scholarly journals Mechanical Properties of Elastomeric Impression Materials: An In Vitro Comparison

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Dino Re ◽  
Francesco De Angelis ◽  
Gabriele Augusti ◽  
Davide Augusti ◽  
Sergio Caputi ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Calculated Data ◽  
Insufficient Data ◽  
High Tensile Strength ◽  
Mean Values ◽  
Heavy Body ◽  
Impression Materials ◽  
One Way Anova

Purpose.Although new elastomeric impression materials have been introduced into the market, there are still insufficient data about their mechanical features. The tensile properties of 17 hydrophilic impression materials with different consistencies were compared.Materials and Methods.12 vinylpolysiloxane, 2 polyether, and 3 hybrid vinylpolyether silicone-based impression materials were tested. For each material, 10 dumbbell-shaped specimens were fabricated (n=10), according to the ISO 37:2005 specifications, and loaded in tension until failure. Mean values for tensile strength, yield strength, strain at break, and strain at yield point were calculated. Data were statistically analyzed using one-way ANOVA and Tukey’s tests (α=0.05).Results.Vinylpolysiloxanes consistently showed higher tensile strength values than polyethers. Heavy-body materials showed higher tensile strength than the light bodies from the same manufacturer. Among the light bodies, the highest yield strength was achieved by the hybrid vinylpolyether silicone (2.70 MPa). Polyethers showed the lowest tensile (1.44 MPa) and yield (0.94 MPa) strengths, regardless of the viscosity.Conclusion.The choice of an impression material should be based on the specific physical behavior of the elastomer. The light-body vinylpolyether silicone showed high tensile strength, yield strength, and adequate strain at yield/brake; those features might help to reduce tearing phenomena in the thin interproximal and crevicular areas.

Comparison between traditional and alternative biocompatible welding techniques used in orthodontic devices

2020 ◽  
pp. 146531252097240
Author(s):  
Fernanda de Souza Henkin ◽  
Luciane Macedo de Menezes ◽  
Berenice Anina Dedavid ◽  
Cátia Abdo Quintão
Keyword(s):  
Tensile Strength ◽  
Laser Welding ◽  
Mechanical Performance ◽  
Steel Wire ◽  
Testing Machine ◽  
Mean Values ◽  
Welding Spot ◽  
Microstructural Morphology ◽  
Orthodontic Devices

Objective: To compare the mechanical strength of joints made by conventional soldering with those made by alternative, more biocompatible, methods (spot, tungsten inert gas [TIG] and laser welding), and to compare the microstructural morphology of wires welded with these techniques. Design: In vitro, laboratory study. Methods: Forty stainless-steel wire segments with 0.8-mm diameter were joined by silver soldering, spot, laser and TIG welding. Ten specimens were produced for each one. Tensile strength test was performed 24 h after welding on the Emic DL2000™ universal testing machine, using a load cell of 1000 N with a crosshead speed of 10 mm/min. Results: The highest tensile strength mean values were obtained with silver soldering (532 N), next were laser (420 N), spot (301 N) and TIG (296 N) welding. Statistically significant differences were observed between the groups; the Dunn post-hoc test revealed differences between laser and spot welding ( p=0.046), laser and TIG ( p = 0.016), spot and silver ( p <0.001), and silver and TIG ( p <0.001). Conclusion: Laser welding strength is high, and comparable to silver welding. Spot and TIG techniques present comparable and significantly lower strengths. The four methods presented resistance values compatible with orthodontic use. The microstructural morphology is different for each technique. The association between the mechanical performance and the microstructure evaluation shows that laser presented the highest quality joint.

scholarly journals Surface Hardness of Hybrid Ionomer with Different Curing Time (In Vitro Study)

2017 ◽  
Vol 1 ◽  
Author(s):  
Arfita Sipahutar ◽  
Astrid Yudhit ◽  
Rusfian Rusfian
Keyword(s):  
Standard Deviation ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Hardness Test ◽  
Curing Time ◽  
Mean Values ◽  
The Mean ◽  
One Way Anova ◽  
Group 1

