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1.
Braz Dent J ; 31(6): 657-663, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33237238

RESUMEN

The aim of this study was to evaluate the effect of cleaning solutions on the retention force of o-ring-type overdenture attachments. The effect of four solutions on nitrile rings were evaluated: Cepacol (C), Cepacol with fluoride (CF), Listerine (L) and 0.05% sodium hypochlorite (SH); deionized water (DW) was used as a control. Matrices containing two implants and abutments and acrylic specimens with the metal capsules were obtained and divided into the groups. A simulation of 90 overnight immersions (8 h) was performed, and the tensile strength value was obtained at the beginning (T0) and in every 30 days (T1, T2 and T3) (n=6). In order to analyze o-ring surface damage after the immersions, a scanning electron microscopy (SEM) was used (n=1). For statistical analysis of the results, analysis of variance (ANOVA) and multiple comparisons with Bonferroni adjustment (test power=1.000; a=0.05) were used. There was a significant difference for the factors time (p<0.001), solution (p<0.001) and for the interaction time × solution (p<0.001). Considering the times of each solution, only for DW there was no significant loss of retention over time. Comparing the solutions in each moment, there was no difference among the solutions in T0. From T1, CF and SH provided less retention than DW (p<0.005). Through SEM it was possible to observe changes in the surface of the CF and SH nitrile o-rings. CF and SH should be avoided due to deleterious action in o-rings.


Asunto(s)
Prótesis de Recubrimiento , Hipoclorito de Sodio , Prótesis Dental de Soporte Implantado , Análisis del Estrés Dental , Retención de Dentadura , Ensayo de Materiales , Resistencia a la Tracción
2.
Braz. dent. j ; 31(6): 657-663, Nov.-Dec. 2020. tab, graf
Artículo en Inglés | LILACS-Express | LILACS, BBO - Odontología | ID: biblio-1132344

RESUMEN

Abstract The aim of this study was to evaluate the effect of cleaning solutions on the retention force of o-ring-type overdenture attachments. The effect of four solutions on nitrile rings were evaluated: Cepacol (C), Cepacol with fluoride (CF), Listerine (L) and 0.05% sodium hypochlorite (SH); deionized water (DW) was used as a control. Matrices containing two implants and abutments and acrylic specimens with the metal capsules were obtained and divided into the groups. A simulation of 90 overnight immersions (8 h) was performed, and the tensile strength value was obtained at the beginning (T0) and in every 30 days (T1, T2 and T3) (n=6). In order to analyze o-ring surface damage after the immersions, a scanning electron microscopy (SEM) was used (n=1). For statistical analysis of the results, analysis of variance (ANOVA) and multiple comparisons with Bonferroni adjustment (test power=1.000; a=0.05) were used. There was a significant difference for the factors time (p<0.001), solution (p<0.001) and for the interaction time × solution (p<0.001). Considering the times of each solution, only for DW there was no significant loss of retention over time. Comparing the solutions in each moment, there was no difference among the solutions in T0. From T1, CF and SH provided less retention than DW (p<0.005). Through SEM it was possible to observe changes in the surface of the CF and SH nitrile o-rings. CF and SH should be avoided due to deleterious action in o-rings.


Resumo O objetivo do estudo foi avaliar o efeito de soluções higienizadoras sobre a força de retenção de encaixes do tipo o-ring. Foram avaliadas quatro soluções: Cepacol (C); Cepacol com flúor (CF), Listerine (L), hipoclorito de sódio 0,05% (HS) e água deionizada (controle/AD) em o-rings de nitrilo. Matrizes contendo dois implantes e pilares e espécimes em acrílico com as cápsulas metálicas foram obtidas e divididas entre os grupos. Foi realizada a simulação de 90 imersões noturnas (8 h), sendo obtido o valor da resistência à tração no início e a cada 30 dias (T0, T1, T2 e T3) por meio da máquina de ensaios mecânicos (n=6). Microscopia eletrônica de varredura (MEV) foi utilizada para análise de danos na superfície do o´ring após a imersão (n=1). Para análise estatística dos resultados foi utilizada análise de variância (ANOVA) e múltiplas comparações com ajuste de Bonferroni (poder do teste=1,000; a=0,05). Houve diferença significante para os fatores tempo (p<0,001), solução (p<0,001) e para interação de tempo × solução (p<0,001). Considerando-se os tempos de cada solução, apenas AD não apresentou perda significativa de retenção ao longo do tempo. Comparando as soluções em cada momento, não houve diferença entre as soluções em T0. A partir de T1, CF e HS propiciaram menor retenção quando comparados à AD (p <0,005). Através do MEV foi possível observar alterações nas superfícies dos o-rings de nitrilo imersos em CF e HS. O Cepacol com flúor e hipoclorito de sódio devem ser evitados devido à ação deletéria nos o-rings.

3.
Spec Care Dentist ; 40(5): 493-497, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32620036

RESUMEN

Jeune syndrome (JS) is a rare disease, with systemic manifestations, such as renal and hepatic insufficiency, retinal pigmentation, and respiratory insufficiency. Etiological factors have not been completely elucidated, but the molecular biology has contributed to the diagnosis and understanding of JS with DNA sequencing, showing the association among polymorphisms in different genes DYNC2H1 (MIM 603297) and TCTEX1D2 (MIM617353), which are the main genes associated with JS. There are a few reports on buccal findings in these patients; here, we present dental anomalies and clinical oral findings in a patient with JS, focusing on a multidisciplinary approach for rehabilitation. A 15-year-old boy with JS was referred to our dental clinic. Clinical and radiographic examination revealed the presence of dental agenesis, taurodontism, and geographic tongue with lobulations. The treatment plan consisted of preventive, restorative, surgical, and oral rehabilitation. We observed that the treatment improved the patient's quality of life owing to improved functions, maintenance of oral health, and above all, self-esteem. Clinical findings in this case may contribute to a better characterization of JS and other ciliopathies.

