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1.
J Contemp Dent Pract ; 21(6): 609-614, 2020 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33025927

RESUMEN

AIM: This clinical study aimed to evaluate the efficacy of a toothpaste containing a proprietary REFIX technology (Regenerador + Sensitive DentalClean, Rabbit Corp) against dentin hypersensitivity. MATERIALS AND METHODS: Fifty-three volunteers who fulfilled the inclusion criteria and signed the consent form were included. They were examined for dentin hypersensitivity. The participants received a 1-second blast of air, and the tooth sensitivity, from 0 to 10, was immediately evaluated using a visual analog scale (VAS). Then, the participants brushed their teeth with the multifunctional toothpaste, and dentin hypersensitivity was tested a second time using the same scale. The participants continued to use the toothpaste three times a day for 1 week, after which dentin hypersensitivity was recorded for the third time. Data were statistically analyzed using analysis of variance (ANOVA) and Tukey's test (α = 0.05). RESULTS: The mean patient age was 40 years, and 70% of the 53 subjects were female. There was a significant reduction in dentin hypersensitivity immediately after using the toothpaste and after 1 week. The baseline mean patient-reported pain score was severe (6.5 ± 2.4). Immediately after the first use of the toothpaste, the mean reported pain significantly decreased to mild pain (2.5 ± 2.5) (p < 0.05). After 1 week of consistent use of the toothpaste, the pain score reduced significantly (0.7 ± 1.2) (p < 0.05), and most participants reported no pain, demonstrating the effectiveness of the REFIX technology against dentin hypersensitivity. CONCLUSION: This clinical trial shows that the use of the phosphate-based desensitizing toothpaste containing REFIX technology significantly reduces dentin hypersensitivity after 1 week of consistent use. CLINICAL SIGNIFICANCE: The absence of pain, a desired clinical condition in patients with dentin hypersensitivity, was reached with the use of desensitizing toothpaste containing REFIX technology after 1 week of use. Such condition positively impacts quality of life, providing a healthier daily routine for patients.


Asunto(s)
Desensibilizantes Dentinarios , Sensibilidad de la Dentina , Pastas de Dientes , Arginina , Carbonato de Calcio , Desensibilizantes Dentinarios/uso terapéutico , Sensibilidad de la Dentina/tratamiento farmacológico , Sensibilidad de la Dentina/prevención & control , Método Doble Ciego , Femenino , Fluoruros , Humanos , Calidad de Vida , Fluoruro de Sodio , Cepillado Dental , Pastas de Dientes/uso terapéutico , Resultado del Tratamiento
2.
Acta Odontol Latinoam ; 33(2): 98, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32920611

RESUMEN

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


Asunto(s)
Cerámica/química , Recubrimiento Dental Adhesivo , Porcelana Dental/química , Cementos de Resina/química , Humanos , Ensayo de Materiales , Propiedades de Superficie
3.
Acta odontol. latinoam ; 33(2): 98-103, Sept. 2020. graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1130739

RESUMEN

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


RESUMO O objetivo do presente estudo foi comparar o efeito de duas técnicas de processamento da cerâmica de dissilicato de lítio (prensada e CAD/CAM) no grau de conversão do cimento resinoso quando fotoativado e na resistência de união ao microcisalhamento do cimento resinoso às cerâmicas. Foram fabricados dois discos de cerâmica: um pela técnica prensada e outro pela técnica CAD/CAM. Cinco amostras de cimento resinoso Variolink Veneer foram fotoativadas através de cada disco cerâmico e submetidas à espectroscopia no infravermelho por transformada de Fourier com reflectância total para avaliar seu grau de conversão. Para avaliar a resistência de união ao microcisalhamento, foram preparadas 20 barras de cerâmicas: 10 utilizando a técnica prensada e 10 utilizando a técnica CAD/CAM. As barras foram tratadas com partículas de Al2O3 (50 μm), com ácido fluorídrico a 10% por 20 s e submetidas à aplicação do RelyX Ceramic Primer. Em seguida, o adesivo multiuso Adper Scotchbond foi aplicado nas barras e fotoativado por 10 s. Dois tubos de plástico de 1 mm de comprimento foram colocados em cada barra e preenchidos com cimento resinoso Variolink Veneer. Cada cilindro foi fotoativado por 20 s. Os tubos de plástico foram removidos e a resistência de união ao microcisalhamento de cada cilindro foi testada. Os dados de grau de conversão (%) e resistência de união ao microcisalhamento (MPa) foram submetidos ao teste t de Student (α = 0,05). Tanto o grau de conversão do cimento resinoso fotoativado através da cerâmica quanto a resistência de união do cimento resinoso à cerâmica foram estatisticamente maiores no grupo em que a cerâmica foi confeccionada pela técnica CAD/CAM (44,74% e 22,18 MPa) do que no grupo em que a cerâmica foi confeccionada pela técnica prensada (25,71% e 19,83 MPa). As técnicas de processamento de cerâmica dissilicada de lítio afetaram o grau de conversão do cimento resinoso quando fotoativado através das cerâmicas e a resistência de união do microcisalhamento do cimento resinoso às cerâmicas.

