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 Shear bond strength of novel calcium aluminate-based cement (EndoBinder) to root dentine

2014 ◽  
Vol 08 (04) ◽  
pp. 498-503 ◽  
Author(s):  
Lucas da Fonseca Roberti Garcia ◽  
Hebert Luis Rossetto ◽  
Fernanda de Carvalho Panzeri Pires-de-Souza
Keyword(s):  
Bond Strength ◽  
Calcium Aluminate ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Mineral Trioxide Aggregate ◽  
Acrylic Resin ◽  
Promising Alternative ◽  
Mean Values ◽  
Significant Difference ◽  
Molar Teeth

ABSTRACT Objective: To evaluate the shear bond strength of a novel calcium aluminate-based cement, EndoBinder (EB), to dentine in comparison with Grey and White Mineral Trioxide Aggregate (MTA). Materials and Methods: Root canal hemi-sections obtained from 30 extracted molar teeth were embedded in self-polymerized acrylic resin and were grounded wet in order to obtain a flat dentine surface. Next, the roots were randomly assigned into three groups (n = 10), according to the cement used, as follows: EB: EndoBinder; WMTA: White MTA and GMTA: Grey MTA. The shear bond strength test was performed using a Universal Testing Machine (0.5 mm/min) and the data were submitted to statistical analysis (1-way ANOVA and Tukey tests, P < 0.05). Results: EB presented the highest shear bond strength values; however, there was no statistically significant difference in comparison with GMTA (P > 0.05). WMTA presented the lowest mean values, which were significant in comparison with EB (P < 0.05). Conclusions: The novel calcium aluminate-based cement presented higher shear bond strength than WMTA, and should be considered as a promising alternative in endodontic therapy.

The Effect of Gongronema Latifolum (Utazi) on Some Haematological Parameters of Rabbit

2020 ◽  
Author(s):  
Obeagu Emmanuel Ifeanyi
Keyword(s):  
Mean Value ◽  
Control Group ◽  
Mean Values ◽  
Platelet Counts ◽  
Group A ◽  
The Mean ◽  
Group B ◽  
Differential White Blood Cell ◽  
Group D ◽  
Gongronema Latifolium

The hematological features of Gongronema latifolium, aqueous leaves extract was evaluated using standard methods. After 10 days of consecutive infusions into 9 experimental animals (rabbits). The rabbits were monitored and the following parameters determined; hemoglobin (HB), PCV, Platelet, WBC, Differential White Blood Cell. The Rabbits were grouped into 4, one consisting of control (group A), group B was fed with 0.5 mg/kg, group C with 1.0 mg/kg, and Group D with 1.5mg/kg of the aqueous extract of Gongronemalatifolium. The mean values obtained for hemoglobin estimation for the control group is 5.9 ± 4.1 g/dl, 9.1 ± 2.9 g/dl for group B 10.2 ± 1.8 g/dl for group C and 12.8 ± 0.1 g/dl for group D with no significant increase on the PCV estimation, the mean value for the control (group A) is 17.7 ± 12.3%, 27.3 ± 8.7% for group B, group C (30.6 ± 5.4%) and D (28.4 ± 0.3) show increase that statistically significant (p > 0.01). the platelet counts of group C (600 ± 0 x 109/L) and D(600 ± 0 x 109/L) show significant increase (p > 0.01) when compared with the control (600 ± 00). But the platelet value of group B (550 ± 50 x 109/L) shows no difference. No significant changes were observed in the White Blood Counts of the test groups B (3.5 ± 0.5 x 109/L), C (1.9 + 2.1 x 109/L) and D(3.6 ± 0.4) when compared with the control group (2.9 ± 1.9). The values obtained from the differential White Blood Counts (Neutrophils, Lymphocytes, Eosinophils and Monocytes) were not significant. Therefore, Gongronemalatifolium, when properly taken as a nutritional diet, causes beneficial changes on hemoglobin, packed cell volumes and platelet counts of consumers.

scholarly journals Effect of Provisional Cements on Shear Bond Strength of Porcelain Laminate Veneers

