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

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.

2021 ◽  
Vol 8 ◽  
Author(s):  
Dalia El naggar ◽  
Ahmed Mohamed Alam-Eldein ◽  
Maha Mostafa Halim ◽  
Hoda Mohammed Amin Rashad

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.


2021 ◽  
Vol 32 (5) ◽  
pp. 105-113
Author(s):  
Laerte Ohse ◽  
Deborah Stona ◽  
Marília M. Sly ◽  
Luiz Henrique Burnett Júnior ◽  
Ana Maria Spohr

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.


2018 ◽  
Vol 30 (3) ◽  
pp. 189
Author(s):  
Actara Rahmadita ◽  
Dwi Tjahyaning Putranti

Pendahuluan: Resin akrilik polimerisasi panas (RAPP) merupakan bahan basis gigi tiruan yang paling banyak digunakan, namun memiliki sifat kekuatan tarik dan tekan yang rendah, sehingga diperlukan modifikasi dengan penambahan bahan penguat pada RAPP berupa aluminium oksida (Al2O3) atau alumina. Tujuan penelitian untuk menganalisi pengaruh penambahan aluminium oksida pada bahan basis gigi tiruan RAPP terhadap kekuatan tarik dan tekan. Metode: Jenis penelitian eksperimental laboratoris. Sebanyak 25 sampel berbentuk flat dumbbell shaped berukuran 60x12x3,9 (mm) untuk uji kekuatan tarik dan 25 sampel  berbentuk balok dengan ukuran 10x10x4 (mm) untuk uji kekuatan tekan. Pencampuran bubuk resin-aluminium oksida konsentasi 0,5%, 1,5%, 2,5% dan 3,5% dengan cairan resin dilakukan secara manual. Sampel direndam dalam air dan dimasukkan ke dalam inkubator. Uji dilakukan menggunakan universal testing machine dengan beban 1000N dan kecepatan crosshead 1mm/menit. Data dianalisis dengan uji ANOVA satu arah dan uji LSD. Hasil: Nilai kekuatan tarik kelompok kontrol dan keempat kelompok perlakuan penambahan aluminium oksida 0,5%, 1,5%, 2,5 %, 3,5% berturut turut adalah 50,867 MPa, 47,895 MPa, 45,107 MPa, 42,476 MPa, dan 39,753 MPa; sedangkan nilai kekuatan tekan kelompok kontrol dan keempat kelompok perlakuan penambahan aluminium oksida 0,5%, 1,5%, 2,5%, 3,5% berturut turut adalah 88,267 MPa, 106,085 MPa, 122,283 MPa, 135,367 MPa, dan 156,571 MPa. Penambahan bubuk aluminium oksida pada RAPP dapat menurunkan kekuatan tarik dan meningkatkan kekuatan tekan secara signifikan (p=0,0001 (p<0,05)), seiring dengan meningkatnya jumlah konsentrasi aluminium oksida yang ditambahkan. Simpulan: Penambahan aluminium oksida pada bahan basis gigi tiruan resin akrilik polimerisasi panas berpengaruh terhadap kekuatan tarik dan tekan.Kata kunci: Resin akrilik polimerisasi panas, aluminium oksida, kekuatan tarik, kekuatan tekan. ABSTRACT            Introduction: Heat-polymerised acrylic resin (HPAR) is the most widely used denture base material but has a low tensile and compressive strength thus modification is needed by adding reinforcement in the form of aluminium oxide (Al2O3) or alumina. The research objective was to analyse the effect of adding aluminium oxide on the tensile and compressive strength of HPAR denture base material. Methods: An experimental laboratory research was conducted towards the total of 25 samples in the form of flat dumbbell shape sized 60 x 12 x 3.9 mm for the tensile strength test, and 25 samples in the form of blocks with the size of 10 x 10 x 4 mm for the compressive strength test. The mixture of powdered aluminium oxide resin with the concentrations of 0.5%, 1.5%, 2.5%, and 3.5% with a liquid resin was carried out manually. The sample was then immersed in the water and put in an incubator. The test was performed using a universal testing machine with 1000 N loads and 1 mm/minute crosshead speed. Data obtained were analysed using the one-way ANOVA and LSD test. Result: The tensile strength values of the control group and all four treatment groups added with 0.5%, 1.5%, 2.5%, and 3.5% aluminum oxide were 50.867 MPa, 47.895 MPa, 45.107 MPa, 42.4476 MPa and 39.753 MPa respectively, while the compressive strength values were 88.267 MPa, 106.085, 122.283 MPa, 135.367 MPa, and 156.571 MPa consecutively. Addition of aluminium oxide powder to the HPAR can significantly reduce the tensile and compressive strength (p = 0.0001 (p < 0.05)) along with increasing concentration. Conclusion: Addition of aluminium oxide towards the HPAR denture base affected its tensile and compressive strength.Keywords: Heat-polymerised acrylic resin, aluminium oxide, tensile strength, compressive strength.