4.
J Oral Sci ; 62(1): 103-106, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31996511

RESUMEN

This study aims to evaluate the effect of mouth rinses on the color, microhardness, and surface roughness of tooth enamel. Sixty dental blocks were collected from human third molars and divided in five groups (n = 12): the control group (CG) without immersion in mouth rinse, Listerine Zero, Colgate Plax Fresh Mint, Listerine Whitening, and Colgate Luminous White. The groups were subjected to initial color analysis; the microhardness and roughness of the enamel surfaces were evaluated. Next, the samples were subjected to immersion in mouth rinses or brushing with conventional fluoride toothpaste (CG) according to the manufacturer's instructions; after a 12-week treatment, the color, microhardness, and roughness were once again assessed and compared with the initial analysis. Data were tabulated and analyzed through a two-way analysis of variance (ANOVA) (color and roughness) followed by Tukey's test. Microhardness was analyzed through the Kruskal-Wallis test followed by Dunn's test; the level of significance was 5%. All groups immersed in mouth rinses had a higher level of microhardness loss than CG; additionally, all groups showed changes in the enamel surface. Enamel surface loss was observed using a roughness test, and the mouth rinses promoted a higher level of color changes than CG. Given the results, it can be concluded that the mouth rinses led to significant changes in tooth enamel.


Asunto(s)
Blanqueamiento de Dientes , Diente , Esmalte Dental , Humanos , Antisépticos Bucales , Pastas de Dientes
5.
Minerva Stomatol ; 69(3): 153-158, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31633319

RESUMEN

BACKGROUND: The objective was to examine the microshear bond strength values of different dual resin cements to computer-aided design (CAD)/computer-aided manufacturing (CAM)-created ceramics containing lithium disilicate, which underwent different surface treatments. METHODS: Two dual resin cements (RelyX ARC and RelyX Ultimate) and three surface treatments of lithium disilicate ceramic blocks (Ceramic Primer (CP; containing silane) plus Adper Scotchbond Multipurpose (ASM) adhesive; CP plus Single Bond Universal (SBU) adhesive; and SBU adhesive alone) were tested. The SBU adhesive includes silane in its formulation. Each sample underwent a microshear test and bond strength values were subjected to analysis of variance (ANOVA) followed by Tukey's test (α=0.05). Fracture patterns were also observed with light microscopy. RESULTS: RelyX ARC treated with CP+ASM or CP+SBU presented resistance values that were significantly higher than the same treatments for RelyX Ultimate. Conversely, for the blocks treated with SBU alone, the mean resistance value for RelyX Ultimate was higher than that of RelyX ARC. Regarding the different types of treatment for each resin, the mean resistance value of RelyX ARC treated with CP+ASM was significantly highest, followed by treatment with CP+SBU and SBU treatment alone. Meanwhile, RelyX Ultimate treated with CP+ASM or CP+SBU presented resistance values that were significantly higher than SBU treatment alone. In all of the groups, an adhesive fracture pattern was predominantly observed. CONCLUSIONS: The present results indicate that silanization is important for ASM and SBU adhesives to be effective.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Cerámica , Diseño Asistido por Computadora , Cementos Dentales , Porcelana Dental , Ensayo de Materiales , Propiedades de Superficie
6.
Acta Odontol Latinoam ; 33(3): 221-227, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-33523088