2011 ◽  
Vol 05 (04) ◽  
pp. 373-379 ◽  
Author(s):  
Subutay Han Altintas ◽  
Onjen Tak ◽  
Asli Secilmis ◽  
Aslihan Usumez
Keyword(s):  
Bond Strength ◽  
Calcium Hydroxide ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Resin Cement ◽  
Control Group ◽  
Molar Teeth ◽  
Laminate Veneers ◽  
Selection Of

ABSTRACTObjectives: The purpose of this study was to evaluate the effect of three provisional cements and two cleaning techniques on the final bond strength of porcelain laminate veneers. Methods: The occlusal third of the crowns of forty molar teeth were sectioned and embedded in autopolymerizing acrylic resin. Dentin surfaces were polished and specimens were randomly divided into four groups (n=10). Provisional restorations were fabricated and two provisional restorations were cemented onto each tooth. Restorations were fixed with one of three different provisional cements: eugenol-free provisional cement (Cavex), calcium hydroxide (Dycal), and light-cured provisional cement (Tempond Clear). Provisional restorations were removed with either a dental explorer and air-water spray, or a cleaning bur (Opticlean). In the control group, provisional restorations were not used on the surfaces of specimens. IPS Empress 2 ceramic discs were luted with a dual-cured resin cement (Panavia F). Shear bond strength was measured using a universal testing machine. Data were statistically analyzed by ANOVA, Tukey’s HSD and Dunnett tests. Surfaces were examined by scanning electronic microscopy. Results: Significant differences were found between the control group and both the light-cured provisional cement groups and the eugenol-free provisional cement-cleaning bur group (P<.05). Groups that had received light-cured provisional cement showed the lowest bond strength values. Conclusions: Selection of the provisional cement is an important factor in the ultimate bond strength of the final restoration. Calcium hydroxide provisional cement and cleaning with a dental explorer are advisable. (Eur J Dent 2011;5:373-379)

CD59 Deficient Granulocytes in High Risk Groups of Myelodysplastic Syndromes (MDS).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4717-4717
Author(s):  
Georgia Kaiafa ◽  
Vasiliki Tsavdaridou ◽  
Athanasios Papadopoulos ◽  
Christos Savopoulos ◽  
Apostolos Hatzitolios ◽  
...  
Keyword(s):  
Normal Subjects ◽  
Risk Groups ◽  
Mean Value ◽  
Control Group ◽  
Refractory Anaemia ◽  
Mean Values ◽  
Significant Difference ◽  
The Mean ◽  
Group B ◽  
Pnh Clone