2017 ◽  
Vol 751 ◽  
pp. 657-662
Author(s):  
Phakphum Srinuan ◽  
Jeerapatr O. Baiyokvichit ◽  
Rasana Boonpeng ◽  
Tanapol Wongwisatekit ◽  
Pacharaporn Pattanasukwasan ◽  
...  

The effect of thermoforming on the tear strength of ethylene vinyl acetate (EVA) mouthguard material (Bioplast®) has not been widely investigated. The present study compared the tear strengths of non-processed and processed EVA specimens in various thicknesses. Two groups of EVA sheet (non-processed and processed) in three different thicknesses of 3, 4 and 5 mm were used in specimen fabrication. The processed EVA sheets were achieved by forming the EVA sheet on the cylindrical stone model with the pressure-molding device (Biostar®). Twelve of tear strength specimens of non-processed and processed group in each thickness were prepared following the modified ASTM D 624-00 guideline. The tear strength test was conducted using universal testing machine (Lloyd® 1K series) with the speed of 500 mm/min. The mean thickness and tear strength of the non-processed and processed specimens in each thickness were compared using independent T-test. The differences in the mean tear strength for each thickness of non-processed and process specimens were determined using one-way ANOVA. The mean tear strength and mean thickness of processed EVA specimens was significantly lower than the non-processed EVA specimens for every thickness (P ≤ 0.05). There was no significant difference in the mean tear strength of EVA specimens among each thickness in both non-processed and processed groups. It can be concluded that the thermoforming process has the significant effect on the tear strength of the EVA mouthguard material formed by pressure molding device in every thicknesses. The tear strength of processed specimens were significant lower than the non-processed. Thus, it is more relevant for testing properties of the processed mouthguard material that the mouthguard material before processing.


Author(s):  
Ahmad Adlie Shamsuri ◽  
Siti Atiqa Al Zahra Mat Darus

The tensile strength and flexural strength are the most important mechanical properties as they provide the value of maximum tensile stress and flexural stress. The objective of this study is to analyze statistically the tensile strength and flexural strength data obtained from a universal testing machine. The tests were conducted upon a thermoplastic, specifically high-density polyethylene (HDPE), which was in-house molded by using an injection-molding machine. Three different persons have performed the tensile and flexural tests. Three other laboratories have also been involved in these tests. The relative standard deviation (RSD) values were calculated to express the precision and repeatability of the tests. Later, the standard score (z-score) values were also calculated to aid the comparison of the data. Finally, the single-factor analysis of variance (ANOVA) was employed to investigate statistically significant differences between the means of the tensile strength and flexural strength data of each person and laboratory. From the calculation, the RSD values of all three persons and laboratories were lower than 5%, indicating that the data were consistent. The z-score values of all three persons were within the range from -2 to 2, suggesting that the data were close to average. However, the z-score value for one of three laboratories was not within the range, demonstrating that the data was unusual. The P-values of all three persons were higher than 0.05 (except for flexural strength), implying that the difference between the means of the data was not statistically significant. Nevertheless, the P-values of all three laboratories were lower than 0.05, indicating that the difference between the means of the data was statistically significant.


2020 ◽  
Vol 206 ◽  
pp. 01018
Author(s):  
Rui Li ◽  
Lei Liu ◽  
Zhihua Zhang ◽  
Huaming An

Concrete is one of the most significant materials in modern society. It is widely used in many projects. Thus it is essential to study the strength and the failure patterns of this material. As well known, the compressive strength is much higher than the tensile strength for concrete. Thus, it is easy to fail due to the tensile strength for concrete. Thus, this paper focuses on the study of the tensile strength of the concrete and its failure patterns. Three types of concretes are made for studying the tensile strengths and the failure patterns of the concretes. Then the Brazilian tensile strength test method is employed in this study. The mythology of calculating tensile strength by the Brazilian tensile strength test method is introduced. Many discs are made for the tests. The Rock mechanics testing machine is used to excavate pressure on the top and bottom of the disc. It is concluded that the failure of the disc is along the vertical diameter between the top and bottom plates contacting the dis. The tensile failure is not obviously influenced by the ratios of the materials while the tensile strength is significantly influenced by the ratios of the concrete. The damage index of concrete is also proposed to describe the capabilities of resisting failure.


2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Agustina Mandasari ◽  
Mutya Fika Safitri ◽  
Essy Risa Perangin-angin ◽  
Dian Sunarwati ◽  
Wulan Dwi Safitri ◽  
...  

