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1.
Braz. j. oral sci ; 20: e211670, jan.-dez. 2021. ilus
Article in English | LILACS, BBO | ID: biblio-1254259

ABSTRACT

Aim: To evaluate the effect of different surface treatments and adhesive approaches on the microshear bond strength of resin cement to a polymer-infiltrated ceramic network (PICN). Methods: PICN blocks were randomly assigned into 9 groups (n=10): CTRL: no treatment; HF: 5% hydrofluoric acid etching; HF-S: HF + silane; HF-S-A: HF-S + adhesive (Adper Single Bond 2); HF-UA: HF + universal adhesive (Single Bond Universal); SB: sandblasting with 50 µm Al2O3 particles; SB-S: SB + silane; SB-S-A: SB-S + adhesive; SB-UA: SB + universal adhesive. Resin cement microcylinders (Ø = 0.96 mm; height = 1 mm) (RelyX Ultimate) were built upon the PICN surface after roughness and contact angle measurements. Next, microshear bonding tests (µSBS) were performed (0.5 mm/min) after water storage (37ºC, 90 days) and thermocycling (12,000 cycles; 5ºC-55ºC). Failure modes were observed under stereomicroscope. Bond strength data were analyzed by two-way ANOVA/Tukey's test and t-tests. Kruskal-Wallis/Dunn's tests were conducted for roughness and contact angle data (α = 0.05). Results: A rougher surface and lower contact angles were observed for Sandblasting. HF-S (18.54 ± 2.03 MPa), SB-S (19.00 ± 1.66 MPa) and SB-UA (18.07 ± 2.36 MPa) provided the highest bond strength values, followed by the other treated groups. The CTRL group resulted in lower bond strength (7.18 ± 2.34 MPa). Conclusion: Hydrofluoric acid etching followed by silane application and sandblasting followed by silane or universal adhesive are useful clinical steps to enhance bonding to PICN. Adhesive applications after HF etching have no advantages in bonding to PICN


Subject(s)
Surface Properties , Ceramics , Dentin-Bonding Agents , Resin Cements , Air Abrasion, Dental , Hydrofluoric Acid
2.
Braz. dent. sci ; 24(3): 1-8, 2021. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1281041

ABSTRACT

Objectives: this in vitro study was done to evaluate the effect of packable P60 composite and Tetric N-Ceram composite veneer material on fracture strength of zirconia cores. Material and Methods:Twenty four zirconium cores (Vita, Germany) with 0.7 mm thickness were fabricated by CAD/CAM technology and then subjected to air abrasion with 50 µm of Al2O3. Cores were randomly divided into three groups according to veneering material (group A: control group sandblasted with 50 µm Al2O3 veneered by IPS E-max Ceram porcelain, group C: sandblasted with 50 µm Al2O3, etching with hydrofluoric acid and veneered with P60 composite, group E: sandblasted with 50 µm Al2O3, etching with hydrofluoric acid and veneered with Tetric N-Ceram composite). All crowns were subjected to fracture strength test in the testing machine, with load application by steel ball indenter and 0.5 mm/min. cross head speed. Results: statistical analysis was carried out utilizing one-way ANOVA, LSD. The results of fracture strength value test showed the highest mean value was registered for group (A), and the lowest mean for group (E). One-way ANOVA test represented that, there was a statistically high significant different among all groups. LSD results showed a high significant difference increase in fracture resistance for Group A at p value (*p < 0.001 High significant). Conclusions: Within the limitation of this study, sandblasting zirconia core with 50 µm Al2O3 and veneering with conventional ceramic produced restoration with acceptable fracture resistance value (AU)


Objetivo: o objetivo desse estudo in vitro foi avaliar o efeito dos compósitos P60 compactáveis e material laminado de compósitos Tetric-N Ceram na resistência à fratura de núcleos de zircônia. Material e métodos:Vinte e quatro núcleos de zircônia (Vita, Germany) com 0.7 mm de espessura fabricados por tecnologia de CAD/CAM e sinterizados em alta temperatura (1450ºC por 60 min) de acordo com as instruções do fabricante. Núcleos totalmente de zircônias foram submetidos a abração com 50 µm de Al2O3. Os núcleos de zircônia foram divididos de forma randomiza em três grupos de acordo com o material de revestimento (grupo A: grupo controle jateado com 50 µm Al2O3 folheado com porcelana IPS E-max Ceram, grupo C: jateado com 50 µm Al2O3 , coberto com concentração 9,5% de ácido fluorídrico e folheado com resina composta compatível, grupo E: jateado com 50 µm Al2O3 coberto com concentração 9,5% de ácido fluorídrico e folheado com porcelana IPS E-max Ceram. Todos os espécimes (coroas) foram submetidos a teste de resistência a fratura com máquina de teste universal, essa máquina utilizou para aplicação de carga bola de aço com 6mm de diâmetro 0,5 mm/min de velocidade da cruzeta. Resultados: análise estatística foi realizada utilizando One-way ANOVA, LSD. O resultado da resistência a fratura mostra que o maior valor médio foi registrado no grupo A e a menor média para o grupo E. O resultado do teste One-Way ANOVA representaram que houve uma diferença estatisticamente alta e significante entre todos os grupos. LSD foi executada para mostrar a fonte de significância. Os resultados do LSD mostraram um aumento da diferença significativa alta na resistência à fratura para o grupo A no valor de p (p < 0.001 signicancia alta). Conclusão: Dentro das limitações desse estudo o uso convencional de jateamento com 50 µm Al2O3 e estratificação com cerâmica convencional produziu restauração com valor aceitável de resistência a fratura (AU)


Subject(s)
Composite Resins , Aluminum Oxide , Flexural Strength , Hydrofluoric Acid
3.
Braz. oral res. (Online) ; 34: e018, 2020. tab, graf
Article in English | LILACS | ID: biblio-1089390