4.
Int J Prosthodont ; 33(3): 315-320, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32320185

RESUMEN

PURPOSE: To evaluate the antimicrobial activity of effervescent tablets on the surfaces of cobalt-chromium (Co-Cr) and heat-polymerized resin. MATERIALS AND METHODS: From a metal matrix, 55 circular wax patterns (Ø 12 × 3 mm) were obtained and cast in Co-Cr alloy. Muffles for acrylic resin were prepared from circular wax patterns (Ø 20 × 5 mm). The metal specimens were positioned in the muffle, and the resin was pressed into its surroundings to simulate the composition of a removable partial denture (RPD). The mixed specimens were sterilized and contaminated with Streptococcus mutans, Staphylococcus aureus, Candida albicans, and Candida glabrata, composing a multispecies biofilm, and subsequently immersed according to the manufacturer's instructions in four cleansing solutions: Polident 3 Minute denture cleanser (P3M), Polident for Partials (PP), Corega Tabs (CT), and NitrAdine (Ni); as well as distilled water (positive control) and no contamination (negative control). After cleansing, viable microorganisms were quantified by counting the number of colony-forming units (CFU/mL). From the CFU values, log10(CFU + 1) values were calculated for statistical analysis. Kruskal-Wallis test with Dunn post hoc test were performed (α = .05). RESULTS: There was a significant reduction (P = .001) of S mutans after immersion in Ni (median [95% CI] 3.27 [2.92; 3.45]) compared to the CT (3.86 [3.75; 4.01]) and control (4.08 (3.73; 4.22]) groups, while the PP (3.63 [3.28; 4.11]) and P3M (3.83 [3.61; 4.04]) groups presented an intermediate action. The effervescent tablets did not present antimicrobial action against S aureus (P = .537), C albicans (P = .795), or C glabrata (P = .519). CONCLUSION: Ni exhibited moderate antimicrobial action. The effervescent tablets did not promote reduction of multispecies biofilm, and their daily use should be carefully considered.


Asunto(s)
Antiinfecciosos , Dentadura Parcial Removible , Biopelículas , Candida albicans , Limpiadores de Dentadura , Dentaduras , Streptococcus mutans , Propiedades de Superficie , Comprimidos
5.
J Prosthodont ; 29(2): 142-150, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30381847

RESUMEN

PURPOSE: To compare the effect of solutions of effervescent tablets (ET), cetylpyridinium chloride (CPC), and experimental solutions of Ricinus communis on the surface of cobalt-chromium (Co-Cr) alloys. MATERIALS AND METHODS: Fifty-five specimens of Co-Cr were prepared by the lost-wax casting method using circular patterns (∅12 × 3 mm). The specimens were randomly divided into 5 groups: deionized water (control); 2% R. communis; 10% R. communis; ET, and CPC. The surface roughness of specimens (n = 10) was evaluated before immersion (baseline), and at simulated times of ½, 1, 2, 3, 4, and 5 years, by laser confocal microscope (Sa, µm) and profilometer (Ra, µm). The surface topography and chemical composition (n = 1) was qualitatively analyzed with scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS). Data were subjected to Kruskal-Wallis followed by Dunn tests, and Friedman followed by Wilcoxon tests (α = 0.05). RESULTS: For Sa, there was no difference for the solution factor. For the time factor a significant difference was found with 2% R. communis solution among baseline and ½, 2, 3, and 5 years (p < 0.001) and with 10% R. communis solution between 1 and 2 years (p = 0.007), with decreasing roughness over time. For Ra, cetylpyridinium chloride exhibited less roughness than 10% R. communis solution in ½ (p = 0.048) and 5 years (p = 0.013). In the SEM and EDS analysis the solutions did not present deleterious effects or changes in the chemical composition on the surfaces. CONCLUSIONS: Although a significant difference was found for the roughness, the results, below 0.2 µm, are clinically acceptable. Thus, all solutions can be used safely in removable partial denture cleaning for a period of 5 years.


Asunto(s)
Limpiadores de Dentadura , Dentadura Parcial Removible , Aleaciones de Cromo , Ensayo de Materiales , Propiedades de Superficie
6.
J Prosthodont ; 28(1): e337-e341, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29573505

RESUMEN

PURPOSE: Removable denture hygiene care is very important for the longevity of the rehabilitation treatment; however, it is necessary to analyze the effects that denture cleansers can cause on the surfaces of prostheses. Thus, this study evaluated the effect of alkaline peroxide-effervescent tablets on the surface of cobalt-chromium alloys (Co-Cr) used in removable partial dentures. MATERIALS AND METHODS: Circular metallic specimens (12 × 3 mm) were fabricated and were immersed (n = 16) in: control, Polident 3 Minute (P3M), Steradent (S), Efferdent (E), Polident for Partials (PFP), and Corega Tabs (CT). The surface roughness (µm) (n = 10) was measured before and after periods of cleanser immersion corresponding to 0.5, 1, 2, 3, 4, and 5 years. Ion release was analyzed (n = 5) for Co, Cr, and molybdenum (Mo). Scanning electron microscopy (SEM) analysis and an Energy-dispersive X-ray spectroscopy (EDS) were conducted in one specimen. The surface roughness data were statistically analyzed (α = 0.05) with the Kruskal-Wallis test to compare the solutions, and the Friedman test compared the immersion durations. Ion release analysis was performed using 2-way ANOVA and Tukey's test. RESULTS: There was no significant surface roughness difference when comparing the solutions (p > 0.05) and the immersion durations (p = 0.137). Regarding ion release (µg/L), CT, E, and control produced a greater release of Co ions than S (p < 0.05). CT produced a greater release of Cr ions than control, S, and P3M (p < 0.05). Finally, E caused the greatest release of Mo ions (p < 0.05). SEM confirmed that the solutions did not damage the surfaces and EDS confirmed that there were no signs of oxidation. CONCLUSION: The various solutions tested did not have any deleterious effects on the Co-Cr alloy surface. Steradent, however, presented the smallest ionic release.


