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AIM: To evaluate the impact of different light-curing times on dentin microtensile bond strength of two restorative systems after 24 h and 6 months of water storage. METHODS: Standardized Class II preparations were performed in 56 freshly-extracted human molars (n = 7), restored with methacrylate- or silorane-based restorative systems, and light-cured using a light-emitting diode at 1390 mW/cm2 by the recommended manufacturers' time or double this time. After storage for 24 h at 37 oC, the teeth were sectioned to yield a series of 0.8-mm thick slices. Each slab was trimmed into an hourglass shape of approximately 0.64 mm2 area at the gingival dentin-resin interface. Specimens were tested using universal testing machine at crosshead speed of 0.5 mm/min until failure, after 24 h and 6 months of storage. Data were statistically analyzed by three-way ANOVA and Tukey's test (α = 0.05). RESULTS: The highest bond strength values were recorded for the groups restored with methacrylate system (p<0.001) as well as for extended light-curing time (p = 0.0034). There was no statistically significant difference between 24 h and 6 months storage on bond strength (p>0.05). CONCLUSIONS: Bond strength was influenced by the material and light-curing time, but the 6-month storage did not affect the bond strength of restorations...
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Humanos , Masculino , Feminino , Resinas Compostas , Lâmpadas de Polimerização Dentária , Colagem Dentária , Dentina , Metacrilatos , Polimerização , Resinas de SiloranoRESUMO
OBJECTIVE: To evaluate quantitatively the marginal microleakage of restorations carried out with self-etching adhesives with or without prior phosphoric enamel acid etching of silorane or methacrylate resin-based composite restorations subjected to thermal cycling. MATERIALS AND METHODS: Forty cavities were prepared at the proximal surface of bovine incisors and randomly divided according to the etching of the enamel and restorative system used. The groups were restored with methacrylate [Adper SE Plus adhesive (3M ESPE) + Filtek Z250 (3M ESPE)] or silorane [Filtek LS adhesive (3M ESPE) + Filtek LS composite (3M ESPE)] restorative systems, light-cured using a LED unit (Bluephase 16i, Vivadent). After restorative procedure and thermocycling (1000 cycles), the specimens were immersed in methylene blue for 2 h. The specimens were triturated and the powder was used for analysis in an absorbance spectrophotometer. Data were statistically analyzed by 2-way ANOVA (alpha = 0.05). RESULTS: No statistical difference between the restorative materials tested with or without previous acid etching of enamel in Class II marginal microleakage was observed (p > 0.05). CONCLUSIONS: The use of acid etching prior to self-etching adhesives did not interfere on the microleakage of methacrylate- or silorane-based restorations.
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Condicionamento Ácido do Dente/métodos , Resinas Compostas/química , Esmalte Dentário/ultraestrutura , Infiltração Dentária/classificação , Materiais Dentários/química , Animais , Bovinos , Corantes , Lâmpadas de Polimerização Dentária , Preparo da Cavidade Dentária/classificação , Cura Luminosa de Adesivos Dentários/instrumentação , Teste de Materiais , Metacrilatos/química , Azul de Metileno , Ácidos Fosfóricos/química , Distribuição Aleatória , Resinas de Silorano/química , Espectrofotometria/instrumentação , Temperatura , Fatores de TempoRESUMO
CONTEXT: The food wrap films are used to cover the tip of curing light units in order to avoid contamination and prevent damage to the light guide. However, their effects on resin polymerization are not fully known. AIMS: We investigated the effects on restoration efficiency of a food wrap protective barrier used on the tip of curing light units. MATERIALS AND METHODS: For each treatment, five replications were performed, a total of 60 bovine incisor. The degree of conversion (%DC) of restorations with the composite resin Opallis EA2 was evaluated using 3 curing light devices (Optilux 501, Optilight and Ultra LED) and 2 curing distances (0 and 5 mm). The composite resin was tested for restoration of cavities in bovine crowns. %DC values were measured by the Fourier transform infrared spectroscopy-attenuated total reflectance technique. STATISTICAL ANALYSIS USED: The data were analyzed using 3-way ANOVA and Tukey's test. RESULTS: Use of the protective film lowered %DC (F = 4.13; P = 0.05), and the effects of curing distance were associated to the curing light device (F = 3.61; P = 0.03). CONCLUSIONS: The distance from the light curing tip and use of a translucent protective barrier on the light-cure device can both impair composite resin %DC.
