential threat to ice protection. This paper aims to investigate the impacts of thermal and mechanical cycles on heating elements of the electro-thermal anti-icing system. Specimens were manufactured with CFRP (carbon fiber reinforced polymer) laminated composite, glass fiber prepreg and copper screen, in which sprayable metal film (SMF) was embedded as the heating element. The study focuses on electric resistance variation of SMF and functional fatigue life under the cycling load. Thermal cycling tests were carried out in an insulated chamber where the specimens were heated up to 80 °C and then cooled down to −55 °C for 1000 cycles. Mechanical cycling tests were conducted on a fatigue testing machine where the specimens were imposed on tension-compression loading for 106 cycles. Results showed that the electric resistance of SMF increased with the number of loading cycles. The resistance was increased by 20% and the heating power was decreased by 16.67% after 1000 thermal cycles. During the mechanical cycling tests, it was found that the heating element was destructed before the structural failure, which indicated that the fatigue life of function was lower than that of the structure.

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Evaluation of Different in Vitro Testing Methods for Mechanical Properties of Veneer Ceramics/ Евалуација На Тестовите In Vitro За Одредување На Механичките Особини На Порцеланските Маси За Фасетирање

PRILOZI ◽

10.1515/prilozi-2015-0050 ◽

2015 ◽

Vol 36 (1) ◽

pp. 225-230 ◽

Cited By ~ 1

Author(s):

Aneta Mijoska ◽

Mirjana Popovska

Keyword(s):

Flexural Strength ◽

Mechanical Characteristics ◽

Testing Machine ◽

In Vitro Testing ◽

Biaxial Test ◽

Testing Methods ◽

Dental Ceramic ◽

Universal Testing ◽

Biaxial Tests

Abstract Metal-ceramic and all-ceramic prosthetic restorations in the patient mouth are often damaged by esthetic and functional problems that reduce their success and longevity. Аim: To evaluate methods for testing mechanical characteristics of dental ceramics through analysis of different testing methods. Material and methods: Dental ceramic materials are tested with in vivo and in vitro methods for their most important mechanical characteristics: hardness, toughness, flexural strength and abrasion. In vitro testing methods are faster and more efficient, without subjective factors from the patient according to ISO standards. Testing is done with universal testing machines, like Zwick 1445, Universal Testing Machine (Zwick DmbH & Co.KG, Ulm, Germany), Instron 4302 (Instron Corporation, England), MTS Sintech ReNew 1123 or in oral chewing simulators. Results: According to the testing results, flexure strength is one of the most important characteristic of the dental ceramic to be tested, by the uniaxial and biaxial tests. Uniaxial tests three-point and four-point flexure are not most appropriate because the main stress on the lower side of the tested specimens is tension that causes beginning fractures at the places with superficial flow. Uniaxial results for flexural strength are lower than actual force, while with biaxial test defects and flows on the edges of tested specimens are not directly loaded. Conclusion: Biaxial flexural method has advantages over uniaxial because of real strength results, but also for simple shape and preparing of the testing specimens.

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Fracture Resistance of Implant Abutments Following Abutment Alterations by Milling the Margins: An In Vitro Study

Journal of Oral Implantology ◽

10.1563/aaid-joi-d-16-00010 ◽

2016 ◽

Vol 42 (6) ◽

pp. 464-468 ◽

Cited By ~ 2

Author(s):

Anuya Patankar ◽

Mohit Kheur ◽

Supriya Kheur ◽

Tabrez Lakha ◽

Murtuza Burhanpurwala

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Vitro Study ◽

Maximum Resistance ◽

Universal Testing ◽

Implant Abutments ◽

Implant Abutment ◽

Different Levels

This in vitro study evaluated the effect of different levels of preparation of an implant abutment on its fracture resistance. The study evaluated abutments that incorporated a platform switch (Myriad Plus Abutments, Morse Taper Connection) and Standard abutments (BioHorizons Standard Abutment, BioHorizons Inc). Each abutment was connected to an appropriate implant and mounted in a self-cured resin base. Based on the abutment preparation depths, 3 groups were created for each abutment type: as manufactured, abutment prepared 1 mm apical to the original margin, and abutment prepared 1.5 mm to the original margin. All the abutments were prepared in a standardized manner to incorporate a 0.5 mm chamfer margin uniformly. All the abutments were torqued to 30 Ncm on their respective implants. They were then subjected to loading until failure in a universal testing machine. Abutments with no preparation showed the maximum resistance to fracture for both groups. As the preparation depth increased, the fracture resistance decreased. The fracture resistance of implant abutment junction decreases as the preparation depth increases.

