scholarly journals THE LABORATORY STUDY OF THE FLEXURAL STRENGTH OF REINFORCED BIS-ACRYLIC MATERIAL FOR PROVISIONAL FIXED RESTORATIONS

2018 ◽  
Vol 14 (4) ◽  
pp. 121-126
Author(s):  
Олег Петрикас ◽  
Oleg Petrikas ◽  
Дмитрий Трапезников ◽  
Dmitry TRAPEZNIKOV ◽  
Эмилия Змеева ◽  
...  
Keyword(s):  
Mechanical Test ◽  
Testing Machine ◽  
Control Group ◽  
Test Results ◽  
Flexural Test ◽  
Routine Procedure ◽  
Universal Testing ◽  
Glass Fiber Reinforced ◽  
Cad Cam

Background. The use of provisional (interim, temporary) restorations has become a routine procedure in modern dentists after the end of the era of brazed-stamped bridges. The use of traditional acrylic plastics does not provide the necessary strength for the long-term functioning of provisional prostheses. Bis-acrylic materials have helped to eliminate some of the problems associated with traditional acrylic materials. However the disadvantage of bis-acryls is that they can break relatively easily when placed in areas of increased stress. The use of provisional prostheses, obtained by casting or CAD/CAM technology, undoubtedly solve problems, however, prosthetics are significantly more expensive. Another known and cheaper way is to harden polymers by reinforcing them. Objectives ― to study, when conducting a mechanical test, the fracture resistance of glass fiber-reinforced bis-acrylic composite beams. Methods. On a universal testing machine (three-point flexural test), 8 groups of samples were studied depending on the material — Re-fine Bright acrylic material (Yamahachi Dental MFG., CO., Japan), or Luxatemp bis-acrylic material (DMG) and Protemp 4 (3M ESPE), and also, the method of reinforcement of Protemp 4 with GlasSpan fiberglass tape (GlasSpan). The fracture strength (F) was calculated in MPa. Statistical differences between groups were determined using T-test. Results. Comparison of the fracture strengths results between the first control group (Protemp 4 bis-acrylic plastic without reinforcement) and other groups (glass tape reinforcement) revealed a significant hardening of Protemp 4 after reinforcement (p <0,05). Conclusions. The use of reinforcing glass tape with a full impregnation with an adhesive and a flowable composite increases the strength of Protemp 4 more than 2 times.

scholarly journals Torque Mechanical Evaluation for 3D Printed Orthodontic Springs with Different Parameters: Invitro Study

2020 ◽  
Author(s):  
Ahmed Othman ◽  
Steven Hartman ◽  
Dragan Ströbele ◽  
Jassin Arnold ◽  
Constantin von See
Keyword(s):  
Testing Machine ◽  
Control Group ◽  
3D Printer ◽  
Coil Design ◽  
Flexible Material ◽  
Universal Testing ◽  
Length Group ◽  
Cad Cam ◽  
3D Printed ◽  
Sydney Australia

Abstract Background: The purpose of the presented investigation is to evaluate the resulting torque on loaded 3D printed springs using different coil thickness and length. Methods: Specimens were designed and printed using the 3D printer MAX (Asiga, Sydney, Australia) with 3D printable, experimental, flexible material (Code:BM2008, GC, Tokyo, Japan). The specimens were divided into three groups according to spring coil design. Control group (n=18), length group (n=19) and thickness group (n=22). Groups were tested using a Sauter Machine for torque calculation (DB, Grindelwald, Switzerland) in conjunction with a universal testing machine (Zwick Z010, Ulm, Germany) for clock-wise and anti-clockwise testing. Statistical analysis was performed using the Steel-Dwass test to compare median values of the three groups in both testing directions (p<0.001). Results: The highest torque value was determined in the thickness group for both clockwise and anti-clockwise testing directions, achieving 44.00N/mm and 39.62N/mm respectively. For the thickness group values ranged from 21.28N/mm anti-clockwise to 44.00N/mm clockwise. The length group ranged from 21.65N/mm to 11.04N/mm in clockwise direction and from 18.04N/mm to 11.38N/mm in counter-clockwise testing. The control group ranged from 22.72N/mm to 17.18N/mm in the clock-wise direction while in the anti-clock wise testing it ranged from 21.34N/mm to 16.02N/mm. Conclusions: 3D printed springs are being affected by diameter than length as a design parameter compared to the control group. The thickness group values are statistically significant than the length group (P<0.001). Key words: CAD/CAM, 3D printing, Digital Orthodontics, Torque, Springs.