Abstract Background: Blood cells are deficient in membrane-bound glycosyl-phosphatidylinositol (GPI)-anchored proteins in paroxysmal nocturnal hemoglobinuria (PNH) because of an acquired disorder of the pluripotent stem cell. CD55 and CD59 antigens are the most common GPI-anchored proteins that are used for the diagnosis of the presence of PNH clone. The association of MDS with PNH is rather controversial. There are few published individual cases of PNH arrived from a previous MDS or MDS following PNH. Aim: Recent studies have demonstrated the existence of PNH clone in some MDS patients. These studies were performed mostly on erythrocytes and to the best of our knowledge they are only 4. Granulocytes appear to be more sensitive markers of PNH clone existence than erythrocytes and therefore we investigate the expression of PNH clone on granulocytes of patients with MDS. Material-Methods: A total number of 95 patients 25–80 yrs old with MDS {A:19 with refractory anaemia (RA), B:9 with refractory anaemia with ring sideroblasts (RARS), C:17 with refractory anaemia with excess blasts (RAEB), D: 12 with refractory anaemia with excess blasts in transformation (RAEB-t) and E: 19 with chronic myelomonocytic leukemia (CMLL)} and 19 healthy donors were included in our study. The presence of GPI-anchored proteins (CD55, CD59)-deficient granulocytes was examined by flow cytometry. For the detection of the PNH clone the commercial kit by Beckman Coulter (cellquant CD55/CD59) was used. Statistical analysis was made by ANOVA, while Robust test was performed because there was no homogeneity of variances by ANOVA. Results: Table 1 shows the percentages of CD55 and CD59 deficient granulocytes in the 5 groups of pts with MDS comparing with the control group. a) Although the mean values of CD55 deficient granulocytes in the groups RAEB, RAEB-t and CMLL were higher enough than those of the normal subjects, there were no statistically significant differences (p>0.10) in the comparison of the mean values of CD55 deficient granulocytes between each group of patients with the control group. b) On the contrary there was a very statistically significant difference in the comparison of the mean value of CD59 deficient granulocytes between the three last groups (C, D and E) of pts with the control group (p< 0.086, p< 0.001 and p<0.001 respectively). The percentages of CD55 and CD59 deficient granulocytes in the 5 groups of patients with MDS and in the control group CD55 CD55 CD59 CD59 Groups N Mean Value Std deviation Mean Value Std deviation A (RA) 19 2.89 2.79 2.91 2.85 B (RARS) 9 1.05 1.14 3.89 3.63 C (RAEB) 17 4.78 4.76 11.75 6.06 D (RAEB-t) 12 4.23 2.85 23.76 8.53 E (CMLL) 19 6.01 4.97 38.26 16.18 Control 19 3.67 2.89 3.67 2.89 Total 95 4.00 3.87 14.44 16.39 Conclusions: There are relatively large CD59 negative subpopulations (mean values 11.75–38.26%) of granulocytes in the last three groups (RAEB, RAEB-t, CMLL) of MDS patients. On the contrary the two low risk forms (RA, RARS) revealed no such populations. Non-expression of CD59 antigen on granulocytes is a more sensitive marker than that of CD55 antigen for the presence of a possible PNH clone in MDS patients.

scholarly journals Effects of Different Laser Treatments on Some Properties of the Zirconia-Porcelain Interface

2021 ◽  
Vol 12 ◽  
pp. e2-e2
Author(s):  
Abdulsatar M Abdulsatar ◽  
Basima M A Hussein ◽  
Ali M Mahmood
Keyword(s):  
Surface Roughness ◽  
Bond Strength ◽  
Surface Treatment ◽  
Co2 Laser ◽  
Nd:Yag Laser ◽  
Light Microscope ◽  
Shear Bond Strength ◽  
Control Group ◽  
Fractional Co2 Laser ◽  
Laser Treatments

Introduction: This study was performed to compare the effect of Fractional CO2 laser or Q switched Nd:YAG laser of surface treatment on the shear bond strength of zirconia-porcelain interface. Methods: Fractional CO2 laser at 30 W, 2 ms, time interval 1 ms, distance between spots 0.3 mm, and number of scans is (4) or Q switched Nd:YAG laser at 30 J/mm2 and 10 Hz were used to assess the shear bond strength of zirconia to porcelain. Pre-sintered zirconia specimens were divided into three groups (n = 10) according to the surface treatment technique used: (a) untreated (Control) group; (b) CO2 group; (c) Nd:YAG group. All samples were then sintered and veneered with porcelain according to the manufacturer’s instructions. Surface morphology was examined using a light microscope, the surface roughness test was done by the atomic force microscope (AFM), and the shear bond strength (SBS) test was done by a universal testing machine. After debonding following shear bond test, zirconia surfaces were examined under a light microscope to determine their fracture mode. Results: The Results of this study showed that the lowest SBS was recorded in the control group, and the highest SBS recorded in the Fractional CO2 group, followed by the Q switched Nd:YAG laser group, as well as an increase in surface roughness and change in the morphology and mode of failure in the experimental groups . Conclusion: This study shows that Fractional CO2 laser and Q switched Nd:YAG laser treatments significantly increase the bond strength than untreated zirconia .

scholarly journals The effect of polyamide microparticles addition on some mechanical prop-erties of light-cured acrylic resin