ABSTRACT

Abstract The objective of this study was to evaluate the influence of hydrofluoric acid (HF) concentration, etching time, and application of phosphoric acid (PA) followed by neutralization with sodium bicarbonate on the bond strength between a feldspar ceramic and resin cement. Thus, 80 blocks (10 x 12 x 2 mm) of glass ceramic (VM - Vita Mark II - Vita Zahnfabrik) were made and randomly assigned to eight groups (n = 10) according to the factors: HF concentration (5 and 10%), etching time (60 and 120 s), and use of phosphoric acid (PA) (with and without). According to the experimental group, 37% PA (Condac, FGM) was applied after HF etching for 60s. Afterwards, samples were immersed in sodium bicarbonate for 1 min then in an ultrasonic bath in distilled water (5 min) for cleaning. After surface bonding treatment, cylinders (Ø = 2 mm; h = 2 mm) of dual resin cement (AllCem / FGM) were made in the center of each block. The samples were then stored in water (37ºC) for 90 days and submitted to the shear bond test (50 KgF, 1 mm/min). Failure analysis was performed by stereomicroscope and scanning electron microscopy. Data (MPa) were analyzed with 3-way ANOVA and Tukey's test. Only the factor "HF concentration" was significant (p = 0.02). Most failures were of cohesive in ceramic (40%) and mixed types (42.5%). The 10% HF resulted in higher shear bond strength value than the 5% HF. Surface cleaning with phosphoric acid followed by sodium bicarbonate and HF time (60 or 120 seconds) did not influence the resin bond strength to feldspar ceramic.


Subject(s)
Phosphoric Acids/chemistry , Dental Bonding/methods , Potassium Compounds/chemistry , Aluminum Silicates/chemistry , Hydrofluoric Acid/chemistry , Reference Values , Silanes/chemistry , Surface Properties , Time Factors , Materials Testing , Microscopy, Electron, Scanning , Reproducibility of Results , Analysis of Variance , Resin Cements/chemistry , Shear Strength/drug effects , Dental Porcelain/chemistry , Methacrylates/chemistry
4.
Article in English | WPRIM | ID: wpr-811433

ABSTRACT

PURPOSE: The aim of this study was to evaluate the microshear bond strength (µSBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols.MATERIALS AND METHODS: Four different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, μSBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests.RESULTS: The findings revealed that silane application yielded higher µSBS values (P<.05). All surface treatments were showed a significant increase in µSBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05).CONCLUSION: Surface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases.


Subject(s)
Adhesives , Aluminum Oxide , Ceramics , Clinical Protocols , Dental Bonding , Dental Restoration Repair , Hydrofluoric Acid , Microscopy, Electron, Scanning , Polymers , Shear Strength , Silicon Dioxide
5.
Article in English | WPRIM | ID: wpr-811426

ABSTRACT

OBJECTIVES: This study investigated the effects of a hydrofluoric acid (HA; solution of hydrogen fluoride [HF] in water)-based smart etching (SE) solution at an elevated temperature on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics in terms of bond strength and morphological changes.MATERIALS AND METHODS: Eighty sintered Y-TZP specimens were prepared for shear bond strength (SBS) testing. The bonding surface of the Y-TZP specimens was treated with 37% phosphoric acid etching at 20°C–25°C, 4% HA etching at 20°C–25°C, or HA-based SE at 70°C–80°C. In all groups, zirconia primers were applied to the bonding surface of Y-TZP. For each group, 2 types of resin cement (with or without methacryloyloxydecyl dihydrogen phosphate [MDP]) were used. SBS testing was performed. Topographic changes of the etched Y-TZP surface were analyzed using scanning electron microscopy and atomic force microscopy. The results were analyzed and compared using 2-way analysis of variance.RESULTS: Regardless of the type of resin cement, the highest bond strength was measured in the SE group, with significant differences compared to the other groups (p < 0.05). In all groups, MDP-containing resin cement yielded significantly higher bond strength values than MDP-free resin cement (p < 0.05). It was also shown that the Y-TZP surface was etched by the SE solution, causing a large change in the surface topography.CONCLUSIONS: Bond strength significantly improved when a heated HA-based SE solution was applied to the Y-TZP surface, and the etched Y-TZP surface was more irregular and had higher surface roughness.


Subject(s)
Ceramics , Hot Temperature , Hydrofluoric Acid , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Resin Cements
6.
Braz. dent. j ; 30(6): 587-591, Nov.-Dec. 2019. tab, graf
Article in English | LILACS | ID: biblio-1055447

ABSTRACT

Abstract This study to evaluate the effects of different hydrofluoric acid (HF) concentrations and thermal cycling on the shear bond strength (SBS) of brackets to ceramic. Cylinders of ceramic were divided into 10 groups (n=15), according to HF concentrations: 1-1%;2-2.5%;3-5%;4-7.5%;5-10% (storage 24 h); 6-1%;7-2.5%;8-5%;9-7.5%; and, 10-10% (thermal cycling). All cylinders were etched for 60s and received one layer of silane. Metallic brackets were bonded to the cylinders using Transbond-XT, light activated for 40 s, using a LED (Radii Plus) and stored in deionized water at 37o C for 24h. The groups 6 to 10 were submitted to thermal cycling (7,000 cycles - 5o/55oC). SBS was performed in an Instron at crosshead speed of 1.0 mm/min. Data were submitted to two-way ANOVA and Tukey's post-hoc test (α=0.05). The Adhesive Remaining Index (ARI) was evaluated at 40x magnification. The different HF acid concentrations influenced on the SBS of the brackets to ceramic (p<0.05). The thermal cycling decreased the SBS of the brackets to ceramic for all acid concentrations (p<0.05). The ARI showed a predominance of scores 0 for all groups, with an increase in scores 1, 2 and 3 for the group storage for 24 h. In conclusion, the different HF acid concentrations 5.0%, 7.5% and 10% influenced on the SBS of brackets to ceramic. The thermal cycling decreased significantly the SBS of brackets to ceramic.