<p class="AbstractContent"><strong>Objective:</strong> The aim of this study was to evaluate the surface hardness of hybrid ionomer with different curing times (20, 30, 40, and 50 seconds).</p><p class="AbstractContent"><strong>Methods</strong>: This was an experimental laboratory with posttest only group design. Twenty-four disk shape hybrid ionomer specimens with a diameter of 5 mm and 2 mm in thickness were prepared and polymerized with Quartz Tungsten Halogen (QTH) for 20, 30, 40, and 50 seconds as group 1, 2, 3, and 4 respectively. All samples were immersed in distilled water under 37°C temperature for 24 hours as initial treatment. Surface hardness test was done using Vickers Hardness Test with load 50 gf for 20 second. The Data was analyzed with one way ANOVA (<em>p </em>≤ 0.05).</p><p class="AbstractContent"><strong>Results</strong>: Using one way anova test (<em>p </em>≤ 0.05) shows the mean and standard deviation of the group 1 is 25,900 ± 2,5659VHN; group 2 is 29,800 ± 1,1983 VHN; group 3 is 31,283 ± 0,5037 VHN; group 4 is 36, 183 ± 2,3430 VHN and the obtained value <em>p </em>= 0.000 (<em>p </em>≤ 0.05).</p><p class="AbstractContent">The mean values and standard deviation were 25.900 ± 2.5659 VHN; 29.800 ± 1.1983 VHN; 31.283 ±0.5037 VHN; 6.183 ± 2.3430 VHN for group 1, 2, 3, and 4 respectively. Statistic analyzed showed a significant different among groups with <em>p</em> value =0.000 (<em>p</em> &lt; 0.05).</p><strong>Conclusion</strong> There are significant differences in surface hardness of hybrid ionomer with different curing time (20, 30,40, and 50 seconds). The longer curing time will increase the surface hardness of hybrid ionomer.

23 IMPROVING EFFICIENCY IN WORK WITH TRANSFER OF CLONED PIG EMBRYOS

2014 ◽  
Vol 26 (1) ◽  
pp. 126 ◽  
Author(s):  
H. Callesen ◽  
Y. Liu ◽  
R. Li ◽  
M. Schmidt
Keyword(s):  
Large White ◽  
Mean Values ◽  
Xenopus Egg Extract ◽  
Egg Extract ◽  
Donor Cells ◽  
Chi Squared ◽  
Xenopus Egg ◽  
Working Day ◽  
One Way Anova

Cloning is a quite inefficient procedure with only around 10% of offspring born based on number of cloned embryos transferred. Every step to increase this level is therefore welcomed. Our group has worked with cloning of pig embryos since 2006, with the main purpose to establish a well-functioning cloning system to have transgenic piglets born as animal models for important human diseases. Here we report results from our attempts to improve efficiencies in several steps in the whole cloning procedure. Over 7.5 years, donor cells from 3 breeds were nontransgenic (50%, 4 types) or transgenic with 1 of 6 different types of gene. Oocytes from Large White (LW) sows or gilts were handmade cloned, so the zona-free cloned embryos were in vitro cultured until Day 5 to 6 to select 13 311 embryos (morulae or blastocysts) for transfer to 171 LW recipient sows or gilts. Of these, 126 were pregnant (74%; Day 35), but 20 aborted before term. A total of 704 offspring were delivered; half of the piglets were alive after 4 weeks and developed normally after that. Frequencies were compared using Chi-squared test; mean values by one-way ANOVA (SAS version 9.2; SAS Institute Inc., Cary, NC, USA). Specific improvements were tested in 4 areas: (1) donor cells: stimulating reprogramming using Xenopus egg extract (Liu et al. 2013 Reprod. Fertil. Dev. http://dx.doi.org/10.1071/RD13147); (2) oocytes: preferably from sows, but also using larger gilt oocytes (Li et al. 2013 Zygote http://dx.doi.org/10.1017/S0967199412000676); (3) transfer: using both uterine sides (Theriogenology 74 : 1233); (4) number of embryos transferred: after cloning with same nontransgenic cells, embryo numbers per recipient were reduced from 90 to 30 (see Table 1). As a consequence of these different activities, overall results improved over the 7.5-year period [first 3.5 years v. last 4 years: 48% (32/67) v. 90% (94/104) recipients pregnant after transfer (P < 0.05); 5.6 ± 0.6 (n = 22) v. 6.9 ± 0.5 (n = 84) piglets/litter]. In our system, one good cloning person can now produce all embryos needed for one recipient in one good working day. Transfer of fewer cloned embryos results in fewer piglets, but it reduces the workload to produce cloned embryos and does not reduce efficiency. Further work is still needed to better understand the biological and technical challenges in work with cloning; 2 important areas are quality evaluation of the donor cells used for cloning and the recipient's reaction to transfer of many embryos. In conclusion, a reasonable increase in the overall efficiency in pig cloning work was achieved, which reduces the need for personnel, time, and material when working with this technology. Table 1.Results of improving efficiency of cloning

