ABSTRACT
Current innovations in restorative dentistry include nanofilled composite resinmaterials for direct and indirect restorations. Moreover, the advances in adhesivedentistry have provided autopolymerising, dual-polymerizing and lightpolymerizing resin-based adhesives for ceramic restoration bonding. In addition,resin cements have been combined with self-adhesive components for adhesiveprocedures. Composite failure has been a great challenge for dental clinician all overthe world , making it difficult for the dentist to satisfy patients. Major problems seeninclude polymerization, shrinkage and colour instability. There being no perfectmethod for this restorative material to overcome the problems, clinicians must keepin mind as to what material and technique should be used in a patient dependingupon the case. The success of composite restorations is due to their colour stabilityover time. Accurate shade matching of tooth coloured restoration with the adjacentdentition is essential not only at the time of fabrication but also for the lifetimedurability. Discolouration of composite resins can be caused by internal or externalfactors. Internally induced discolouration is permanent and is related to polymerquality, filler type, and amount, as well as the synergist added to the photo initiatorsystem. Alterationof matrix or filler components of resin composites andincomplete polymerization constitute intrinsic factors leading to discolouration. It isreported that saliva, food components, and beverages may affect the aesthetics andintegrity of dental composites. This is a factual truth for dental porcelain but incontradiction, colour instability in porcelain restoration is a common dilemmanowadays, especially when they are exposed to routinely consumable beverages.We have reviewed different factors responsible for colour stability of compositerestoration, and different s
ABSTRACT
@# Colour stability of the material is an essential factor that contributes to the selection of a flexible denture material. Staining effects on the denture may result in unattractive appearance, the dissatisfaction of the wearer, and limited usage period of the denture. This study aims to identify the colour stability of the Valplast flexible denture material using three types of beverages. Methods: A total of 32 disc-shaped flexible resin materials (20 +/- 0.1 mm in diameter and thickness 3 +/- 0.1 mm) were prepared based on the manufacturer instructions. The samples were randomly divided into 4 groups of immersion: distilled water (control), coffee solution, tea solution and red wine. The samples were left in the specified immersion solution for up to 60 days. Colour changes were measured after 1, 3, 7, 14, 21, 30, 45 and 60 days of immersion. Results: The samples immersed in coffee solution changed from S1 to S2, whereas samples in tea solution changed from S1 to S3. Additionally, samples in red wine changed from S1 to S4, as observed using the Valplast colour tone guide. The highest reflection measured using spectroscopy was 65.146 at 385.19 nm of the control samples, whereas the lowest reflection was 1.974 at the wavelength of 385.97 nm on the samples immersed in the red wine. Conclusion: The most significant difference can be observed in the red wine group, followed by samples in tea and coffee solutions. Moreover, increasing the immersion period causes increasing staining effect of the denture.
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Objective: To evaluate the effect of several beverages on the physical properties of SonicFill (Kerr Corp.,USA), a new bulk-fill dental composite, over a period of time. Methods: A total of 28 discs (10 mm x 2mm) were prepared and randomly assigned into 4 groups (n=7) according to the beverages they wouldbe immersed in. The beverages chosen were Coca-Cola?, Nescafe? coffee, Lipton tea? and distilledwater (control). Surface roughness, microhardness and colour stability were evaluated using 3D opticalsurface texture analyser, Vickers microhardness tester and spectrophotometer respectively. Readingswere recorded at the time intervals of 24 hours, 1 week and 1 moth after immersion. The data obtainedwere analysed using one-way ANOVA, repeated measures ANOVA and MANOVA. Results: There weresignificant differences in surface roughness for only two pairs of groups (distilled water and Coca-Cola,distilled water and coffee). However, there was no significant difference between the groups within thechosen time. Statistical analysis showed significant difference in microhardness between time only forCoca-Cola, with significant differences between 24 hours and 1 week; and 24 hours and 1 month. Forthe colour evaluation, there was significant difference between the groups within time. Conclusions:All the beverages chosen were able to affect the physical properties of the SonicFill. However, noparticular beverage had a higher or lower impact on the surface roughness than the other beverages.Microhardness was affected by distilled water and Coca-Cola, in ascending order. Colour was affectedmost by coffee, followed by tea and Coca-Cola.
ABSTRACT
Composite resins Amaris is claimed to have hydrophobic effect which minimizes the staining intake. This study is to investigate the colour stability of Amaris compared to Filtek Z250 in coffee solution. Sixty discs of composite resins Filtek Z250 (3M ESPE) and Amaris (Voco) with diameter of 5mm and depth of 2mm were fabricated by packing in a drinking straw and sectioned with hard tissue cutter (Exakt, Japan). The surfaces of the specimens were polished with Sof-Lex disc before each group of the samples is immersed in coffee solution. They were kept in the solution for 4 days at 370C and assessed at the period of 2 hours, 1 day, 2 days, 3 days, and 4 days. The staining was assessed visually and recorded using Lobene (1968) Stain Index and score was given accordingly. The colour changes of both groups were not statistically significant (p<0.05) for period of 2 hours, 1day, 2 days, 3 days and 4 days All groups showed the score values increased gradually with time. Both composite resins have similar colour stability in coffee solutions.
