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1.
Wiad Lek ; 73(8): 1726-1729, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33055342

RESUMO

OBJECTIVE: The aim of out research was to determine the effectiveness of the sealing property of adhesive systems V and VII generations by studying the depth of curing, water absorption and water solubility of their samples. PATIENTS AND METHODS: Materials and methods: The study was performed according to ISO / TS 11405: 2015 at the Central Factory Laboratory of JSC "CTOMA", Kharkiv, Ukraine, Certificate of Attestation No. 100-062 / 2015 dated 03/04/2015. For the study we used specially prepared laboratory samples which were made in the form of plates from adhesive system "DC Adhesive NF" (Dental Central) of V generation "Single bond Universal" (3M ESPE) of VII generation. А monitor and analyze the results obtained used micrometer MK-25, №4694, №03 / 5321 from 08/18/17; caliper SC-1, No. 267447, No. 03/5322 from 08/18/17; scales AP 210, №112144137, №87027 / 9 from 24.11.2017. RESULTS: Results: According to the results of the investigation the following results were obtained: 1) the average curing depth of V and VII generation of adhesive systems was 4.08mm and 3.51mm respectively at the rate of 2mm; 2) average water absorption: 45.97 µg/mm3 and 30.89 µg/mm3 for V and VII generations respectively; 3) the average water solubility was 6.94 µg / mm3 and 4.17 µg / mm3, respectively. CONCLUSION: Conclusions: According to the results of our laboratory studies, it can be concluded that adhesive systems of V and VII generations can be used for restoration of lesions of tooth hard tissued. Along with this, it can be recommended to use V generation adhesives in closed defects where direct polymerization should be performed and oral fluid access is minimal. Adhesive sysyems of VII generation can be recommended in such cases as: opened restorations, pregingival areas of teeth, cases where a permanent contact of restorations with oral fluid be found along with the cases of autonomic application of adhesive system.


Assuntos
Cimentos Dentários , Água , Teste de Materiais , Ucrânia
2.
J Adhes Dent ; 22(5): 443-453, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33073776

RESUMO

PURPOSE: To systematically review the literature to determine whether silane combined with adhesive application improves the repair bond strength of direct methacrylate-based resin composites in comparison to the use of an adhesive alone. MATERIALS AND METHODS: The literature up to December 2019 was searched through PubMed/MEDLINE, Scopus, and Lilacs databases with no publication year or language limits. From 676 potentially eligible studies, 81 were selected for full-text analysis, and 19 were included in the systematic review. Two reviewers independently selected the studies, extracted data, and assessed the risk of bias. Meta-analyses were conducted using a random effects model to calculate pooled mean differences between adhesive- vs silane-plus-adhesive surface treatments (global meta-analysis) and considering subgroup analyses (immediate and aged repair bond strengths and type of silane - hydrolyzed or nonhydrolyzed). Statistical analyses were performed using RevMan5.3 at a significance level of 5%. RESULTS: Global meta-analysis showed that the use of silane prior to adhesive application produced significantly higher repair bond strengths (p=0.003). A higher mean difference (effect size: 7.30, 95% CI: 2.91-17.51) between groups was found when nonhydrolyzed silanes were used. The heterogeneity was high. Studies scored between medium and high risk of bias. CONCLUSION: An additional silane application step could increase the repair bond strength of methacrylate-based resin composites.


Assuntos
Colagem Dentária , Silanos , Cimentos Dentários , Teste de Materiais , Cimentos de Resina
3.
J Adhes Dent ; 22(5): 483-501, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33073780

