scholarly journals Dimensional stability of two solder index materials

2016 ◽  
Vol 10 (02) ◽  
pp. 259-263
Author(s):  
Amir Ali Reza Khaledi ◽  
Soheil Pardis ◽  
Negar Pourhatami ◽  
Zahra Hashemi Ardakani
Keyword(s):  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Time Lapse ◽  
Reference Points ◽  
Repeated Measure ◽  
Control Group ◽  
Measure Anova ◽  
Measurement Control ◽  
Digital Microscope ◽  
The Mean

ABSTRACT Objectives: This study aimed to compare the dimensional accuracy of two indexing materials, an acrylic resin (GC pattern resin) and a castable composite (Bredent). The effect of time lapse until investment was also investigated. Materials and Methods: Two standardized brass dies 15 mm apart were prepared and then 20 identical coping-bar assemblies were designed and fabricated by a rapid prototyping device. Each bar was sectioned at the center, and indices were fabricated from an acrylic resin or castable composite (n = 10 per group). The distances between the reference points were measured with a digital microscope at ×80 magnifications at 15 min, 60 min, and 24 h after indexing. Data were statically analyzed using repeated-measure ANOVA (α = 0.05). Results: The distance between the reference points without the coping being joined was considered as the baseline measurement (control group). The mean distance was 19.30 ± 0.04 mm between the reference points where the copings were not joined. When indexed with acrylic resin, the mean ± standard deviation (SD) dimensions were 19.27 ± 0.087 mm (15 min), 19.25 ± 0.09 mm (60 min), and 18.98 ± 0.1 mm (24 h). The mean ± SD dimensions for composite were 19.29 ± 0.087 mm (15 min), 19.28 ± 0.08 mm (60 min), and 19.26 ± 0.08 mm (24 h). All tested groups showed significant differences compared to the control group except when it was indexed with composite and where the distances were measured after 15 and 60 min (P > 0.05). Conclusions: The most accurate indexed-assemblies belonged to castable composite at 15 and 60 min.

scholarly journals A Comparative Evaluation of the Dimensional Accuracy of Heat Polymerized Acrylic Resin Denture Base Clamped by the Conventional Method and by New-press Technique and Cured by Long Curing Cycle: An in vitro Study

2012 ◽  
Vol 13 (6) ◽  
pp. 842-849
Author(s):  
T Shankar ◽  
N Venugopal Rao ◽  
Snigdha Gowd ◽  
Syed Tauqheer Ahmed ◽  
V Vinod ◽  
...  
Keyword(s):  
Conventional Method ◽  
Comparative Evaluation ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Reference Points ◽  
Control Group ◽  
Denture Base ◽  
Group A ◽  
Curing Cycle

ABSTRACT Aim The aim of this study is to evaluate the dimensional accuracy of heat polymerized acrylic resin denture base clamped by the conventional method and by new-press technique and cured by long curing cycle. Materials and methods In this study, a total of 60 standardized maxillary record bases were fabricated with seven reference points as follows: • Point A Incisive papilla, • Point B and C Canine region on either side • Point E and G Midpoint of tuberosities on either side • Point F Midpoint of the line joining the two tuberosities • Point D Midpoint between the line joining A and F Group A Ten maxillary record bases were fabricated by conventional clamping method and cured by long curing cycle. Group A’ Ten maxillary record bases were fabricated by New Press or RS tension clamping method and cured by long curing cycle. The distances between the reference points, i.e. A-B, A-C, A-D, D-F, B-E, C-G, E-F, F-G, B-D, D-G, C-D, D-E of all three thermoplastic denture base plates were measured and recorded with the help of travelling microscope and were used for comparison with the measured and recorded readings of processed acrylic denture bases. The data obtained was analyzed by using the one-way analysis of variance and HSD Multiple Comparison Test. Results The overall results of the study indicate that among all the denture bases cured by the two clamping systems and the long curing cycle, group A‘ were the most dimensionally stable, followed by control group A. Conclusion The study concluded that the denture bases fabricated by the New Press method using the long curing cycle would produce the most dimensionally stable denture bases. How to cite this article Shankar T, Gowd S, Ahmed ST, Vinod V, Goud MV, Rao NV. A Comparative Evaluation of the Dimensional Accuracy of Heat Polymerized Acrylic Resin Denture Base Clamped by the Conventional Method and by New-press Technique and Cured by Long Curing Cycle: An in vitro Study. J Contemp Dent Pract 2012;13(6):842-849.

