scholarly journals Influence of a cobalt-chromium metal framework on surface roughness and Knoop hardness of visible light-polymerized acrylic resins

2006 ◽  
Vol 14 (3) ◽  
pp. 208-212 ◽  
Author(s):  
Joane Augusto de Souza Júnior ◽  
Renata Cunha Matheus Rodrigues Garcia ◽  
Juliana Silva Moura ◽  
Altair Antoninha Del Bel Cury
Keyword(s):  
Visible Light ◽  
Diamond Particle ◽  
In Vitro Study ◽  
Knoop Hardness ◽  
Water Bath ◽  
Cobalt Chromium ◽  
Significance Level ◽  
Acrylic Resins ◽  
Metal Framework

Although visible light-polymerized acrylic resins have been used in removable partial dentures, it is not clear whether the presence of a metal framework could interfere with their polymerization, by possibly reflecting the light and affecting important properties, such as roughness and hardness, which would consequently increase biofilm accumulation. The aim of this study was to compare the roughness and Knoop hardness of a visible light-polymerized acrylic resin and to compare these values to those of water-bath- and microwave-polymerized resins, in the presence of a metal framework. Thirty-six specimens measuring 30.0 x 4.0 ± 0.5 mm of a microwave- (Onda Cryl), a visible light- (Triad) and a water-bath-polymerized (Clássico) (control) acrylic resins containing a cobalt-chromium metal bar were prepared. After processing, specimens were ground with 360 to 1000-grit abrasive papers in a polishing machine, followed by polishing with cloths and 1-µm diamond particle suspension. Roughness was evaluated using a profilometer (Surfcorder SE 1700) and Knoop hardness (Kg/mm²) was assayed using a microhardness tester (Shimadzu HMV 2000) at distances of 50, 100, 200, 400 and 800 µm from the metal bar. Roughness and Knoop hardness means were submitted to two-way ANOVA and compared by Tukey and Kruskal Wallis tests at a 5% significance level Statistically significant differences were found (p<0.05) for roughness and Knoop hardness, with light-polymerized resin presenting the highest values (Ra = 0.11 µm and hardness between 20.2 and 21.4 Kg/mm²). Knoop values at different distances from the metal bar did not differ statistically (p>0.05). Within the limitations of this in vitro study, it was concluded that the presence of metal did not influence roughness and hardness values of any of the tested acrylic resins.

Shear Strength of Visible Light Cured-Urethane Dimethacrylate and Polymethylmethacrylate Denture Base Material to Cobalt Chromium Dental Prosthesis: An In-Vitro Study

2017 ◽  
Vol 7 (10) ◽  
pp. 1008-1013
Author(s):  
Abdulaziz M. Albaker ◽  
Faisal M. Fahmi ◽  
Merna F. Fahmi ◽  
Abdullah M. Alfarraj Aldosari ◽  
Ishfaq A. Bukhari ◽  
...  
Keyword(s):  
Shear Strength ◽  
Visible Light ◽  
Base Material ◽  
In Vitro Study ◽  
Dental Prosthesis ◽  
Vitro Study ◽  
Cobalt Chromium ◽  
Denture Base ◽  
Urethane Dimethacrylate

scholarly journals Comparison of Fracture Resistance in Thermal and Self-Curing Acrylic Resins—An In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Research Work ◽  
Testing Machine ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Thermosetting Resins ◽  
Acrylic Resins ◽  
The Difference

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.

scholarly journals Impact of refrigeration on the surface hardness of hybrid and microfilled composite resins

2009 ◽  
Vol 20 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Fernando Henrique Ruppel Osternack ◽  
Danilo Biazzetto de Menezes Caldas ◽  
Rodrigo Nunes Rached ◽  
Sérgio Vieira ◽  
Jeffrey A. Platt ◽  
...  
Keyword(s):  
Room Temperature ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Knoop Hardness ◽  
Composite Resins ◽  
Bottom Surface ◽  
Steel Mold ◽  
Polymerization Condition ◽  
Post Hoc

This in vitro study evaluated the Knoop hardness of the composite resins Charisma® (C) and Durafill VS® (D) polymerized in 3 different conditions: at room temperature (A) (23 ± 1°C); refrigerated at 4 ± 1°C and immediately photo-activated after removal from the refrigerator (0); and, refrigerated at 4 ± 1°C and photo-activated after a bench time of 15 min at room temperature (15). One hundred and twenty specimens (4 mm diameter and 2 mm depth) were made using a stainless steel mold and following manufacturer's instructions. All specimens were tested immediately after polymerization (I) and after 7 days of water storage in the dark at room temperature (7d). The data were subjected to ANOVA and post-hoc Tukey's test (a=0.05). On the top surface, CAI was statistically similar to C15I and DAI to D15I (p>0.05). On the bottom surface, CAI presented higher hardness values when compared to COI and C15I (p<0.05). The D groups showed no significant differences (p>0.05) on the bottom surfaces for any tested polymerization condition. After 7 days of storage, the Knoop hardness decreased significantly (p<0.05) for groups C7d and D7d except for C07d, which was not different from COI at either surface (p>0.05). D07d showed higher Knoop hardness (p<0.05) values on the top surface when compared to the other groups.