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A device for performing whole bone torsional testing in a single-axis linear motion testing machine

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.3415/vcot-07-10-0091 ◽

2008 ◽

Vol 21 (05) ◽

pp. 478-480 ◽

Cited By ~ 6

Author(s):

J. M. Tyler ◽

W. Larinde ◽

S. H. Elder

Keyword(s):

Fracture Healing ◽

Rotational Motion ◽

Testing Machine ◽

Compression Testing ◽

Linear Motion ◽

Universal Testing ◽

Torsional Testing ◽

Strength And Stiffness ◽

Electromechanical Equipment ◽

Torsional Properties

Summary Objectives: To design a device for the conversion of linear to rotational motion and to use it in order to determine torsional properties of canine tibiae in a universal tension/compression testing machine. Methods: A fixture incorporating a cable and pulley at one end and a guide block and rail assembly at the other was used to test 10 whole canine tibiae to failure in torsion at 1°/s. Results: The device produced spiral fractures in all tibiae. Torsional strength and stiffness were 13.9 ± 1.4 N m and 0.53 ± 0.07 N m/degree, respectively. Clinical significance: This inexpensive device can be used to evaluate the mechanical properties of long bones after various interventions to improve fracture healing. The device can be adapted for use with any single-axis linear motion testing machine. Assessment of fracture healing often includes loading to failure in torsion (1–5). Torsional testing is typically performed using a biaxial servohydraulic testing machine or similar sophisticated electromechanical equipment. Due to its high cost, many researchers do not have such equipment at their disposal. However, uniaxial tension-compression testing machines are widely available. Therefore, a device that can be used to perform torsional testing in a tension-compression machine would be beneficial. In this study we present a custom fixture for converting the vertical linear motion of a universal testing machine to rotational motion and validate its performance in torsional testing of canine tibiae.

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Comparative evaluation of the effects of different methods of post space preparation in primary anterior teeth on the fracture resistance of tooth restorations

Journal of Dental Research Dental Clinics Dental Prospects ◽

10.15171/joddd.2019.022 ◽

2019 ◽

Vol 13 (2) ◽

pp. 141-146

Author(s):

Bahman Seraj ◽

Sara Ghadimi ◽

Ebrahim Najafpoor ◽

Fatemeh Abdolalian ◽

razieh khanmohammadi

Keyword(s):

Sodium Hypochlorite ◽

Root Canal ◽

Treatment Modality ◽

Fracture Resistance ◽

Comparative Evaluation ◽

Testing Machine ◽

Anterior Teeth ◽

Universal Testing ◽

Light Curing ◽

Post Space

Background. Severely damaged teeth do not have adequate structure to support the composite crown; therefore, use of the canal space has been suggested to increase retention. Furthermore, the effect of post space irrigation protocols on the fracture resistance of the primary anterior teeth has not definitely been studied in postoperative modalities. This study compared the fracture resistance of restorations of primary anterior teeth following irrigation of the post space with sodium hypochlorite and chlorhexidine with and without application of burs. Methods. Ninety-four extracted primary anterior teeth were selected. Root canal treatments were carried out, 4 mm of the post space was left empty and 1 mm was regarded as a bed. The post space was prepared with and without a bur and the irrigation procedures were carried out with 0.2% chlorhexidine and 2.5% sodium hypochlorite solutions. Composite posts were inserted into the canals and the crowns were restored. Following composite etching and light-curing, the fracture resistance of the restored teeth was determined by a universal testing machine. Results. In the sodium hypochlorite group, fracture resistance of the teeth was 376.8±107.29 N and 475.5±186.89 N without and with bur preparation, respectively. For chlorhexidine protocol, the values were 370.88±175.46 N and 430.85±178.22 N without and with bur preparation, respectively. The effect of irrigating material was not significant; however, the bur and irrigating preparation significantly increased the fracture resistance of the restored teeth (P=0.02). Conclusion. Post space irrigation with 0.2% chlorhexidine or 2.5% sodium hypochlorite did not significantly affect the fracture resistance of primary anterior teeth in the post treatment modality.