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OBJECTIVES: The aim of this study was to evaluate the effects of different light sources and curing time on the degree of conversion and microhardness of two surfaces within a nanofilled composite resin. METHODS: Four experimental groups (n=10) were formed in accordance with the light source (quartz-tungsten halogen (QTH - 600mW/cm(2)), or light-emitting-diode (LED - 800mW/cm(2))) and the time of curing (20 s or 40 s). The specimens were prepared with a circular mould (5 mm ∅ and 2 mm thick), according to the respective protocol, and the Knoop microhardness and degree of conversion was measured at the top and the base of the specimens. The degree of conversion was evaluated by the Fourier transform infrared spectrometer (FTIR). The results were analyzed by ANOVA two-way repeated measures and Tukey's test (α=,05). RESULTS: Both the degree of conversion and microhardness were higher at the top than at the bottom of the specimens. The QTH light source presented better values on the degree of conversion evaluation, but this result was not observed in the microhardness evaluation. Although forty seconds of curing promotes an increased level of microhardness, it did not influence the degree of conversion. CONCLUSION: It could be concluded that increasing the time of curing to 40 s promotes an increase in microhardness, but it does not influence the degree of conversion of a nanofilled composite resin. QTH promote better monomeric conversion; however, the microhardness values are similar to LED curing. For all situations tested, the bottom of the specimens presented lower results than the top.
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The aim of this study was to evaluate the influence of different curing lights and chemical catalysts on the degree of conversion of resin luting cements. A total of 60 disk-shaped specimens of RelyX ARC or Panavia F of diameter 5 mm and thickness 0.5 mm were prepared and the respective chemical catalyst (Scotchbond Multi-Purpose Plus or ED Primer) was added. The specimens were light-cured using different curing units (an argon ion laser, an LED or a quartz-tungsten-halogen light) through shade A2 composite disks of diameter 10 mm and thickness 2 mm. After 24 h of dry storage at 37°C, the degree of conversion of the resin luting cements was measured by Fourier-transformed infrared spectroscopy. For statistical analysis, ANOVA and the Tukey test were used, with p ≤ 0.05. Panavia F when used without catalyst and cured using the LED or the argon ion laser showed degree of conversion values significantly lower than RelyX ARC, with and without catalyst, and cured with any of the light sources. Therefore, the degree of conversion of Panavia F with ED Primer cured with the quartz-tungsten-halogen light was significantly different from that of RelyX ARC regardless of the use of the chemical catalyst and light curing source. In conclusion, RelyX ARC can be cured satisfactorily with the argon ion laser, LED or quartz-tungsten-halogen light with or without a chemical catalyst. To obtain a satisfactory degree of conversion, Panavia F luting cement should be used with ED Primer and cured with halogen light.
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Bis-Fenol A-Glicidil Metacrilato/química , Iluminação , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Cimentos de Resina/química , Catálise , Lâmpadas de Polimerização Dentária , Lasers de Gás , Iluminação/instrumentação , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Aim: To evaluate the influence of light-curing units and light-curing time on the microhardness of a nanofilled composite resin. Methods: Forty-five composite resin (Z350 - 3M) specimens were randomly prepared using Teflon ring molds (4.0 mm internal diameter and 2 mm depth) and divided into nine experimental groups (n=5): three polymerization units (conventional - 450 mW/ cm2; 2nd generation LED - 1100 mW/cm2; and 3rd generation LED - 700 mW/cm2) and three lightcuring times (20 s, 40 s, and 60 s). All specimens were polymerized with the light-curing tip positioned 8 mm far from the top surface of the specimen. After 24 h, Knoop microhardness measurements were made on the top and bottom surfaces of the specimen, with a load of 10 g for 10 s. Five indentations were made on each surface. All results were analyzed statistically by subdivided parcel ANOVA (Split-Plot) and Tukey's tests (p<0.05). Results: There were no statistically significant differences for the polymerization unit and light-curing time factors in either top or bottom surface. For all experimental conditions, the top surfaces showed greater hardness than the bottom surfaces (p<0.0001). Conclusions: The mode of polymerization and the lightcuring time did not affect the hardness of the nanofilled composite resin, and increasing the lightcuring time did not improve the hardness of the bottom surface of the composite resin.