ABSTRACT
Se evaluaron las propiedades del color y la estabilidad a diferentes factores (temperatura y pH) de soluciones de los antranoides prenilados ferruginina A (FRA) y ?-hidroxiferruginina A (HFA), obtenidos a partir de las bayas de las especies Vismia guianensis y V. baccifera ssp. ferruginea. El estudio de la influencia de la temperatura sobre las características espectrales reveló que las soluciones en propilenglicol de la FRA y la HFA son relativamente estables al calor a las temperaturas de 50 y 80 °C , mientras que a 100 y 150 °C presentaron cambios ligeros en la intensidad (e) y tonalidad (?vis-max, coordenadas colorimétricas CIE L* a* b*). Adicionalmente, las variaciones del color (?vis-max, e) para los antranoides en el rango de pH 1,0-11,0 durante 60 días de almacenamiento a 4 y 25 °C , demostraron una mayor estabilidad del color en condiciones de refrigeración y pH 6,0 y 8,0, la cual fue superior para las soluciones de HFA. Las buenas características de los compuestos los hacen potencialmente útiles como colorantes naturales en la industria de los cosméticos, textil y farmacológica.
Colour properties and stability to different factors (temperature and pH) of solutions of prenylated anthranoids ferruginin A (FRA) and ? -hydroxyferruginin A (HFA), obtained from berries of Vismia guianensis and V. baccifera ssp. ferruginea, were evaluated. Spectral characteristics influenced by different temperatures, revealed that the solutions in propylenglycol of the FRA and HFA were relatively stable to the heat to temperatures of the 50 and 80 °C , whereas to temperatures of 100 and 150 °C they displayed slight changes in the intensity ( e ) and tonality ( ? vis-max, colorimetric co-ordinates in the CIE L* a* b* scale). Additionally, colour variation ( ? vis-max, e ) for both anthranoids in the pH range 1.0 - 11.0 during a period of 60 days storage at 4 and 25 °C , showed higher colour stability in refrigerated conditions and pH values of 6.0 and 8.0, being better for solutions of HFA. The good characteristics of compounds make them potentially useful like natural colourants in the textile, cosmetic and pharmacological industry.
Foram avaliadas as propriedades da cor e a estabilidade de fatores diferentes (temperatura e pH) de soluções dos antranoides prenilados ferruginina A (FRA) e ? -hidroxiferruginina A (HFA), obtidos das bagas das espécies Vismia guianensis e V. baccifera ssp. ferruginea. O estudo da influência da temperatura nas características espectrais mostra que as soluções em etilenglicol da FRA e a HFA foram relativamente estáveis ao calor para as temperaturas de 50 e 80 °C , enquanto para temperaturas de 100 e 150 °C apresentaram mudanças leves na intensidade ( e ) e tonalidade ( ? vis-max, coordenadas CIE L* a* b*). Além do mais, as variações da cor ( ? vis-max, e ) dos antranoides no rango de pH 1,0-11,0 durante 60 dias de armazenamento a 4 e 25 °C mostraram uma estabilidade maior em condições refrigerasão e em valores de pH de 6,0 e de 8,0, sendo melhor para soluções do HFA. As características boas dos compostos os fazem potencialmente úteis como corantes naturais nas indústrias das cosméticas, têxtil e farmacêutica.
ABSTRACT
In a preliminary study of various excipients that could stabilize the colour of tetracycline hydrochloride (TC), it was found that sodium metabisulfite yielded the maximum stability and it was then chosen for a further study. Comparative studies of the colour and chemical stability of TC powder in capsules in different of colour capsule shells, different types of containers, as well as the omission and addition of 0.1% sodium metabisulfite were then made. The results showed that, after 36 months at ambient temperature, there was no significant difference in colour of the drug powder in each formula resulting from the type of container or colour of the capsule shell. At ambient temperature, the addition of sodium metabisulfite prolonged shelf life from 3 to 9 mnths in colour stability aspect, but the rate constant of 4-epianhydrotetracycline production (Zero order reaction) increased from 0.0012-0.0056% to 0.0052-0.0093% per month. The tentative shelf life of TC with and without sodium metabisulfite at 95% confidence were then more than 5 years. However, storage in refrigerator (14-15oC) for 36 months, TC preparation with and without sodium metabisulfite gave good colour stability (yellow powder) and a shelf life longer than 36 months.