scholarly journals Stress analysis of over-denture abutments treated with two obturation techniques

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Ahmed N. Elsherbini ◽  
Mohamed M Nagy ◽  
Nancy N Elsherbini
Keyword(s):  
Stress Analysis ◽  
Testing Machine ◽  
The Other ◽  
Strain Gauges ◽  
Universal Testing Machine ◽  
Universal Testing ◽  
Supporting Structures

Aim: Evaluation of stresses induced on over-denture abutments endodonticaly treated with two different obturation techniques.Materials and methods: eight mandibular permanent canines were inserted in four pesudo-realistic models.  In each model two canines were placed in it. One canine was treated with lateral obturation technique and the other canine with vertical obturation technique. Four over-denture prostheses were fabricated on the four models. Then strain gauges were attached on the coronal one third of the root buccally and lingually for all eight canines. A metal rod was placed occlusally on the premolar –molar area, and a 50 N load was applied on the middle of the rod using the universal testing machine. Readings were collected. Results: from the collected data the lateral obturation showed 85.25±104.901 µε and the vertical obturation showed 4.875±3.555 µε with significance difference of P<0.05 between the groups.Conclusion: it can be concluded that the abutments treated with vertical obturation techniques reduced the stresses induced to the supporting structures when compared with the lateral condensation technique.

scholarly journals Effect Of Accelerating Aging On Retention And The Release Period Of Clips In A Bar Retained Maxillary Implant Overdenture

2021 ◽  
Vol 8 ◽  
Author(s):  
Dalia El naggar ◽  
Ahmed Mohamed Alam-Eldein ◽  
Maha Mostafa Halim ◽  
Hoda Mohammed Amin Rashad
Keyword(s):  
Testing Machine ◽  
Accelerated Aging ◽  
The Other ◽  
Universal Testing Machine ◽  
Universal Testing ◽  
Retention Loss ◽  
Significant Difference ◽  
Implant Overdenture

Objectives: This study was made to detect the effect of accelerating aging on retention and measuring the release period of clips in a 2 and 3 bar retained maxillary implant overdenture. Materials and Methods: Four implants were placed in two maxillary edentulous epoxy models. One model had two bar attachments with two clips overdenture while the other model had three bar attachments with three clips in the overdenture. Retention and release period of the clips were checked before applying insertion removal cycles. Retention was measured using universal testing machine after 540 cycles (6 months) and 1080 cycles (1 year) of insertion removal on a chewing simulator.Results and Conclusions: There was a significant difference in retention and release period between two bars and three bars implant retained maxillary overdentures. A significant difference was also seen in each group after accelerated aging. Therefore, the three bar implant retained overdenture had higher retention values than two bar. Retention loss occurred in both groups after the insertion removal cycles. Release period value was lower in two bar overdenture than three bar overdenture.

scholarly journals Retention of provisional crowns cemented with eight temporary cements: comparative study

2004 ◽  
Vol 12 (3) ◽  
pp. 209-212 ◽  
Author(s):  
Mariana Ribeiro de Moraes Rego ◽  
Luiz Carlos Santiago
Keyword(s):  
Tensile Strength ◽  
Comparative Study ◽  
Testing Machine ◽  
Strength Test ◽  
The Other ◽  
Universal Testing Machine ◽  
Tensile Strength Test ◽  
Universal Testing ◽  
Significant Difference ◽  
Crown Preparation

Many temporary cements are commercially available; therefore, it is necessary to indicate them for each clinical requirement with regard to the tensile strength of prosthetic retainers. Thus, the purpose of this study was to compare the retention of provisional crowns cemented with eight temporary cements, over full crown preparations with standardized mechanical principles as height, taper, and length. For that purpose, eighty human first premolars received full crown preparation with standardized height and taper. Provisional crowns were fabricated and luted with eight brands of temporary cements. Twenty four hours after cementation, the restorations were submitted to tensile strength test in a universal testing machine and the data submitted to ANOVA and Bonferroni tests. Mean tensile strength values ranged from 20.1N for Nogenol cement to 67.5N for Hydro C cement. Statistically significant difference (p<0.05) was found between Hydro C and the other groups, except for Temp Bond and Rely X Temp, which presented statistically significant difference when compared to Freegenol and Nogenol temporary cements. The crowns cemented with Hydro C cement were more retentive that than those cemented with the other cements, except for Rely X Temp and Temp Bond. The less retentive crowns were those cemented with Nogenol and Freegenol temporary cements.

scholarly journals Fracture strength of teeth restored with milled ultrathin occlusal veneers made of polymer-infiltrated ceramic