scholarly journals Effectiveness of a silicon-based root canal sealer for filling of simulated lateral canals

2007 ◽  
Vol 18 (1) ◽  
pp. 20-23 ◽  
Author(s):  
João Vicente Baroni Barbizam ◽  
Matheus Souza ◽  
Doglas Cecchin ◽  
Jakob Dabbel
Keyword(s):  
Root Canal ◽  
In Vitro Study ◽  
Root Canal Sealer ◽  
Human Teeth ◽  
Significance Level ◽  
Working Length ◽  
Group 3 ◽  
Group 2 ◽  
Silicon Based

The purpose of this in vitro study was to evaluate the ability of a silicon-based root canal sealer, compared to zinc oxide and eugenol and an epoxy resin-based sealers, for filling of simulated lateral canals. Thirty extracted single-rooted human teeth were selected, conventional access was made and the working length was established 1 mm from the apical foramen. Three simulated lateral canals, one in each root third (coronal, middle and apical) were prepared in both the mesial and distal surfaces of each tooth using a size 15 reamer adapted to a low-speed handpiece. Each root canal was instrumented using ProTaper rotary files up to file F3 at the working length, and then irrigated with 2.5% NaOCl followed by EDTA. The teeth were assigned to 3 groups (n=10), according to the root canal sealer: Roeko Seal (Group 1), Sealer 26 (group 2) and Grossman's sealer (Group 3). Gutta-percha cold lateral condensation technique was performed in all groups. Postoperative radiographs were taken and the images were projected for evaluation of the quality of lateral canal filling. Data were submitted to statistical analysis by Kruskal Wallis test at 5% significance level. The results showed that Grossman's sealer filled a larger number of lateral canals than Roeko Seal (p<0.05) and Sealer 26 (p<0.01). It may be concluded that Roeko Seal silicone-based root canal sealer was not as effective as the Grossman's sealer for filling of simulated lateral canals. The lateral canals localized in the apical third of the root were more difficult to be filled.

scholarly journals Erratum to: Bactericidal effect of visible light in the presence of erythrosine on Porphyromonas gingivalis and Fusobacterium nucleatum compared with diode laser, an in vitro study

LASER THERAPY ◽  
2014 ◽  
Vol 23 (4) ◽  
pp. 263-271 ◽  
Author(s):  
Ghanbari Habiboallah ◽  
Zakeri Mahdi ◽  
Naderi Nasab Mahbobeh ◽  
Zareian Jahromi Mina ◽  
Faghihi Sina ◽  
...  
Keyword(s):  
Visible Light ◽  
Diode Laser ◽  
Porphyromonas Gingivalis ◽  
In Vitro Study ◽  
Fusobacterium Nucleatum ◽  
Bactericidal Effect ◽  
Vitro Study

scholarly journals Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1853 ◽  
Author(s):  
Ella Naumova ◽  
Felix Roth ◽  
Berit Geis ◽  
Christine Baulig ◽  
Wolfgang Arnold ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
In Vitro Study ◽  
Storage Conditions ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Cobalt Chromium ◽  
Retention Force ◽  
Implant Abutments ◽  
Aging Conditions

The retention force of cemented crowns on implant abutments with various luting materials was evaluated. Cobalt–chromium crowns were cemented onto tapered titanium abutments (Camlog) with eugenol-free temporary cement (RelyX TempBond NE), composite-based temporary cement (Bifix Temp), zinc phosphate cement (Harvard Cement), glass-ionomer cements (Meron, Fuji I), and resin-modified glass-ionomer cements (Fuji II, Fuji Plus, Ketac Cem Plus). Specimen aging via hydrostress was performed in artificial saliva at 37 °C for 14 days (S1), followed by hydrothermal stress with thermocycling (S2). The crowns were removed, and the force was recorded (T1). Subsequently, the crowns were recemented, aged, and removed, and the force was recorded (T2, T3). The retention forces differences were statistically significant according to the storage conditions at T1 (p = 0.002) and T3 (p = 0.0002). After aging (S1), Ketac Cem Plus had the highest retention force median value difference (T3 versus T1) (−773 N), whereas RelyX TempBond NE had the lowest (−146 N). After aging (S2), Meron had the highest retention force median value difference (−783 N), whereas RelyX TempBond NE had the lowest (−168 N). Recementation decreased the retention force of the implant-supported cobalt–chromium crowns cemented and recemented with the same luting materials. Luting materials (at T1) and aging conditions significantly impacted the retention force.