Asunto(s)
Aleaciones de Cromo , Materiales Dentales , Peróxidos/farmacología , Técnicas In Vitro , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Propiedades de Superficie/efectos de los fármacos
7.
Braz Dent J ; 27(6): 700-704, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27982182

RESUMEN

This study evaluated the efficacy of cleanser solutions on denture biofilm removal by a crossover randomized clinical trial. Thirty two edentulous patients were instructed to brush their dentures (specific brush and liquid soap) three times a day (after breakfast, lunch and dinner) and to soak them (≥ 8 h) in: (C) control -water; (AP): alkaline peroxide; or (SH) 0.5% sodium hypochlorite. Each solution was used for 21 days (three cycles of 7 days). At the end of each cycle, the inner surfaces of maxillary dentures were disclosed (1% neutral red) and photographed (HX1 - Sony). Areas (total and stained biofilm) were measured (Image Tool software) and the percentage of biofilm calculated as the ratio between the area of the biofilm multiplied by 100 and total surface area of the internal base of the denture. Data were compared by means of generalized estimating equation (α=5%) and multiple comparisons (Bonferroni; α=1.67%). Immersion in SH reduced biofilm (%) (8.3 ± 13.3B) compared to C (18.2 ± 14.9A) and AP (18.2 ± 16.6A). The 0.5% sodium hypochlorite solution was the most efficacious for biofilm removal. Alkaline peroxides may not lead to further biofilm removal in patients with adequate denture maintenance habits.


Asunto(s)
Biopelículas , Dentaduras/microbiología , Peróxidos/administración & dosificación , Hipoclorito de Sodio/administración & dosificación , Estudios Cruzados , Femenino , Humanos , Masculino
8.
Braz. dent. j ; 27(6): 700-704, Nov.-Dec. 2016. tab, graf
Artículo en Inglés | LILACS | ID: biblio-828054

RESUMEN

Abstract This study evaluated the efficacy of cleanser solutions on denture biofilm removal by a crossover randomized clinical trial. Thirty two edentulous patients were instructed to brush their dentures (specific brush and liquid soap) three times a day (after breakfast, lunch and dinner) and to soak them (≥ 8 h) in: (C) control -water; (AP): alkaline peroxide; or (SH) 0.5% sodium hypochlorite. Each solution was used for 21 days (three cycles of 7 days). At the end of each cycle, the inner surfaces of maxillary dentures were disclosed (1% neutral red) and photographed (HX1 - Sony). Areas (total and stained biofilm) were measured (Image Tool software) and the percentage of biofilm calculated as the ratio between the area of the biofilm multiplied by 100 and total surface area of the internal base of the denture. Data were compared by means of generalized estimating equation (α=5%) and multiple comparisons (Bonferroni; α=1.67%). Immersion in SH reduced biofilm (%) (8.3 ± 13.3B) compared to C (18.2 ± 14.9A) and AP (18.2 ± 16.6A). The 0.5% sodium hypochlorite solution was the most efficacious for biofilm removal. Alkaline peroxides may not lead to further biofilm removal in patients with adequate denture maintenance habits.


Resumo Este estudo avaliou a eficácia de soluções higienizadoras na remoção do biofilme de dentadura por meio de ensaio clínico randomizado cruzado. Trinta e dois pacientes desdentados foram instruídos a escovar suas dentaduras (escova específica e sabão líquido) três vezes ao dia (após café da manhã, almoço e jantar) e imergi-las (≥ 8 horas) em: (C) controle - água; (PA): peróxido alcalino; ou (HS) hipoclorito de sódio a 0,5%. Cada solução foi usada por 21 dias (três ciclos alternados de 7 dias). Ao final de cada ciclo, a superfície interna da dentadura maxilar foi evidenciada (vermelho neutro 1%) e fotografada (HX1- Sony). As áreas (total e corada com biofilme) foram medidas (software Image Tool), e a porcentagem de biofilme calculada como a relação entre a área do biofilme multiplicado por 100 e área da superfície total da base interna da dentadura. Os dados foram comparados por meio de equações de estimação generalizadas (α=5%) e comparações múltiplas (Bonferroni - α=1,67%). A imersão em HS reduziu o biofilme (%) (8,3 ± 13,3B) em comparação com C (18,2 ± 14,9A) e PA (18,2 ± 16,6A). A solução de hipoclorito de sódio a 0,5% foi a mais eficaz na remoção do biofilme. Peróxidos alcalinos podem não levar a maior remoção do biofilme em pacientes com hábitos adequados de manutenção de dentadura.


Asunto(s)
Humanos , Masculino , Femenino , Biopelículas , Dentaduras/microbiología , Peróxidos/administración & dosificación , Hipoclorito de Sodio/administración & dosificación , Estudios Cruzados
9.
Am J Dent ; 29(3): 149-53, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27505991

RESUMEN

PURPOSE: To evaluate the in vitro antimicrobial efficacy of alkaline peroxides against microbial biofilms on acrylic resin surfaces. METHODS: Denture base acrylic resin (Lucitone 550; n= 360) circular specimens (15 x 3 mm) were obtained from a circular metal matrix and sterilized with microwave irradiation (650 W, 6 minutes). The specimens were then contaminated with suspensions [106 colony-forming units (CFU)/mL] of Candida albicans (Ca), Candida glabrata (Cg), Staphylococcus aureus (Sa), Streptococcus mutans (Sm), Bacillus subtilis (Bs), Enterococcus faecalis (Ef), Escherichia coli (Ec), and Pseudomonas aeruginosa (Pa). After contamination, the specimens were incubated at 37 degrees C for 48 hours and then placed in a stainless steel basket, which was immersed in a beaker with one of the following solutions prepared and used according to the manufacturers' instructions (n= 10 per group): Group PC (positive control), phosphate-buffered saline (PBS) solution; Group MI, NitrAdine, Medical Interporous; Group EF, Efferdent Plus; Group CT, Corega Tabs; and Group NC (negative control; n= 5), no contamination and immersed in PBS. After incubation (37 degrees C, 24 hours), the number of colonies with characteristic morphology was counted, and CFU/mL values were calculated. The data were processed following the transformation into the formula log" (CFU + 1) and statistically analyzed by the Kruskal-Wallis and Dunn's tests (alpha = 0.05). RESULTS: There were significant differences between the groups for the evaluated microorganisms with a significant reduction in the CFU/mL. MI was effective for Ca, Cg, Sa, Sm, Ef, Ec and Pa; EF was effective for Cg, Sm, Ef, Ec and Pa; and CT was effective for Sa, Bs and Ec, when compared with the PC group.