RESUMO

PURPOSE: Universal adhesives (UAs) are applied in 2-step etch-and-rinse (2-E&R) or 1-step self-etch (1-SE) mode. This study investigated whether three UAs could benefit from a highly filled extra bonding layer (EBL), turning them into 3-E&R and 2-SE UAs, respectively, thus also compensating for the commonly thin film thickness of UAs. MATERIALS AND METHODS: Microtensile bond strength (µTBS) to bur-cut dentin of Clearfil Universal Bond Quick (C-UBq, Kuraray Noritake), G-Premio Bond (G-PrB, GC) and Prime&Bond Active (P&Ba, Dentsply Sirona), applied in E&R and SE mode without/with the adhesive resin (EBL) of OptiBond FL (Opti-FL_ar, Kerr), was compared to that of the 3-E&Ra OptiBond FL (Opti-FL; Kerr), which was also employed in 2-SE mode. As a cross reference, the SE primer of Clearfil SE Bond 2 (Kuraray Noritake) was combined with Opti-FL_ar (C-SE2/Opti-FL) and again applied in 2-SE and 3-E&R mode. µTBS was measured after 1 month of water storage (37°C) and additional 25,000 and 50,000 thermocycles (TC). All µTBS were statistically analyzed using three different linear mixed-effects models with specific contrasts (p < 0.05). RESULTS: Overall, the four parameters (adhesive, bonding mode, aging, EBL) significantly influenced µTBS. G-PrB and P&Ba benefited from EBL when applied in both E&R and SE bonding modes. In E&R mode, P&Ba generally revealed the highest µTBS; C-UBq presented an intermediate and G-PrB the lowest µTBS. No significant differences were found between different bonding modes. C-SE2/Opti-FL outperformed Opti-FL in 3-E&R and 2-SE_1 month/25k. CONCLUSION: The overall benefit of EBL on the 1-month and TC-aged bonding efficacy differed for the different UAs tested.


Assuntos
Colagem Dentária , Adesivos Dentinários , Cimentos Dentários , Dentina , Teste de Materiais , Resistência à Tração
4.
J Adhes Dent ; 22(5): 523-530, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33073783

RESUMO

PURPOSE: To evaluate the effect of composite resin polymerization shrinkage stress on the stress distribution in the implant-supported crown-access hole, and on the bond strength between the ceramic and composite resin. MATERIALS AND METHODS: A 3D model of a ceramic crown, in which the access hole was filled with composite resin (conventional or bulk-fill), was used to evaluate the stress distribution in the access hole using finite element analysis. The contacts were considered bonded and the polymerization shrinkage was simulated based on the coefficient of linear thermal expansion of each resin. The push-out test (1 mm/min, 100 kgf) was performed on perforated lithium disilicate samples filled with conventional or bulk-fill resins to validate the stress data of the bond strength. One-way ANOVA and Tukey's test were used to analyze the bond strength data, with α set at 5%. RESULTS: Conventional resin showed the worst stress distribution and highest displacement values, von Mises stress, maximum principal strain, maximum principal stress, and maximum shear stress vs the bulk-fill resin. Statistically significantly greater bond strength was observed for bulk-fill (13.40 ± 5.59 MPa) than the conventional resin (8.70 ± 3.02 MPa). CONCLUSION: Comparing both materials tested in the present study, the use of bulk-fill composite resin to seal the screw-access hole is suggested to reduce the stress concentration and increase bond strength to the ceramic crown.


Assuntos
Parafusos Ósseos , Resinas Compostas , Coroas , Teste de Materiais , Polimerização
5.
Compend Contin Educ Dent ; 41(9): 477-482, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33001658

RESUMO

Lithium disilicate and layered zirconia appear to be the most prevalent materials used for single-unit anterior crowns. These materials offer the necessary mechanical properties as well as sufficient optical characteristics needed in this type of restoration. There now are also more translucent versions of zirconia available that can be used for monolithic anterior restorations. This article discusses the factors that clinicians must take into account when determining a restorative material for single-unit anterior crowns. Considerations for lithium-disilicate crowns, 4 and 5 mol% yttria-containing (4Y and 5Y) zirconia materials, and layered 3Y zirconia restorations are provided.


