Color in Business, Science, and Industry

Calcium hydroxide-based root canal sealers: a review.

www.fob.usp.br/jaos or www.scielo.br/jaos J Appl Oral Sci. 2009;17(5):388-91 COLOR STABILITY OF A NANOFILL COMPOSITE: EFFECTOF DIFFERENT IMMERSION MEDIA Silvia Terra FONTES 1 , Maria Raquel FERNANDEZ 1 , Claudia Modena de MOURA 2 , Sonia Saeger MEIRELES 3 1- DDS, MS, PhD student, Department of Operative Dentistry, Dental School, Federal University of Pelotas, Pelotas, RS, Brazil.2- DDS, Private Practice, Porto Alegre, RS, Brazil.3- DDS, MS, PhD, Adjunct Professor, Department of Operative Dentistry, Federal University of Paraiba, Joao Pessoa, PB, Brazil . Corresponding address: Sonia Saeger Meireles - Avenida Umbuzeiro, 755 apt 901, Bairro: Manaira - 58038-180, Joao Pessoa - PB - Brazil - Phone:+55 83 32167250 - e-mail: soniasaeger@hotmail.com Received: August 13, 2008 - Modification: May 18, 2009 - Accepted: November 09, 2008 bjective: The aim of this in vitro study was to evaluate the color stability of a nanofill composite resin (Filtek Z350) in differentimmersion media. Materials and methods: Twelve resin-based composite specimens were prepared using a silicon cylindrical moldmeasuring ≅1mm of thickness and ≅ 10mm of diameter. Specimens were light-cured for 40 s from both sides using a LED Radii at1400 mW/cm

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Color stability of a nanofill composite: effect of different immersion media

The effects of finishing and polishing techniques on surface roughness and color stability of nanocomposites

The purpose of this in vitro study was to evaluate the color stability of two brands of porcelain teeth and three brands of acrylic denture teeth. Samples were immersed into three staining drinks as test groups and distilled water as a control. Color measurements of teeth were performed by using a spectrophotometer. Before immersion, the initial color value of each tooth was recorded. Color change values were determined after 1 day, 1 week, 2 weeks, and 4 weeks of immersion. Color differences were characterized using the CIE L*a*b* color space. The color stability of all teeth was significantly affected by the immersion period (p<0.0001). Instant coffee was found to be the most chromogenic agent among the solutions tested (p<0.0001). Among the materials tested, porcelain was found to be more resistant to discoloration. It was concluded that acrylic teeth showed a higher degree of color change and that the amount of color change for each group increased proportionally with time.

Color Stability of Different Denture Teeth Materials against Various Staining Agents

The purpose of this study was to evaluate the discoloration of two nanohybrids, two microhybrids, and a posterior composite resin restorative material upon exposure to different drinks — namely tea, cola, coffee, red wine, and water. The colors of all specimens before and after storage in the solutions were measured by a colorimeter based on CIE Lab system, and the color differences thereby calculated. Data were analyzed by two-way analysis of variance (ANOVA) and Tukey's HSD test. According to ANOVA, the restorative material, staining agent, and their interaction were found to play a statistically significant role (P=0.0001) in color change. Among the staining agents, water consistently showed the lowest ΔE* value for all materials, whereas red wine showed the highest ΔE* value. In other words, for all the materials tested, their color change in staining agents ranked in this increasing order: water < cola < tea < coffee < red wine. In terms of comparison among the five restorative materials, Filtek P60 and Z250 were observed to manifest less color change than the nanohybrids and Quadrant LC.

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Color stability of resin composites after immersion in different drinks.

The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme). Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd), polishing discs then diamond polishing paste (PdP), polishing discs then a liquid polishing system (Biscover) (PdB), and combinations of these (PdPB) were used. Unpolished specimens served as the control (C). The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DE*) were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (a=0.05). The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme). The posterior (Filtek P60) and universal (Filtek Z250) composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA), were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme) and universal (Quadrant LC) composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish system (PdB and PdPB groups).

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Effects of polishing procedures on color stability of composite resins

Objectives The aim of this study was to compare bacterial penetration following obturation with 5 different techniques. Study design This study was performed on 120 teeth including negative control (n = 10), positive control (n = 10), and experimental groups (n = 100). One hundred teeth were randomly divided into 5 groups of 20 teeth each and obturated with System B (Sb), Lateral Compaction (Lc), Thermafil (T), Single ProTaper Gutta-percha (P), and laterally compacted ProTaper Gutta-percha (PLc). Enterococcus faecalis was used for determination of the bacterial penetration. Evaluation was carried out for 60 days. Results At 30 days, the χ 2 test showed that the slowest penetration was observed in Group Sb and Group PLc, which were not significantly different from each other. The fastest penetration in the all experimental groups was observed in Group T and Group P, which were not significantly different from one another. Also, there was no statistically significance difference ( P > .05) among all groups at 60 days. Conclusion It may be concluded that under the conditions of this study System B and laterally compacted ProTaper Gutta-percha prevent bacterial penetration of the root canal at 30 days. Furthermore, there was no difference among obturation techniques at 60 days.

Effects of different root canal obturation techniques on bacterial penetration.

Bacterial Penetration After Obturation With Four Different Root Canal Sealers

The aim of this study was to compare new irrigation systems with a conventional irrigation technique for the removal of inter-appointment calcium hydroxide [Ca(OH)2 ] Forty-seven extracted human single-rooted teeth were instrumented, and Ca(OH)2 paste was placed into root canals by using a lentulo spiral at the apical third Teeth were randomly divided into three groups according to different irrigation protocols using a 30-gauge slot-tipped needle, EndoVac system and ProUltra® PiezoFlow™ ultrasonic irrigation system Scanning electron microscopic images of the selected root canal surfaces (cervical, middle and apical third) were evaluated using a 5-grade scale The influence of the irrigation system was evaluated using a two-way analysis of variance test and Tukey's test The EndoVac and PiezoFlow groups demonstrated the lowest scale values (cleanest canals); however, there was no statistical difference between these two groups The conventional irrigation group exhibited significantly higher scores (P < 005) The conventional needle irrigation was not sufficient to remove Ca(OH)2 from the root canal system Irrigation with EndoVac and PiezoFlow™ ultrasonic irrigation systems improved the removal of the intracanal medicament resulting in cleaner root canal walls

Ali Çağın Yücel

Papers

Color stability of resin composites after immersion in different drinks.

Effects of polishing procedures on color stability of composite resins

Effects of different root canal obturation techniques on bacterial penetration.

Bacterial Penetration After Obturation With Four Different Root Canal Sealers

Comparison of final irrigation techniques in removal of calcium hydroxide.