scholarly journals Effect of Crossfit Training on Jump and Strength

2018 ◽  
Vol 7 (1) ◽  
pp. 121 ◽  
Author(s):  
Oğuzhan Yüksel ◽  
Bolat Gündüz ◽  
Mert Kayhan
Keyword(s):  
Repeated Measure ◽  
Control Group ◽  
Control Groups ◽  
Squat Jump ◽  
Repeated Measure Anova ◽  
Measure Anova ◽  
Wilks Lambda ◽  
The Mean ◽  
Crossfit Training ◽  
Experimental Group

The purpose of this study is to investigate the effect of regular CrossFit training on some force and jump parameters. 32 healthy wrestling men participated in the study, 16 experimental and 16 control groups. For the experimental group, CrossFit training, known as Cindy, was practiced three times a week for 8 weeks. The training consisted of 5 bars, 10 push-ups and 15 squats for 20 minutes. The control group continued the classical wrestling practice. Myotest accelerometric system was used for measurements of participants’ values. For the analysis of the data, repeated measure ANOVA was used. According to the results, as a result of CrossFit training, athletes' squat jump heights increased (Wilks' Lambda = .541, F (1,30) = 25, p = .00). The mean post-training leap values (33.778 ± 5.48) were higher than the pre-training leap values (32.169 ± 4.95) (p <0.05). It can be concluded that Cindy CrossFit studies improve jumping and strength ability.

scholarly journals The effect of acceptance and commitment based on the fear of delivery pain- A randomized educational trial study

2020 ◽  
pp. 26-35
Keyword(s):  
Maternal Care ◽  
Sampling Method ◽  
Treatment Approach ◽  
Intervention Group ◽  
Repeated Measure ◽  
Control Group ◽  
Consent Forms ◽  
Measure Anova ◽  
Acceptance And Commitment ◽  
The Mean

Background and Aim: Pregnancy due to physiological and psychological changes can affect the mental health of mothers. This study aims to investigate the Approach of acceptance and commitment based on the fear of delivery pain. Materials and Methods: This study was a randomized educational trial with a commitment-based treatment approach that was performed on pregnant women in Arak in 2016-2017. After obtaining written consent forms, 42 subjects were selected through the available sampling method. Subjects were grouped in the intervention group (ACT) and in the control group. Eight 90-minute sessions were held for 8 consecutive weeks of counseling Fear of delivery pain at 10 and one month after the intervention was measured in 2 groups by the Likert scale of pain (1-7) score. Data analysis was performed through repeated measure ANOVA by using SPSS (Version 18). Results: Results showed that the mean pain immediately after the intervention was 2.52±2.20 in the intervention group and 4.66±1.80 in the control group. Which is a month later in the intervention group compared to the control group had a significant decrease (3.52±1.81 vs. 4.52±2.30) (P=0.001). Conclusion: In this study, counseling with the approach of acceptance and commitment reduction the fear of delivery pain, which is the most important reason for choosing cesarean section in women, Therefore, it seems that empowering midwives to counseling approaches can be useful to improve maternal care during pregnancy, especially in the administration of delivery preparation classes.

scholarly journals Influence of Silver Nanoparticles on the Specific Properties of Acrylic Resin for Ocular Prosthesis

2018 ◽  
Vol 11 (3) ◽  
pp. 1573-1581 ◽  
Author(s):  
Maha M. Turki ◽  
Faiza M. Abdul-Ameer
Keyword(s):  
Surface Roughness ◽  
Impact Strength ◽  
Flexural Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Acrylic Resin ◽  
Control Group ◽  
Mean Values ◽  
The Mean ◽  
Group B