RESUMEN

The aim of this study was to evaluate the precision and accuracy of molds made with four commercial brands of alginate scanned at different times using digital model analysis. Eighty molds of a standard Typodont were made using 4 types of alginate (CCC: Cavex Color Change; IA: Identic Alginate; HY5: Hydrogum 5 and JP: Jeltrate Plus). The molds were scanned at four times: immediately (T1), 24h (T2), 72h (T3) and 120h (T4) after molding. Measurements were taken in three dimensions: anteroposterior, transverse and vertical. Significant differences in dimensional changes were noted between the materials over time (p <0.05). Anteroposterior dimensional variation was noted between times, especially for IA and JP. For transverse and vertical variables, a difference was found between the groups, especially at 24 h, 72 h and 120 h. CCC presented significant dimensional shrinkage only at T120 (transverse). IA and JP presented larger dimensional distortions in the vertical measurements. The molding materials used were not dimensionally stable when evaluated after 120 hours of molding. However, such evidence suggests that alginates with longer storage time, such as Cavex Color Change, are more accurate than conventional alginates.


Asunto(s)
Alginatos/química , Materiales de Impresión Dental/química , Modelos Dentales , Técnica de Impresión Dental , Humanos , Ensayo de Materiales
7.
Minerva Stomatol ; 68(5): 259-264, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31822050

RESUMEN

BACKGROUND: To evaluate the effects of adhesive systems and primer systems on microshear bond strength of chemically activated resin cemented to Co-Cr cast dental alloy. METHODS: Seventy-two rectangular blocks of Co-Cr metal alloy were manufactured and air-abraded with 50-µm Al2O3 particles. Metal primers (alloy primer [AP] or Clearfil ceramic primer [CP]) and adhesives (Adper Scotchbond Multi-Purpose Adhesive activated by Adper Scotchbond Multi-Purpose Adhesive Catalyst [SASC], or Primer & Bond 2.1 activated by Self Cure Activator [PBCA]) were applied and subsequently divided into six groups (SASC; AP+SASC; CP+SASC; PBCA; AP+PBCA; CP+PBCA; N.=12). Then, resin cement (Enforce) was applied. Data about microshear bond strength values were statistically evaluated by analysis of variance and Tukey's test. RESULTS: The bond strength was lower (P<0.001) in groups with adhesive system alone (SASC and PBCA) compared with groups with addition of primers alloy primer (AP+SASC and AP+PBCA) and ceramic primer (CP+SASC and CP+PBCA). CONCLUSIONS: The application of primers improves the bond strength of the cement resin to the Co-Cr metal alloy.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Aleaciones , Análisis del Estrés Dental , Ensayo de Materiales , Metacrilatos , Resistencia al Corte , Propiedades de Superficie
8.
Am J Dent ; 32(5): 235-239, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31675191

RESUMEN

PURPOSE: To evaluate the effect of whitening mouthrinses on sorption (SP) and solubility (SL), percentage of microhardness change (%M), loss of surface (LS), and color change (ΔE) in bulk-fill composites when compared with conventional composites. METHODS: Three bulk-fill composites, Surefil SDR (SF), Filtek Bulk-Fill (BF), and Filtek Bulk-Fill Flow (BFF), and one conventional resin, Filtek Z350 (FZ), were selected. Eighteen samples of each composite were subdivided into three groups based on the type of treatment: Listerine Whitening mouthrinse (LW), Colgate Plax Whitening mouthrinse (CP), and distilled water (DW; control). The samples were prepared according to ISO 4049:2009. Color, roughness, and microhardness were evaluated before and after treatment, while SP and SL values were measured after treatment. The surface morphology of the specimen was examined using scanning electron microscopy. Data were analyzed using two-way ANOVA and Tukey's test. RESULTS: FZ presented significantly lower ΔE when immersed in DW. Additionally, LS was lowest in FZ when compared with the other resins. SF and BFF demonstrated high %M. SL was significantly higher in SF, whereas SP was lowest in BFF after CP treatment. No significant alterations in surface morphology were noted in the BF composites. The BF composites showed a decrease in their properties after immersion in the two types of mouthrinses or in DW, without alterations in the surface morphology. CLINICAL SIGNIFICANCE: Flowable bulk-fill composites showed the greatest changes in their properties when exposed to different mouthrinses or water. Thus, they should be used with caution in areas that will stay exposed to the oral cavity.