2021 ◽  
Vol 32 (5) ◽  
pp. 105-113
Author(s):  
Laerte Ohse ◽  
Deborah Stona ◽  
Marília M. Sly ◽  
Luiz Henrique Burnett Júnior ◽  
Ana Maria Spohr
Keyword(s):  
Fracture Strength ◽  
Testing Machine ◽  
Strength Test ◽  
The Other ◽  
Single Bond ◽  
Third Molars ◽  
Universal Testing Machine ◽  
Universal Testing

Abstract The purpose was to evaluate, in vitro, the fracture strength of teeth restored with 0.3- or 0.6-mm-thick occlusal veneers made of Vita Enamic® bonded to enamel or dentin. Fifty third molars were allocated into five groups (n=10): Group C - control (sound teeth); Group 0.3E - 0.3-mm-thick occlusal veneers bonded to enamel; Group 0.6E - 0.6-mm-thick occlusal veneers bonded to enamel; Group 0.3D - 0.3-mm-thick occlusal veneers bonded to dentin; Group 0.6D - 0.6-mm-thick occlusal veneers bonded to dentin. After luting with Single Bond Universal and Filtek Z-100, the samples were subjected to fracture strength test in a universal testing machine. The fractures were classified as irreparable and reparable. Data were analyzed with 2-way and 1-way ANOVA (α=.05) followed by Tukey’s test. The teeth restored with 0.3-mm-thick occlusal veneers (2658 N) achieved significantly higher fracture strength compared to the teeth restored with 0.6-mm-thick occlusal veneers (2070 N) (p=0.017). The teeth restored with occlusal veneers bonded to enamel (2648 N) had significantly higher fracture strength compared to the teeth restored with occlusal veneers bonded to dentin (2049 N) (p=0.015). Group C (3355 N) and Group 0.3E (2965 N) did not differ significantly from each other, being the fracture strength significantly higher than the other groups (p<0.05). The fractures were predominantly reparable. The teeth restored with 0.3-mm-thick occlusal veneers achieved higher fracture strength compared to the teeth restored with 0.6-mm-thick occlusal veneers. The supporting substrate influenced the fracture strength, which was higher for the teeth restored with occlusal veneers bonded to enamel.

Study on Characteristics of Ultrasonic Velocity for the Concrete under Stress

2013 ◽  
Vol 438-439 ◽  
pp. 220-223 ◽  
Author(s):  
Ling Zhang ◽  
Chun Ling Yan
Keyword(s):  
Ultimate Strength ◽  
Ultrasonic Velocity ◽  
Ultrasound Examination ◽  
Testing Machine ◽  
Strength Level ◽  
Growth Trend ◽  
Universal Testing Machine ◽  
Universal Testing ◽  
Three Stages ◽  
The Relationship

Cube concrete (150×150×150mm) of five ages (7, 14, 21, 28 and 35 days) under different stress conducted the ultrasound examination by non-metallic detector and universal testing machine. The results show that the relationship curve of the stress and the ultrasonic velocity can be divided into three stages, the smooth straight stage, the linear deceleration stage and the attenuation destruction stage from the load beginning to the ultimate strength for the same age. There is a growing trend about the ultrasonic velocity with the increase of the age to concrete samples of C10 and C20 in the same loading; however, the overall growth trend of the velocity is not obvious to concrete samples of C30, C35, C40 and C45. It also shows that the relationship curve of strength level and the velocity can be divided into two distinct stages, the sharply increasing stage (C10-C30) and the fluctuating stage (C30-C45). Simultaneously, the paper further illustrates and explains the reasons to appear these stages and the phenomena.

Comparison of characteristic of iron (Fe) powder using underground explosive pressing and universal testing machine

2018 ◽  
Author(s):  
Rafika Norhidayu Rosdi ◽  
Nor Azmaliana Azmi ◽  
Nurain Abdul Latheef ◽  
Ahmad Humaizi Hilmi ◽  
Arifin Ismail ◽  
...  
Keyword(s):  
Testing Machine ◽  
Universal Testing Machine ◽  
Universal Testing ◽  
Fe Powder ◽  
Explosive Pressing

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 PENGARUH PENINGKATAN DERAJAT DEFORMASI CANAI HANGAT TERHADAP KARAKTERISTIK DEFORMATION BAND PADUAN Cu-Zn 70/30

