scholarly journals Improving Weathering Performance of Wood by Borates Impregnation and Liquid Glass Coating

2020 ◽  
Vol 71 (4) ◽  
pp. 347-354
Author(s):  
Mustafa Kucuktuvek ◽  
Hilmi Toker ◽  
Turkay Turkoglu ◽  
Ahmet Gunduz ◽  
Caglar Altay ◽  
...  

Weathering performance of impregnated and coated wood products is an important issue that influences their appearance as well as their service life after outdoor or indoor exposure. A novel procedure to improve the weathering performance of Scots pine wood (Pinus sylvestris L.) is proposed in this study. Wood samples were impregnated with ammonium tetrafluoroborate (ATFB), ammonium pentaborate (APB) and boric acid (BA), and afterward coated with a layer of liquid glass (LG). Surface hardness, color changes, and surface roughness of wood samples were investigated after 250 h and 500 h of exposure to artificial weathering. The results revealed that, except for untreated (control), all other treatment groups caused an increase in surface hardness of Scots pine after weathering. A decrease in the CIE L* value corresponds to the darkening of samples after weathering. Borates-impregnated and LG-coated Scots pine samples possessed the highest color stability. However, all treatment combinations resulted in reddish and yellowish tones after weathering. Exposure to weathering increased surface roughness of wood samples. The surface roughness of the untreated (control) group was higher than that of impregnated and coated samples.

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
İzgen Karakaya ◽  
Esra Cengiz

The aim of this study was to evaluate color stability of 3 restorative materials, discoloration ability of different solutions, efficacy of 2 office bleaching agents, and surface roughness and topography. Sixty specimens for Clearfil Majesty Esthetic (CME), Lava Ultimate (LU), and Vita Enamic (VE) were prepared. They were immersed into 3 staining solutions for 2 weeks and then they were bleached. According to the measuredL⁎,a⁎, andb⁎parameters described by CIELAB system, color changes (ΔE00), translucency parameters (TP), whiteness index values (W⁎), and changes in closeness to pure white (ΔW⁎) were calculated. Then 3 specimens from each group were scanned with an atomic force microscope for surface analysis. After staining, CME groups and control groups of LU and VE showed clinically acceptable color changes (ΔE00<1,8). After bleaching, while a reverse effect on color was observed, VE showed the furthest color values to pure white. There was no statistically significant difference between whiteness index values of LU and CME. LU was the most translucent material during the study and TP values of materials showed minimal differences. Most of the VE groups and a control group of LU showed surface roughness (Ra) values higher than critical value for biofilm accumulation (0,2 μm).


2018 ◽  
Vol 5 (4) ◽  
pp. 76
Author(s):  
Mone Laiz Bortoli ◽  
Cristina Von Appen ◽  
Camila Longoni ◽  
Carmen Beatriz Borges Fortes ◽  
Jefferson Tomio Sanada

Aim: This work aimed to evaluate the color stability of an acrylic resin chemically activated (ARCA) using different handling techniques, and a bisacrylic resin when exposed to different pigmentation solutions.Material and Methods: Silicon matrixes were confectioned (10x10x3mm) to be used as specimens. The groups were designed as follows: Group Pot, Group Brush, Group Manufacturer and Group Bisacrylic (n=18). Each group was exposed to three different pigmentation solutions: distilled water, coke and chlorhexidine digluconate 0.12%. Three readings were performed for each specimen using a spectrophotometer, and the evaluations were carried out in three different time. After the color reading, three averages and the standard deviation of variation were performed after 24 hours (T1), 7 days (T2) and 14 days (T3). Data were submitted to the ANOVA and 2 criteria and Tukey (P<0.05) in the statistical software SSPS 18 for Macintosh (SPSS Inc., Chicago, USA).Results: When compared the solutions in each group of material, there was no statistically significant difference, except for T3, where the group Dencor Brush and Bisacrylic demonstrated higher color variation in all the solutions, even in the control group, and the values in Chlorhexidine higher than the other, showing greater instability after 14 days.Conclusions: With the results, bisacrylic resin used as provisory prosthesis material presents greater color instability than the ARCA, when submitted to different solutions. Bisacrylic resin and Dencor Brush present significantly visible color changes in chlorhexidine solution after 14 days. All the materials in coke solution present homogeneity in the color change after 7 days exposition to the solution, with no visible color change.