Study of the Difference in Microstructures and Properties of Cold Rolled Dual Phase Steel with Different Composition

2012 ◽  
Vol 251 ◽  
pp. 351-354
Author(s):  
Hui Wang ◽  
Cheng Jiang Lin ◽  
Zhao Jun Deng ◽  
Ji Bin Liu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Yield Strength ◽  
Grain Boundaries ◽  
Dual Phase Steel ◽  
Dual Phase ◽  
High Tensile Strength ◽  
Cold Rolled ◽  
The Difference

The difference in microstructures and properties of 600MPa cold rolled dual phase steel with the different composition had been studied in this paper. It can be noticed that the Si-Mn-Cr steel have finer ferrite and more martensite whose content is about 25%; the Mn-Cr-Mo steel have coarser ferrite and some coarse pearlite as well as little martensite; the microstructures of the Mn-Al-Mo steel are consist of mainly ferrite which have even grain size and 16% martensite which distributed homogenously along the ferrite grain boundaries. The difference in microstructure makes the steel own the different properties. The Si-Mn-Cr steel has the highest tensile strength and yield strength but the worst elongation, the Mn-Cr-Mo steel has the lowest tensile strength, the Mn-Al-Mo steel has the an excellent mechanical properties with low yield strength and high tensile strength as well as higher elongation.

scholarly journals Toothbrush-Dentifrice Abrasion of Dental Sealants: An In Vitro Study

2021 ◽  
Author(s):  
Angkhana Sangpanya ◽  
Pornpoj Fuangtharnthip ◽  
Vanida Nimmanon ◽  
Praewpat Pachimsawat
Keyword(s):  
Abrasive Wear ◽  
In Vitro Study ◽  
Mean Values ◽  
Flowable Composite ◽  
Dental Sealants ◽  
The Mean ◽  
D Values ◽  
Almost All ◽  
One Way Anova

Abstract Objective This study sought to investigate the toothbrush-dentifrice abrasion of dental sealants. Materials and Methods Weight loss (∆W) and depth loss (∆D) were used as abrasion indicators. Sealant samples from nine products were soaked in dentifrice slurry and abraded by using a toothbrushing machine with a brushing force of 300 g. The mean percentages of ∆W and mean values of ∆D after 24,000 and 48,000 strokes of brushing were compared by using paired t-test. A comparison of these mean values among sealant products was performed by using one-way ANOVA and multiple comparison analysis (Scheffe's test). Results Abrasive wear was observed in all sealants. Teethmate F-1 (Kuraray Noritake, Tokyo, Japan)—a fluoride-releasing unfilled sealant—exhibited the maximum abrasive wear, with ∆W and ∆D values of 1.14% ± 0.37% and 12.84 ± 4.28 µm, respectively. Delton (Dentsply Sirona, Charlotte, North Carolina, United States), a light-cured unfilled sealant, showed the minimum abrasive wear, with ∆W and ∆D values of 0.41% ± 0.09% and 2.93 ± 1.23 µm, respectively. No statistical differences were observed among unfilled sealants except when compared with Teethmate F-1. Similarly, no differences were observed when comparing among filled sealants and flowable composite. Conclusion Abrasive wear occurred in all sealants after brushing with dentifrice. Almost all unfilled sealants showed less wear compared with both filled sealants and flowable composite. However, the low abrasive values of all sealants after brushing with dentifrice implied that there is no clinical significance to this finding.