Effect of Different Computer-aided Design/Computer-aided Manufacturing (CAD/CAM) Materials and Thicknesses on the Fracture Resistance of Occlusal Veneers

2018 ◽  
Vol 43 (5) ◽  
pp. 539-548 ◽  
Author(s):  
JP Andrade ◽  
D Stona ◽  
HR Bittencourt ◽  
GA Borges ◽  
LH Burnett ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Control Group ◽  
Computer Aided Manufacturing ◽  
Universal Testing ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

SUMMARY The aim was to evaluate, in vitro, the influence of different computer-aided design/computer-aided manufacturing (CAD/CAM) materials (IPS e.max CAD, Vita Enamic, and Lava Ultimate) and thicknesses (0.6 mm and 1.5 mm) on the fracture resistance of occlusal veneers. Sixty human third molars were prepared to simulate advanced erosion of the occlusal surface, and the teeth were randomly divided into six experimental groups (n=10) according to the material and thickness used to build the veneers. Ten sound teeth formed the control group. The veneers were adhesively luted and submitted to mechanical cyclic loading (1 million cycles at 200-N load). The fracture resistance test was performed in a universal testing machine. The failures were classified as “reparable” and “irreparable.” According to two-way analysis of variance and the Tukey test, the interaction (material × thickness) was significant (p=0.013). The highest fracture resistance was obtained for IPS e.max CAD at a 1.5-mm thickness (4995 N) and was significantly higher compared to the other experimental groups (p&lt;0.05). The lowest fracture resistance was obtained for Vita Enamic at 0.6 mm (2973 N), although this resistance was not significantly different from those for IPS e.max CAD at 0.6 mm (3067 N), Lava Ultimate at 0.6 mm (3384 N), Vita Enamic at 1.5 mm (3540 N), and Lava Ultimate at 1.5 mm (3584 N) (p&gt;0.05). The experimental groups did not differ significantly from the sound teeth (3991 N) (p&gt;0.05). The failures were predominantly repairable. The occlusal veneers of IPS e.max CAD, Vita Enamic, and Lava Ultimate, with thicknesses of 0.6 mm and 1.5 mm, obtained fracture resistances similar to those associated with sound teeth.

scholarly journals Preliminary feasibility torque mechanical evaluation for 3D printed orthodontic springs with different parameters: invitro study

2020 ◽  
Author(s):  
Ahmed Othman ◽  
Steven Hartman ◽  
Dragan Ströbele ◽  
Jassin Arnold ◽  
Constantin von See
Keyword(s):  
Testing Machine ◽  
Control Group ◽  
3D Printer ◽  
Coil Design ◽  
Flexible Material ◽  
Universal Testing ◽  
Length Group ◽  
Cad Cam ◽  
3D Printed ◽  
Sydney Australia

Abstract Background: The purpose of the presented investigation is to evaluate the resulting torque on loaded 3D printed springs using different coil thickness and length.Methods: Specimens were designed and printed using the 3D printer MAX (Asiga, Sydney, Australia) with 3D printable, experimental, flexible material (Code:BM2008, GC, Tokyo, Japan). The specimens were divided into three groups according to spring coil design. Control group (n=18), length group (n=19) and thickness group (n=22). Groups were tested using a Sauter Machine for torque calculation (DB, Grindelwald, Switzerland) in conjunction with a universal testing machine (Zwick Z010, Ulm, Germany) for clock-wise and anti-clockwise testing. Statistical analysis was performed using the Steel-Dwass test to compare median values of the three groups in both testing directions (p<0.001). Results: The highest torque value was determined in the thickness group for both clockwise and anti-clockwise testing directions, achieving 44.00N/mm and 39.62N/mm respectively. The length group ranged from 21.65N/mm to 11.04N/mm in clockwise direction and from 18.04N/mm to 11.38N/mm in counter-clockwise testing. The control group ranged from 22.72N/mm to 17.18N/mm in the clock-wise direction while in the anti-clock wise testing it ranged from 21.34N/mm to 16.02N/mm.Conclusions: The amount of torque produced from the CAD/CAM springs is being affected by diameter more than the length design parameter in comparison to the control group. The values of the thickness group are significantly higher than those of the length group (P<0.001).

scholarly journals Flexibility of K3 and ProTaper universal instruments

2011 ◽  
Vol 22 (3) ◽  
pp. 218-222 ◽  
Author(s):  
Renata Grazziotin-Soares ◽  
Flares Barato Filho ◽  
José Roberto Vanni ◽  
Susimara Almeida ◽  
Elias Pandonor Motcy de Oliveira ◽  
...  
Keyword(s):  
Mechanical Test ◽  
Testing Machine ◽  
Universal System ◽  
Universal Testing Machine ◽  
The Third ◽  
Universal Testing ◽  
Before And After ◽  
Level Of Significance ◽  
Flexible Instruments