2013 ◽  
Vol 07 (02) ◽  
pp. 165-171 ◽  
Author(s):  
Duygu Tuncer ◽  
Emel Karaman ◽  
Esra Firat

ABSTRACT Objective: To investigate the effect of beverages′ temperature on the surface roughness, hardness, and color stability of a composite resin. Materials and Methods: Fifty specimens of the Filtek Z250 composite (3M ESPE, Dental Products, St.Paul, MN, USA) were prepared and initial roughness, microhardness, and color were measured. Then the specimens were randomly divided into five groups of 10 specimens each: Coffee at 70°C, coffee at 37°C, cola at 10°C, cola at 37°C, and artificial saliva (control). After the samples were subjected to 15 min × 3 cycles per day of exposure to the solutions for 30 days, the final measurements were recorded. Results: After immersion in beverages, the artificial saliva group showed hardness values higher than those of the other groups (P < 0.001) and the microhardness values were significantly different from the initial values in all groups except for the control group. Both cola groups showed roughness values higher than the baseline values (P < 0.05), while the other groups showed values similar to the baseline measurements. When ΔE measurements were examined, the 70°C coffee group showed the highest color change among all the groups (P < 0.05). Conclusion: High-temperature solutions caused alterations in certain properties of composites, such as increased color change, although they did not affect the hardness or roughness of the composite resin material tested.


Holzforschung ◽  
2020 ◽  
Vol 74 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Benedikt Neyses ◽  
Olov Karlsson ◽  
Dick Sandberg

AbstractCompressing the surface of sawn timber results in a substantial increase in hardness, and this opens up new market opportunities of using low-density timber species as the raw material for high-value wood products. Unfortunately, widespread commercialisation is hindered by the lack of an industrially viable surface densification process, the major obstacle being the set-recovery (SR) of the densified wood cells upon exposure to moisture. Our hypothesis is that partial dissolution of the crystalline cellulose during densification will largely prevent the SR of densified wood. We therefore evaluated the effect of ionic liquid (IL) or organic superbase pre-treatment on the elastic spring-back (SB), SR and Brinell hardness (HB) of surface-densified wood. Specimens of Scots pine were treated with solutions of ILs or superbases, and then densified in a hot press at temperatures between 200°C and 270°C. The SR was reduced from 90% for the control group to only about 10% for the treated materials. The treated and densified specimens exhibited a higher HB than their untreated and densified counterparts. The method presented in this study is a precursor to the development of a continuous densification process adapted for an open system. Further studies are needed to understand the underlying mechanisms of the pre-treatment.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Ayman A. Al-Dharrab ◽  
Seham B. Tayel ◽  
Mona H. Abodaya

Objective. This study aimed to evaluate the effect of different storage solutions that simulate acidic, alkaline, and sebum conditiions on the physical properties of pigmented (colorant elastomer) cosmesil M511 maxillofacial prosthetic material. Materials and Methods. Sixty specimens were prepared according to the manufacturer's instructions and were tested before and after immersion of different storage conditions for six months at 37 °C. The following tests were performed: color changes (group I), solution absorption (group II), surface roughness (group III), and scanning electron microscopy (group IV). Results. There were no significant changes observed in the color and solution absorption tests while surface roughness revealed significant difference between control group and other testing storage medium groups, and this result was supported by SEM analysis that revealed limited surface changes. Conclusions. Cosmaseil material is an acceptable cross-linked formulation that withstands storage in different solutions with variable pH. The addition of pigment cannot vary the physical properties of these materials. Surface roughness test as well as SEM microscopic study showed moderate changes indicating a limited effect on the surface of the material.