Resumo Este estudo avaliou os efeitos de diferentes concentrações de ácido hidrofluorídrico (HF) e ciclagem térmica na resistência de união ao cisalhamento (RUC) de bráquetes metálicos a cerâmica. Cilindros da cerâmica feldspática foram divididos em 10 grupos (n=15). De acordo com as concentrações do ácido HF: 1-1%;2-2,5%;3-5%;4-7,5%; e, 5-10% (armazenagem por 24 h); 6-1%;7-2,5%;8-5%;9-7,5%; e, 10-10% (ciclagem térmica). Todos os cilíndros foram condicionados por 60s e receberam uma camada de silano. Bráquetes metálicos foram colados aos cilíndros usando o transbond-XT, fotoativado por 40 s, usando o LED (Radii Plus; SDI) e armazenados em água deionizada a 37o C por 24 h. Os Grupos 6 a 10 foram submetidos à ciclagem térmica (7.000 ciclos - 5o/55oC). RUC foram realizadas na Instron a velocidade de 1.0 mm/min. Os dados foram submetidos à análise de variância dois-fatores e ao teste de Tukey's post-hoc (α=0,05). O Índice de Remanescente do Adesivo (IRA) foi avaliado com 40x de aumento. As diferente concentrações do ácido HF influenciou na RUC dos bráquetes na cerâmica (p<0,05). A ciclagem térmica diminuiu a RUC dos bráquetes na cerâmica para todas as concentrações do ácido (p<0,05). O IRA mostrou predominância de escores 0 para todos os grupos, com aumento de escores 1, 2 e 3 para os grupos armazenados por 24 h. Concluíndo, as concentrações do ácido HF 5,0%, 7,5% e 10% influenciaram na RUC de braquetes à cerâmica. A ciclagem térmica diminuiu significativamente a RUC do bráquetes à cerâmica.


Subject(s)
Dental Bonding , Orthodontic Brackets , Silanes , Ceramics , Resin Cements , Shear Strength , Dental Stress Analysis , Hydrofluoric Acid
7.
Braz. dent. j ; 30(2): 171-178, Mar.-Apr. 2019. tab, graf
Article in English | LILACS | ID: biblio-1001436

ABSTRACT

Abstract To evaluate the effect of combining 5% hydrofluoric acid (HF) and silane (SI) with the self-etching ceramic primer on the immediate and after 1-year of water storage on bonding efficacy, conditioning pattern (CP) and chemical interaction (CI) to the lithium disilicate. A total of 16 CAD/CAM blocks of lithium disilicate (LD) were cut into four square sections (n=64). For bonding efficacy evaluation, the LD specimens were divided into 4 groups (n=10): 1) HF+SI; 2) self-etching ceramic primer (MEP); 3) HF+MEP; 4) MEP+SI. After each treatment, an adhesive system was applied and Tygon matrices were filled with a dual-cured resin cement followed by light curing. Cylinder specimens (0.8 mmx0.5mm) were stored in water (37 °C for 24 h or 1-year) and submitted to the μSBS test (2-way ANOVA and Tukey's test; a=0.05). CP and CI were only evaluated qualitatively. No significant difference on the μSBS was observed between groups (p=0.73), but reduced μSBS was observed after 1-year of water storage (p>0.0001). After application of HF+SI and MEP, reduction in a number of siloxane bonds was observed, suggesting the coupling of SI on the LD surface. HF or HF+MEP produced a higher dissolution of the glassy matrix than the use of MEP alone. The MEP can be an alternative to traditional ceramic treatment once the chemical interaction and long-term bond strength were similar between both groups. The association of hydrofluoric acid or silane with a self-etching ceramic primer did not add any benefits in terms of chemical interaction and bonding stability.


Resumo Avaliar o efeito da combinação de ácido fluorídrico ou silano com o primer autocondicionante de cerâmicas sobre a eficácia da união imediata e após 1 ano de armazenamento em água, padrão de condicionamento e interação química desses tratamentos com o dissilicato de lítio. Um total de 16 blocos CAD/CAM de dissilicato de lítio (DL) foram cortados em quatro seções quadradas (n=64). Os espécimes de DL foram divididos em 4 grupos: 1) ácido fluorídrico a 5% + silano (HF + SI); 2) primer autocondicionante de cerâmica (MEP); 3) HF + MEP; 4) MPE + SI. Após cada tratamento, o sistema adesivo foi aplicado e as matrizes Tygon foram preenchidas com cimento resinoso dual (Variolink® II), seguido de fotopolimerização. Espécimes em forma de cilindro (0.8 mmÆ x 0.5 mm), foram armazenados em água (37 °C por 24h ou 1 ano) e submetidos ao teste μSBS (ANOVA dois fatores e teste de Tukey; a=0,05). Para avaliação das interações químicas por Espectroscopia Raman, os espécimes de DL foram divididos em 3 grupos (n=4): 1) sem tratamento (DL); 2) HF + SI; e 3) MEP. Para avaliação do padrão de condicionamento da superfície cerâmica após os tratamentos por MEV, os espécimes de DL foram divididos em 3 grupos (n=3): 1) DL; 2) HF; 3) MEP; e 4) HF + MEP. Ambos os métodos foram avaliados apenas qualitativamente. Não foi observada diferença significativa na μSBS imediata entre os grupos (p=0,73), mas após 1 ano de armazenamento das amostras em água, reduziu μSBS (p>0,0001). HF ou HF + MEP produziram uma maior dissolução da matriz vítrea do que o uso de MEP sozinho. Após a aplicação de SI e MEP, observou-se redução de ligações de siloxano, sugerindo o acoplamento da camada de silano na superfície do DL. O primer autocondicionante cerâmico pode ser uma alternativa ao tratamento cerâmico tradicional, uma vez que a interação química e a resistência de união a longo prazo, quando comparada ao tratamento tradicional foram estatisticamente semelhantes. A associação de ácido fluorídrico ou agente de acoplamento silano com um primer autocondicionante de cerâmicas não agregou nenhum benefício em termos de interação química e estabilidade.


Subject(s)
Dental Bonding , Hydrofluoric Acid , Silanes , Surface Properties , Materials Testing , Ceramics , Resin Cements , Dental Porcelain , Dental Stress Analysis
8.
Braz. dent. sci ; 22(3): 305-312, 2019. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1008364

ABSTRACT

Objective: The aim of the study was to evaluate the influence of different surface post-etching treatments in flexural strength, contact angle and surface roughness of a lithium disilicate ceramic. Material and Methods: 60 bars (16 x 2 x 4 mm) were divided in six groups (n=10): C, no treatment; HF, hydrofluoric acid for 20 s (HF) + washing (60 s), drying (30s); HFL, HF + washing (60 s), drying (30 s) and luting; HFNL, HF + washing (60 s) + neutralization with sodium bicarbonate (SB) for 40 s + washing (5s), drying (30 s) and luting; HFUL, HF + washing (60 s) + ultrasonic bath (UB) for 4 min, drying (30 s) and luting; HFNUL, HF + washing (60 s) + SB (40 s) + UB (4 min) and luting. The bars were submitted to three-points flexural strength test. 25 ceramic blocks (12 x 7 x 7 mm) were divided into five groups (n=5) to evaluate roughness and contact angle C - no treatment; HF - HF ; HFU - HF and UB for 5 min ; HFN - HF and SB; HFNU - HF, UB and SB. A scanning electron microscope (SEM) showed the surface of the samples. ANOVA one-way statistical analysis was done for comparison of results. Results: There was no statistical difference for flexural strength (p-value = 0.15) and for surface roughness (p-valor = 0.15). However, it was obtained statistically significant difference for contact angle (p-valor = 0.00). SEM images showed precipitates after the acid etching, which were removed by post-etching treatments. Conclusion: It can be concluded that the different post-etching surface treatments did not increase the flexural strength, surface roughness, but it influenced the ceramic wetting and SEM images (AU)