Telah dilakukan karakterisasi uji kekuatan tarik (tensile strength) film plastik biodegradable dari tandan kosong kelapa sawit dengan penguat zink oksida dan gliserol. Penelitian ini bertujuan untuk mengetahui kekuatan tarik film plastik biodegradable yang dihasilkan dari tandan kosong kelapa sawit dengan variasi ZnO dan gliserol (a) 0 %  ZnO dan 50% gliserol; (b) 2% ZnO dan 25% gliserol; (c) 9% ZnO dan 25% gliserol; (d) 3% ZnO dan 50 % gliserol. Metode penelitian yang digunakan adalah analisis sifat mekanik dan uji kekuatan tarik film plastik menggunakan Universal Testing Machine (UTM). Hasil penelitian menunjukan bahwa kuat tarik pada film plastik biodegradable dipengaruhi oleh konsentrasi gliserol dan ZnO. Kuat tarik maksimal yang didapat dari penelitian yaitu 12,642 MPa dengan komposisi gliserol 25% dan ZnO 9%. Hal ini menunjukkan bahwa semakin banyak penambahan komposisi gliserol dan ZnO maka kuat tarik plasik akan semakin baik. Kata kunci : biodegradable film, kuat tarik, tandan kosong kelapa sawit


2015 ◽  
Vol 1 (1) ◽  
pp. 102
Author(s):  
Pramudya Aditama ◽  
Siti Sunarintyas ◽  
Widjijono Widjijono

Resin akrilik merupakan bahan yang sering digunakan dalam pembuatan basis gigi tiruan. Kelemahan resin akrilik adalah mudah patah. Salah satu cara untuk mengatasi masalah tersebut adalah dengan menambahkan polyethylene (PE) atau glass fiber. Tujuan dari penelitian ini untuk mengetahui pengaruh jenis dan volumetrik fiber terhadap kekuatan transversal reparasi plat resin akrilik. Penelitian ini menggunakan dua puluh lima plat resin akrilik kuring panas berukuran 65 x 10 x 2,5 mm. Subjek dipreparasi untuk membuat jarak 3 mm dan sudut bevel 45o. Subjek dibagi menjadi 5 kelompok, masingmasing kelompok terdiri dari 5 subjek. Kelompok 1 (kontrol) tanpa penambahan fiber, kelompok II dengan penambahan 3,7% v/v PE fiber, kelompok III dengan penambahan 7,4% v/v PE fiber, kelompok IV dengan penambahan 3,7% v/v E-glass fiber, dan kelompok V dengan penambahan 7,4% v/v E-glass fiber. Seluruh plat direndam dalam air destilasi selama satu hari pada suhu 37oC. Pengujian kekuatan transversal plat resin akrilik dengan menggunakan Universal Testing Machine dan data yang didapat dianalisis menggunakan ANAVA dua jalur dengan tingkat kepercayaan 95%. Rerata kekuatan transversal (MPa) reparasi plat resin akrilik yang diperkuat fiber: 3,7% v/v PE fiber (67,77±3,34); 7,4% v/v PE fiber (80,37±8,42); 3,7% v/v E-glass fiber (96,72±5,43); 7,4% v/v E-glass fiber (109,44±4,98); sedangkan reparasi plat resin yang tidak diperkuat fiber menghasilkan kekuatan transversal 56,27±4,7 MPa. Hasil analisis menggunakanANAVA dua jalur menunjukkan variabel jenis dan volumetrik fiber memberikan pengaruh signifikan (p<0,05), sedangkan interaksi antara jenis dan volumetrik fiber tidak berpengaruh signifikan (p>0,05). Uji post hoc Tukey menunjukkan perbedaan signifikan (p<0,05) untuk seluruh kelompok perlakuan. Penambahan E-glass fiber dalam reparasi plat resinakrilik mampu meningkatkan kekuatan transversal lebih tinggi dibandingkan dengan menggunakan PE fiber. Peningkatan volumetrik fiber dapat meningkatkan kekuatan transversal reparasi plat resin akrilik. Effect Of Type And Volumetric Fiber On Transverse Strength Of Acrylic Resin Plate Repair. Acrylic resin is the most common denture base material. A disadvantage of acrylic resin is that it is easily fractured. One way to resolve this problem is by adding polyethylene (PE) or glass fibers. The purpose of this research is to find out about the effect of type and volumetric fiber on transverse strength of acrylic resin plate repaired. The experiment involved twenty five plates of heat cured acrylic with the dimensions of 65 x 10 x 2.5 mm. The speciments were prepared to create a 3 mm gap and 45° bevel. The subjects were divided into 5 groups; each group consisted of 5. Group I (control) was without fiber reinforcement, group II reinforced with 3.7% v/v PE fiber, group III reinforced with 7.4% v/v PE fiber, group IV reinforced with 3.7% v/v E-glass fiber, and group V reinforced with 7.4% v/v E-glass fiber. All plates were soaked in distilled water for one day at 37° C temperature. The plates were tested for transverse strength with Universal Testing Machine and all data obtained were analyzed with two way ANOVA at 95% confidence level. The mean of transverse strength (MPa) of the acrylic resin plate repair reinforced with fiber: 3.7% v/v PE fiber was (67.77±3.34); 7.4% v/v PE fiber (80.37±8.42); 3.7% v/v E-glass fiber (96.72±5.43); 7.4% v/v E-glass fiber (109.44±4.98); while the transverse strength of the acrylic resin plate with no fiber reinforced was 56.27±4.7 MPa. Two way ANOVA analysis shows that type and volumetric fiber had significant effect (p<0.05), while the interaction between type and volumetric fiber had no significant effect (p>0.05). Tukey post hoc test shows significant difference (p<0.05) for all groups. The addition of E-glass fibers in the acrylic resin plate repaired increased the transverse strength higher than that with PE fibers. The increase in volumetric fibers might improve the transverse strength of the acrylic resin plate repaired.