2019 ◽  
Vol 10 (2) ◽  
pp. 1464-1469
Author(s):  
Adnan R. Al Assal ◽  
Abdalbaset A Fatalla ◽  
Mohammed Moudhaffar ◽  
Ghasak H Jani
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Base Material ◽  
Acrylic Resin ◽  
Strength Test ◽  
Control Group ◽  
Denture Base ◽  
Mean Values ◽  
Transverse Strength ◽  
Transverse Tensile

The general upgrading of polymer denture base material and research continuously looking for ideal restorative dental material with better properties, adequate esthetic properties, less expensive and easier to handle material to develop photo polymerization dental materials. This study was conducted to evaluate the effect of addition polyamide on mechanical microparticle properties light cure denture base material. One hindered sixty specimens from light-cured acrylic resin (Aurora). The divided mainly into four groups according to test used (Transverse strength test, impact strength test, hardness test and tensile strength test) with 40 specimens for each group. The results show an increase in Transverse strength, impact strength, hardness and tensile strength in all experimental group when compared to control group the highest mean values for all tests included in the study appeared in group B 1% polyamide. The addition of polyamide microparticle improves transverse, tensile, impact strength and hardness properties of denture base material.

scholarly journals Evaluation of the flexural strength and surface roughness of dental material after immersion in coffee

2021 ◽  
Vol 10 (3) ◽  
pp. e30510312486
Author(s):  
Patrícia Capellato ◽  
Ana Paula Rosifini Alves Claro
Keyword(s):  
Surface Roughness ◽  
Flexural Strength ◽  
Testing Machine ◽  
Dental Material ◽  
Bending Test ◽  
Control Group ◽  
Test Surface ◽  
Physiological Serum ◽  
Group A ◽  
Group B

This study was done in order to evaluate the changes in flexural strength and surface roughness in dental material restorations after immersion in coffee. Bars specimens (2mm x 2mm x 25 mm) of Z100 3M/ESPE were made according to ISO 4049 using aluminum molds. After curing, the specimens were then randomly divided into five groups and conditioned at 37°C in physiological serum. In all groups, except control, samples were immersed in coffee for ten minutes daily. In group A, the samples were immersed in coffee. For group B, after to be immersed in coffee, samples were immersed in distilled water for one minute. For group C, samples were immersed in mouthwash for one minute. For group D, samples were brushing for ten minutes, with load of 250g and 4250 cycles after all treatments the samples were stored in physiological serum again. In control group, samples were only stored in physiological serum. The five groups were then divided into 2 subgroups according storage time, six and nine weeks, respectively. Flexural strength was determined using three point bending test in a universal testing machine. All the tests were carried out at a room temperature and samples were maintained in physiological serum during the test. Surface roughness measurements were made using a surface roughness tester. All data were analyzed using one-way analysis of variance (ANOVA) followed by Dunnet tests. The ANOVA indicated no difference in the means of surface roughness and significant was observed for flexural strength between control group and one group (coffee).

scholarly journals Evaluation of a novel fixed-space maintainer made of light-cured acrylic resin: an in vitro study

BDJ Open ◽  
2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Yasser R. Souror ◽  
Tayseer Maaly ◽  
Mohammed Sameer Khawandanah
Keyword(s):  
Flexural Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Tooth Surface ◽  
Significant Difference ◽  
Space Maintainer ◽  
Fixed Space

Abstract To evaluate a fixed-space maintainer made of light-cure acrylic resin (LCAR) for its flexural and shear bond strength using different bonding systems to the enamel. 45 extracted primary teeth were selected. They were randomly divided into three equal groups (n = 15) along with the type of adhesive system (Tetric Flow, Transbond XT, and Fuji Ortho LC) used for bonding (LCAR) to the tooth surface. Surfaces were treated; LCAR was attached to the treated surfaces using a split Teflon mold. For flexural strength testing, ten bars of LCAR were made using another Teflon-split mold. Shear bond strength and mean flexural strength values were evaluated by a universal testing machine. The highest values of bond strength were recorded for Transbond XT, followed by Tetric Flow, while the lowest values were for Fuji Ortho LC. Various groups had a significant difference as investigated by ANOVA. ARI scores showed no significant difference in debond sites. Mean value and standard deviation of flexural strength for LCAR were 82.83  ± 5.2. LCAR has superior mechanical properties and could be an alternative to currently-in-use space maintainer though in vivo and in vitro trials are needed to progress the ultimate design of LCAR.