Objetivo: O objetivo do estudo foi avaliar a influência de diferentes tratamentos pós-condicionamento na resistência à flexão, ângulo de contato e rugosidade superficial de uma cerâmica de dissilicato de lítio. Material e Métodos: 60 barras (16 x 2 x 4 mm) foram divididas em seis grupos (n = 10): C, sem tratamento; HF, ácido fluorídrico durante 20 s (HF) + lavagem (60 s), secagem (30 s); HFL, lavagem com HF + (60 s), secagem (30 s) e cimentação; HFNL, HF + lavagem (60 s) + neutralização com bicarbonato de sódio (SB) por 40 s + lavagem (5s), secagem (30 s) e cimentação; HFUL, HF + lavagem (60 s) + banho ultrassônico (UB) por 4 min, secagem (30 s) e cimentação; HFNUL, HF + lavagem (60 s) + SB (40 s) + UB (4 min) e cimentação. As barras foram submetidas ao teste de resistência à flexão de três pontos. 25 blocos cerâmicos (12 x 7 x 7 mm) foram divididos em cinco grupos (n = 5) para avaliação da rugosidade superficial e ângulo de contato C - sem tratamento; HF - HF; HFU - HF e UB por 5 min; HFN - HF e SB; HFNU - HF, UB e SB. Um microscópio eletrônico de varredura (MEV) foi utilizado para análise da superfície das amostras. A análise estatística unidirecional ANOVA-um fator foi realizada para comparação dos resultados. Resultados: Não houve diferença estatística para a resistência à flexão (p-valor = 0,15) e para a rugosidade superficial (p-valor = 0,15). No entanto, obteve-se diferença estatisticamente significante para o ângulo de contato (p-valor = 0,00). Imagens de microscopia eletrônica de varredura mostraram a formação de precipitados após o ataque ácido, que foram removidos pelos tratamentos pós-condicionamento. Conclusão: Pode-se concluir que os diferentes tratamentos de superfície pós-condicionamento não aumentaram a resistência à flexão, rugosidade da superfície, mas influenciaram na molhabilidade da cerâmica e nas imagens em MEV.(AU)


Subject(s)
Electron Microscope Tomography , Hydrofluoric Acid
9.
Braz. oral res. (Online) ; 33: e041, 2019. tab, graf
Article in English | LILACS | ID: biblio-1001595

ABSTRACT

Abstract: The objective of this study was to evaluate the effect of the hydrofluoridric acid (HF) concentration and time of acid conditioning on bond strength of three glass ceramics to a resin cement. Thus, fifty blocks (10 mm x 5 mm x 2 mm) of each ceramic (LDCAD: IPS e.max CAD; LCAD: IPS Empress CAD and LDHP: IPS e.max Press) were made and embedded in acrylic resin. The surfaces were polished with sandpaper (#600, 800, 1000, and 1200 grits) and blocks were randomly divided into 15 groups (n = 10) according to the following factors: Concentration of HF (10% and 5%), conditioning time (20 s and 60 s) and ceramic (LDCAD, LDHP, and L). After conditioning, silane (Prosil / FGM) was applied and after 2 min, cylinders (Ø = 2 mm; h = 2 mm) of dual resin cement (AllCem / FGM) were made in the center of each block using a Teflon strip as matrix and light cured for 40 s (1,200 mW/cm2). Then, the samples were thermocycled (10,000 cycles, 5/55°C, 30s) and submitted to the shear bond test (50 KgF, 0.5 mm/min). The data (MPa) were analyzed with 3-way ANOVA and Tukey's test (5%). Failure analysis was performed using a stereomicroscope (20x) and a scanning electron microscope (SEM). ANOVA revealed that the "concentration" factor (p = 0.01) and the interaction "acid concentration X ceramic" (p = 0.009) had a significant effect, however, the "ceramic" (p = 0.897) and "conditioning time" (p = 0.260) factors did not influence the results. The LDHP10%60s (10.98 MPa)aA* group presented significantly higher bond strength than LDHP10%20s (6.57 MPa)bA, LCAD5%20s (6,90 ±3,5)aB and LDHP5%60s (5.66 ± 2,9MPa)aA* groups (Tukey). Failure analysis revealed that 100% of specimens had mixed failure. In conclusion, etching with 5% HF for 20 seconds is recommended for lithium disilicate and leucite-reinforced CAD/CAM ceramics. However, for pressed lithium disilicate ceramic, 10% HF for 60 s showed significantly higher bond strength to resin cement.


Subject(s)
Ceramics/chemistry , Dental Bonding/methods , Hydrofluoric Acid/administration & dosage , Surface Properties , Time Factors , Acid Etching, Dental , Materials Testing , Microscopy, Electron, Scanning , Resin Cements/chemistry , Shear Strength , Dental Porcelain/chemistry , Dental Stress Analysis , Hydrofluoric Acid/chemistry
10.
Braz. dent. sci ; 22(4): 488-496, 2019. ilus, tab
Article in English | LILACS, BBO | ID: biblio-1024449