Asunto(s)
Resinas Compuestas , Ensayo de Materiales , Solubilidad
9.
Braz Dent J ; 30(5): 453-458, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31596329

RESUMEN

The aim of this study was to analyze the effects of MTA on the structure and enzymatic activity of sPLA2 in order to provide subsidies for improvement in the formulation of the product. MTA powder was incubated for 60 min in the presence of sPLA2 and was analyzed by chromatography, electrospray mass (ESI-MS) and small-angle X-ray scattering (SAXS). It was find that the elution profile, retention time, and fragmentation of sPLA2 were altered after treatment with MTA. Calcium was the MTA component that most amplified the inflammatory signal. Significant interactions were found between MTA and sPLA2, which could aid in our understanding of the mechanisms of action of MTA during the inflammatory process and it may facilitate the structural modification of MTA, thereby improving its biological safety and consequently the rate of the treatment success.


Asunto(s)
Materiales de Obturación del Conducto Radicular , Compuestos de Aluminio , Compuestos de Calcio , Combinación de Medicamentos , Óxidos , Dispersión del Ángulo Pequeño , Silicatos , Difracción de Rayos X
10.
Braz. dent. j ; 30(5): 453-458, Sept.-Oct. 2019. graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1039141

RESUMEN

Abstract The aim of this study was to analyze the effects of MTA on the structure and enzymatic activity of sPLA2 in order to provide subsidies for improvement in the formulation of the product. MTA powder was incubated for 60 min in the presence of sPLA2 and was analyzed by chromatography, electrospray mass (ESI-MS) and small-angle X-ray scattering (SAXS). It was find that the elution profile, retention time, and fragmentation of sPLA2 were altered after treatment with MTA. Calcium was the MTA component that most amplified the inflammatory signal. Significant interactions were found between MTA and sPLA2, which could aid in our understanding of the mechanisms of action of MTA during the inflammatory process and it may facilitate the structural modification of MTA, thereby improving its biological safety and consequently the rate of the treatment success.


Resumo O objetivo deste estudo foi analisar os efeitos do MTA na estrutura e atividade enzimática da sPLA2 a fim de fornecer subsídios para melhoria na formulação do produto. O MTA em pó foi incubado por 60 min na presença de sPLA2 e analisado por cromatografia, espectroscopia de massa por eletropulverização (ESI-MS) e espalhamento de raios-X de baixo ângulo (SAXS). Encontrou-se que o perfil de eluição, o tempo de retenção e a fragmentação da sPLA2 foram alterados após o tratamento com MTA. O cálcio foi o componente do MTA que mais ampliou o sinal inflamatório. Encontraram-se interações significativas entre o MTA e o sPLA2, o que poderia auxiliar na compreensão dos mecanismos de ação do MTA durante o processo inflamatório e facilitar a modificação estrutural do MTA, melhorando sua segurança biológica e consequentemente a taxa de sucesso do tratamento.

11.
Acta Odontol Latinoam ; 31(3): 144-149, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30829369

RESUMEN

The purpose of this study was to describe and characterize (using the tensile test) an alternative handling technique for calcium hydroxide cement in temporary crown cementation. In the group treated with the conventional technique (n=10), the base and catalyst pastes of a calcium hydroxide cement (Dycal) were dispensed at a 1:1 ratio and mixed. The cement was then applied to the internal cervical surfaces of the provisional restoration, and the restoration was placed on the prepared tooth and kept in place with digital pressure. In the group treated with the alternative technique (n=10), the base paste of the calcium hydroxide cement (Dycal) was placed on the tooth and the catalyst paste was inserted into the temporary crown.The provisional prosthesis was placed on the tooth and kept in place with digital pressure. Tensile values were evaluated and compared between groups using Student's t test with a 5% level of significance (α = 0.05). Use of this alternative technique resulted in significantly lower tensile strength compared to the conventional technique (0.58 ± 0.12 vs. 1.08 ± 0.13 MPa; p<0.001). The technique presented here (alternative) could avoid the undesired removal of cemented cast posts or cores at the time of provisional prosthesis removal and ensures the cementation of extensive provisional prostheses with calcium hydroxide cement.