Asunto(s)
Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Candida/efectos de los fármacos , Dentaduras/microbiología , Desinfección , Biopelículas , Recuento de Colonia Microbiana , Bases para Dentadura
10.
Braz Oral Res ; 282014.
Artículo en Inglés | MEDLINE | ID: mdl-24918370

RESUMEN

This study evaluated the effect of cleanser solutions on the color of heat-polymerized acrylic resin (HPAR) and on the brightness of dental alloys with 180 immersion trials. Disk-shaped specimens were made with I) commercially pure titanium, II) nickel-chromium-molybdenum-titanium, III) nickel-chromium molybdenum, and IV) nickel-chromium-molybdenum beryllium. Each cast disk was invested in the flasks, incorporating the metal disk into the HPAR. The specimens (n=5) were then immersed in solutions containing: 0.05% sodium hypochlorite, 0.12% chlorhexidine digluconate, 0.500 mg cetylpyridinium chloride, a citric acid tablet, one of two different sodium perborate/enzyme tablets, and water. The color measurements (∆E) of the HPAR were determined by a colorimeter in accordance with the National Bureau of Standards. The surface brightness of the metal was visually examined for the presence of tarnish. The results (ANOVA; Tukey test-α=0.05) show that there was a significant difference between the groups (p<0.001) but not among the solutions (p=0.273). The highest mean was obtained for group III (5.06), followed by group II (2.14). The lowest averages were obtained for groups I (1.33) and IV (1.35). The color changes in groups I, II and IV were slight but noticeable, and the color change was considerable for group III. The visual analysis showed that 0.05% sodium hypochlorite caused metallic brightness changes in groups II and IV. It can be concluded that the agents had the same effect on the color of the resin and that the metallic alloys are not resistant to the action of 0.05% sodium hypochlorite.


Asunto(s)
Resinas Acrílicas/química , Aleaciones de Cromo/química , Limpiadores de Dentadura/química , Coloración de Prótesis , Titanio/química , Aleaciones/química , Análisis de Varianza , Color , Desinfectantes Dentales/química , Humanos , Inmersión , Ensayo de Materiales , Polimerizacion , Distribución Aleatoria , Hipoclorito de Sodio/química , Propiedades de Superficie , Factores de Tiempo
11.
Braz. dent. j ; 24(6): 630-634, Nov-Dec/2013. graf
Artículo en Inglés | LILACS | ID: lil-697662

RESUMEN

This study evaluated the tensile and flexural strength of tungsten inert gas (TIG) welds in specimens made of commercially pure titanium (CP Ti) compared with laser welds. Sixty cylindrical specimens (2 mm diameter x 55 mm thick) were randomly assigned to 3 groups for each test (n=10): no welding (control), TIG welding (10 V, 36 A, 8 s) and Nd:YAG laser welding (380 V, 8 ms). The specimens were radiographed and subjected to tensile and flexural strength tests at a crosshead speed of 1.0 mm/min using a load cell of 500 kgf applied on the welded interface or at the middle point of the non-welded specimens. Tensile strength data were analyzed by ANOVA and Tukey's test, and flexural strength data by the Kruskal-Wallis test (α=0.05). Non-welded specimens presented significantly higher tensile strength (control=605.84±19.83) (p=0.015) and flexural strength (control=1908.75) (p=0.000) than TIG- and laser-welded ones. There were no significant differences (p>0.05) between the welding types for neither the tensile strength test (TIG=514.90±37.76; laser=515.85±62.07) nor the flexural strength test (TIG=1559.66; laser=1621.64). As far as tensile and flexural strengths are concerned, TIG was similar to laser and could be suitable to replace laser welding in implant-supported rehabilitations.


Este estudo avaliou a resistência à tração e à flexão de soldas feitas com gás inerte de tungstênio (TIG) em amostras de titânio comercialmente puro (Ti CP) em comparação com a solda a laser. Sessenta amostras cilíndricas (diâmetro de 2 mm e espessura de 55 mm) foram distribuídas aleatoriamente em três grupos para cada ensaio (n=10): sem solda (controle), solda TIG (10V, 36A, 8 s) e solda com laser de Nd:YAG (380 V, 8 ms). As amostras foram radiografadas e submetidas aos testes de resistência à tração e à flexão em máquina de ensaios mecânicos à velocidade de 1mm/min com célula de carga de 500 kgf aplicada na interface soldada ou no ponto médio das amostras controle. Os dados de resistência à tração foram analisados estatisticamente por ANOVA e teste de Tukey e os dados de resistência à flexão pelo teste de Kruskal-Wallis (α=0,05). Espécimes não-soldados apresentaram resistência à tração (controle=605,84±19,83) (p=0,015) e resistência à flexão (controle=1908,75) (p=0,000) significantemente maiores que os solados com TIG ou laser. Não houve diferença estatisticamente significante (p>0.05) entre os tipos de solda no teste de resistência à tração (TIG=514,90±37,76; laser=515,85±62,07) nem no teste de resistência à flexão (TIG=1559,66; laser=1621,64). As resistências à tração e à flexão foram similares quando as amostras foram soldadas com TIG e a laser.