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Resinas Compostas , Polimerização , DurezaRESUMO
PURPOSE: To evaluate interface degradation leading to marginal microleakeage in Class II restorations that had received an application of surface sealant at the tooth/restoration interface or not. MATERIALS AND METHODS: Eighty bovine incisors were used, and the teeth were split obliquely, 10 mm from the amelodentinal proximal junction, and finished with water abrasive papers to obtain a smooth, flat incisal surface. Cavities were made to simulate Class II preparations (8 mm high, 4 mm wide and 1.5 mm deep), and the restorations were performed with a composite resin. Teeth were then randomly allocated into 8 groups according to the surface sealant (none, Fortify, Single Bond 2, or Scothbond MP Plus) and aging process (none or thermocycling and storage for 6 months). Microleakage was then evaluated using a dye penetration method immediately after the restoration or after aging. The samples were triturated and assessed by spectrophotometer. RESULTS: Microleakage was statistically similar in all groups when assessed immediately after the restorative procedure. After aging, teeth sealed with Fortify presented better results than the other groups. CONCLUSION: Aging causes interface degradation and increased microleakage. Surface sealant can reduce these effects and decrease microleakage in Class II restorations.
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Colagem Dentária , Infiltração Dentária/prevenção & controle , Adaptação Marginal Dentária , Restauração Dentária Permanente , Cimentos de Resina , Animais , Bovinos , Resinas Compostas , Restauração Dentária Permanente/classificação , Restauração Dentária Permanente/métodos , Análise do Estresse Dentário , Armazenamento de Medicamentos , Teste de Materiais , Espectrofotometria , Propriedades de Superfície , Colo do Dente , ÁguaRESUMO
STATEMENT OF PROBLEM: It is unknown whether the staining pigment concentration would affect the color of composite resin and whether the absorption of the staining pigment is related to the degree of conversion (DC). PURPOSE: The purpose of this study was to evaluate the effect of light-curing units (LCUs) on DC, superficial staining (ΔE), and pigment concentration (PC) in a nanofilled composite resin (Z350, 3M ESPE) using different beverages. MATERIALS AND METHODS: Specimens were polymerized for 20 seconds using four LCUs (N=50): quartz-tungsten-halogen (QTH)--450 mW/cm(2); laser (LAS)--300 mW/cm(2); second-generation light-emitting diode (LED)-1100 mW/cm(2); and third generation LED--700 mW/cm(2). DC (%) was measured using Fourier transform infrared spectroscopy. Specimens concerning each group (N=10) were then immersed in one of the solutions (distilled water, red wine, whisky, coffee, and cola--40 min/day, for 40 days). Specimen's color was measured before and after exposure to solutions using a colorimeter (Commission Internacionale de I'Eclairaga L*a*b* color scale), and ΔE was calculated. Specimens were then prepared for the spectrophotometric analysis to measure PC. Data were submitted to two-way analysis of variance and Tukey's test (p=0.05). RESULTS: DC: QTH presented the lowest DC, with statistical differences for LAS, LED 2, and LED 3. Whisky and wine showed lower PC mean values than cola and coffee. No statistical difference was observed for LCUs regarding PC and all staining solutions, except cola. Whisky showed the highest values for ΔE regarding all LCUs. Wine showed statistically lower ΔE than whisky, with water presenting the lowest ΔE. LAS and QTH showed higher values than LED 2 concerning ΔE. CONCLUSION: LCUs interfered with DC and altered the PC and ΔE of the composite resin submitted to different staining solutions. There was no correlation among DC, PC, and ΔE. CLINICAL SIGNIFICANCE: Light-curing modes might interfere with staining susceptibility, stain's retention, and DC of a composite resin, compromising the clinical performance. The highest pigment absorption was not associated with the highest superficial staining of the composite resin. Alcoholic drinks lead to greater superficial staining and non-alcoholic solutions lead to a higher pigment concentration.