Asunto(s)
Hidróxido de Calcio , Cementación/métodos , Coronas , Cementos Dentales , Animales , Bovinos , Incisivo , Modelos Animales , Resistencia a la Tracción , Preparación Protodóncica del Diente/métodos
12.
Acta Odontol Latinoam ; 30(1): 13-18, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28688181

RESUMEN

This study compared the surface detail reproduction and dimensional accuracy of molds after disinfection using 2% sodium hypochlorite, 2% chlorhexidine digluconate or 0.2% peracetic acid to those of molds that were not disinfected, for four elastomeric impression materials: polysulfide (Light Bodied Permlastic), polyether (Impregum Soft), polydimethylsiloxane (Oranwash L) andpolyvinylsiloxane (Aquasil Ultra LV). The molds were prepared on a matrix by applying pressure, using a perforated metal tray. The molds were removed following polymerization and either disinfected (by soaking in one of the solutions for 15 minutes) or not disinfected. The samples were thus divided into 16 groups (n=5). Surface detail reproduction and dimensional accuracy were evaluated using optical microscopy to assess the 20-µm line over its entire 25 mm length. The dimensional accuracy results (%) were subjected to analysis of variance (ANOVA) and the means were compared by Tukey's test (a=5%). The 20-µm line was completely reproduced by all elastomeric impression materials, regardless of disinfection procedure. There was no significant difference between the control group and molds disinfected with peracetic acid for the elastomeric materials Impregum Soft (polyether) and Aquasil Ultra LV (polyvinylsiloxane). The high-level disinfectant peracetic acid would be the choice material for disinfection.


Asunto(s)
Desinfectantes Dentales , Materiales de Impresión Dental , Polímeros , Técnica de Impresión Dental , Precisión de la Medición Dimensional , Elastómeros , Ensayo de Materiales , Propiedades de Superficie
13.
Minerva Stomatol ; 65(2): 65-71, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27009411

RESUMEN

BACKGROUND: This study evaluated the influence of 2-hydroxyethyl methacrylate (HEMA) on the degree of conversion (DC) and cytotoxicity of a dental bonding resin (DBR). METHODS: A monomer mixture based on 61.9 wt% of bisphenol A glycidyl methacrylate (Bis-GMA), 36.9 wt% of triethylene glycol dimethacrylate (TEGDMA), and photoactivated using a binary system based on camphoroquinone (0.4 wt%) and ethyl 4-dimethylamine benzoate (0.8 wt%) was used as DBR. Different groups were obtained with addition of HEMA in crescent concentrations. DC was accessed by Real time Fourier Transform infrared spectroscopy. The cytotoxicity was evaluated with MTT assay. The DC and cytotoxicity were analyzed by one-way ANOVA followed by Tukey's Test (P<0.05). RESULTS: A decrease in the DC was observed in the group with higher amount of HEMA. All tested-extracts were cytotoxic and there was an increased cytotoxic effect with higher HEMA addition. CONCLUSIONS: Higher amount of HEMA in the DBR resulted in adverse effects, with more cell toxicity and lower degree of conversion.


Asunto(s)
Bisfenol A Glicidil Metacrilato , Recubrimiento Dental Adhesivo , Humanos , Resinas Sintéticas , Espectroscopía Infrarroja por Transformada de Fourier
14.
Acta Odontol Latinoam ; 28(2): 156-61, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26355886

RESUMEN

This study compared the surface detail reproduction and dimensional accuracy of stone models obtained from molds prepared using different alginate impression materials (Cavex ColorChange, Hydrogum 5, or Jeltrate Plus) and with different storage times (1, 3, and 5 days) to models from molds that were filled immediately with no storage time. The molds were prepared over a matrix containing 50-µm line, (ISO 1563 standard) under pressure with a perforated metal tray. The molds were removed 2 minutes after loss of sticky consistency and either filled immediately or stored in closed jars at 100% relative humidity and 37°C for 1, 3, or 5 days. The molds were filled with dental plaster (Durone IV). Surface detail reproduction and dimensional accuracy were evaluated using optical microscopy on the 50-µm wide line, which was 25 mm in length, according to ISO 1563 standard. The dimensional accuracy results (%) were subjected to analysis of variance. The 50-µm wide line (ISO 1563 standard) was completely reproduced by all alginate impression materials regardless of the storage time. There was no statistically significant difference in the mean dimensional accuracy values of stone models made from molds composed of different alginate impression materials and with different storage times (p = 0.989). In conclusion, storing the mold for five days prior to filling did not change the surface detail reproduction or dimensional accuracy of the alginates examined in this study.