2015 ◽  
Vol 660 ◽  
pp. 165-169
Author(s):  
Simona Stoleriu ◽  
Sorin Andrian ◽  
Galina Pancu ◽  
Irina Nica ◽  
Andrei Victor Sandu ◽  
...  

The aim of the study was to evaluate the surface hardness of two different traditional glass ionomer cements after their exposure to two commercial oral rinsing solutions. Fuji IX GP (GC Corporation, Tokyo, Japan) and Ketac Molar Easymix (3MESPE, Germany) were used in the study. Twenty-one cement samples of each material were split in three groups. In control group the samples were stored in artificial saliva (AFNOR NF S90-701) for 14 days. In groups 2 and 3 the samples of each material were immersed in Listerine and in Corsodyl two times on a day for 14 days. Between the immersion periods the samples were stored in artificial saliva. The samples were subjected to microhardness evaluation using digital microhardness tester (Micro-Vickers Hardness System CV-400DMTM, CV Instruments Namicon). Significant results were obtained when compared the surface hardness of both glass ionomer cements after their immersion in Listerine and in Corsodyl to control group. The surface hardness of Fuji IX in control and in study groups was significantly higher when compared to Ketac Molar Easymix In the conditions of the study, Listerine and Corsodyl decreased the surface hardness of Fuji IX GP and Ketac Molar Easymix glass ionomer cements.


2018 ◽  
Vol 17 ◽  
pp. e18901
Author(s):  
Débora Oro Ferrari ◽  
Rafael Guerra Lund ◽  
Luana Zanella ◽  
Walter Antônio Roman Júnior ◽  
Sinval Adalberto Rodrigues-Junior

Denture use may aggravate the occurrence of oral infections, considering it enhances microbial adherence. Aim: This study assessed the reduction of microbial loads of Candida albicans, Staphylococcus aureus, and Klebsiella oxytoca by disinfecting the polymethylmethacrylate (PMMA) of complete dentures with hydroalcoholic extract of Salvia officinalis. Additionally, the effect of such extract on the properties of PMMA was examined. Methods: Microorganisms were isolated from saliva samples collected from complete denture wearers. The hydroalcoholic extract of S. officinalis was produced according to the Brazilian Pharmacopoeia 5. The PMMA specimens (n=188) were immersed in microbial inoculum and incubated at 37°C for 16 hours per day. Then, they were subjected to a disinfection protocol for 30 days. The specimens were divided into five treatment groups: sterile saline solution (0.85%; control), 0.2% chlorhexidine digluconate, and hydroalcoholic extract of S. officinalis (0.2%, 0.8%, and 1.16%). Microorganism adherence to the PMMA surface was also assessed, as well as surface roughness (Ra in µm) and color stability of the PMMA (mean ΔE). Changes in microbial load and surface roughness after the disinfection protocol were verified with paired t-test. Substances at day 10, adherence, and color stability were compared by the Kruskall-Wallis and Mann-Whitney tests, and one-way ANOVA was used to compare substances at the beginning and end of the experiment (α=0.05). Results: The 1.16% S. officinalis extract significantly reduced the microbial load of all the microorganisms after 30 days of disinfection (p<0.05). The microbial load of K. oxytoca was also reduced at lower concentrations of the S. officinalis extract (0.2% and 0.8%) (p<0.02). Antimicrobial and anti-adherent effects against microorganisms isolated from the oral cavity were observed. There was no significant change in surface roughness (p>0.05) and color stability was significantly higher in the control group (p<0.0001). Conclusions: The hydroalcoholic extract of S. officinalis may be used as a disinfectant solution for dentures.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Turkay Turkoglu ◽  
Ergun Baysal ◽  
Hilmi Toker

The aim of this study was to investigate effects of natural weathering on color stability of Scots pine (Pinus sylvestrisL.) and Oriental beech (Fagus orientalisL.) impregnated with some chemicals [tanalith-E (TN-E), adolit-KD5 (AD-KD5), and chromated copper arsenate (CCA)] and then varnished [synthetic varnish (SV) and polyurethane varnish (PV)]. While applying varnish increased lightness, impregnation decreased lightness of the wood specimens before natural weathering. Natural weathering caused greenish, bluish, and dark color tones of the wood surface. Total color change was increased with increasing exposure times in natural weathering. Untreated (control) wood specimens exhibited higher color changes than the other wood specimens in all the stages of natural weathering. The total color changes of untreated Oriental beech specimens were less than untreated Scots pine specimens. The color stability of impregnated and varnished wood specimens gave better results than untreated and solely varnished wood specimens after natural weathering. The best color stability was obtained from both Oriental beech and Scots pine wood impregnated with TN-E before PV coating.


Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1376
Author(s):  
Yara Khalid Alkhadim ◽  
Malak Jameel Hulbah ◽  
Hani Mohammad Nassar

The aim of this study was to compare color shift, color stability, and post-polishing surface roughness of esthetic restorative materials. Twenty-five disc-shaped specimens (10 mm in diameter and 2 mm in thickness) from five esthetic resin materials (Z250XT, IPS Empress-Direct, G-ænial, Vit-l-escence, and Ceram.X) were fabricated. Color shift before and immediately after light-curing (∆E0) then color stability after immersion in tea, coffee, berry juice, and distilled water were measured using a spectrophotometer. Color changes were measured after 2 (ΔE2), 4 (ΔE4), 6 (ΔE6), and 8 weeks (ΔE8). Surface roughness values (Rq) were determined using an optical profilometer after polishing using a rotary polishing system. Data were analyzed using ANOVA and multiple comparison methods at 0.05 significance level. There were no significant differences between the tested materials regarding color shift except between Vit-l-escence and Ceram.X (p = 0.033). There was no significant difference between coffee and tea solutions (p = 1.0) and between berry juice and distilled water (p = 0.15). There was no difference between the tested materials regarding Rq (p = 0.057). Ceram.X was associated with the lowest ΔE8 values overall. Tested materials were comparable regarding color shift and post-polishing surface roughness. Susceptibility to staining was dependent on the material.


Medicina ◽  
2020 ◽  
Vol 56 (5) ◽  
pp. 234
Author(s):  
Mohammed M. Al Moaleem ◽  
Rashad AlSanosy ◽  
Nasser M. Al Ahmari ◽  
Mansoor Shariff ◽  
Abdulkhaliq A. Alshadidi ◽  
...  

Background and Objectives: Khat chewing is considered as a daily habit that is practiced by more than five million people globally. The effect of khat chewing on the surface roughness and the color stability of natural teeth and the material used in the fabrication of dental prosthesis remains unknown. This study was conducted to explore and compare the effect of khat homogenate (KH) on the surface roughness (Ra) and the average color changes (ΔE*) amongst natural teeth and selected shades from different porcelain types, namely, feldspathic metal ceramic (MC) VM13, computer-aided design/computer assisted manufacture (CAD/CAM) feldspathic (Vitablocs Mark II), and multilayer zirconia (Ceramill Zolid PS) porcelains. Materials and Methods: Seventy samples were prepared from natural teeth, feldspathic MC, CAD/CAM Vitablocs Mark II, and zirconia porcelain. The Ra values were measured using a profilometer and expressed in micrometers, whereas the ΔE* values were measured using VITA Easyshade® V spectrophotometer for all samples before and after frequent immersion and thermocycling in KH for 30 days. The surface topography was used to assess the materials surfaces (glazed or polished) after KH immersion by using a white light interferometry machine. Results: Results revealed that the Ra and the ΔE* values of the different types of tested porcelain were influenced by KH. The order of surface roughness values was glazed or polished MC > polished Zircon > polished Vitablocs Mark II > natural teeth. The lowest ΔE* values were recorded for glazed Vitablocs Mark II and MC, and the values could be arranged as polished zircon > natural teeth > glazed zircon > polished MC > polished Vitablocs Mark II. P values were significantly varied (<0.001) among all the tested groups, except the zircon group (>0.05) for both Ra and ΔE*. Conclusions: KH significantly affected both surface parameter and color of glazed or polished porcelain materials and natural teeth.


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