ABSTRACT

Objective: To assess the influence of 5% hydrofluoric acid etching time (ET), cementation protocol (CP), and thermal cycling (TC) aging on the microshear bond strength (µSBS) of zirconia reinforced lithium silicate ceramic (ZLS) to adhesive resin cement. Material and Methods: Ten VITA Suprinity® ceramic blocks were cut in 120 slices (1.4 mm thickness) and randomly assigned to 12 groups (n = 10) according to the combination of factors (2x3x2 design): etching time (20 or 30 s), cementation protocol (silane + universal adhesive + resin cement; universal adhesive + resin cement; silane + resin cement) and thermal cycling (cycled or no-cycled). RelyX Ceramic Primer and Scotchbond™ Universal Adhesive were used respectively as silane (S) and universal adhesive (Ua). Ceramic surface was etched, and the cementation protocol performed on the delimited bonding area. Then, resin cement (RelyX™ Ultimate Cement [Rc]) cylinders were bonded and light cured. After, specimens were stored in deionized water at 37°C for 7 days and subjected to the µSBS test. Results: Data passed the normality test and three-way ANOVA analysis showed statistical difference (p < 0.01) for isolated; double (ET/TC) (p < 0.05), and triple (p < 0.05) factor interactions. Conclusion: The combination 30s etching-Ua-Rc presented higher adhesive bond strength after thermal aging. (AU)


Objetivo: Avaliar a influência do tempo de condicionamento com ácido fluorídrico 5% (ET), protocolo de cimentação (CP), e envelhecimento por termociclagem (TC) na resistência de união ao microcisalhamento (µSBS) da cerâmica de silicato de lítio reforçada com zircônia (ZLS) ao cimento resinoso adesivo. Material e Método: Dez blocos da cerâmica VITA Suprinity® foram cortados e 120 fatias (com espessura de 1,4 mm) e distribuídos aleatoriamente em 12 grupos (n=10) de acordo com o fator de combinação (2x3x2): tempo de condicionamento (20 ou 30 s), protocolo de cimentação (silano + adesivo universal + cimento resinoso; adesivo universal + cimento resinoso; silano + cimento resinoso) e ciclagem térmica (ciclado ou não ciclado). RelyX Ceramic Primer e adesivo Scotchbond™ Universal foram utilizados respectivamente como silano (S) e adesivo universal (Ua). A superfície cerâmica foi condicionada e o protocolo de cimentação aplicado sobre área de cimentação delimitada. Portanto, cilindros de cimento resinoso (cimento RelyX™ Ultimate [Rc]) foram cimentados e fotopolimerizados. Após, os espécimes foram armazenados em água deionizada a 37°C por 7 dias e submetidos ao teste de µSBS. Resultados: Após teste de normalidade, os dados foram analisados pelo teste ANOVA três critérios mostrando diferença estatística (p < 0.01) para a análise do fator isolado; para a interação entre dois fatores (ET/TC) (p < 0.05), e interação entre os três fatores (p < 0.05). Conclusão: A combinação 30s de condicionamento-Ua-Rc apresentou a maior resistência de união adesiva após a ciclagem térmica.(AU)


Subject(s)
Dentin-Bonding Agents , Dental Cements , Hydrofluoric Acid
11.
Rev. odontol. UNESP (Online) ; 47(6): 348-353, nov.-dez. 2018. tab, ilus
Article in English | LILACS, BBO | ID: biblio-985735

ABSTRACT

Introduction: Despite being one of the most studied ceramics today, zirconia still does not have a well-defined adhesion protocol. Objective: Evaluate the influence of different etching times and hydrofluoric acid (HF) concentrations on the zirconia surface and bond strength between a vitrified Y-TZP ceramic and a resin cement. Materials and method: The zirconia surface treatments were: sandblasting with silica-coated alumina (Co); glaze application + 5% HF etching for 5s (G5-5s), 10s (G5-10s) or 20s (G5-20s); glaze application + 10% HF etching for 5s (G10-5s), 10 (G10-10s) or 20s (G10-20s) . Then, cement cylinders (3.3 × 3.3 mm) were built up for shear bond test on all specimens. The specimens were subjected to 6000 thermal cycling before the test. Fractures were analyzed by stereomicroscope. Data were statistically analyzed by Kruskal-Wallis and Dunn statistical tests (5%). Extra samples of each group were made to obtain profilometry and scanning electron microscopy (SEM). Result: Zirconia-cement bond strength was affected by the ceramic surface treatments (p = 0.001). G10-5s (2.71 MPa) recorded the highest bond strength values, followed by the Co (2.05 MPa) while G5 groups had the lowest bond value. Adhesive failure of the samples predominated. The image analysis revealed G5 groups seem to have a lower roughness when compared to groups treated by 10% HF. The creation of pores in the low-fusing porcelain glass layer surface occurred only when 10% HF was used. Conclusion: The low-fusing porcelain glass layer application was able to overcome the sandblasting and obtain a greater adhesive bond to the resinous cement, however, only when 10% HF was used for an interval of 5 seconds.


Introdução: Apesar de ser uma das cerâmicas mais estudadas atualmente, a zircônia ainda não possui um protocolo bem definido para uma cimentação adesiva. Objetivo: Avaliar a influência de diferentes tempos de condicionamento e concentrações do ácido fluorídrico (AF) na superfície da zirconia e na resistência de união entre uma cerâmica Y-TZP vitrificada e um cimento resinoso. Material e método: Os tratamentos de superfície foram: jateamento com óxido de alumínio revestido com sílica (Co); aplicação de glaze + condicionamento com AF 5% por 5s (G5-5s), 10s (G5-10s) ou 20s (G5-20s); aplicação de glaze + condicionamento com AF 10% por 5s (G10-5s), 10 (G10-10s) ou 20s (G10-20s). Em seguida, cilindros de cimento (3,3 × 3,3mm) para teste de cisalhamento foram feitos em todos os espécimes. Os espécimes foram submetidos a 6000 ciclos térmicos antes do teste de adesão. As fraturas foram analisadas por estereomicroscópio. Os dados foram analisados ​​estatisticamente por Kruskal-Wallis e Dunn (5%). Amostras extra de cada grupo foram feitas para realização de perfilometria e microscopia eletrônica de varredura (MEV). Resultado: A resistência de união zircônia-cimento foi afetada pelos tratamentos de superfície (p = 0,001). Os grupos G10-5s (2,71 MPa) registraram os maiores valores de resistência de união, seguidos pelos Co (2,05 MPa), enquanto os grupos G5 apresentaram o menor valor de união. Falhas adesivas foram predominantes. As análises por imagem revelaram que os grupos G5 parecem ser menos rugosos quando comparados aos grupos tratados com AF 10%. A criação de poros na superfície vítrea (glaze) ocorreu apenas quando foi utilizado AF 10%. Conclusão: A aplicação de camada de vidro de porcelana de baixa fusão foi capaz de superar o jateamento e obter uma maior adesão adesiva ao cimento resinoso, no entanto, somente quando foi utilizado 10% de HF por um intervalo de 5 segundos.