Scleral acrylic resin is widely used to synthesize ocular prosthesis. However, the properties of this material change over time, thus requiring the prosthesis to be refabricated. Many studies were conducted to improve these properties by reinforcing this material with nanoparticles. This study aims to evaluate the effect of silver nanoparticle powder on the mechanical properties (transverse flexural strength, impact strength, shear bond strength, surface microhardness, and surface roughness) of scleral acrylic resin used for ocular prostheses. Two concentrations were selected from the pilot study and evaluated for their effects on scleral acrylic resin properties. According to the pilot study, 0.01 and 0.02wt% AgNPs powder improved the transverse flexural strength, microhardness, and surface roughness compared with other percentages. The specimens in the main study were divided into (3) main groups, (50) specimens without additives (control group A), (50) experimental specimens (with 0.01wt% AgNPs group B), and (50) experimental specimens (with 0.02 wt% AgNPs group C). Each group was subdivided into (5) equal subgroups depending on the tests used. The data were studied using one way ANOVA and post hoc LSD test. At 0.01 wt% AgNPs addition, the mean values of transverse flexural strength insignificantly increased (p> 0.05), and those of impact strength and shear bond strength significantly increased (p< 0.05) compared with those of the control group. At 0.02 wt% AgNPs addition (group C), the mean value of transverse flexural strength significantly increased (p< 0.05), that of impact strength insignificantly increased (p> 0.05), and that of shear bond strength increased with high significance (p< 0.01) compared with those of the control group. Group C showed insignificant increase in the mean values of transverse flexural strength, impact strength, and shear bond strength (p. 0.05) compared with group B. The scleral acrylic resin added with 0.01 and 0.02 wt% AgNPs showed insignificant increase in microhardness and insignificant decrease in surface roughness. The addition of AgNPs powder in both concentrations improved the mechanical properties of scleral acrylic resin used for ocular prostheses.

scholarly journals PENGARUH PENAMBAHAN ZIRKONIUM OKSIDA DAN SERAT POLIPROPILEN TERHADAP KEKUATAN IMPAK DAN TRANSVERSAL BAHAN BASIS GIGI TIRUAN RESIN AKRILIK POLIMERISASI PANAS

2018 ◽  
Vol 12 (2) ◽  
pp. 177-182
Author(s):  
Eddy Dahar ◽  
Raudhatul Husna
Keyword(s):  
Polypropylene Fiber ◽  
Acrylic Resin ◽  
Mean Value ◽  
Zro2 Nanoparticles ◽  
Control Group ◽  
Denture Base ◽  
Transverse Strength ◽  
Significant Difference ◽  
The Mean ◽  
The Impact

Heat polymerized acrylic resin is the most common material used for making denture base because of it’s advantages. However, this material still hasn’t fulfill all the ideal requirements as a denture base. Some disadvantages that need to be fixed are low impact and transverse strength causing an easy base of fracture. Several attempts were made to improve the mechanical properties of heat polymerized acrylic resin materials by adding reinforcing materials. Zirconium oxide is one of chemical group that can be used as a reinforcing material and polypropylene fiber which is including in fiber reinforcing groups. This study aims to determine whether there is a difference in the effect of the addition of 5% ZrO2 nanoparticles and 2% chopped polypropylene fibers 6 mm in length on the impact and transverse strength of heat polymerized acrylic resin denture base material. The design of this study is a laboratory experimental and the number of samples in this study are 60 samples. The result of this study shows the mean value of the impact and transverse strength of heat polymerized acrylic resin with ZrO2 nanoparticles reinforced is greater than the control group and heat polymerized acrylic resin group with polypropylene fiber reinforced with significant difference, and the mean value of impact and transverse strength of heat polymerized acrylic resin with polypropylene fibers reinforced is greater than the control group with significant difference.

scholarly journals Evaluation and Comparison of the Effectiveness of Physical Methods of Disinfection on Heat-Polymerized Polymethyl Methacrylate – An In-vitro Study

2021 ◽  
pp. 285-293
Author(s):  
Kapil Soni ◽  
Vivek Choukse ◽  
Rajeev Shrivastava ◽  
Umesh Palekar ◽  
Prabha Shakya Newaskar ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Microwave Irradiation ◽  
Uv Radiation ◽  
Acrylic Resin ◽  
Positive Control ◽  
Mean Value ◽  
Control Group ◽  
Group A ◽  
The Mean ◽  
Group B