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Bebidas , Resinas Compostas/efeitos da radiação , Lâmpadas de Polimerização Dentária/classificação , Materiais Dentários/efeitos da radiação , Nanocompostos/efeitos da radiação , Bebidas Alcoólicas , Bebidas Gaseificadas , Café , Cor , Colorimetria , Resinas Compostas/química , Materiais Dentários/química , Humanos , Lasers , Teste de Materiais , Nanocompostos/química , Pigmentos Biológicos/química , Pigmentos Biológicos/efeitos da radiação , Polimerização , Espectrofotometria , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Fatores de Tempo , Água/química , VinhoRESUMO
O restabelecimento da anatomia oclusal com uma estética favorável é uma exigência da sociedade hoje, sendo a resina composta indicada para restauração de dentes posteriores. Porém, para desempenharem esta função de forma satisfatória, modificações na composição deste material foram necessárias, como a melhoria da estética e, principalmente, de suas propriedades mecânicas. Entretanto, a contração de polimerização, um problema inerente do compósito odontológico, é uma propriedade física desfavorável do material, pois quanto maior a tensão de contração de polimerização maior o risco de ocorrer falha na interface dente-restauração, causando sensibilidade pós-operatória e microinfiltração aumentando o risco de desenvolvimento de lesão de cárie secundária, levando a falha do procedimento restaurador e consequente prejuízo na longevidade da restauração. O presente trabalho teve como objetivo revisar os principais aspectos envolvidos durante o procedimento restaurador de cavidades tipo Classe II que visam maior longevidade clínica
Restoration of occlusal anatomy with an acceptable aesthetic is a requirement of society today, and the composite resin indicated for restoration of posterior teeth. However, to perform this function satisfactorily, changes in the composition of this material were required, with improved aesthetics, and especially their mechanical properties. However, polymerization shrinkage, a problem inherent in the dental composite, is an unfavorable physical properties of the material, since the greater the tension of polymerization shrinkage increased the risk of failure occurs in the tooth-restoration interface, causing post-operative sensitivity and microleakage increasing the risk of developing secondary caries lesion, leading to failure of the restorative procedure and consequent loss in the longevity of the restoration. This study aimed to review the main aspects involved during the restorative procedure for Class II wells improved clinical longevity
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Materiais Dentários , Resinas Compostas , Restauração Dentária PermanenteRESUMO
This study analyzed the esthetics components of the smile, evaluating the relationship between the curve formed by the incisal line of the anterior superior teeth and the curve of the inferior lip, the touch of this incisal line on the inferior lip, the teeth displayed during smile, the relationship between the facial midline with the arch midline, the location of the arch midline and gender differences. Eighty-eight undergraduate students of the dentistry course of the TiradentesUniversity were selected. Two photographs were taken (smiling face and smile) using digital camera. The statistical analysis was performed after image tracing evaluation. Results show that the coincidence of the facial midline with the arch midline occurred only on half of the students. Most of the students presented parallelism between the incisal plan and the interpupillary line. Smiles with or without touch of the incisal line on the lower lip, smiles revealing up to the seconds premolars or firsts molars, and parallel or straight smiles were also most commonly observed. The majority of the men presented centeredmidline arch while women presented deviation to the right. No difference was found between the distribution of the arch midline.
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Adolescente , Adulto , Humanos , Masculino , Feminino , Arco Dental , Oclusão Dentária , Estética Dentária , SorrisoRESUMO
Este estudo analisou a prevalência da proporção áurea de indivíduos com sorrisos agradáveis, e sua diferença entre os sexos. Oitenta e oito estudantes do curso de odontologia da Faculdade Tiradentes foram selecionados, sendo 51 mulheres e 37 homens, entre 18 e 25 anos, obedecendo aos critérios da pesquisa. Foram realizadas as tomadas fotográficas dos dentes, utilizando câmera digital e papel milimetrado. Para a análise dos dados foi selecionado o teste do Qui-quadrado (χ2), utilizando-se o nível de significância de 5%, realizou-se a estatística com o software Bio-Estat 2.0. Os resultados mostraram que homens e mulheres não diferem quanto à presença da proporção áurea entre os incisivos centrais e laterais no lado esquerdo e a proporção áurea no lado direito está mais prevalente em mulheres do que nos homens. Homens e mulheres não apresentam proporção áurea entre os incisivos laterais e caninos no lado direito e a proporção áurea no lado esquerdo está mais prevalente em mulheres do que nos homens. A relação de proporção áurea não é aplicada na maior parte da população.