scholarly journals Spectrophotometric Analysis of the Effect of aging on Color change of Maxillofacial Silicone

2021 ◽  
Vol 67 (2) ◽  
pp. 1497-1504
Author(s):  
aya fawzy ◽  
Nada khourazaty
2017 ◽  
Vol 2 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Jayaprakash Thumu ◽  
Anirudh Kadiyala ◽  
Indira Priyadarshini Bollu ◽  
Srinidhi Vishnu Ballullaya ◽  
Srihari Devalla

ABSTRACT Aim This study is aimed to evaluate the effect of staining solutions on the color stability of bulk fill and conventional nanohybrid resin composites (RCs) when subjected to various immersion periods. Materials and methods A total of 120 cylindrical Teflon molds (4 × 4 mm) were obtained and divided into four groups of 30 each. Molds of groups I and II were filled with Tetric N Ceram Bulk Fill (Ivoclar Vivadent, Schaan, Liechtenstein) and Filtek Bulk Fill (3M ESPE, St. Paul, MN, USA). Molds of groups III and IV were filled with Tetric N Ceram (Ivoclar Vivadent) and Filtek Z250 XTE (3M ESPE) incremental fill RC. Photo-activation was performed and specimens were incubated. Spectrophotometer analysis was done according to Commission Internationale d'Eclairage Lab color scale. After taking the baseline measurements, 10 samples from each group were immersed in distilled water (control, subgroup a), tea (subgroup b), and coffee (subgroup c) respectively, for 1, 7, and 30 days. The color values of each specimen were remeasured and color change value (E*ab) was calculated after 1, 7, and 30 days. Data were analyzed by Friedman's test and Mann–Whitney U-test; p < 0.05 is considered to be statistically significant. Results Group III specimens showed perceptible color changes at 30-day immersion period in coffee and tea. In group I specimens, color changes were perceptible at 7- and 30-day immersion periods in coffee and only 30-day immersion period in tea. Groups II and IV specimens showed perceptible color changes after all immersion periods in coffee and after 30 days in tea. Conclusion It can be concluded that Tetric N Ceram has less color change than the other nanohybrid RCs investigated when immersed in coffee and tea after various immersion periods. How to cite this article Thumu J, Kadiyala A, Bollu IP, Ballullaya SV, Devalla S. Effect of Staining Solutions on the Color Stability of Conventional and Bulk Fill Nanohybrid Resin Composites: A Spectrophotometric Analysis. J Oper Dent Endod 2017;2(1):1-5.


2021 ◽  
Vol 22 (4) ◽  
pp. 1556
Author(s):  
Malgorzata Latos-Brozio ◽  
Anna Masek

Few scientific reports have suggested the possibility of using natural phenolic acids as functional substances, such as stabilizers for polymeric materials. The replacement of commercial stabilizers in the polymer industry can be beneficial to human health and the environment. The aim of this study was to obtain biodegradable composition of polylactide (PLA) and polyhydroxyalkanoate (PHA) with natural amber (succinic) acid. The materials were subjected to controlled thermooxidation and solar aging. The research methodology included thermal analysis, examination of surface energy, mechanical properties and spectrophotometric analysis of the color change after aging. The samples of aliphatic polyesters containing from 1 to 2 parts by weight of succinic acid were characterized by increased resistance to oxidation (DSC analysis). Natural acid, preferably at a concentration of 1–1.5 parts by weight, acted as a stabilizer in the polymer compositions. On the other hand, materials that had amber acid above 2 parts by weight added were more susceptible to oxidation (DSC). They also showed the lowest aging coefficients (K). The addition of acid at 2.5–4 parts by weight caused a pro-oxidative effect and accelerated aging. By adding amber acid to PLA and PHA, it is possible to design their time in service and their overall lifetime.


2019 ◽  
Vol 15 (1) ◽  
pp. 34-39
Author(s):  
Indra Kumar Limbu ◽  
Bishal Babu Basnet

Background: Various factors such as metal alloy, thickness of the opaque porcelain, different methods of condensation of ceramic, thickness of the dentine ceramic, different ceramic firing condition affect the color of final ceramic restoration. It is not considered significant while taking single variable into account but several subtle changes in these factors lead to discernible color change. Purpose: The aim of this study was to evaluate the influence of ceramic thickness over color of ceramic layered on the titanium casting. Methods: Ultra low fusing ceramics of different thickness (0.5mm, 1mm, 1.5mm and 2mm) was veneered over a metal substrate of pure titanium and spectrophotometric analysis of 20 such discs was done to determine parameters (CIELAB system). One-way ANOVA and multiple comparison results of ANOVA were performed for statistical analysis. Results: The different thickness of ceramic significantly influences the ΔE value. There was significant change in the L* value (P<0.05) with different thickness of titanium metal ceramic tabs. There was also significant difference in C*ab values with different thickness of ceramic. Conclusions: The thickness of the ceramic has significant effect in the L* value of the titanium ceramic restoration. The thicker restoration appeared darker than the thinner one. There was also significant effect in the color saturation or chroma with different thickness of ceramic. Chroma decreased with increased thickness. Color difference between groups were significant. Overall thickness had effect on the final color of the titanium ceramic restoration.  