Subject(s)
Zirconium , Microscopy, Electron, Scanning , Air Abrasion, Dental , Dental Cements , Dental Porcelain , Hydrofluoric Acid , Ceramics , Statistics, Nonparametric
12.
Prensa méd. argent ; 104(9): 428-452, nov 2018. fig
Article in Spanish | LILACS, BINACIS | ID: biblio-1047020

ABSTRACT

Los accidentes con ácido fluorhídrico en Argentina son un motivo de consulta infrecuente, a pesar de ser utilizado en varias actividades laborales. Es uno de los pocos cáusticos con tratamiento específico que se debe tener en cuenta. Reportamos el caso de un paciente de 35 años que estuvo en contacto con esta sustancia con posterior compromiso de miembro superior, presentando placa eritematosa en región palmar derecha y lesión ampollar con descamación posterior y sangrado en lecho ungueal. Recibió tratamiento local con gluconato de calcio al 20% en toda la extensión de la zona afectada durante 48 hs con recuperación completa a los quince días. La sospecha clínica temprana y la administración adecuada de gluconato de calcio evitan lesiones de mayor grado y extensión


In Argentina, hydrofluoric acid accidents are a rare reason for consultation, despite being a commonly used substance in laboral activities. It is one of the few caustics with a specific treatment that must be taken into account. We report the case of a 35 year old patient affected by said substance, in which we observe an impairment of the upper limb, presenting on the right palmar region, an erythematous plaque with a blister lesion with posterior scaling and bleeding of the nail bed. The importance of the early clinical suspicion and the proper administration of calcium gluconate would avoid bigger and more extensive lesions


Subject(s)
Humans , Male , Adult , Poisoning/therapy , Occupational Risks , Calcium Gluconate/administration & dosage , Calcium Gluconate/therapeutic use , Early Diagnosis , Hydrofluoric Acid/adverse effects
13.
Braz. dent. j ; 29(5): 492-499, Sept.-Oct. 2018. tab, graf
Article in English | LILACS | ID: biblio-974174

ABSTRACT

Abstract This study evaluated the effect of different hydrofluoric acid (HF) concentrations on the bond strength between a lithium disilicate-based glass ceramic and a resin cement. Eighty ceramic-blocks (12×7×2 mm) of IPS e.Max CAD (Ivoclar Vivadent) were produced and randomly assigned to 8 groups, considering 2 study factors: HF concentration in 4 levels, i.e., 1% (HF1), 3% (HF3), 5% (HF5), and 10% (HF10), and storage in 2 levels, i.e., baseline (tests were performed 24 h after cementation), and aged (storage for 150 days + 12,000 thermal-cycles at 5°C and 55°C). Acid etching (20 s) was performed, followed by washing, drying, and silanization. Four resin cement cylinders (ϕ= 0.96 mm) were built-up from starch matrices on each ceramic sample (n= 40). Additional ceramic samples were etched and analyzed for contact angle, micro-morphology, and roughness. In baseline condition (without aging), the HF3, HF5, and HF10 groups showed similar bond strength values (13.9 - 15.9 MPa), and HF1 (11.2 MPa) presented lower values than HF5, being that statistically different (p= 0.012). After aging, all the mean bond strengths statistically decreased, being that HF3, HF5, and HF10 (7.8 - 11 MPa) were similar and higher than HF1 (1.8 MPa) (p= 0.0001). For contact angle, HF3, HF5, and HF10 presented similar values (7.8 - 10.4°), lower than HF1 and CTRL groups. HF5 and HF10 presented rougher surfaces than other conditions. For better bond strength results, the tested ceramic may be etched by HF acid in concentrations of 3%, 5%, and 10%.


Resumo Este estudo avaliou o efeito de diferentes concentrações de ácido fluorídrico (HF) na resistência de união entre uma cerâmica vítrea à base de dissilicato de lítio e um cimento resinoso. Oitenta blocos cerâmicos (12×7×2 mm) de IPS e.Max CAD (Ivoclar Vivadent) foram produzidos e distribuídos aleatoriamente em 8 grupos, considerando 2 fatores de estudo: concentração de HF em 4 níveis, isto é, 1% (HF1), 3% (HF3), 5% (HF5), e 10% (HF10), e armazenamento em 2 níveis, isto é, condição inicial (testes foram realizados 24 h após a cimentação), e envelhecidos (150 dias de armazenamento + 12.000 ciclos térmicos a 5°C e 55°C). Condicionamento ácido (20 s) foi realizado, seguido por lavagem, secagem e silanização. Quatro cilindros de cimento resinoso (ϕ= 0.96 mm) foram construídos a partir de matrizes de amido em cada amostra cerâmica (n= 40). Amostras cerâmicas adicionais foram condicionadas e analisadas quanto ao ângulo de contato, micro-morfologia e rugosidade. Na condição inicial (sem envelhecimento), os grupos HF3, HF5, e HF10 mostraram valores de resistência de união similares (13.9 - 15.9 MPa), e HF1 apresentou valores menores que HF5, sendo estatisticamente diferente (p= 0.012). Após o envelhecimento, todas as médias de resistência de união diminuíram estatisticamente, sendo que HF3, HF5 e HF10 foram similares e maiores que HF1 (p= 0.0001). Para o ângulo de contato, HF3, HF5 e HF10 apresentaram valores similares (7.8 - 10.4°), menores que os grupos HF1 e CTRL. HF5 e HF10 apresentaram superfícies mais rugosas que as outras condições. Para melhores resultados de resistência de união, a cerâmica testada pode ser condicionada com ácido fluorídrico nas concentrações de 3%, 5% e 10%.