Assuntos
Coroas , Dente , Materiais Dentários , Teste de Materiais
6.
Beijing Da Xue Xue Bao Yi Xue Ban ; 52(5): 943-947, 2020 Oct 18.
Artigo em Chinês | MEDLINE | ID: mdl-33047734

RESUMO

OBJECTIVE: To select the most effective method among different masking treatments, such as different thickness and transparence, tissue surface's opaque coating, and opaque resin cement to restore discolored teeth esthetically by porcelain veneer. METHODS: Four extracted intact maxillary central incisors were prepared for porcelain veneer restoration and each three heat pressed porcelain veneers from three thicknesses (0.8 mm, 1.0 mm, 1.2 mm) and two transparency(high transparence, HT and low transparence, LT))in Vita shade A2 were fabricated for each tooth, in total of 72 pieces. The surfaces of three prepared teeth were then painted to mimic situations of severe dental fluorosis, severe tetracycline teeth, and necrotic teeth. Each of the veneers was temporarily cemented to the corresponding tooth surface using try-in cements with three different colors (transparent, opaque, and yellow), then used the shade guide (3D master) and electronic colorimeter (easy shade) to record the shade of each porcelain veneer through hue, lightness, and chroma reading. After that, high-transparence porcelain veneers in thickness of 0.8 mm was fused with a layer of opaque porcelain in tissue surface, and were shade matched again after cementation. Statistic treatments were performed to analyze the difference in each masking method. RESULTS: For each 0.2 mm increase in the veneer thickness of porcelain, the average lightness was reduced by 1 unit, while the chroma was not changed which was independent of the type of the resin cements. When the thickness of the porcelain veneer was decreased to 0.8 mm, the opacity effect was not remarkable even if a low-transparence porcelain veneer was used. Transparent and yellow resin cements had poor opaque performance, while opaque resin cement could reduce the lightness by 2 units and the chroma was also reduced. The opaque layer of the tissue surface could be applied uniformly, and the lightness and chroma could be reduced to Vita 2M1 to 2M1.5 levels regardless of the color of resin cements, which suggested a stable opacity effect for different discolored teeth in this study. CONCLUSION: For porcelain veneer restoration of discolored teeth, thickened veneers are the most effective means to display a natural transmittance and color. Tissue surface's opacity coatings and opaque resin cements can also be used to reduce grayscale and increase lightness.


Assuntos
Descoloração de Dente , Cor , Humanos , Teste de Materiais , Pigmentação em Prótese , Cimentos de Resina , Descoloração de Dente/terapia
7.
Adv Clin Exp Med ; 29(9): 1111-1116, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33001590

RESUMO

BACKGROUND: The primary reason for using a post is to retain the core with the objective to restore the missing coronal tooth structure. To achieve optimum results, the materials that are used to restore endodontically treated teeth should have physical and mechanical properties that are similar to that of dentin. OBJECTIVES: To characterize the strength parameters of fiber-reinforced composite (FRC) posts with the application of a three-point test. The mean fracture load, flexural strength and flexural modulus were taken into consideration. MATERIAL AND METHODS: For the three-point strength tests, 5 kinds of fiberglass root-posts were used: GC Fiber Post (GC America, Alsip, USA), Mirafit White (Hager Werken, Duisburg, Germany), Innopost (InnoTech, Verona, Italy), Rebilda Post (Voco, Cuxhaven, Germany), and EverStick Post (GC Europe, Leuven, Belgium). For each system, 15 FRC posts were tested. All posts had the same diameter, length and shape. The three-point test was carried out in accordance with ISO 10477:2004, using the Instron-5944 testing machine (Instron, Norwood, USA). The test was carried out until the sample was broken. RESULTS: The highest force values (67.6 N) were recorded for the GC posts, and the lowest force required to break the sample (29.6 N) was noted for the EverStick Posts. In the case of bending strength, the highest values were also recorded for GC posts (912.4 MPa). Low bending strengths were obtained for the Mirafit White posts (537.2 MPa); however, the EverStick Posts were the weakest (436.2 MPa). Rebilda posts showed the highest modulus of elasticity - 31.1 GPa. The lowest values of the elastic modulus were registered for EverStick Posts - 12.5 GPa. CONCLUSIONS: There were statistically significant differences in fracture loads, flexural strengths and flexural modulus of the FRC-post systems tested. Individually polymerized FRC material showed lower flexural properties than compared prefabricated FRC posts.