Effect of Zirconia Surface Roughness on Shear Bond Strength to Resin Cements

2012 ◽  
Vol 512-515 ◽  
pp. 1765-1769 ◽  
Author(s):  
Chen Hu ◽  
Long Quan Shao ◽  
Yuan Fu Yi ◽  
Qi Liu ◽  
Bin Deng ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Treated Group ◽  
Control Group ◽  
Ceramic Surface ◽  
Resin Cements ◽  
Population Means ◽  
Significant Difference ◽  
Rotary Cutting

Despite the expanded application for zirconia in restoration dentistry, there is less clear recommendation in the literature regarding the relation between zirconia surface roughness and its shear bond strength to resin cements. The aim of this study was to assess the effect of surface roughness of Cercon zirconia on its shear bond strength to resin cements. 66 Zirconia rectangular specimens (10 mm×10 mm×3 mm) were prepared from Cercon zirconia blocks, finished using a diamond rotary cutting instrument, sintered, and then assigned into 6 groups. The specimens in the first group without polishing were used as control. Other groups were polished against 120#, 240#, 360#, 500# and 600# sand paper after sintered, respectively. Ceramic surface were analyzed by scanning electron microscopy (SEM) and Surface profilometer. 10 samples of each group were bonded with Variolink N resin cements respectively and submitted to shear bond strength test. Shear bond strength was measured and statistically analyzed. The results showed that the population means of 6 groups of samples were not equal. There was no significant difference between control group and 600# sand paper treated group, 500#, 360# and 240# sand paper treated groups (P>0.05), but a significant difference among the other groups (P<0.05). Findings of this study revealed that the shear bond strength might be raised by increasing the surface roughness of Cercon zirconia. Therefore, the surface roughness of Cercon zirconia has an effect on the shear bond strength, but is not the determining factor in clinical use.

scholarly journals Effect of Thermocycling, Teeth, and Polymerization Methods on Bond Strength Teeth-Denture Base

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Sandra Lúcia Andrade de Freitas ◽  
William Cunha Brandt ◽  
Milton Edson Miranda ◽  
Rafael Pino Vitti
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Water Bath ◽  
Microwave Method ◽  
Denture Base ◽  
Mean Values ◽  
Acrylic Resins ◽  
Artificial Teeth

Objective. To evaluate the shear bond strength between different artificial teeth and denture base polymerized by two polymerization methods submitted to thermocycling. Materials and Methods. Two acrylic resins were selected according to the polymerization method (water-bath and microwave), and four different artificial teeth (Biotone, Dentsply; Trilux, Vipi Dent; Premium 8, Heraeus Kulzer; Soluut PX, Yamahachi) were also tested. The polymerization of the acrylic resin was performed by using conventional cycle (8 h at 74°C) in water-bath and using two cycles (20 min at 270 W + 5 min at 360 W) by the microwave method. The shear bond strength was evaluated after 24 h of water storage at 37°C (immediately) and after the thermocycling test (5,000 cycles, 5–55°C). The shear bond strength (n=10) was performed using a universal testing machine (Instron 4411) at a crosshead speed of 1.0 mm/min. Modes of failures were classified as cohesive and adhesive. The data (MPa) were statistically analyzed by three-way ANOVA, and the mean values were compared by the Tukey test (α = 0.05). Results. In general, the polymerization by microwave showed the highest shear bond strength values, and Trilux artificial teeth had the lowest bond strength values (p<0.05). Thermocycling did not affect the shear bond strength (p<0.05). There was a predominance of cohesive failures for all groups. Conclusions. The chemical composition of the artificial teeth affects the bond strength, and the microwave method is preferable to perform the acrylic resin polymerization.

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