Asunto(s)
Rayos Láser , Tungsteno , Titanio/química , Soldadura/métodos , Porosidad , Resistencia al Corte , Resistencia a la Tracción
12.
Braz Dent J ; 24(1): 40-6, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23657412

RESUMEN

This study evaluated the casting accuracy of crown margins and metal-ceramic shear bond strength (SBS) of pure titanium injected into casting molds made using 2 investment types at 3 mold temperatures. Sixty crown (30-degree beveled finish line) and 60 cylinder (5mm diameter × 8mm high) patterns were divided into 6 groups (n=10), and cast using a phosphate-bonded investment (P) and a magnesium oxide-bonded investment (U), at 400°C (groups P400 and U400), 550°C (groups P550 and U550) and 700°C (groups P700 and U700) mold temperatures. Crown margins were recorded in impression material, the degree of marginal rounding was measured and margin length deficiencies (µm) were calculated. Titanium-ceramic specimens were prepared using Triceram ceramic (2mm high) and SBS was tested. Failure modes were assessed by optical microscopy. Data were subjected to two-way ANOVA and Tukey's HSD test (α=0.05). For casting accuracy, expressed by marginal deficiency (µm), investment U provided more accurate results (64 ± 11) than P (81 ± 23) (p<0.001). The increase in temperature resulted in different effects for the tested investments (p<0.001), as it provided better casting accuracy for U700 (55 ± 7) and worse for P700 (109 ± 18). Casting accuracy at 700°C (82 ± 31) was significantly different from 400°C (69 ± 9) and 550°C (68 ± 9) (p<0.05). For SBS, there was no significant differences among the groups for factors investment (p=0.062) and temperature (p=0.224), or for their interaction (p=0.149). Investment U provided better casting accuracy than investment P. The SBS was similar for all combinations of investments and temperatures.


Asunto(s)
Coronas , Recubrimiento Dental Adhesivo , Revestimiento para Colado Dental , Técnica de Colado Dental , Aleaciones de Cerámica y Metal , Titanio , Análisis de Varianza , Adaptación Marginal Dental , Análisis del Estrés Dental , Humanos , Óxido de Magnesio , Fosfatos , Resistencia al Corte , Estadísticas no Paramétricas , Temperatura
13.
Braz Dent J ; 24(1): 47-52, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23657413

RESUMEN

This study compared the levels of biofilm in maxillary and mandibular complete dentures and evaluated the number of colony-forming units (cfu) of yeasts, after using auxiliary brushing agents and artificial saliva. Twenty-three denture wearers with hyposalivation and xerostomia were instructed to brush the dentures 3 times a day during 3 weeks with the following products: Corega Brite denture dentifrice, neutral liquid soap, Corega Brite combined with Oral Balance (artificial saliva) or tap water. For biofilm quantification, the internal surfaces of the dentures were disclosed, photographed and measured using a software. For microbiological analysis, the biofilm was scrapped off, and the harvested material was diluted, sown in CHROMagar™ Candida and incubated at 37°C for 48 h. Data were analyzed statistically by two-way ANOVA and Tukey's test (α=0.05). Mandibular dentures presented a mean biofilm percentage (µ=26.90 ± 21.10) significantly greater than the maxillary ones (µ=18.0 ± 15.0) (p<0.05). Brushing using Corega Brite combined with Oral Balance (µ=15.87 ± 18.47) was more effective (p<0.05) than using the denture dentifrice (µ=19.47 ± 17.24), neutral soap (µ=23.90 ± 18.63) or tap water (control; µ=32.50 ± 20.68). For the microbiological analysis, the chi-square test did not indicate significant difference between the hygiene products for either type of denture. The more frequently isolated species of yeasts were C. albicans, C. tropicalis and C. glabrata. In conclusion, mandibular dentures had more biofilm formation than maxillary ones. Denture brushing with Corega Brite dentifrice combined with the use of Oral Balance was the most effective method for reduction of biofilm levels, but the use of products did not show difference in yeast cfu counts.


Asunto(s)
Biopelículas , Candida , Limpiadores de Dentadura , Dentadura Completa/microbiología , Cepillado Dental , Adulto , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Candida/aislamiento & purificación , Recuento de Colonia Microbiana , Estudios Cruzados , Femenino , Humanos , Masculino , Persona de Mediana Edad , Saliva Artificial , Jabones , Estadísticas no Paramétricas , Xerostomía
14.
Braz Dent J ; 24(6): 630-4, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24474361

RESUMEN

This study evaluated the tensile and flexural strength of tungsten inert gas (TIG) welds in specimens made of commercially pure titanium (CP Ti) compared with laser welds. Sixty cylindrical specimens (2 mm diameter x 55 mm thick) were randomly assigned to 3 groups for each test (n=10): no welding (control), TIG welding (10 V, 36 A, 8 s) and Nd:YAG laser welding (380 V, 8 ms). The specimens were radiographed and subjected to tensile and flexural strength tests at a crosshead speed of 1.0 mm/min using a load cell of 500 kgf applied on the welded interface or at the middle point of the non-welded specimens. Tensile strength data were analyzed by ANOVA and Tukey's test, and flexural strength data by the Kruskal-Wallis test (α=0.05). Non-welded specimens presented significantly higher tensile strength (control=605.84 ± 19.83) (p=0.015) and flexural strength (control=1908.75) (p=0.000) than TIG- and laser-welded ones. There were no significant differences (p>0.05) between the welding types for neither the tensile strength test (TIG=514.90 ± 37.76; laser=515.85 ± 62.07) nor the flexural strength test (TIG=1559.66; laser=1621.64). As far as tensile and flexural strengths are concerned, TIG was similar to laser and could be suitable to replace laser welding in implant-supported rehabilitations.


Asunto(s)
Rayos Láser , Titanio/química , Tungsteno , Soldadura/métodos , Porosidad , Resistencia al Corte , Resistencia a la Tracción
15.
Braz. dent. j ; 24(1): 40-46, 2013. tab, graf
Artículo en Inglés | LILACS | ID: lil-671357

RESUMEN

This study evaluated the casting accuracy of crown margins and metal-ceramic shear bond strength (SBS) of pure titanium injected into casting molds made using 2 investment types at 3 mold temperatures. Sixty crown (30-degree beveled finish line) and 60 cylinder (5 mm diameter × 8 mm high) patterns were divided into 6 groups (n=10), and cast using a phosphate-bonded investment (P) and a magnesium oxide-bonded investment (U), at 400°C (groups P400 and U400), 550°C (groups P550 and U550) and 700°C (groups P700 and U700) mold temperatures. Crown margins were recorded in impression material, the degree of marginal rounding was measured and margin length deficiencies (µm) were calculated. Titanium-ceramic specimens were prepared using Triceram ceramic (2 mm high) and SBS was tested. Failure modes were assessed by optical microscopy. Data were subjected to two-way ANOVA and Tukey's HSD test (α=0.05). For casting accuracy, expressed by marginal deficiency (µm), investment U provided more accurate results (64 ± 11) than P (81 ± 23) (p<0.001). The increase in temperature resulted in different effects for the tested investments (p<0.001), as it provided better casting accuracy for U700 (55 ± 7) and worse for P700 (109 ± 18). Casting accuracy at 700°C (82 ± 31) was significantly different from 400°C (69 ± 9) and 550°C (68 ± 9) (p<0.05). For SBS, there was no significant differences among the groups for factors investment (p=0.062) and temperature (p=0.224), or for their interaction (p=0.149). Investment U provided better casting accuracy than investment P. The SBS was similar for all combinations of investments and temperatures.