Assuntos
Cavidade Pulpar , Técnica para Retentor Intrarradicular , Teste de Materiais
8.
Am J Dent ; 33(5): 239-242, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33017525

RESUMO

PURPOSE: Concurrently with the growing interest in CAD-CAM systems, several new materials of different chemical nature have become available. As an alternative to ceramics, numerous polymer-based materials have recently been proposed for permanent prosthetic restorations. Aim of this study was to test the CAD-CAM polymer-based materials available on the market, comparing mean flexural strength, Weibull characteristic strength and Weibull modulus. METHODS: Seven types of polymer-based blocks were tested: Lava Ultimate, 3M; Brilliant Crios, Coltene; Cerasmart, GC; Block HC, Shofu; Katana Avencia, Noritake; Grandio Blocs, Voco; Tetric CAD, and Ivoclar-Vivadent. Specimens were cut out from blocks, finished, polished, and tested in a three-point bending test apparatus until failure (n=30). Flexural strength, Weibull characteristic strength, and Weibull modulus were calculated. Flexural strength data were statistically analyzed. ANOVA on Ranks was applied, followed by the Dunn's test for post hoc comparisons (P= 0.05). RESULTS: Flexural strength values (MPa) were measured (mean±standard deviation). Different letters in parentheses label statistically significant differences: Grandio Blocs 266±24(a), Brilliant Crios 259±21(ab); Tetric CAD 254±15(ab); Katana Avencia 241±29(bc); Cerasmart 221±24(cd); Lava Ultimate 196±23(de); Block HC 139±10(e). All the tested materials had flexural strengths greater than 100 MPa, thereby satisfying the requirements of ISO standards for polymer-based materials. For all the tested materials the Weibull characteristic strength was greater than 100 MPa. Weibull modulus ranged between 21.20 (Tetric CAD) and 9.09 (Katana Avencia). CLINICAL SIGNIFICANCE: Even though all the CAD-CAM polymer-based materials marketed in blocks tested in the present study satisfy the requirements of ISO standard for polymer-based materials, their flexural resistance differs significantly. The data presented in the study may be helpful to clinicians for selecting the most appropriate materials for each clinical case.


Assuntos
Proantocianidinas , Cerâmica , Esmalte Dentário , Teste de Materiais , Propriedades de Superfície
9.
Am J Dent ; 33(5): 243-247, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33017526

RESUMO

PURPOSE: Concurrently with the growing interest in CAD-CAM systems, several new materials of different chemical nature have become available. As an alternative to ceramics, numerous polymer-based materials have recently been proposed for permanent prosthetic restorations. Aim of this study was to test the CAD-CAM polymer-based materials available on the market, comparing mean flexural strength, Weibull characteristic strength and Weibull modulus. METHODS: Seven types of polymer-based blocks were tested: Lava Ultimate, 3M; Brilliant Crios, Coltene; Cerasmart, GC; Block HC, Shofu; Katana Avencia, Noritake; Grandio Blocs, Voco; Tetric CAD, and Ivoclar-Vivadent. Specimens were cut out from blocks, finished, polished, and tested in a three-point bending test apparatus until failure (n=30). Flexural strength, Weibull characteristic strength, and Weibull modulus were calculated. Flexural strength data were statistically analyzed. ANOVA on Ranks was applied, followed by the Dunn's test for post hoc comparisons (P= 0.05). RESULTS: Flexural strength values (MPa) were measured (mean±standard deviation). Different letters in parentheses label statistically significant differences: Grandio Blocs 266±24(a), Brilliant Crios 259±21(ab); Tetric CAD 254±15(ab); Katana Avencia 241±29(bc); Cerasmart 221±24(cd); Lava Ultimate 196±23(de); Block HC 139±10(e). All the tested materials had flexural strengths greater than 100 MPa, thereby satisfying the requirements of ISO standards for polymer-based materials. For all the tested materials the Weibull characteristic strength was greater than 100 MPa. Weibull modulus ranged between 21.20 (Tetric CAD) and 9.09 (Katana Avencia). CLINICAL SIGNIFICANCE: Even though all the CAD-CAM polymer-based materials marketed in blocks tested in the present study satisfy the requirements of ISO standard for polymer-based materials, their flexural resistance differs significantly. The data presented in the study may be helpful to clinicians for selecting the most appropriate materials for each clinical case.