This study used a mechanical test to evaluate the flexibility of instruments from the K3 (conicity 0.04) and the ProTaper Universal systems when they were new and after 5 uses in simulated canals. Five sets of instruments of each system were tested: K3 (15, 20, 25, 30, 35, 40 and 45) and ProTaper Universal (S1, S2, F1, F2, F3, F4 and F5). Each set of instruments was used to prepare a simulated canal and the same set of instruments was used 5 times (50 canals). The number of each subgroup represented the number of uses: 0 (control), 1, 3 and 5 uses. Before and after each use, the instruments were submitted to a mechanical flexibility test performed in a Versat 502 universal testing machine. Interactions between the instrument and the number of uses were analyzed by ANOVA and Tukey's test at a 5% level of significance. Instruments from both systems presented lower flexibility after the third use compared to the flexibility obtained after uses 0 and 1 (p<0.05), and maintained the same flexibility after the fifth use. The flexibility of instruments from the K3 system decreased with the increase of diameter, irrespective of the number of uses. Among the instruments from the ProTaper Universal system, the shaping files presented greater flexibility than the finishing files. F2 and F3 were the least flexible instruments, and F4 and F5 presented flexibility values similar to those of F1.

scholarly journals Effect of Incisal Porcelain Veneering Thickness on the Fracture Resistance of CAD/CAM Zirconia All-Ceramic Anterior Crowns

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Noha Badran ◽  
Sanaa Abdel Kader ◽  
Fayza Alabbassy
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
Mode Iii ◽  
Nickel Chromium ◽  
Significant Difference ◽  
All Ceramic ◽  
Metal Ceramic ◽  
Cad Cam ◽  
Ceramic Crown

Statement of Problem. In some clinical situations, the vertical length of either a prepared tooth or an implant abutment is short, while the occlusal clearance to be restored by a porcelain crown is large. Incisal thickness of the veneering porcelain should be considered to prevent mechanical failure of the crown. Purpose. The aim of this study is to evaluate the effect of two different incisal veneering porcelain thickness on the fracture resistance of the anterior all-ceramic CAD/CAM zirconia crown system as compared with the conventionally used metal ceramic crown system. Method. CAD/CAM zirconia all-ceramic and metal ceramic crowns were fabricated on the prepared dies with standardized dimensions and designs using standardized methods according to the manufacturer’s instructions. All crowns were then adhesively luted with resin-based cement (Multilink cement system), subjected to thermal cycling and cyclic loading, and were loaded until fracture using the universal testing machine to indicate the fracture resistance for each crown material in each veneering thickness. Results. Statistical analysis was carried out, and the results showed that the fracture resistance of the nickel-chromium metal ceramic group was significantly higher than that of the CAD/CAM zirconia all-ceramic group. Also, the fracture resistance of crowns with 1.5 mm incisal veneering thickness was significantly higher than those with 3 mm incisal veneering thickness in both groups. Furthermore, there was no significant difference in the fracture mode of the two groups where 50% of the total specimens demonstrated Mode II (veneer chipping), while 35% demonstrated Mode I (visible crack) and only 15% demonstrated Mode III (bulk fracture). Conclusion. High failure load values were demonstrated by the specimens in this study, which suggest sufficient strength of both incisal veneering thickness in both crown systems to withstand clinical applications; however, the fracture patterns still underline the requirement of a core design that support a consistent thickness of the veneering ceramic, and it is recommended to conduct long-term prospective clinical studies to confirm findings reported in the present study.

Effect Analysis of Temperature on the Rubber Material Stress-Strain Relationship

2014 ◽  
Vol 977 ◽  
pp. 116-119 ◽  
Author(s):  
Yu Liang Yang ◽  
Liang Qiao ◽  
Cong Wang ◽  
Fei Lu ◽  
Xiao Hui Kang
Keyword(s):  
Environmental Temperature ◽  
Testing Machine ◽  
Test Results ◽  
Stress Strain ◽  
Rubber Material ◽  
Effect Analysis ◽  
Universal Testing ◽  
Different Temperatures ◽  
Strain Relationship ◽  
Relationship Of

For the effect of environmental temperature on the rubber material stress-strain relationships, rubber tensile specimens, compression specimens and shear specimens were made. Through the electronic universal testing machine Instron 5500R, the stress-strain curves of three kinds of specimens at different temperatures were obtained. The test results showed that the stress-strain relationship of rubber material was typically nonlinear. As the temperature increased, the elastic modulus of rubber material decreased.

