Mechanical and Biological Properties of Acrylic Resins Manipulated and Polished by Different Methods

Santos, Rogério Lacerda dos; Pithon, Matheus Melo; Carvalho, Fabíola Galbiatti de; Ramos, Aretha Aliny dos Santos; Romanos, Maria Teresa Villela

doi:10.1590/0103-6440201302293

Cited by 8 publications

(7 citation statements)

References 19 publications

(32 reference statements)

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“…Another interesting fact when mechanical and biological properties were compared was that manipulation techniques (mass or saturation) and polishing methods (mechanical or chemical) showed more influence on the cytotoxicity in cell cultures than on flexural strength of denture base acrylic resins for periods of 24 to 168 h (15). The addition of nanostructured silver vanadate (β-AgVO 3 ) may provide the acrylic resins antibacterial activities but reduces the impact strength (16).…”

Section: Discussionmentioning

confidence: 99%

Effect of Polymerization Cycles on Gloss, Roughness, Hardness and Impact Strength of Acrylic Resins

et al. 2016

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The aim of this study was to evaluate the conventional and boiled polymerization cycles on gloss, roughness, hardness and impact strength of acrylic resins. Samples were made for each Classico and QC-20 materials (n=10) in dental stone molds obtained from rectangular metallic matrices embedded in metallic flasks. The powder-liquid ratio and manipulation of the acrylic resins' were accomplished according to manufacturers' instructions and the resins were conventionally packed in metallic flasks. After polymerization by (1) conventional: 74 °C for 9 h (Classico) and (2) boiled: 20 min (QC-20) cycles, the samples were deflasked after cooling at room temperature and conventionally finished and polished. The properties were evaluated after storage in water at 37 °C for 24 h. Gloss was verified with Multi Gloss 268 meter (Konica Minolta), surface roughness was measured with Surfcorder SE 1700 rugosimeter (Kosaka), Knoop hardness number was obtained with HMV-200 microdurometer, and impact strength was measured in an Otto Wolpert-Werke device by Charpy system (40 kpcm). Data were subjected to Student's t-test (at α=0.05). The results were: Gloss: 67.7 and 62.2 for Classico and QC-20 resins, respectively; Surface roughness: 0.874 and 1.469 Ra-µm for Classico and QC-20, respectively; Knoop hardness: 27.4 and 26.9 for Classico and QC-20, respectively; and Impact strength: 37.6 and 33.6 kgf/cm2 for Classico and QC-20, respectively. No statistically significant difference (p>0.05)were found between the resins for the evaluated properties. In conclusion, conventional and boiled polymerization cycles had similar effects on gloss, roughness, hardness and impact strength of both Classico and QC-20 resins.

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Section: Discussionmentioning

confidence: 99%

Effect of Polymerization Cycles on Gloss, Roughness, Hardness and Impact Strength of Acrylic Resins

et al. 2016

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“… 10 However, the in vivo manipulation of acrylic monomer might be cytotoxic, acting as an adjuvant agent at either the sensitization or elicitation step in the allergic dermatitis induced by nickel. 20 - 22 Ageing process was performed with water instead of saliva, once water is the principal compound of the saliva. Moreover, water easily penetrate the polymer and provoke hydrolysis in the PfT polymeric chains.…”

Section: Discussionmentioning

confidence: 99%

Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets

Cumerlato

Lima

Osório

et al. 2017

Dental Press J. Orthod.

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Objective: The aim of this in vitro study was to evaluate and compare the effects of grinding, drilling, sandblasting, and ageing prefabricated teeth (PfT) on the shear bond strength (SBS) of orthodontic brackets, as well as the effects of surface treatments on the adhesive remnant index (ARI). Methods: One-hundred-ninety-two PfT were divided into four groups (n = 48): Group 1, no surface treatment was done; Group 2, grinding was performed with a cylindrical diamond bur; Group 3, two drillings were done with a spherical diamond bur; Group 4, sandblasting was performed with 50-µm aluminum oxide. Before the experiment, half of the samples stayed immersed in distilled water at 37oC for 90 days. Brackets were bonded with Transbond XT and shear strength tests were carried out using a universal testing machine. SBS were compared by surface treatment and by ageing with two-way ANOVA, followed by Tukey’s test. ARI scores were compared between surface treatments with Kruskal-Wallis test followed by Dunn’s test. Results: Surface treatments on PfT enhanced SBS of brackets (p< 0.01), result not observed with ageing (p= 0.45). Groups II, III, and IV showed higher SBS and greater ARI than the Group 1 (p< 0.05). SBS was greater in the groups 3 and 4 (drilling, sandblasting) than in the Group 2 (grinding) (p< 0.05). SBS and ARI showed a positive correlation (Spearman’s R2= 0.57; p< 0.05). Conclusion: Surface treatment on PfT enhanced SBS of brackets, however ageing did not show any relevance. Sandblasting and drilling showed greater SBS than grinding. There was a positive correlation between SBS and ARI.

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“…Some studies have shown that the polishing techniques of acrylic resin can influence its mechanical properties by increasing the ratio of monomers, especially when the polishing is chemical (MCCABE;BASKER, 1976;STAFFORD;BROOKS, 1985;KEDJANURE et al, 1999;RANTALA et al, 2003;RUIZ-GENAO et al, 2003;FALTERMEIER et al, 2007;SANTOS et al, 2013). This high amount of residual monomer (MELLO et al, 2003;.…”

Section: Discussionmentioning

confidence: 99%

“…In dentistry, the use of acrylic resin or poly methyl methacrylate (PMMA) is common among professionals, especially by orthodontists in the confection of several orthodontic devices such as space maintainers, reclaimers and dental retainers among others (SANTOS et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Influence of the manipulation technique of acrylic resin on mechanical strength of orthodontic plates

Pithon¹,

Santos²,

Soares³

et al. 2015

Biosci. J.

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ABSTRACT:The focus of this study was to test the fracture resistance of upper arch dental retainers, made by two different manipulation techniques of acrylic resin. 84 plates Wraparound type retainers were made by two different manipulation techniques forming two groups (n = 42): Group 1 (Addition Technique) and Group 2 (Pressing Technique). All the retainers were duly shaped in U form with the aid of standardized plaster cast models. During the confection process the standardizing of the retainers was conducted carefully regarding their thickness and dimensions with the aid of a gauge and a straight caliper. After confection they remained immersed in water for 24 hours at 37°C. Next, they were tested through mechanical compression until fracture in a universal mechanical testing machine. Data were analyzed by Student's t test. The significance level was set at 5% (α = 0.05). It was found that the average was of 79.12 N for Group 1 and of 77.07 N for Group 2 with a standard deviation of 17.30 N and 16.31, respectively, showing that there is no significant difference in resistance for the retainers when made through any of the two methods (P=0.788). The addition and pressure techniques of acrylic resin do not influence the resistance to compression of the upper dental retainers.

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Mechanical and Biological Properties of Acrylic Resins Manipulated and Polished by Different Methods

Cited by 8 publications

References 19 publications

Effect of Polymerization Cycles on Gloss, Roughness, Hardness and Impact Strength of Acrylic Resins

Effect of Polymerization Cycles on Gloss, Roughness, Hardness and Impact Strength of Acrylic Resins

Effect of surface treatment of prefabricated teeth on shear bond strength of orthodontic brackets

Influence of the manipulation technique of acrylic resin on mechanical strength of orthodontic plates

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