O objetivo neste estudo foi avaliar a precisão da fundição de margens de coroas e a resistência de união metalocerâmica do titânio puro injetado em moldes de fundição feitos com 2 tipos de revestimentos em 3 diferentes temperaturas. Sessenta copings (com linha de término em bisel de 30°) e 60 padrões em forma de cilindros (diâmetro de 5 mm e altura de 8 mm) foram separados em 6 grupos (n=10) e fundidos usando revestimento aglutinado por fosfato (P) ou revestimento aglutinado por óxido de magnésio, nas temperaturas finais do molde: 400° (grupos P400 e U400), 550° (grupos P550 e U550) e 700° (grupos P700 e U700). As margens dos copings foram registradas em material de moldagem, o grau de arredondamento marginal foi medido e as deficiências marginais (µm) foram calculadas. Os espécimes metalocerâmicos foram confeccionados com cerâmica Triceram (altura de 2 mm) e submetidos aos ensaios de resistência de união por cisalhamento. Os tipos de fratura foram avaliados em microscópio óptico. Os dados foram submetidos à ANOVA e teste de Tukey (α=0,05). Para precisão de fundição (µm), o revestimento U promoveu melhores resultados (64 ± 11) que o P (81 ± 23) (p<0,001); o aumento da temperatura do molde resultou em efeitos diferentes para os revestimentos avaliados (p<0,001), considerando que promoveu melhor precisão de fundição para U700 (55 ± 7) e pior para P700 (109 ± 18). Os valores promovidos por 700°C (82 ± 31) foram significantemente diferentes de 400°C (69 ± 9) e 550°C (68 ± 9) (p<0,05). Para resistência de união ao cisalhamento, a ANOVA não demonstrou diferença significante para os fatores revestimento (p=0,062) e temperatura (p=0,224), nem para a interação deles (p=0,149). O revestimento U promoveu melhor precisão de fundição que o revestimento P. A resistência de união ao cisalhamento foi similar para todas as combinações de revestimentos e temperaturas do molde.


Asunto(s)
Humanos , Coronas , Recubrimiento Dental Adhesivo , Revestimiento para Colado Dental , Técnica de Colado Dental , Aleaciones de Cerámica y Metal , Titanio , Análisis de Varianza , Adaptación Marginal Dental , Análisis del Estrés Dental , Óxido de Magnesio , Fosfatos , Resistencia al Corte , Estadísticas no Paramétricas , Temperatura
16.
Braz. dent. j ; 24(1): 47-52, 2013. tab, graf
Artículo en Inglés | LILACS | ID: lil-671358

RESUMEN

This study compared the levels of biofilm in maxillary and mandibular complete dentures and evaluated the number of colony-forming units (cfu) of yeasts, after using auxiliary brushing agents and artificial saliva. Twenty-three denture wearers with hyposalivation and xerostomia were instructed to brush the dentures 3 times a day during 3 weeks with the following products: Corega Brite denture dentifrice, neutral liquid soap, Corega Brite combined with Oral Balance (artificial saliva) or tap water. For biofilm quantification, the internal surfaces of the dentures were disclosed, photographed and measured using a software. For microbiological analysis, the biofilm was scrapped off, and the harvested material was diluted, sown in CHROMagar™ Candida and incubated at 37°C for 48 h. Data were analyzed statistically by two-way ANOVA and Tukey's test (α=0.05). Mandibular dentures presented a mean biofilm percentage (µ=26.90 ± 21.10) significantly greater than the maxillary ones (µ=18.0 ± 15.0) (p<0.05). Brushing using Corega Brite combined with Oral Balance (µ=15.87 ± 18.47) was more effective (p<0.05) than using the denture dentifrice (µ=19.47 ± 17.24), neutral soap (µ=23.90 ± 18.63) or tap water (control; µ=32.50 ± 20.68). For the microbiological analysis, the chi-square test did not indicate significant difference between the hygiene products for either type of denture. The more frequently isolated species of yeasts were C. albicans, C. tropicalis and C. glabrata. In conclusion, mandibular dentures had more biofilm formation than maxillary ones. Denture brushing with Corega Brite dentifrice combined with the use of Oral Balance was the most effective method for reduction of biofilm levels, but the use of products did not show difference in yeast cfu counts.