Assuntos
Resistência à Flexão , Polímeros , Desenho Assistido por Computador , Materiais Dentários , Teste de Materiais
10.
J Contemp Dent Pract ; 21(7): 713-717, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33020351

RESUMO

AIM: The purpose of this study was to evaluate the effects of air abrasion with aluminum oxide or glass beads to three types of zirconia containing various levels of cubic crystalline phases (3Y-TZP, Katana ML; 4Y-PSZ, Katana STML; and 5Y-PSZ, Katana UTML, Noritake) on the shear bond strength of resin cement. MATERIALS AND METHODS: Thirty block specimens (8 × 8 × 3.5 mm) were milled out of each zirconia material and mounted in plastic pipe. Ten specimens of each of the zirconia materials were air-abraded using 50 µm aluminum oxide particles, ten specimens were abraded using 80 µm glass beads, and ten specimens served as a control and received no surface treatment. A zirconia primer was applied to the surface of the zirconia specimens. Composite disks were bonded using a resin cement and light-cured. The specimens were stored in 37°C distilled water for 24 hours and thermocycled for 2,500 cycles. The specimens were loaded in shear on a universal testing machine. Data were analyzed with one-way and two-way ANOVAs and Tukey's post hoc tests (α = 0.05). RESULTS: A significant difference in shear bond strength was found based on the surface treatment (p < 0.001), but not on the type of zirconia (p = 0.132). CONCLUSION: Air abrasion with glass beads or no surface treatment resulted in significantly lower bond strength of the resin cement to all three zirconia types compared to air abrasion with aluminum oxide. CLINICAL SIGNIFICANCE: Although air abrasion with aluminum oxide may reportedly be more likely to weaken cubic-containing zirconia compared to air abrasion with glass beads, the use of aluminum oxide results in greater bond strength of the resin cement.


Assuntos
Óxido de Alumínio , Colagem Dentária , Abrasão Dental por Ar , Análise do Estresse Dentário , Teste de Materiais , Propriedades de Superfície , Zircônio
11.
J Contemp Dent Pract ; 21(7): 728-732, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33020354

RESUMO

AIM: The aim of the present study is twofold: to evaluate cyclic fatigue resistance differences of two different nickel-titanium rotary instruments, brand new and after an ex vivo instrumentation of single root extracted teeth. MATERIALS AND METHODS: Twenty new S One 20.06 were randomly divided into two groups. The first group (n = 10) was immediately subjected to a cyclic fatigue test (S One Group I). The second group (n = 10) (S one Group II) performed a cyclic fatigue test after three ex vivo root canal treatment with a single-file technique. The same process has been carried out for 20 M-Two 20.06 instruments. RESULTS: Mean time to fracture (TtF) for Group I was 51.14 ± 1.28 for S One and 32.62 ± 0.17 for M-Two 20.06 and for Group II was 46.00 ± 0.99 for S One and 27.75 ± 1.58 for M-Two 20.06. The reduction in TtF values from Group I to Group II was 11% for S One and 15% for M-Two. Statistical analysis found significant differences in all the groups examined (p value < 0.05). Mean fragment length (FL) for Group I was 3.07 ± 0.17 for S One and 3.05 ± 0.14 for M-Two 20.06 and for Group II was 3.05 ± 0.07 for S One and 3.05 ± 0.14 for M-Two 20.06. Statistical analysis was pursued, and no significant difference was found (p value > 0.05). CONCLUSION: The S-One showed significantly more resistance to cyclic fatigue stress than M-Two for both new and used instruments. This validates the hypothesis that the AF H wire enables the S One files to endure more the cyclic fatigue stresses. CLINICAL SIGNIFICANCE: This study demonstrates the cyclic fatigue resistance of a new endodontic instrument after repetitive usage.