Introduction: The common relationship of Candida and the ample proof that acrylic resin dentures are related to denture stomatitis in the oral cavity, which can range from simple mucosal lesions to a fatal systemic form. The current study aims to assess and compare the efficacy of microwave irradiation and UV radiation in the disinfection of Candida albicans infection in heat-polymerized polymethyl methacrylate. Materials and Methods: A total of 90 specimens were prepared with heat-polymerized acrylic resin, out of which 30 were used for Microwave irradiation, and 30 were used for UV irradiation, and 30 were used for positive control. There were three groups: Group A (Positive Control group); Group B (Microwave irradiation); Group C (UV radiation). After preparing the samples they were chemically sterilized, then infected with C. Albicans, and again Group B is disinfected with Microwave irradiation, Group C is disinfected by UV light and Group A is kept as Positive control without disinfection. Turbidity was measured for each group after re-infection of every specimen in CFU/ml. Results: In the present study, the CFU/ml of Candida albicans in the control group was 2.97x107±0.6 x 107 (P= .000), for microwave irradiation, the mean value was 5.3±11.1 (P= .000), and for UV radiation, the mean value was 19.3±22.9 (P= .003). Conclusion: According to the results of the current study, microwave irradiation (6 minutes at 650W) is more effective than UV radiation (10 minutes each side at 254nm wavelength) of Candida albicans infection on the heat-polymerized acrylic resin in laboratory conditions.

scholarly journals Effect of microwave treatments on dimensional accuracy of maxillary acrylic resin denture base

2005 ◽  
Vol 16 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Sabrina Pavan ◽  
João Neudenir Arioli Filho ◽  
Paulo Henrique dos Santos ◽  
Francisco de Assis Mollo Jr.
Keyword(s):  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Microwave Treatment ◽  
Control Group ◽  
Denture Base ◽  
Group Iii ◽  
Dental Prostheses ◽  
Group I ◽  
Group Ii ◽  
Cycle Group

Microwave energy has been used as an alternative method for disinfection and sterilization of dental prostheses. This study evaluated the influence of microwave treatment on dimensional accuracy along the posterior palatal border of maxillary acrylic resin denture bases processed by water-bath curing. Thirty maxillary acrylic bases (3-mm-thick) were made on cast models with Clássico acrylic resin using routine technique. After polymerization and cooling, the sets were deflasked and the bases were stored in water for 30 days. Thereafter, the specimens were assigned to 3 groups (n=10), as follows: group I (control) was not submitted to any disinfection cycle; group II was submitted to microwave disinfection for 3 min at 500 W; and in group III microwaving was done for 10 min at 604 W. The acrylic bases were fixed on their respective casts with instant adhesive (Super Bonder®) and the base/cast sets were sectioned transversally in the posterior palatal zone. The existence of gaps between the casts and acrylic bases was assessed using a profile projector at 5 points. No statistically significant differences were observed between the control group and group II. However, group III differed statistically from the others (p<0.05). Treatment in microwave oven at 604 W for 10 min produced the greatest discrepancies in the adaptation of maxillary acrylic resin denture bases to the stone casts.

scholarly journals Relationship between the Occlusal Plane corresponding to the Lateral Borders of the Tongue and Ala-tragus Line in Edentulous Patients

2012 ◽  
Vol 13 (5) ◽  
pp. 590-594 ◽  
Author(s):  
Carole Abi-Ghosn ◽  
Carla Zogheib ◽  
Joseph E Makzoumé
Keyword(s):  
Acrylic Resin ◽  
Repeated Measure ◽  
Occlusal Plane ◽  
Significant Difference ◽  
Measure Analysis ◽  
The Mean ◽  
Edentulous Patients ◽  
Student’S T ◽  
Inferior Border ◽  
The Relationship

ABSTRACT Aim Definitions of the ala-tragus line (ATL) cause confusion, because the exact points of reference for this line do not agree. This study determined the relationship between the prosthetic occlusal plane (OP) corresponding to the lateral borders of the tongue and ATL which was established by using the inferior border of the ala of the nose and (1) the superior border of the tragus (ATL 1), (2) the tip (ATL 2) and (3) the inferior border of the tragus (ATL 3). Materials and methods Neutral zone moldings using phonation and autopolymerizing acrylic resin were recorded and leveled with the lateral borders of the tongue. Lateral cephalometric radiographs were taken of each subject by a standard method. Tracings were obtained on acetate paper to show the prosthetic OP and the three ATLs. The relationship between the prosthetic OP and each of ATL was measured for each subject. Mean and standard deviation values were then calculated for the relationship. Statistical analysis was performed using repeated measure analysis of variance followed by Bonferroni pairwise comparisons and Student's t-test (α = 0.05). Results Significant difference was found between the three mean angles (p = 0.001). There was no significant difference between the mean angle (5.00° ± 4.38) formed by OP and ATL 2, and the mean angle (4.90° ± 3.50) formed by OP and ATL 3 (p = 1.00) which revealed the smallest. Conclusion The findings of this study indicated that ATLs, extending from the inferior border of the ala of the nose to (1) the tip of the tragus of the ear, and (2) the inferior border of the tragus presented the closest relationship to the prosthetic OP corresponding to the lateral borders of the tongue. Clinical significance When the ATL is used for orientation of the OP in denture construction, it would seem preferable to define it as running from the inferior border of the ala of the nose to the tip or to the inferior border of the tragus of the ear. How to cite this article Abi-Ghosn C, Zogheib C, Makzoumé JE. Relationship between the Occlusal Plane corresponding to the Lateral Borders of the Tongue and Ala-tragus Line in Edentulous Patients. J Contemp Dent Pract 2012;13(5):590-594.