2020 ◽  
Vol 19 ◽  
pp. e208204
Author(s):  
Maria Helena Rossy Borges ◽  
Carmen Gilda Tavares Dias ◽  
Cristiane de Melo Alencar ◽  
Cecy Martins Silva ◽  
Renata Antunes Esteves

Aim: The purpose of this study was to compare the microhardness, diametral tensile strength, compressive strength and the rheological properties of self-adhesive versus conventional resin cements. Methods: Specimens of a conventional (RelyX ARC) and 3 self-adhesive (RelyX U200, Maxcem Elite, Bifix SE) types of resin cements were prepared. The Knoop test was used to assess the microhardness, using a Microhardness Tester FM 700. For the diametral tensile strength test, a tensile strength was applied at a speed of 0.6 mm/minute. A universal testing machine was used for the analysis of compressive strength and a thermo-controlled oscillating rheometer was used for the Rheology test. One-way ANOVA and Tukey’s test (α=0.05) were used for data analysis. Results: According to microhardness analysis, all the cements were statistically similar (p>0.05), except for Maxcem that presented lower hardness compared with the other cements in relation to the top surface (p<0.05). In the diametral tensile strength test, Relyx U200 and RelyX ARC cements were statistically similar (p>0.05), presented higher value when compared to the Maxcem and Bifix cements (p<0.05). The compressive strength of RelyX ARC and Maxcem Elite cements was statistically higher than RelyX U200 and Bifix cements (p<0.05). Regarding the rheology test, Maxcem Elite and RelyX ARC cements showed a high modulus of elasticity. Conclusions: The self-adhesive cements presented poorer mechanical properties than conventional resin cement. Chemical structure and types of monomers employed interfere directly in the mechanical properties of resin cements.


2021 ◽  
pp. 030157422110044
Author(s):  
I Ranganayakulu ◽  
D Praveen Kumar Varma ◽  
Padma Priya CV ◽  
RSVM Raghu Ram ◽  
K Anand Viswanadh ◽  
...  

Objectives: To evaluate and compare the effect of adhesion boosters on shear bond strength (SBS) of orthodontic brackets on bleached teeth. Materials and Methods: A sample of 90 extracted maxillary premolars was equally divided into 2 groups of bleached and non-bleached teeth. Twenty-two percent carbamide peroxide gel was used as an agent for bleaching. Each group was further divided equally into 3 subgroups depending on the type of adhesive booster used (Enhance LC, All-bond 2, and no adhesive booster [control]) and maxillary premolars brackets were bonded. Debonding was done with a universal testing machine, and the SBS was recorded. Results: The SBS of non-bleached teeth was highest for All-bond 2 (14.78 ± 2.47 MPa) followed by Enhance LC (13.15 ± 3.49 MPa) and control (10.30 ± 1.06 MPa). The SBS of bleached teeth was highest for All bond 2 (12.23 ± 1.41 MPa) followed by Enhance LC (11.76 ± 1.71 MPa) and control (9.63 ± 1.06 MPa). All subgroups showed a significant difference in SBS (P = .000) on bleached and non-bleached teeth. The SBS showed a significant difference between the bleached and non-bleached teeth in All-bond 2 group (P = .019). Conclusion: Adhesive boosters increased the SBS of both bleached and non-bleached teeth significantly. Among the two adhesive boosters used, All-bond 2 showed more SBS values.


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