Assuntos
Níquel , Titânio , Cavidade Pulpar , Desenho de Equipamento , Falha de Equipamento , Teste de Materiais , Preparo de Canal Radicular
12.
J Contemp Dent Pract ; 21(6): 615-620, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33025928

RESUMO

AIM: The aim of this study is to compare the effect of the use of second-generation and third-generation LED light-curing units (LCUs) on the degree of conversion (DC) and microhardness (VHN) of bulk-fill resin composites. MATERIALS AND METHODS: Thirty cylindrical specimens (each n = 5) of Tetric N-Ceram Bulk-Fill, Filtek™ Bulk-Fill Posterior Restorative, and SDR flow were prepared in metal molds (5 mm in diameter and 4 mm in thickness) and cured with second-generation LED (SmartLite® Focus®, Dentsply Sirona) and third-generation LED (Bluephase® style, Ivoclar Vivadent) resulting in six groups. Degree of conversion was determined using Fourier transform infrared spectroscopy (FTIR), and microhardness with Vickers microhardness tester. Data were statistically analyzed using one-way ANOVA and least significance difference (LSD) test, and DC and microhardness were correlated using Pearson's correlation (α = 0.05). RESULTS: There was a significant difference between DC and VHN between all groups of bulk-fill which were cured by second-generation LED curing light and third-generation LED curing light. Then there is no significant difference between DC of the three composite bulk-fill resins by (second-generation LED vs third-generation LED curing light). CONCLUSION: The second-generation LED curing light can still be used to cure bulk-fill resin composites by increasing the duration of irradiation. CLINICAL SIGNIFICANCE: In the microhardness test, there was a significant difference in the Filtek™ Bulk-Fill Posterior Restorative resin composites.


Assuntos
Resinas Compostas , Luzes de Cura Dentária , Teste de Materiais , Polimerização , Espectroscopia de Infravermelho com Transformada de Fourier
13.
J Contemp Dent Pract ; 21(6): 636-639, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33025932

RESUMO

AIM: Variation in the surface roughness of archwires not only leads to more accumulation of plaque but also modifies the coefficient of friction. This necessitated for the present study to evaluate the surface characteristics of 0.016 × 0.022-inch nickel-titanium, beta-titanium, and copper-nickel-titanium archwires, before and after their use in the oral cavity using atomic force microscopy. MATERIALS AND METHODS: The control and experimental samples were measured at three different positions under atomic force microscopy. The surface roughness was measured using roughness average, root mean square, and maximum height before and after use in the oral cavity among 60 adult participants. Data were analyzed using a one-way analysis of variance and Student's t tests using the Statistical Package for Social Software (SPSS) v.20.0. RESULTS: The surface roughness of archwires increased considerably after their clinical use compared to controls for nickel-titanium (p = 0.013) and beta-titanium (p = 0.002). A similar trend was noticed for root mean square where nickel-titanium (p = 0.014) and beta-titanium (p = 0.013) had increased root mean square. Maximum height was also noticed in nickel-titanium (p = 0.031) and beta-titanium (p = 0.016). CONCLUSION: Surface roughness and the level of friction of the orthodontic wires increase significantly for nickel-titanium and beta-titanium after the clinical use. There is a difference in increase of surface roughness of the archwire within and between the bracket slots. CLINICAL SIGNIFICANCE: Nickel-titanium and beta-titanium wires show more roughness and resultant higher friction levels after use in the oral cavity. Hence, care related to plaque accumulation is essential.


Assuntos
Cobre , Níquel , Ligas Dentárias , Humanos , Teste de Materiais , Propriedades de Superfície , Titânio
14.
J Contemp Dent Pract ; 21(6): 678-682, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33025938