scholarly journals Effect of Different Impression Techniques on the Dimensional Accuracy of Impressions using Various Elastomeric Impression Materials: An in vitro Study

2012 ◽  
Vol 13 (1) ◽  
pp. 98-106 ◽  
Author(s):  
Kishan Singh ◽  
Sukant Sahoo ◽  
KD Prasad ◽  
Meenu Goel ◽  
Anupam Singh
Keyword(s):  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Denture Base ◽  
Heavy Body ◽  
Impression Materials ◽  
Natural Teeth ◽  
Crown Preparation ◽  
Maxillary Arch

ABSTRACT Production of exemplary crowns and fixed partial dentures depends upon the usage of impression material and its technique of usage that accurately reproduces prepared teeth and their relationship to the adjacent oral structure. Aim To evaluate the linear dimensional accuracy of the elastomeric impressions using various impression techniques using different combinations of viscosities of impression materials. Materials and methods Crown preparation was done in a dentulous acrylic resin denture base model with six natural teeth embedded into it was made to represent the dentulous maxillary arch. A total of 55 impressions were obtained and poured in die stone using various impression techniques with different combinations of viscosities of impression materials. Results Among the six techniques used, the heavy body light body two-step technique using custom tray showed the least distortion which was closely followed by the putty wash two-step technique with 2 mm spacer using stock tray. Conclusion The study revealed that the heavy body light body two-step technique with custom tray provided the best results. Clinical significance Dimensional accuracy of impressions is very much required for precisely fitting of prosthesis. This study may be helpfull to select the technique and materials as per clinical requirement of accuracy of impressions. How to cite this article Singh K, Sahoo S, Prasad KD, Goel M, Singh A. Effect of Different Impression Techniques on the Dimensional Accuracy of Impressions using Various Elastomeric Impression Materials: An in vitro Study. J Contemp Dent Pract 2012;13(1):98-106.

scholarly journals AN IN VITRO STUDY TO EVALUATE THE TEAR STRENGTH OF AUTOCLAVABLE PVS, SMART WETTING PVS AND CONDENSATION SILICONE AND COMPARE THEM UPON AUTOCLAVING AND DISINFECTION.

2020 ◽  
pp. 67-70
Author(s):  
Garima Gothwal ◽  
Hemant Kumar Sharma ◽  
Kusum Singh ◽  
Richa Sengar
Keyword(s):  
Statistical Analysis ◽  
Testing Machine ◽  
In Vitro Study ◽  
Tear Strength ◽  
Universal Testing ◽  
Impression Materials ◽  
Different Types ◽  
Post Hoc ◽  
One Way Anova

Aim: The tear strength of three different types of elastomeric impression materials was measured after disinfection and sterilization. Material and Method: Dumb-bell shaped Tear strength specimens were prepared according to ISO 34-1 standardization. Ninety samples were prepared followed by disinfection and sterilization and tested with trouser piece method on Instron universal testing machine at a speed of 10 mm/min. One-way ANOVA, followed by Tukey post hoc test was used for statistical analysis. Results: No signicant difference was found when AFFINIS, SPEEDEX and AQUASIL were compared individually. When materials were compared with each other signicant difference was present, highest AQUASIL while SPEEDEX and AFFINIS almost alike. Conclusion: It was concluded that tear strength of AQUASIL was the highest. Disinfection and autoclaving had no signicant inuence on the three materials and showed adequate tear strength.

scholarly journals Effect of Surfosept and Deconex® 53 Disinfectant Agents on the Accuracy and Dimensional Stability of Panasil Dental Impression Materials: An Experimental Study

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Mostafa Alam ◽  
Parviz Amini ◽  
Arash Ghaffarpasand ◽  
Nasim Khajeh Dalooei ◽  
Alireza Hadi ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Antimicrobial Properties ◽  
In Vitro Study ◽  
Viral Envelope ◽  
Control Group ◽  
Ammonium Compound ◽  
Mean Values ◽  
Impression Materials ◽  
Significant Difference