Asunto(s)
Propiedades de Superficie , Materiales de Impresión Dental , Técnica de Impresión Dental , Materiales Dentales , Modelos Dentales , Ensayo de Materiales , Presión
15.
Eur J Oral Sci ; 121(4): 377-81, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23841791

RESUMEN

The objective of this study was to evaluate the antioxidant effect of green tea on microtensile bond strength (µTBS) to bleached enamel. Forty-two human third molars were randomly divided into six experimental groups (n = 7 each group): group 1, no treatment; group 2, bleaching (10% carbamide peroxide); group 3, bleaching + 10% sodium ascorbate gel (SA); group 4, bleaching + 10% green tea gel (GT); group 5, SA; and group 6, GT. In groups 2, 3, and 4, bleach was applied onto the enamel surface for 6 h, every day for 14 d. In groups 3 and 5, SA was applied for 1 h; and in groups 4 and 6, GT was applied for 1 h. Immediately after treatment, the specimens were bonded with Adper Single Bond 2 and Filtek Z350 XT. The µTBS of the specimens was tested using a universal testing machine. Fracture mode analysis of the bonded enamel surface was performed using scanning electron microscopy. The mean µTBS values for each group were: group 1, 33.2 ± 5.8 MPa; group 2, 22.6 ± 5.5 MPa; group 3, 30.0 ± 5.2 MPa; group 4, 31.6 ± 3.8 MPa; group 5, 29.1 ± 4.2 MPa; and group 6, 32.2 ± 4.5 MPa. All groups had a higher percentage of mixed failures. In conclusion, green tea can be used as an alternative antioxidant on bleached enamel before bonding procedures.


Asunto(s)
Ácido Ascórbico/química , Recubrimiento Dental Adhesivo/métodos , Esmalte Dental/química , Peróxidos/efectos adversos , Cementos de Resina/química , Té/química , Blanqueamiento de Dientes/efectos adversos , Urea/análogos & derivados , Análisis de Varianza , Antioxidantes/química , Peróxido de Carbamida , Análisis de Falla de Equipo , Geles/química , Humanos , Microscopía Electrónica de Rastreo , Resistencia a la Tracción , Urea/efectos adversos
16.
Gerodontology ; 29(2): e553-9, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21787371

RESUMEN

OBJECTIVE: To verify the influence of repeated microwave disinfections on the shear bond strength of two commercial types of teeth to acrylic resin, when the ridge lap surfaces were unmodified, bur abraded, bur grooved or etched by monomer. MATERIAL AND METHODS: Eighty specimens (n = 10) were adhered to the tooth ridge lap surface, polymerised in a water bath at 74°C for 9 h. Microwaved specimens were individually immersed in 150 ml of water and submitted to five simulated disinfections in a microwave oven calibrated at 650 W for 3 min. Control specimens were not microwave treated. Shear bond strength tests were performed in an Instron machine with a cross-speed of 1 mm/min. The fracture load values were transformed into shear bond strength as a function of the bonding area (0.28 cm(2)). Data were submitted to ANOVA and Tukey's test (α = 0.05). Fractured areas were classified as adhesive, cohesive (resin or tooth) or mixed failures. RESULTS: Repeated microwave disinfections increased the shear strength of the tooth/resin bond. Mechanical retention in microwaved and non-microwaved procedures improved the shear bond strength. CONCLUSIONS: The different commercial types of teeth influenced shear bond strength values, with Biotone teeth showing the lower values.