Analysis on the Reasons of 500kV High-Voltage Disconnectors Hoop Fracture

2014 ◽  
Vol 915-916 ◽  
pp. 992-995
Author(s):  
Shuang Liu ◽  
Wei Tan Cui ◽  
Hong Wu Zhang ◽  
Yong Quan Ma
Keyword(s):  
Mechanical Properties ◽  
High Voltage ◽  
Chemical Elements ◽  
Testing Machine ◽  
Optical Microscope ◽  
Test Results ◽  
Tightening Force ◽  
Hardness Tester ◽  
Universal Testing ◽  
Fracture Appearance

The fracture reasons of 500kV high-voltage disconnectors hoops were analyzed. The fracture appearance, composition of chemical elements, metallographic, mechanical properties of the fractured hoops were investigated by ICP-AES, SEM, optical microscope, brinell hardness tester, universal testing machine. The test results that one reason is substandard products of this batch hoop. The composition of chemical elements and mechanical properties is fails to comply with applicable standards prescribed and the casting defects are found. Another reason is that the large pre-tightening force and tightens reverse order.

scholarly journals Pengaruh penambahan hidroksiapatit terhadap porositas dan compressive strength basis resin akrilik heat-curedEffect of hydroxyapatite addition towards porosity level and compressive strength of heat-cured acrylic resin base

2020 ◽  
Vol 32 (2) ◽  
pp. 91
Author(s):  
Chaterina Diyah Nanik Kusumawardani ◽  
Ronaldo Triputro Chondro ◽  
Ivan Andrian ◽  
Rima Parwati Sari
Keyword(s):  
Compressive Strength ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Load Cell ◽  
Control Group ◽  
Porosity Level ◽  
Universal Testing ◽  
White Spots ◽  
Sem Imaging ◽  
One Way Anova

Pendahuluan: Resin akrilik heat cured (HC) merupakan pilihan utama bahan sebagai basis gigi tiruan. Hidroksiapatit (HAP) adalah molekul kristalin yang sudah banyak digunakan di kedokteran gigi. Penelitian terdahulu membuktikan bahwa HAP mampu mengurangi monomer sisa pada resin akrilik HC, yang akan mengurangi juga porositas resin akrilik tersebut. Berkurangnya porositas resin akrilik, diharapkan akan meningkatkan kekuatan mekanik resin akrilik tersebut. Tujuan penelitian menganalisis pengaruh penambahan hidroksiapatit terhadap porositas dan compressive strength resin akrilik HC. Metode: Jenis penelitian eksperimental laboratoris. Sampel penelitian 20 resin akrilik HC berbentuk silindris (6x3mm), dibagi menjadi 4 kelompok. Kelompok kontrol (tanpa penambahan HAP), kelompok HAP 2%, kelompok HAP 5%, dan kelompok HAP 10%. Permukaan sampel diteliti menggunakan SEM untuk porositasnya. Penghitungan compressive strength sampel menggunakan Universal Testing Machine (load cell 300kg/mm2). Hasil: Uji one-way ANOVA dan Tukey-HSD menunjukkan perbedaan signifikan (p<0,05) antara kelompok kontrol (90±13,5MPa) dengan 5%HAP (105±4,3MPa) dan 10%HAP (113±10,2MPa), begitu pula antara 2%HAP (96±8,4MPa) dengan 10%HAP. Uji SEM menunjukkan tidak adanya reaksi kimia antara HAP dan resin akrilik HC. Tampak pula bercak putih tersebar tidak merata pada permukaan sampel akrilik di kelompok-kelompok perlakuan. Bercak putih ditemukan meningkat sebanding dengan peningkatan konsentrasi HAP, dengan diameter yang semakin besar. Simpulan: Penambahan HAP pada basis resin akrilik HC mampu menurunkan tingkat porositas dan meningkatkan nilai compressive strength. Penurunan tingkat porositas meningkat seiring dengan penambahan HAP. Compressive strength yang paling tinggi didapatkan pada basis resin akrilik heat cured dengan penambahan 10% hidroksiapatit.Kata kunci: Compressive strength, uji SEM, resin akrilik heat cured, hidroksiapatit. ABSTRACT Introduction: Heat-cured acrylic resin has been commonly used as a denture base, whereas hydroxyapatite (HAP) is a crystalline molecule widely used in the field of dentistry. Previous research has been proofed that HAP could reduce the residual monomer of heat-cured acrylic resin, which will reduce the porosity level in advance, so it was expected for better mechanical properties. This research was aimed to analyse the effect of HAP addition towards the porosity level and compressive strength of heat-cured acrylic resin. Methods: An experimental laboratory research was conducted towards 20 cylindrical samples (6 x 3 mm) of heat-cured acrylic resins, which were divided into four groups: Control group (without HAP addition), 2% HAP addition group, 5% HAP addition group, and 10% HAP addition group. Compressive strength was tested using Universal Testing Machine (load cell of 300kg / mm2). Each sample surface porosity was observed using the scanning electron microscope (SEM). Results: One-way ANOVA and Tukey-HSD tests results showed significant differences (p < 0.05) between compressive strength in the control group (90 ± 13.5 MPa) compared to 5% (105 ± 4.3 MPa) and 10% HAP addition group (113 ± 10.2 MPa), significant differences were also shown between the 2% (96±8.4MPa) and 10% HAP addition group. SEM imaging showed that there was no chemical reaction between HAP and heat-cured acrylic resin. It showed uneven white spots in acrylic sample’s surface in all treatment groups. Those white spots were likely to be found more in the higher concentration of HAP, so did the diameter of white spots was also found more in the higher concentration. Conclusion: The addition of hydroxyapatite to the base of heat-cured acrylic resin can reduce the level of porosity and increase the compressive strength value. The decrease in the porosity level increases with the addition of hydroxyapatite. The highest compressive strength is obtained with the addition of 10% hydroxyapatite.Keywords: Compressive strength, SEM imaging, heat-cured acrylic resin, hydroxyapatite.