Aim and Objective. Impression materials and stone casts are the main sources of cross-contamination and transmission of dental infections between dental offices and laboratories. Both Surfosept (alcohol-based) and Deconex® (quaternary ammonium compound) are biocompatible solutions that have superior antimicrobial properties against bacteria, fungi, and viral envelope. Considering the influence of disinfection substances on the dimensions of impression materials, this study aimed to compare the effect of Surfosept and Deconex® 53 on the accuracy and dimensional stability of the Panasil® dental addition silicone material. Materials and Methods. This in vitro study was performed on 30 dental casts. The samples were divided into one control group and two experimental groups to be disinfected with Surfosept (1%) and Deconex® 53 (2%) using a sequential sampling method (10 per group). The impressions in the experimental groups (i.e., Surfosept and Deconex® 53) were rinsed and dried; then, the disinfectant was sprayed on the impressions and remained for 30 seconds before pouring with stone. In the control group, the impressions were only rinsed and dried and were poured in 10 minutes. Cast dimensions were measured by a profile projector device, and the mean values obtained from the experimental groups were compared with those of the control group. Results. There were no significant differences among the groups regarding the height of the resulting dies without undercut ( P = 0.62 ). Moreover, there was no significant difference among the groups regarding the distance between the two dies ( P = 0.77 ). However, the diameter of the dies with undercut and without undercut was different significantly among the control and experimental groups ( P < 0.005 ). Conclusion. In general, no significant difference was encountered between dimensional stability and accuracy of the dental impressions using Surfosept and Deconex® 53 in this study.

scholarly journals Adhesion to eroded dentin submitted to different surface treatments

2014 ◽  
Vol 17 (4) ◽  
pp. 40
Author(s):  
Thayanne Monteiro Ramos Oliveira ◽  
Thaysa Monteiro Ramos ◽  
Bruna Uglik Garbui ◽  
Fernando Seishim Hanashiro ◽  
Patricia Moreira De Freitas
Keyword(s):  
Bond Strength ◽  
Composite Resin ◽  
Fracture Pattern ◽  
Strength Test ◽  
Mean Values ◽  
Diamond Bur ◽  
Significant Difference ◽  
Microshear Bond Strength ◽  
One Way Anova

<p><strong>Objective: </strong>This <em>in vitro</em> study measured the microshear bond strength (µSBS) of a composite resin to sound and artificially eroded dentin, submitted to surface treatment with diamond bur (DB) or Er,Cr:YSGG laser (L). <strong>Material and Methods:</strong> Bovine dentin samples were randomly divided into six groups (n=11): G1-sound dentin, G2-eroded dentin, G3-eroded dentin treated with Er,Cr:YSGG laser at 1.5W, G4-eroded dentin treated with Er,Cr:YSGG laser at 2.0W, G5-eroded dentin treated with Er,Cr:YSGG laser at 2.5W and G6-eroded dentin treated with diamond bur. Erosive cycling was performed by immersion in 0.05M citric acid (pH2.3;10min; 6x/day) and in remineralizing solution (pH7.0, 1h, between acid attacks), for 5 days. Three composite resin cylinders were bonded to the samples and after 24h storage in distilled/deionized water (37<sup>o</sup>C), samples were submitted to microshear bond strength test and mean values (MPa) were analyzed by one-way ANOVA and Tukey tests (α=0.05). <strong>Results:</strong> G1 (19.9±7.6) presented the highest µSBS mean followed by G6 (12.2±3.8), which showed no statistically significant difference compared with the other groups, except from G4. The lowest µSBS value was found for G4 (7.1±1.5), which did not differ statistically from G2 (7.5±1.8), G3 (8.4±1.8) and G5 (8.6±3.2). Analysis of the fracture pattern revealed a higher incidence of adhesive fractures for all experimental groups. <strong>Conclusion:</strong> The results indicate that Er,Cr:YSGG laser at the parameters used in this <em>in vitro</em> study  did not enhance composite resin bonding to eroded dentin.</p>

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