scholarly journals Evaluation of some properties of recycled polymethylmethacrylate incorporated to the acrylic resin

2020 ◽  
Vol 11 (3) ◽  
pp. 2765-2771
Author(s):  
Amrah Y. Al Jmmal ◽  
Nada Z. Mohammed ◽  
Amer A. Taqa
Keyword(s):  
Water Sorption ◽  
Surface Hardness ◽  
Base Material ◽  
Acrylic Resin ◽  
Control Group ◽  
Residual Monomer ◽  
Denture Base ◽  
Significant Difference ◽  
The Mean ◽  
And Control

Many attempts have been made enhancing properties of PMMA denture base material. Adding fillers to PMMA was a commonly used method to improve physical and mechanical properties. To estimate the effects of incorporating recycled polymethylmethacrylate with a different percentage with conventional heat-cured acrylic resin on some properties of heat-cured denture base resin. The recycled polymethylmethacrylate (Chaini-HK G) particles dissolved at (5%,10%,15%) was added to heat-cured polymethylmethacrylate (Spofadental, Czech Republic) polymer and mixed with a ratio of 2:1 with the polymethylmethacrylate monomer. A total number of specimens were 80, which divided into three experimental groups (5%, 10%, 15%) and control group. Each group have 20specimens. The surface hardness, water sorption, solubility and residual monomer of test groups measured as well as compared to that of control groups. Fourier transform infrared spectroscopy test (FTIR) was done for three experimental and control group. This study shows a statistically significant difference at (p<0.01) in the hardness of recycled polymethylmethacrylate incorporate material (10 %,15%) groups when compared with a control group; while recycled polymethylmethacrylate incorporated (5%) group show no significant difference, group with 15% shows the highest Vickers hardness value. The mean values of water sorption test solubility test and residual monomer were decreased with the increase of incorporating a percentage of recycled polymethylmethacrylate as compared to the mean value of the control group. The incorporation of recycled polymethylmethacrylate to heat acrylic resin at different percentage improves some of its properties.

scholarly journals Dimensional accuracy of different impression techniques of partially edentulous mandibular arch

2017 ◽  
Vol 65 (1) ◽  
pp. 25-29
Author(s):  
Rafael Pino VITTI ◽  
Victor Pinheiro FEITOSA ◽  
Ataís BACCHI ◽  
William Cunha BRANDT ◽  
Milton Edson MIRANDA ◽  
...  
Keyword(s):  
Stainless Steel ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Reference Points ◽  
Vitro Study ◽  
Dimensional Changes ◽  
Mandibular Arch ◽  
Body Techniques

ABSTRACT Objective: The purpose of this in vitro study was to assess and compare the dimensional accuracy of three impression techniques: 1-step putty/light-body, 2-step putty/light-body, and the monophase technique. Methods: A partially edentulous standard stainless steel mandibular arch cast with reference points on the teeth was used to make the impressions. The anteroposterior and transverse distances were measured. All impressions were made with a polyvinyl siloxane using stock metallic (1- and 2-step putty/light-body techniques) or acrylic resin (monophase technique) trays. The monophase impressions were made using a light-body material and the 1- and 2-step putty/light-body impressions with putty and light-body materials. After impression procedures, the accuracy of each technique was assessed measuring the stone casts (n = 5) poured from the impressions using a microscope at 30x magnification and at 0.5 µm accuracy. The data were analyzed statistically using 2-way ANOVA and Tukey's test (p<0.05). Results: Stone casts made by all techniques had significantly negative linear changes (shrinkage). The anteroposterior distances showed more dimensional changes than the transverse distances. The edentulous side showed more shrinkage than the anteroposterior side. Conclusion: No differences between the impression techniques were found, but significant dimensional changes were observed.

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