Asunto(s)
Resinas Acrílicas/efectos de la radiación , Recubrimiento Dental Adhesivo , Materiales Dentales/efectos de la radiación , Bases para Dentadura , Desinfección/métodos , Microondas/uso terapéutico , Diente Artificial , Grabado Ácido Dental/métodos , Resinas Acrílicas/química , Adhesividad , Grabado Dental/instrumentación , Materiales Dentales/química , Análisis del Estrés Dental/instrumentación , Humanos , Ensayo de Materiales , Cerámicas Modificadas Orgánicamente/química , Cerámicas Modificadas Orgánicamente/efectos de la radiación , Polimerizacion , Resistencia al Corte , Estrés Mecánico , Propiedades de Superficie , Temperatura , Factores de Tiempo , Agua/química
17.
Gerodontology ; 27(3): 236-42, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20545779

RESUMEN

OBJECTIVE: The purpose of this study was to verify the effect of microwave treatment on the shear bond strength of commercial types of teeth to acrylic resin, when the glossy ridge laps were unmodified (groups 1 and 5), bur abraded (groups 2 and 6), bur grooved (groups 3 and 7) or etched by monomer (groups 4 and 8). BACKGROUND: Controversial findings have shown that mechanical or chemical changes in ridge-lap surface of the tooth increase or decrease the bond strength between tooth and acrylic resin, and the microwave disinfection may cause different changes on this bond strength. MATERIALS AND METHODS: Eighty specimens (n = 10) were made with the acrylic resin bonded to tooth glossy ridge lap, polymerised in water at 74 degrees C for 9 h, and deflasked after flask cooling. Specimens of the groups 5, 6, 7 and 8 were individually immersed in 150 ml of water and submitted to microwave treatment in an oven at 650 W for 3 min. Control specimens (groups 1, 2, 3 and 4) were not microwave treated. Shear bond strength test was performed in an Instron machine with a cross-speed of 1 mm/min. Collected data were submitted to anova and Tukey's test (alpha = 0.05). RESULTS: Microwave treatment decreased the shear bond strength values of the tooth/resin bond. In the microwaved and non-microwaved procedures, mechanical retention improved the shear bond strength when compared with the control and monomer treatments. CONCLUSION: Shear bond strength of the tooth/resin bond was influenced by the microwave treatment and different commercial teeth association, and was lower for the Biotone tooth.


Asunto(s)
Resinas Acrílicas/efectos de la radiación , Recubrimiento Dental Adhesivo , Materiales Dentales/efectos de la radiación , Microondas , Diente Artificial , Resinas Acrílicas/química , Grabado Dental/métodos , Materiales Dentales/química , Análisis del Estrés Dental/instrumentación , Humanos , Ensayo de Materiales , Polimerizacion , Resistencia al Corte , Estrés Mecánico , Propiedades de Superficie , Temperatura , Factores de Tiempo , Agua/química
18.
J Oral Sci ; 50(2): 137-42, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18587202

RESUMEN

The aim of this study was to determine the effect of different types of composites (Filtek Z250, Esthet X and Filtek Supreme) and dentin thicknesses (0.5 or 1.0 mm) on the generation of heat during photoactivation by QTH (conventional halogen light), LED (light emitting diode), and PAC (xenon plasma light) light-curing units. Temperature changes were recorded with a thermocouple type K connected to a digital thermometer. Twenty chemically polymerized acrylic resin bases were prepared in order to guide the thermocouple and to support the dentin disks. On the acrylic resin base, elastomer molds of 2.0-mm thickness were adapted. The temperature increase was measured after composite photoactivation and the matrix was stored at 37 degrees C. After 24 hours, photoactivation was performed again and the temperature increase was measured. Obtained data were analyzed by ANOVA and Tukey's test (alpha= 0.05). The mean temperature increase produced by QTH was significantly lower than that of the other photoactivating units (P < 0.05), due to its low radiant exposure. There were no significant differences among the samples with regard to dentin thickness and type of composites (P > 0.05). The immediate temperature rise was statistically higher when compared to the increase after additional polymerization (24 h), in all groups (P < 0.05). Light intensity and exposure time appeared to be the most important factors causing temperature change.


Asunto(s)
Resinas Compuestas/química , Materiales Dentales/química , Dentina/anatomía & histología , Iluminación/instrumentación , Resinas Acrílicas , Animales , Bovinos , Resinas Compuestas/efectos de la radiación , Materiales Dentales/efectos de la radiación , Diseño de Equipo , Calor , Humedad , Luz , Ensayo de Materiales , Polímeros/química , Polímeros/efectos de la radiación , Dosis de Radiación , Temperatura , Termómetros , Factores de Tiempo
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