2005 ◽  
Vol 38 (22) ◽  
pp. 16
Author(s):  
TIMOTHY F. KIRN
Keyword(s):  

2014 ◽  
Vol 1 (1) ◽  
pp. 24-34
Author(s):  
Alireza K. ◽  
Hossein Ahmadi ◽  
Mohsen Mohammadi

Lubricants and leather dressings are the most common treatments of dry and water logged historical leathers. Color change has a great importance during the time and treatment process, due to visual and aesthetic values of historic leather relics. Polyethylene glycol (PEG) and silicone oil (SiO) are frequently used leather dressings in the conservation procedures. Therefore, color stability of treated leathers with PEG and SiO were investigated before and after heat accelerated aging. Moreover, application of ascorbic acid was evaluated as an antioxidant additive for PEG (PEG+AA).Color change after treatment and aging were studied by colorimetry technique in the CIE *L*a*b system. Results indicated to severe color alteration in PEG treated and aged leathers with or without ascorbic acid. Whereas, SiO treated samples showed better stability and minimum color shift after aging. Silicone oil was characterized as the best dressing for historical leathers with compared to PEG and PEG+AA, due to its high stability and aesthetical properties.


2020 ◽  
Vol 45 (6) ◽  
pp. 589-597
Author(s):  
BGS Casado ◽  
EP Pellizzer ◽  
JR Souto Maior ◽  
CAA Lemos ◽  
BCE Vasconcelos ◽  
...  

Clinical Relevance The use of laser light during bleaching will not reduce the incidence or severity of sensitivity and will not increase the degree of color change compared with nonlaser light sources. SUMMARY Objective: To evaluate whether the use of laser during in-office bleaching promotes a reduction in dental sensitivity after bleaching compared with other light sources. Methods: The present review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and is registered with PROSPERO (CDR42018096591). Searches were conducted in the PubMed/Medline, Web of Science, and Cochrane Library databases for relevant articles published up to August 2018. Only randomized clinical trials among adults that compared the use of laser during in-office whitening and other light sources were considered eligible. Results: After analysis of the texts retrieved during the database search, six articles met the eligibility criteria and were selected for the present review. For the outcome dental sensitivity, no significant difference was found favoring any type of light either for intensity (mean difference [MD]: −1.60; confidence interval [CI]: −3.42 to 0.22; p=0.09) or incidence (MD: 1.00; CI: 0.755 to 1.33; p=1.00). Regarding change in tooth color, no significant differences were found between the use of the laser and other light sources (MD: −2.22; CI: −6.36 to 1.93; p=0.29). Conclusions: Within the limitations of the present study, laser exerts no influence on tooth sensitivity compared with other light sources when used during in-office bleaching. The included studies demonstrated that laser use during in-office bleaching may have no influence on tooth color change.


Author(s):  
A. G. Belova ◽  
E. V. Zimina ◽  
N. P. Simbirtsev

During a pathoanatomic autopsy, it is very important to correctly assess the color change of the organs. However, it is not always clear because the color depends on the spectrum of the incident light. There is also a subjective assessment of color. In addition, in animals with large amounts of circulating blood, for example, dogs, early imbibition occurs, which makes it difficult to assess the color of the organ and pathoanatomical diagnosis. We have proposed a simple and visual method of recognition of two pathological processes – inflammation and edema using colored filters. This technique also allows to accurately differentiate inflammation from postmortem imbibition, to recognize fibrin and hemorrhage well. Postmortem examination of different types of animals (predacious families of mustelids, canids, felids) was performed in accordance with Shore’s method in the prosectorium of the Pathonomy Department, K.I. Skryabin Moscow State Academy of Veterinary Medicine and Biotechnology visual analysis – under various artificial lights (fluorescent lamps with banded spectrum and halogen lamps). In the red filter are well identified the pathological processes associated with the venous blood presence in the tissues (venous hyperemia and pulmonary edema). The focus of venous hyperemia or edema in the red filter looks like a dark zone, and tissues, where arterial bloods predominated, aren’t detected in red filter. In the yellow – green filter the inflammation is clearly detected: the zone is brightly red and surrounding tissues become dark. Red colour filters have rather narrow band of transmittance from 600 to 700 nm. Yellow-green have a width zone – from 500 to 700 nm, including both red, and yellow-green part of spectrum. Oxidized hemoglobin in red part of spectrum absorbs ten time weaker, has more high reflectivity and looks red. Surrounding tissues reflect the red rays, which incident on them also red. Therefore, the zone of edema, venous hyperemia and hemorrhaging, containing venous blood, are detected the dark spot, and inflammation zone merges with the red background. Oxidized hemoglobin in the red spectrum part absorbs ten time weaker than reduced hemoglobin, has high reflectivity of the red spectrum part and looks brightly red, surrounding tissues reflect yellow-green spectrum part and look green. Therefore, the zones of inflammation, active hyperemia and hemorrhaging, containing arterial blood, sharp contrast with green background and are clearly visible. Diagnoses made with the help of color filters are confirmed by histological studies.


2018 ◽  
Vol 756 (1-2) ◽  
pp. 106-110
Author(s):  
A.S. ALMATOV ◽  
◽  
E.O. KALISTRATOVA ◽  
Keyword(s):  

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