Ellagic Acid Cytotoxic and Metalloproteinases Inhibitory Effects Against Oral Squamous Cell Carcinoma: An in Vitro Study

2021 ◽  
Author(s):  
Patricia Maria Wiziack Zago ◽  
Luiza Rodrigues Hellmeister ◽  
Lucas Novaes Teixeira ◽  
Rui Barbosa de Brito Junior ◽  
Elizabeth Ferreira Martinez
Keyword(s):  
Oral Cancer ◽  
Cell Lines ◽  
Ellagic Acid ◽  
Normal Cell ◽  
In Vitro Study ◽  
Significance Level ◽  
Viability Analysis ◽  
Anticancer Properties

Abstract ObjectivesThis study aimed to evaluate the in vitro antitumoral potential of different concentrations of EA against two OSCC cell lines with distinct tissue invasiveness profiles. Material and methodsNormal keratinocytes (NOK) and OSCC´s cells CAL-27 and SCC-9 were treated with concentrations of EA varying from 5 to 662 µM during 24, 48 or 72h. After each time of treatment, cells were submitted to viability analysis using MTT and the secretion of metalloproteinases (MMP-2 and MMP-9) and tissue metalloproteinases inhibitors (TIMP-1 and TIMP-2) were performed by Enzyme-Linked Immunoassay (ELISA). Data were submitted to ANOVA, followed by Bonferroni´s test, considering 5% as significance level. ResultsEA was cytotoxic to OSCC cells in all exposure times, rarely affecting normal cell viability, except for concentrations higher than 82 µM and after 72h treatment. For OSCC cells, EA decreased MMPs and increased TIMPs´s expression without effect on those enzymes for normal cell lines during all times of exposure. ConclusionEA is a promising therapeutic adjuvant to treat oral cancer, however, further in vivo studies are required to clinically validate its potential. Clinical RelevanceThe in vitro anticancer properties showed by Ellagic acid, a phenolic compound that could easily be accessed by oral cancer patients, provides data to base future clinical studies intended to develop a safe topical oral anticancer product.

scholarly journals Evaluation of a Novel Cryoablation System: In vitro Testing of Heat Capacity and Freezing Temperatures

2012 ◽  
Vol 7 (6) ◽  
pp. 403-409 ◽  
Author(s):  
Timo Weimar ◽  
Anson M. Lee ◽  
Shuddhadeb Ray ◽  
Richard B. Schuessler ◽  
Ralph J. Damiano
Keyword(s):  
In Vitro Study ◽  
Negative Temperature ◽  
Water Bath ◽  
Tissue Temperature ◽  
Ice Formation ◽  
In Vitro Testing ◽  
Thermal Loads ◽  
Wide Range ◽  
Linear Probe

Objective Cryoablation has been used to ablate cardiac tissue for decades and has been shown to be able to replace incisions in the surgical treatment of atrial fibrillation. This in vitro study evaluates the performance of a novel cryoprobe and compares it with existing commercially available devices. Methods A new malleable 10-cm aluminum cryoprobe was compared with a rigid 3.5-cm copper linear probe using in vitro testing to evaluate performances under different thermal loads and with different tissue thicknesses. Radial dimensions of ice formation were measured in each water bath by a high-precision laser 2 minutes after the onset of cooling. Probe-surface temperatures were recorded by thermocouples. Tissue temperature was measured at depths of 4 mm and 5 mm from the probe-tissue interface. Time to reach a tissue temperature of −20°C was recorded. Results Ice formation increased significantly with lower water-bath temperatures (P < 0.001). Width and depth of ice formation were significantly less for the rigid linear probe (P < 0.012 and P < 0.001, respectively). There was no difference between the probes in the maximal negative temperature reached under different thermal loads or at different tissue depths. The malleable probe achieved significantly lower temperatures at the proximal compared with the distal end (–61.7°C vs −55.0°C, respectively; P < 0.001). A tissue temperature of −20°C was reached earlier at 4 mm than at 5 mm (P < 0.001) and was achieved significantly faster with the 3011 Maze Linear probe (P < 0.021). Conclusions The new malleable probe achieved rapid freezing to clinically relevant levels in up to 5-mm–thick tissue. Both probes maintained their performance under a wide range of thermal loads.

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