Subject(s)
Acid Etching, Dental/methods , Ceramics/chemistry , Dental Bonding/methods , Resin Cements/chemistry , Dental Porcelain/chemistry , Hydrofluoric Acid/chemistry , Stress, Mechanical , Surface Properties , Materials Testing , Microscopy, Atomic Force , Shear Strength
14.
Rev. cuba. estomatol ; 55(1): 59-72, ene.-mar. 2018. ilus, tab
Article in English | LILACS | ID: biblio-960401

ABSTRACT

Introduction: the clinical success of a restoration is strongly associated with the quality and durability of the ceramic-cement resin interface. In order to obtain an adequate union between these materials of different nature surface treatments are used and achieve mechanical retention or chemical interaction. Objectives: to check if any method promotes a true chemical bond between lithium disilicate ceramics and resin cement. As well as determineif there is any treatment that reports bonding values comparable to hydrofluoric acid and silane (gold standard). Methods: a systematic literature review was developed based on the PRISMA strategy, where the databases were searched: Science Direct, Pubmed (MEDLINE), EMBASE, Springer Journal, SciELO with MeSH and free terms from 2005 to November 2016 for articles in English and Spanish on surface treatments for lithium disilicate. Results: from 58 publications selected a sample of 21 articles. Two articles reported high risk of bias. Conclusions: hydrofluoric acid and silane continue to be the method with the highest and most reliable adhesion values in the literature. Universal adhesives are an alternative to promote chemical adhesion additional to the silane. Diamond burs, Nd: YAG and Er: YAG laser are not recommended as surface treatments(AU)


Introducción: el éxito clínico de una restauración se asocia fuertemente a la calidad y duración de la interface cerámica-cemento resinoso. Para que exista una adecuada unión entre estos materiales de distinta naturaleza se emplean tratamientos de superficie para lograr una buena retención mecánica o interacción química. Objetivos: revisar si algún método promueve una verdadera adhesión química entre la cerámica de disilicato de litio y el cemento resinoso, así como determinar si existe algún tratamiento que reporte valores de unión comparables al ácido fluorhídrico y silano (patrón de oro). Métodos: se desarrolló una revisión sistemática de literatura basada en la estrategia PRISMA, donde se buscó en las bases de datos: Science Direct, Pubmed (MEDLINE), EMBASE, Springer Journal, SciELO con términos MeSH y libres desde el 2005 a noviembre de 2016 para artículos en inglés y español sobre tratamientos de superficie para disilicato de litio. Resultados: de 58 publicaciones, se seleccionó una muestra de 21 artículos. Dos artículos reportaron riesgo de sesgo alto. Conclusiones: el ácido fluorhídrico y silano continúan siendo el método con los valores de adhesión más altos y confiables de la literatura. Los adhesivos universales son una alternativa para promover adhesión química adicional al silano. Fresas diamantadas, laser Nd: YAG y Er:YAG no se recomienda como tratamientos de superficie(AU)


Subject(s)
Humans , Review Literature as Topic , Ceramics/adverse effects , Databases, Bibliographic/statistics & numerical data , Self-Curing of Dental Resins/methods , Hydrofluoric Acid/adverse effects
15.
Braz. oral res. (Online) ; 32: e43, 2018. tab, graf
Article in English | LILACS | ID: biblio-889490

ABSTRACT

Abstract To investigate how the hydrofluoric acid (HF) concentrations applied to a lithium disilicate glass-ceramic (EMX) affects the surface morphology and microtensile bond strength (μTBS) of ceramics to dentin, using light-cured resin cements with or without UDMA. Sixty-three EMX square ceramic blocks were etched for 20 seconds using different HF concentrations (1%, 5% and 10%) and luted to dentin using two types of resin cement combinations: BisGMA/TEGDMA and BisGMA/TEGDMA/UDMA (n = 10). Each bonded EMX-dentin block was sectioned to obtain 1 mm2 sticks for μTBS evaluation. Half of the sticks were tested after 24 hours and the other half was assessed after 6 months of water storage. Data were statistically assessed using split-plot three-way ANOVA and multiple comparisons were performed using the Tukey's post hoc test (α = 0.05). One EMX sample from each HF concentration was analyzed using field-emission scanning electron microscope (FE-SEM) to characterize the etching pattern. According to the FE-SEM images, increasing the concentration of HF from 1 to 5 and then to 10% led to increased removal of glassy matrix and greater exposure of lithium disilicate crystals. The 10% HF concentration yielded higher μTBS when compared to 1% for BisGMA/TEGDMA formulation (p < 0.05); whereas HF 1% and 5% showed similar μTBS values when compared to 10% HF for BisGMA/TEGDMA/UDMA resin matrix (p > 0.05) at both storage times. Water aging decreased the μTBS values (p < 0.05), except when 10% HF was associated with BisGMA/TEGDMA resin cement. Resin cement formulation and hydrofluoric acid concentrations can interfere with the immediate and long-term glass-ceramic bond strength to dentin.


Subject(s)
Ceramics/chemistry , Dental Bonding/methods , Resin Cements/chemistry , Dental Porcelain/chemistry , Hydrofluoric Acid/chemistry , Surface Properties , Tensile Strength , Materials Testing , Microscopy, Electron, Scanning , Dental Stress Analysis
16.
Article in English | WPRIM | ID: wpr-786756

ABSTRACT

We reviewed the chemical/physical properties, toxicity, environmental fate, and ecotoxicity of strong acids in soil and groundwater environments. We recommend that sulfuric acid and hydrofluoric acid be classified as chemicals of priority control based on volumes used, toxicity, carcinogenicity, and past significant spill events. Understanding the behavior and transport of spilled strong acids in soil and groundwater environments requires a multi-disciplinary approach, as they can undergo a variety of geochemical and biochemical reactions with complex geomedia. The toxicity of spilled acid is dependent on the characteristics of the geomedia exposed to the acid and the amount of residual protons following acid–substrate interaction. Soil texture, cation exchange capacity, mineral composition, bedrock type, and aluminum content may be important factors affecting the toxicity of spilled acid in soil-groundwater environments. We expect that the results of this study will contribute preliminary data for future research on chemical spills.