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Fatigue Testing of Dental Bridges on Selected Examples

Acta Mechanica et Automatica ◽

10.1515/ama-2017-0008 ◽

2017 ◽

Vol 11 (1) ◽

pp. 53-57

Author(s):

Dariusz Urban ◽

Marek Jałbrzykowski ◽

Maria Gołębiewska

Keyword(s):

Fatigue Testing ◽

Testing Machine ◽

Cyclic Fatigue ◽

Zirconia Ceramic ◽

Metal Base ◽

Cyclic Loading And Unloading ◽

Universal Testing ◽

Functional Quality ◽

Loading And Unloading

Abstract The paper presents example tests of the functional quality of selected designs of dental bridges. These were: porcelain bridges on a metal base (cobalt based alloy), porcelain bridges on a zirconia base (zirconia ceramic – Zirkon Zahn), and full zirconia bridges (Zirkon Zahn). For the purpose of the study, durability of bridges in cyclic fatigue testing was adopted as a measure of their quality. The tests were carried out on a Zwick Roell Z010 universal testing machine. They consisted in cyclic loading and unloading of dental bridges mounted on gypsum models at a loading force of F= 400 [N] and a frequency of load of f= 1 [Hz]. Each bridge was subjected to a cycle of 7200 loads. The results show that there are no significant differences in the functional quality of the bridges.

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Effect of Alloying Elements on the Microstructure and Properties of AZ91D-xCa-ySr

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.591-593.993 ◽

2012 ◽

Vol 591-593 ◽

pp. 993-996

Author(s):

Qing Zhu Sun ◽

Hai Bo Wang ◽

Yong Chang Zhu

Keyword(s):

Mechanical Properties ◽

Fatigue Testing ◽

Low Cycle Fatigue ◽

Testing Machine ◽

Alloying Elements ◽

Cycle Fatigue ◽

Microstructure And Properties ◽

Universal Testing Machine ◽

Universal Testing ◽

Electronic Microscope

In this paper, the microstructure and properties of AZ91D-xCa-ySr were studied by adding alloying elements. The mechanical properties were investigated by WDT-10 micro-electric universal testing machine and WD-T low cycle fatigue testing machine. The OLYMPUS-GX71 Optical electronic microscope, XRD and SEM were employed to investigate the microstructure of AZ91D. The results showed that the grains were refined by adding Ca,Sr,Gd and Y. Low cycle fatigue (LCF) behavior of AZ91D-0.4Ca-0.3Sr was improved obviously by adding 3.0%Gd and 3.0%Y into material, the tensile strengthen was up to 299Mpa, the elongation was 0.78%.

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Can Fiber Application Affect the Fracture Strength of Endodontically Treated Teeth Restored with a Low Viscosity Bulk-Fill Composite?

BioMed Research International ◽

10.1155/2019/3126931 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Evrim Eliguzeloglu Dalkılıç ◽

Magrur Kazak ◽

Duygu Hisarbeyli ◽

Mehmet Ali Fildisi ◽

Nazmiye Donmez ◽

...

Keyword(s):

Fracture Strength ◽

Fracture Resistance ◽

Testing Machine ◽

The Other ◽

Control Groups ◽

Endodontically Treated Teeth ◽

Low Viscosity ◽

Universal Testing ◽

Significant Difference ◽

Insertion Techniques

Objective. The aim of this study is to evaluate the effects of different fiber insertion techniques and thermomechanical aging on the fracture resistance of endodontically treated mandibular premolar teeth restored using bulk-fill composites. Materials and Methods. Eighty human mandibular premolar teeth were randomly divided into eight groups: Group IN, Group BF, Group PRF1, Group PRF2, Group IN-TMA, Group BF-TMA, Group PRF1-TMA ,and Group PRF2-TMA. Group IN (intact) and Group IN-TMA (intact but subjected to thermomechanical aging) served as control groups. In the other six groups, endodontic treatment was performed and standardized mesio-occluso-distal (MOD) cavities were prepared. In BF, PRF1, and PRF2, the cavities were restored with bulk-fill composite only, bulk-fill/Ribbond, and bulk-fill/additional Ribbond, respectively. In BF-TMA, PRF1-TMA, and PRF2-TMA, the teeth were subjected to thermomechanical aging after the restorations. All of the teeth were fractured on the universal testing machine. Fracture surfaces were analyzed with a stereomicroscope. Results. Control groups showed significantly higher fracture strengths than tested groups (P<0.05). No statistically significant difference was observed among the tested groups (P>0.05). Most of the favorable fractures were seen in PRF1, PRF2, and PRF2-TMA. Most of the unfavorable fractures were seen in BF-TMA. Conclusions. Although fiber insertion with different techniques did not increase the fracture strength of teeth restored with bulk-fill composites, it increased the favorable fracture modes. Thermomechanical aging did not change the fracture strength of the groups.