RESUMO

AIMS: The purpose of this study was to assess the influence of hot and dry weather on the hardness and surface roughness of four different maxillofacial silicone elastomeric materials (MFSEM) including two room-temperature vulcanized (RTV) and two high-temperature vulcanized (HTV) materials. MATERIALS AND METHODS: Eighty test specimens were fabricated according to the manufacturer's instructions into rectangular test specimens. The hardness and surface roughness were tested, after 6 months of exposure to natural hot and dry weather. The hardness was measured through the International Rubber Hardness Degree (IRHD) scale using an automated hardness tester. The surface roughness was measured using a novel 3D optical noncontact technique using a combination of a light sectioning microscope and a computer vision system. Statistical Package for Social Sciences software SPSS/version 24 was used for analysis and a comparison between two independent variables was done using an independent t test, while more than two variables were analyzed, F test (ANOVA) to be used followed by a post hoc test to determine the level of significance between every two groups. RESULTS: The hot and dry weather statistically influenced the hardness and surface roughness of MFSEM. Cosmesil M-511 showed the least hardness in test groups while A-2000 showed the hardest material (p < 0.05). A-2000 showed significant changes from rough in case of nonweathered to become smoother in weather followed by A-2186 (p < 0.05). Cosmesil M-511 showed the roughest material. CONCLUSION: Cosmesil M-511 showed the least hard MFSEM after outdoor weathering while A-2000, the highest and least material showed hardness and surface roughness, respectively. CLINICAL IMPLICATION: A-2000 had a high IRHD scale hardness. This makes this material more suitable for the replacement of ear and nose defects. Cosmesil M-511 is soft and easily adaptable material that makes the material more appropriate for the replacement of small facial defect with undercut area to be easily inserted and removed. Whilst A-2000 is smoother and finer in test specimens after weathering, Cosmesil M-511 became rougher after weathering.


Assuntos
Prótese Maxilofacial , Dureza , Teste de Materiais , Propriedades de Superfície , Tempo (Meteorologia)
15.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(4): 376-379, 2020 Aug 01.
Artigo em Chinês | MEDLINE | ID: mdl-32865354

RESUMO

OBJECTIVE: This study aimed to compare the effects of water storage treatment and thermal cycling on the shear bond strength (SBS) of three self-adhesive dual-cure resin cements. METHODS: Six cubic zirconia specimens with side length of 2 cm were obtained by cutting and sintering. Three self-adhering dual-cure resin cements (i.e., Clearfil SAC, RelyX U200, and Multilink Speed) were selected. According to their bonding modes, they were divided into three groups: direct bonding group (direct coating with resin cement), adhesive group (applying universal adhesives and then coating with resin cement), and primer group (applying Z-Prime Plus and then coating with resin cement). According to experimental conditions, each group was divided into two subgroups: subgroup a (water storage at 37 ℃ for 24 h) and subgroup b (thermalcycling for 5 000 times). SBS data were analyzed by one-way ANOVA by using SPSS 19.0 software (P<0.05). The fractured zirconia surface was observed under a stereomicroscope. RESULTS: After water storage for 24 h, the SBS of the adhesive group and the primer group of the three resin cements was higher than that of the direct adhesive group (P<0.05), but the difference in SBS between the adhesive group and the primer group was not significant (P>0.05). After thermalcycling, the SBS of the three types of resin cements decreased (P<0.05); the SBS of the adhesive group was higher than that of the direct adhesive group and the primer group (P<0.05). Fracture mode analysis revealed that the type Ⅲ fracture mode evidently increased after the thermalcycling treatment compared with the water storage treatment. CONCLUSIONS: The universal adhesives and the primer can improve the SBS of self-adhesive dual-cure resin cement in water storage at 37 ℃ for 24 h. The universal adhesives had a better bonding durability than the zirconia primer.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Cimentos Dentários , Análise do Estresse Dentário , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Zircônio
18.
Acta Odontol Latinoam ; 33(2): 59-68, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920607

RESUMO

The aim of this in vitro study was to evaluate the effect of bleaching protocols on the surface roughness (Ra), color change and surface micromorphology of a low-viscosity bulk-fill composite (Filtek Bulk Fill Flow, 3M ESPE), a highviscosity bulk-fill composite (Filtek Bulk Fill, 3M ESPE) and a conventional nanoparticulate composite resin (control) (Filtek Z350 XT, 3M ESPE). Forty samples of each composite (disks 5 mm in diameter and 2 mm thick) were randomly divided into four groups (n=10), according to bleaching protocol: a) 10% carbamide peroxide gel (Opalescence, Ultradent Products) (2 h/ day, for 14 days); b) 40% hydrogen peroxide gel (Opalescence Boost, Ultradent Products) (three bleaching sessions, once a week, 45 min/session); c) whitening rinse (Listerine Whitening Extreme, Johnson & Johnson) (2 min/day, for 14 days); and d) distilled water (control). The samples were submitted to triplicate readings (Ra and color [CIELAB parameters]) before and after contact with bleaching protocols. Micromorphology was analyzed in a scanning electron microscope (SEM). Ra and color parameters (ΔL, Δa, Δb and ΔE) were analyzed by generalized linear models (α=0.05). The Ra of the high-viscosity bulk-fill was significantly higher than that of the other composites (p<0.05). Ra increased significantly (p<0.05) and surface became more irregular (SEM analysis) in all the composite resins, regardless of the bleaching protocol (p<0.05). The high-viscosity bulk-fill composite resin group had significantly lower ΔE (p<0.05) than the nanoparticulate composite resin group immersed in distilled water. It was concluded that the characteristics of each resin significantly influenced the Ra more than the bleaching protocol. The high-viscosity bulk-fill resin presented minor color change.