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Eka Febriyanti ◽  
Dedi Priadi ◽  
Rini Riastuti
Keyword(s):  
Deformation Band ◽  
Cold Working ◽  
Testing Machine ◽  
Deformation Bands ◽  
Double Pass ◽  
Deformation Degree ◽  
Universal Testing Machine ◽  
Universal Testing ◽  
Hot Rolled ◽  
Zn Alloy

Cu-Zn 70/30 alloy has properties that is relatively soft, ductile, and easy to perform by cold working. However, cold working has the disadvantage that require equipment which has higher loading capacity to generate strength and higher density thus increasing of machining cost. In addition, strain hardening phenomenon due to cold working process resulted in decreasing of ductility material. Therefore, it is necessary alternative fabrication processes to optimize the mechanical properties of Cu-Zn alloy 70/30 that with the TMCP method. TMCP is metal forming material by providing large and controlled plastic strain to the material. TMCP using the deformation percentage variation that 32.25%, 35.48%, and 38.7% from hot rolled research at 500°C temperature in double pass reversible which performed on Cu-Zn 70/30 plate. By tensile testing using universal testing machine can be seen that the Cu-Zn 70/30 alloy on 32.25% degree of deformation, both of UTS and YS respectively are 505 MPa and 460 MPa. Whereas from examination of thickness and density deformation bands by FE-SEM shows denser and thicker deformation band proportional with increasing of deformation degree.Moreover, the values of tensile strength at the edge of the area and the center is directly proportional to the density and thickness of the deformation band.AbstrakPaduan Cu-Zn 70/30 memiliki sifat yang relatif lunak, ulet, dan mudah dilakukan pengerjaan dingin. Namun, pengerjaan dingin memiliki kekurangan yaitu membutuhkan peralatan yang memiliki kapasitas pembebanan tinggi untuk menghasilkan kekuatan dan kepadatan tinggi sehingga meningkatkan biaya permesinan. Selain itu, fenomena pengerasan regang akibat proses pengerjaan dingin menghasilkan penurunan keuletan material. Oleh karena itu, diperlukan alternatif proses fabrikasi untuk mengoptimalkan sifat mekanik paduan Cu-Zn 70/30 salah satunya dengan metode TMCP. TMCP merupakan suatu proses perubahan bentuk suatu material dengan cara memberikan regangan plastis yang besar dan terkontrol terhadap material. TMCP dengan menggunakan variasi persentase deformasi sebanyak 32,25%, 35,48%, dan 38,70% dari penelitian canai hangat di suhu 500oC secara double pass reversible dilakukan pada pelat paduan Cu-Zn 70/30. Dengan melakukan pengujian tarik menggunakan mesin uji tarik universal testing machine dapat dilihat bahwa pada material paduan Cu-Zn 70/30 pada derajat deformasi 32,25% menghasilkan nilai UTS dan YS masing-masing sebesar 505 MPa dan 460 MPa. Sedangkan dari hasil pengamatan ketebalan dan kerapatan deformation band menggunakan FE-SEM menunjukkan deformation band yang lebih rapat dan lebih tebal sebanding dengan semakin meningkatnya derajat deformasi. Selain itu, nilai kekuatan tarik pada daerah tepi dan tengah berbanding lurus dengan kerapatan dan ketebalan deformation band.Keywords: 70/30 Cu-Zn alloy, warm rolled, deformation degree, deformation bands

scholarly journals Sifat Fisiko-Kimia Edible Film Agar – Agar Rumput Laut (Gracilaria sp.) Tersubtitusi Glyserol

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Annisa Setyaningrum ◽  
Ni Ketut Sumarni ◽  
Jaya Hardi
Keyword(s):  
Testing Machine ◽  
Edible Film ◽  
Universal Testing Machine ◽  
Universal Testing

Telah dilakukan penelitian tentang pengaruh penambahan gliserol pada pembuatanedible film dari agar – agar rumput laut (gracilaria sp.). Tujuan penelitian ini adalah untuk mengetahui sifat fisiko-kimia terbaikedible film berbasis agar dengan plasticizer gliserol. Penelitian ini menerapkan variasi konsentrasi gliserol antara lain 30, 35, 40, 45, dan 50%terhadap massa agar-agar atas dasar (b/b). Sifat fisiko-kimia Edible filmyang diuji antara lain ketebalan menggunakan micrometer, laju transmisi uap air, kuat tarik dan elongasi masing-masing diuji dengan Universal Testing Machine. Konsentrasi gliserol terbaik diperoleh pada penambahan gliserol 45% yang memiliki ketebalan 0,0167 mm, laju transmisi uap air sebesar 57,18 g/24jam.m2, kuat tarik sebesar 14,23 MPa, dan elongasi sebesar 12,75%

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