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Influence of Immediate Dentin Sealing Techniques on Cuspal Deflection and Fracture Resistance of Teeth Restored with Composite Resin Inlays

Operative Dentistry ◽

10.2341/12-100-l ◽

2014 ◽

Vol 39 (1) ◽

pp. 72-80 ◽

Cited By ~ 4

Author(s):

L Oliveira ◽

EG Mota ◽

GA Borges ◽

LH Burnett ◽

AM Spohr

Keyword(s):

Fracture Resistance ◽

Axial Load ◽

Composite Resin ◽

Testing Machine ◽

Lowercase Letter ◽

Type Iv ◽

Universal Testing ◽

Maxillary Premolars ◽

Provisional Restoration ◽

And Storage

SUMMARY This research evaluated the influence of immediate dentin sealing (IDS) techniques on cuspal deflection and fracture resistance of teeth restored with composite resin inlays. Forty-eight maxillary premolars were divided into four groups: G1, sound teeth (control); G2, without IDS; G3, IDS with Clearfil SE Bond (CSE); and G4, IDS with CSE and Protect Liner F. The teeth from groups 2, 3, and 4 received mesio-distal-occlusal preparations. The impressions were made with vinyl polysiloxane, followed by provisional restoration and storage in water for seven days. The impressions were poured using type IV die stone, and inlays with Filtek Z250 composite resin were built over each cast. The inlays were luted with Panavia F. After storage in water for 72 hours, a 200-N load was applied on the occlusal surface using a metal sphere connected to a universal testing machine, and the cuspal deflection was measured with a micrometer. The specimens were then submitted to an axial load until failure. The following mean cuspal deflection (μm) and mean fracture resistance (N) followed by the same lowercase letter represent no statistical difference by analysis of variance and Tukey (p<0.05): cuspal deflection: G1, 3.1 ± 1.5a; G2, 10.3 ± 4.6b; G3, 5.5 ± 1.8ac; and G4, 7.7 ± 5.1bc; fracture resistance: G1, 1974 ± 708a; G2, 1162 ± 474b; G3, 700 ± 280b; and G4, 810 ± 343b. IDS with CSE allowed cuspal deflection comparable with that associated with sound teeth. The application of Protect Liner F did not contribute to a decrease in cuspal deflection. The IDS techniques did not influence the fracture resistance of teeth.

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Fracture Resistance of Primary Zirconia Crowns: An In Vitro Study

Children ◽

10.3390/children9010077 ◽

2022 ◽

Vol 9 (1) ◽

pp. 77

Author(s):

AlWaleed Abushanan ◽

Rajashekhara B. Sharanesha ◽

Bader Aljuaid ◽

Tariq Alfaifi ◽

Abdullah Aldurayhim

Keyword(s):

Mechanical Properties ◽

Oral Cavity ◽

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Universal Testing ◽

Zirconia Crowns ◽

Fracture Tests ◽

The Mean

In this study, we evaluated the fracture resistance of three commercially available prefabricated primary zirconia crowns and their correlation with dimensional variance. Methods: a total of 42 zirconia crowns were selected from three companies, (1) NuSmile primary zirconia crowns, (2) Cheng Crowns zirconia, and (3) Sprig EZ crowns. The crowns were divided into two groups based on their location in the oral cavity and further divided into subgroups based on the brand. All of the samples were subjected to fracture tests using a universal testing machine. Results: the mean load observed was highest with Cheng Crowns zirconia anterior crowns (1355 ± 484) and the least load was seen with Sprig EZ anterior crowns with a mean load of 339 ± 94. The mean load observed was highest with Cheng Crowns zirconia posterior crowns (1990 ± 485) followed by NuSmile posterior crowns and the least load was seen with Sprig EZ posterior crowns with a mean load of 661 ± 184. Conclusion: the Cheng crowns showed the highest fracture resistance amongst all three groups. Overall, the zirconia crowns (anterior and posterior) tested showed optimum mechanical properties to withstand the masticatory forces.

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