Assuntos
Resinas Compostas/química , Peróxido de Hidrogênio/química , Clareadores Dentários/química , Clareamento Dental/métodos , Descoloração de Dente/tratamento farmacológico , Viscosidade/efeitos dos fármacos , Cor , Humanos , Teste de Materiais
19.
Acta Odontol Latinoam ; 33(2): 98, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920611

RESUMO

The aim of the current study was to compare the effect of two lithium disilicate ceramic processing techniques (pressing and CAD/CAM) on the degree of conversion of resin cement when it is photoactivated and the microshear bond strength of resin cement to ceramics. Two ceramic discs were manufactured: one by the Press technique and another by CAD/CAM technique. Five Variolink Veneer resin cement samples were photoactivated through each ceramic disc and subjected to attenuated total reflectance Fourier transform infrared spectroscopy to evaluate their degree of conversion. To evaluate microshear bond strength, 20 ceramic bars were prepared: 10 using the Press technique and 10 using the CAD/CAM technique. The bars were air abraded with 50-µm Al2O3 particles, treated with 10% hydrofluoric acid for 20 s and subjected to RelyX Ceramic Primer application. Adper Scotchbond Multi-Purpose Adhesive was applied to the bars and cured for 10 s. Two 1-mm-height plastic tubes were placed on each bar and filled with Variolink Veneer resin cement. Each cylinder was cured for 20 s. Then the plastic tubes were removed and the microshear bond strength of each cylinder was tested. Data for degree of conversion (%) and microshear bond strength (MPa) were subjected to Student's t-test (α = 0.05). Both degree of conversion of resin cement photoactivated through ceramic and microshear bond strength of resin cement to ceramic were statistically higher in the group in which ceramic was prepared by CAD/CAM technique (44.74% and 22.18 MPa) than in the group in which the ceramic was prepared by the Press technique (25.71% and 19.83 MPa). The lithium disilicate ceramic processing techniques affected the degree of conversion of resin cement when it is photoactivated through the ceramics and the microshear bond strength of resin cement to ceramics.


Assuntos
Cerâmica/química , Colagem Dentária , Porcelana Dentária/química , Cimentos de Resina/química , Humanos , Teste de Materiais , Propriedades de Superfície
20.
Acta Odontol Latinoam ; 33(2): 135-142, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920616

RESUMO

This study evaluated the influence of the mode and time of solvent evaporation on the tensile strength (TS), flexural strength (FS) and elastic modulus (EM) of two adhesive systems: Scotchbond Multipurpose (SBMP) and Clearfil SE (CSEB). For this purpose, rectangular samples (2x1x7 mm) were prepared with 10 µL of primer and the solvents were evaporated with air spray at (23±1) ºC, (40±1) ºC and negative control (without spray). For each temperature, the times of 5, 20, 30, and 60 seconds were investigated. The statistical results showed that evaporation at 40±1ºC resulted in better EM for the two adhesives tested and all the evaporation times evaluated. However, there were no significant differences between the times and modes of evaporation for TS. The results of this study indicate that evaporation at a temperature of (40±1) °C could improve the elastic modulus of both adhesives tested, regardless of the evaporating time.


Assuntos
Adesivos/química , Cimentos Dentários/química , Adesivos Dentinários/química , Solventes/farmacologia , Resistência à Tração , Dessecação , Humanos , Teste de Materiais , Volatilização
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