Este estudo comparou os níveis de biofilme em próteses totais maxilares e mandibulares, e analisou o número de unidades formadoras de colônias de leveduras, após o uso de agentes auxiliares da escovação e saliva artificial. Vinte e três usuários de próteses totais com hipossalivação e xerostomia foram orientados a escovar as dentaduras 3 vezes ao dia durante 3 semanas com os seguintes produtos: Corega Brite (dentifrício para prótese), sabonete líquido neutro, Corega Brite associado com o uso do Oral Balance (saliva artificial) ou água de torneira. Para a quantificação do biofilme, as superfícies internas das próteses totais foram evidenciadas, fotografadas e o biofilme quantificado com o auxílio de um software. Para a análise microbiológica, o biofilme foi removido por escovação, coletado, diluído, semeado em meio seletivo CHROMagar™ Candida e incubado a 37°C por 48 h. A análise de variância para dois fatores (p<0,05%) mostrou que as próteses mandibulares apresentaram uma média de porcentagem de biofilme (µ=26,90±21,10) maior que as maxilares (µ=18±15). O teste complementar de Tukey (0,46; p<5%) mostrou que a escovação com Corega Brite e Oral Balance (µ=15,87 ± 18,47) foi mais efetiva que o dentifrício (µ=19,47 ± 17,24), sabonete neutro (µ=23,90 ± 18,63), ou água de torneira (controle; µ=32,50 ± 20,68). Em relação á análise microbiológica, o teste de Qui-Quadrado não indicou diferença entre os produtos de higiene, para ambas as próteses. As espécies de leveduras mais comumente isoladas foram C. albicans, C. tropicalis e C. glabrata. Em conclusão, as próteses mandibulares apresentaram mais biofilme do que as maxilares. Além disso, a escovação das próteses com o Corega Brite associado ao uso do Oralbalance foi o método mais efetivo na redução dos níveis de biofilme, entretanto o uso dos produtos não demonstrou diferença no número de ufc de leveduras.


Asunto(s)
Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Biopelículas , Candida , Limpiadores de Dentadura , Dentadura Completa/microbiología , Cepillado Dental , Análisis de Varianza , Recuento de Colonia Microbiana , Estudios Cruzados , Candida/aislamiento & purificación , Saliva Artificial , Jabones , Estadísticas no Paramétricas , Xerostomía
17.
Braz Dent J ; 23(4): 387-93, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23207854

RESUMEN

Chemical disinfectants are usually associated with mechanical methods to remove stains and reduce biofilm formation. This study evaluated the effect of disinfectants on release of metal ions and surface roughness of commercially pure titanium, metal alloys, and heat-polymerized acrylic resin, simulating 180 immersion trials. Disk-shaped specimens were fabricated with commercially pure titanium (Tritan), nickel-chromium-molybdenum-titanium (Vi-Star), nickel-chromium (Fit Cast-SB Plus), and nickel-chromium-beryllium (Fit Cast-V) alloys. Each cast disk was invested in the flasks, incorporating the metal disk to the heat-polymerized acrylic resin. The specimens (n=5) were immersed in these solutions: sodium hypochlorite 0.05%, Periogard, Cepacol, Corega Tabs, Medical Interporous, and Polident. Deionized water was used as a control. The quantitative analysis of metal ion release was performed using inductively coupled plasma mass spectrometry (ELAN DRC II). A surface analyzer (Surftest SJ-201P) was used to measure the surface roughness (µm). Data were recorded before and after the immersions and evaluated by two-way ANOVA and Tukey's test (α=0.05). The nickel release proved most significant with the Vi-Star and Fit Cast-V alloys after immersion in Medical Interporous. There was a significant difference in surface roughness of the resin (p=0.011) after immersion. Cepacol caused significantly higher resin roughness. The immersion products had no influence on metal roughness (p=0.388). It could be concluded that the tested alloys can be considered safe for removable denture fabrication, but disinfectant solutions as Cepacol and Medical Interporous tablet for daily denture immersion should be used with caution because it caused greater resin surface roughness and greater ion release, respectively.


Asunto(s)
Aleaciones Dentales/química , Bases para Dentadura , Limpiadores de Dentadura/química , Resinas Acrílicas/química , Aleaciones/química , Aluminio/análisis , Berilio/análisis , Boratos/química , Cetilpiridinio/química , Clorhexidina/análogos & derivados , Clorhexidina/química , Cromo/análisis , Aleaciones de Cromo/química , Ácido Cítrico/química , Desinfectantes Dentales/química , Materiales Dentales/química , Humanos , Ensayo de Materiales , Metales/análisis , Metales/química , Molibdeno/análisis , Níquel/análisis , Hipoclorito de Sodio/química , Espectrofotometría Atómica , Sulfatos/química , Propiedades de Superficie , Titanio/análisis , Titanio/química
18.
Braz. dent. j ; 23(4): 387-393, 2012. tab
Artículo en Inglés | LILACS | ID: lil-658015

RESUMEN

Chemical disinfectants are usually associated with mechanical methods to remove stains and reduce biofilm formation. This study evaluated the effect of disinfectants on release of metal ions and surface roughness of commercially pure titanium, metal alloys, and heat-polymerized acrylic resin, simulating 180 immersion trials. Disk-shaped specimens were fabricated with commercially pure titanium (Tritan), nickel-chromium-molybdenum-titanium (Vi-Star), nickel-chromium (Fit Cast-SB Plus), and nickel-chromium-beryllium (Fit Cast-V) alloys. Each cast disk was invested in the flasks, incorporating the metal disk to the heat-polymerized acrylic resin. The specimens (n=5) were immersed in these solutions: sodium hypochlorite 0.05%, Periogard, Cepacol, Corega Tabs, Medical Interporous, and Polident. Deionized water was used as a control. The quantitative analysis of metal ion release was performed using inductively coupled plasma mass spectrometry (ELAN DRC II). A surface analyzer (Surftest SJ-201P) was used to measure the surface roughness (µm). Data were recorded before and after the immersions and evaluated by two-way ANOVA and Tukey's test (α=0.05). The nickel release proved most significant with the Vi-Star and Fit Cast-V alloys after immersion in Medical Interporous. There was a significant difference in surface roughness of the resin (p=0.011) after immersion. Cepacol caused significantly higher resin roughness. The immersion products had no influence on metal roughness (p=0.388). It could be concluded that the tested alloys can be considered safe for removable denture fabrication, but disinfectant solutions as Cepacol and Medical Interporous tablet for daily denture immersion should be used with caution because it caused greater resin surface roughness and greater ion release, respectively.