scholarly journals Effect of beverages on surface properties of resin-based sealants

2017 ◽  
Vol 16 ◽  
pp. 1-7
Author(s):  
Bruna Genari ◽  
Vicente Castelo Branco Leitune ◽  
João Henrique Macedo Saucedo ◽  
Susana Maria Werner Samuel ◽  
Fabrício Mezzomo Collares
Keyword(s):  
Bond Strength ◽  
Testing Machine ◽  
Resin Cement ◽  
Control Group ◽  
Resin Cements ◽  
Universal Testing ◽  
Halogen Light ◽  
Significant Difference ◽  
Tooth Surfaces ◽  
Light Curing

Self-adhesive, dual-polymerizing resin cements require no treatment to the prepared tooth surfaces before cementation. Aim: The aim of this study was to evaluate the influence of curing mode on bond strength (BS) of three cementing systems to bovine dentin. Methods: The buccal enamel surfaces of 50 bovine incisors were removed to expose dentin and to flat the surface. The teeth were divided into five groups (n=10), which consisted of two resin cements (Multilink and Clearfil SA Cement) that were tested in dual- (halogen light for 40 s) and self-cured modes, and a control (RelyX ARC). Two cylinders of resin cements (1.0 mm X 0.75 mm) were prepared on each bonded dentin surface. After 24h at 37oC, resin cylinders were subjected to micro-shear testing in a universal testing machine (4411/Instron - 0.5 mm/min). Data were statistically analyzed by two-way ANOVA, Tukey and Dunnett`s test (5%). Results: Multilink showed higher BS than those observed on Clearfil SA. Light-curing resulted in higher BS for both Multilink and Clearfil SA. When Multilink was light-cured, no significant difference on BS was demonstrated between it and RelyX ARC. Conclusions: The highest BS values were obtained in control group and light-cured Multilink resin cement.

scholarly journals Residual Strength of Carabiners Used by Tree Climbers

2009 ◽  
Vol 35 (2) ◽  
pp. 75-79
Author(s):  
Brian Kane ◽  
H. Dennis Ryan
Keyword(s):  
New York ◽  
Surface Roughness ◽  
Residual Strength ◽  
Testing Machine ◽  
Maximum Load ◽  
Universal Testing Machine ◽  
Universal Testing ◽  
Serious Injury ◽  
Long Term Studies

Tree climbers increasingly use carabiners and apply them in situations for which they are not designed. Because failure of carabiners can result in serious injury or death, the following study tested how well carabiners endure the stress to which climbers subject them. This study distributed carabiners of four types (all manufactured by Petzl) to climbers in Massachusetts and New York, USA, and collected them a year later. Then, carabiners were broken in a universal testing machine and measured the maximum load, as well as surface roughness. No carabiners broke below their rated strength; and used carabiners were, with one exception, as strong as new carabiners. Surface roughness was a weak, but significant, predictor of strength. Findings are discussed in light of climber safety and the importance of conducting long-term studies.

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