Subject(s)
Aluminum , Groundwater , Hydrofluoric Acid , Miners , Protons , Soil , Sulfur
17.
Article in English | WPRIM | ID: wpr-762496

ABSTRACT

BACKGROUND: Resilient individuals have a comprehensive ability to adapt to various life circumstances. Psychological resilience predicts an individual’s physiological response to stress. The 10-item Connor-Davidson Resilience Scale (CD-RISC) is a widely used measure to quantify the level of self-perceived resilience. This study examined the psychometric properties of a Korean version of the 10-item Connor-Davidson Resilience Scale (10-item K-CD-RISC) on workers in Gumi, South Korea, exposed to hydrofluoric acid (HF). METHODS: The questionnaires included the 10-item K-CD-RISC and Beck Anxiety Inventor (BAI), the Impact of Event Scale-Revised-Korean version (IES-R-K), the Rosen-berg Self Esteem Scale (RSES), the Center for Epidemiologic Studies-Depression Scale (CES-D), and the Perceived Stress Scale (PSS). These were randomly distributed at 237 workplaces near the HF-spill site, in the Gumi 4 complex. The responses of 991 (67.3%) workers were analyzed. RESULTS: The exploratory factor analysis shown that a single-factor model was consistent with the original design of the 10-item CD-RISC. The scale also demonstrated good internal consistency (Cronbach’s alpha = 0.95). Scores on the scale reflected different levels of resilience with respect to personal factors (age, gender, marital status, and education and income levels) that are thought to be differentiated. Differences of resilience were also reflected by psychiatric symptoms (anxiety and depression). Moreover, the total score of scale positively correlated with RSES, whereas the IES-R-K, BAI, CES-D, and the PSS negatively correlated with the 10-item K-CD-RISC. CONCLUSIONS: The 10-item K-CD-RISC has good psychometric properties and is applicable for victims exposed to noxious chemical such as HF.


Subject(s)
Anxiety , Education , Humans , Hydrofluoric Acid , Inventors , Korea , Marital Status , Psychometrics , Resilience, Psychological , Self Concept , Stress Disorders, Post-Traumatic
18.
Article in English | WPRIM | ID: wpr-740293

ABSTRACT

The computer-aided design/computer-aided manufacturing (CAD/CAM) system was introduced to shorten the production time of all-ceramic restorations and the number of patient visits. Among these types of ceramic for dental CAD/CAM, they have been processed into inlay, onlay, and crown shapes using leucite-reinforced glass-ceramics to improve strength. The purpose of this study was to observe the mechanical properties and microstructure of leucite-reinforced glass-ceramics for dental CAD/CAM. Two types of leucite-reinforced glass-ceramic blocks (IPS Empress CAD, Rosetta BM) were prepared with diameter of 13 mm and thickness of 1 mm. Biaxial flexural testing was conducted using a piston-on-three-ball method at a crosshead speed of 0.5 mm/min. Weibull statistics were used for the analysis of biaxial flexural strength. Fracture toughness was obtained using an indentation fracture method. Specimens were observed by field emission scanning electron microscopy to examine the microstructure of the leucite crystalline phase after acid etching with 0.5% hydrofluoric acid aqueous solution for 1 minute. The results of strength testing showed that IPS Empress CAD had a mean value of 158.1±8.6 MPa and Rosetta BM of 172.3±8.3 MPa. The fracture toughness results showed that IPS Empress CAD had a mean value of 1.28±0.19 MPa·m(1/2) and Rosetta BM of 1.38±0.12 MPa·m(1/2). The Rosetta BM sample exhibited higher strength and fracture toughness. Moreover, the crystalline phase size and ratio were increased in the Rosetta BM sample. The above results are expected to elucidate the basic mechanical properties and crystal structure characteristics of IPS Empress CAD and Rosetta BM. Additionally, they will help develop leucite-reinforced glass-ceramic materials for CAD/CAM.


Subject(s)
Ceramics , Crowns , Crystallins , Humans , Hydrofluoric Acid , Inlays , Methods , Microscopy, Electron, Scanning
19.
Article in English | WPRIM | ID: wpr-719130

ABSTRACT

We reviewed the chemical/physical properties, toxicity, environmental fate, and ecotoxicity of strong acids in soil and groundwater environments. We recommend that sulfuric acid and hydrofluoric acid be classified as chemicals of priority control based on volumes used, toxicity, carcinogenicity, and past significant spill events. Understanding the behavior and transport of spilled strong acids in soil and groundwater environments requires a multi-disciplinary approach, as they can undergo a variety of geochemical and biochemical reactions with complex geomedia. The toxicity of spilled acid is dependent on the characteristics of the geomedia exposed to the acid and the amount of residual protons following acid–substrate interaction. Soil texture, cation exchange capacity, mineral composition, bedrock type, and aluminum content may be important factors affecting the toxicity of spilled acid in soil-groundwater environments. We expect that the results of this study will contribute preliminary data for future research on chemical spills.


Subject(s)
Aluminum , Groundwater , Hydrofluoric Acid , Miners , Protons , Soil , Sulfur
20.
Article in English | WPRIM | ID: wpr-126537

ABSTRACT

BACKGROUND: On September 27, 2012, at 3:43 pm, a hydrogen fluoride spill occurred in a manufacturing plant located at the 4th complex of the Gumi National Industrial Complex in Gumi City, South Korea. The present study aimed to evaluate the psychological effects of the hydrogen fluoride spill on the members of the community and to investigate their relationships with physical symptoms and changes in psychological effects occurring as time passed after the accident. METHODS: The 1st phase involved a survey of 1359 individuals that was conducted 1 month after the spill, and the 2nd phase involved a survey of 711 individuals that was conducted 7 months after the accident. The questionnaires included items for assessing demographic characteristics, hydrogen fluoride exposure level, physical symptoms, and psychological status. Physical symptoms were assessed to determine the persistence of irritations. Psychological status was assessed to investigate the impact of event level using the Impact of Event Scale – Revised Korean version (IES-R-K), and the anxiety level was assessed using the Beck Anxiety Inventory (BAI). RESULTS: As the hydrogen fluoride exposure level increased, the impact of event and anxiety levels increased significantly both 1 and 7 months after the accident (p < 0.05). The mean score of the impact of event levels decreased significantly from 33.33 ± 14.64 at 1 month after the accident to 28.68 ± 11.80 at 7 months after the accident (p < 0.05). The mean score of the anxiety levels increased significantly from 5.16 ± 6.59 at 1 month after the accident to 6.79 ± 8.41 at 7 months after the accident (p < 0.05). The risk of persistent physical symptoms at 7 months after the accident was significantly higher in females. The risk of persistent physical symptoms also increased significantly, with increasing age, hydrogen fluoride exposure, and impact of event levels (p < 0.05). CONCLUSIONS: The present study found that the impact of event level and anxiety level increased with increasing hydrogen fluoride exposure. Anxiety levels persisted even after time passed. The risk of persistent physical symptoms at 7 months after the accident was higher in females, and it increased with increasing age, hydrogen fluoride exposure level, and impact of event levels.


Subject(s)
Anxiety , Disasters , Female , Humans , Hydrofluoric Acid , Hydrogen , Korea , Plants
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