Desinfetantes químicos são normalmente associados a métodos mecânicos para remover manchas e reduzir a formação do biofilme. Este estudo avaliou o efeito de desinfetantes na liberação de íons metálicos e na rugosidade superficial do titânio comercialmente puro, ligas metálicas e resina acrílica termopolimerizável, simulando 180 ensaios de imersões. Espécimes em formato de discos foram confeccionados com titânio comercialmente puro (Tritan), liga de níquel-cromo-molibdênio-titânio (Vi-Star), liga de níquel-cromo (Fit Cast-SB Plus) e liga de níquel-cromo-berílio (Fit Cast-V). Os espécimes (n=5) foram imersos nestas soluções: hipoclorito de sódio a 0,05%, Periogard, Cepacol, Corega Tabs, Medical Interporous e Polident. Como controle, foi utilizada a água deionizada. A análise quantitativa de liberação de íons metálicos foi realizada por meio de espectrometria de massa com plasma indutivamente acoplado (ELAN DRC II). O rugosímetro (Surftest SJ-201P) foi utilizado para medir a rugosidade superficial (µm). Os dados foram registrados antes e depois das imersões e avaliados por ANOVA com dois fatores e teste de Tukey (α=0,05). A liberação de níquel provou ser mais expressiva nas ligas Vi-Star e Fit Cast-V após a imersão em Medical Interporous. Houve diferença significante na rugosidade superficial da resina (p=0,011) após a imersão. O Cepacol causou maior rugosidade superficial de forma significativa. Os produtos de imersão não influenciaram nos resultados da rugosidade do metal (p=0,388). Pode-se concluir que as ligas metálicas testadas podem ser consideradas seguras para a fabricação de próteses removíveis, mas as soluções desinfetantes como o Cepacol e a pastilha Medical Interporous para a imersão diária da prótese devem ser utilizados com cautela, pois causaram maior rugosidade superficial da resina e maior liberação de íons, respectivamente.


Asunto(s)
Humanos , Bases para Dentadura , Aleaciones Dentales/química , Limpiadores de Dentadura/química , Resinas Acrílicas/química , Aleaciones/química , Aluminio/análisis , Berilio/análisis , Boratos/química , Cetilpiridinio/química , Clorhexidina/análogos & derivados , Clorhexidina/química , Aleaciones de Cromo/química , Cromo/análisis , Ácido Cítrico/química , Desinfectantes Dentales/química , Materiales Dentales/química , Ensayo de Materiales , Metales/análisis , Metales/química , Molibdeno/análisis , Níquel/análisis , Espectrofotometría Atómica , Propiedades de Superficie , Hipoclorito de Sodio/química , Sulfatos/química , Titanio/análisis , Titanio/química
19.
Braz Dent J ; 22(5): 392-7, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22011895

RESUMEN

Removable partial dentures (RPD) demand specific hygienic cleaning and the combination of brushing with immersion in chemical solutions has been the most recommended method for control of biofilm. However, the effect of the cleansers on metallic components has not been widely investigated. This study evaluated the effect of different cleansers on the surface of RPD. Five disc specimens (12 mm x 3 mm metallic disc centered in a 38 x 18 x 4 mm mould filled with resin) were obtained for each experimental situation: 6 solutions [Periogard (PE), Cepacol (CE), Corega Tabs (CT), Medical Interporous (MI), Polident (PO), 0.05% sodium hypochlorite (NaOCl), and distilled water (DW) control] and 2 Co-Cr alloys [DeguDent (DD) and VeraPDI (VPDI)] were used for each experimental situation. A 180-day immersion was simulated and the measurements of roughness (Ra, µm) of metal and resin were analyzed using 2-way ANOVA and Tukey's test. The surface changes and tarnishes were examined with a scanning electronic microscopy (SEM). In addition, energy dispersive x-ray spectrometry (EDS) analysis was carried out at representative areas. Visually, NaOCl and MI specimens presented surface tarnishes. The roughness of materials was not affected by the solutions (p>0.05). SEM images showed that NaOCl and MI provided surface changes. EDS analysis revealed the presence of oxygen for specimens in contact with both MI and NaOCl solutions, which might suggest that the two solutions promoted the oxidation of the surfaces, thus leading to spot corrosion. Within the limitations of this study, it may be concluded that the NaOCl and MI may not be suitable for cleaning of RPD.


Asunto(s)
Resinas Acrílicas/química , Aleaciones de Cromo/química , Materiales Dentales/química , Limpiadores de Dentadura/química , Dentadura Parcial Removible , Boratos/química , Cetilpiridinio/química , Clorhexidina/análogos & derivados , Clorhexidina/química , Ácido Cítrico/química , Corrosión , Humanos , Inmersión , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Oxidación-Reducción , Oxígeno/análisis , Hipoclorito de Sodio/química , Espectrometría por Rayos X , Sulfatos/química , Propiedades de Superficie , Factores de Tiempo
20.
J Prosthodont ; 20(8): 628-31, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21972796

RESUMEN

PURPOSE: This study evaluated the resistance to corrosion in welds made with Tungsten Inert Gas (TIG) in specimens made of commercially pure titanium (cp Ti) in comparison with laser welds. MATERIALS AND METHODS: A total of 15 circular specimens (10-mm diameter, 2-mm thick) were fabricated and divided into two groups: control group-cp Ti specimens (n = 5); experimental group-cp Ti specimens welded with TIG (n = 5) and with laser (n = 5). They were polished mechanically, washed with isopropyl alcohol, and dried with a drier. In the anodic potentiodynamic polarization assay, measurements were taken using a potentiostat/galvanostat in addition to CorrWare software for data acquisition and CorrView for data visualization and treatment. Three curves were made for each working electrode. Corrosion potential values were statistically analyzed by the Student's t-test. RESULTS: Statistical analysis showed that corrosion potentials and passive current densities of specimens welded with TIG are similar to those of the control group, and had lower values than laser welding. TIG welding provided higher resistance to corrosion than laser welding. CONCLUSION: Control specimens welded with TIG were more resistant to local corrosion initiation and propagation than those with laser welding, indicating a higher rate of formation and growth of passive film thickness on the surfaces of these alloys than on specimens welded with laser, making it more difficult for corrosion to occur.


Asunto(s)
Aleaciones Dentales/química , Titanio , Soldadura/métodos , Corrosión , Técnicas Electroquímicas , Rayos Láser , Ensayo de Materiales , Gases Nobles , Óxidos , Saliva Artificial , Titanio/química , Tungsteno
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