Colour stability of 3D-printed resin orthodontic brackets

2021 ◽  
pp. 146531252110010
Author(s):  
Allison S Haynie ◽  
Jeryl D English ◽  
Rade D Paravina ◽  
Audrey Moon ◽  
James Hanigan ◽  
...  
Keyword(s):  
Accelerated Aging ◽  
Orthodontic Brackets ◽  
Colour Stability ◽  
Water Control ◽  
3D Print ◽  
Difference Formula ◽  
Before And After ◽  
Colour Changes ◽  
3D Printed

Objective: To evaluate the colour stability of polymeric resins that could be used to 3D-print orthodontic brackets. Design: In vitro, laboratory study Materials and Methods: Disc-shaped specimens were fabricated via 3D printing using three resins: Dental LT; Dental SG; and Clear. Five conditions were evaluated for each resin (n = 10 per treatment per resin) to assess its corresponding effect on colour and translucency: immersion in (1) red wine, (2) coffee, (3) tea and (4) distilled water (control), and (5) exposure to accelerated aging. Colour and translucency measurements were made before and after exposure using a spectrophotometer. Mean colour differences (ΔE00) and changes in translucency parameter (ΔTP00) were calculated for each sample using the CIEDE2000 colour difference formula. Results: Statistically significant effects of the resin material, the treatment condition and interactions effects of material and condition were observed for ΔE00 and ΔTP00 ( P < 0.001). The most pronounced changes in colour (ΔE00) were a result of the staining effects of wine on all three resins, ranging from 14.5 ± 0.6 to 20.8 ± 1.2. Dental LT, Dental SG and Clear resins all showed changes in colour when exposed to certain staining agents. Dental SG and Clear resins exhibited changes in colour with aging, while the colour of Dental LT resin remained stable with aging. Conclusions: The colour changes of the resins investigated does not support their use in 3D-printed aesthetic bracket applications.

scholarly journals Colour Stability of Veneering Composites after Accelerated Aging

2010 ◽  
Vol 04 (02) ◽  
pp. 137-142 ◽  
Author(s):  
Triantafillos Papadopoulos ◽  
Aspasia Sarafianou ◽  
Andreas Hatzikyriakos
Keyword(s):  
Colour Change ◽  
Accelerated Aging ◽  
Blue Shift ◽  
Colour Stability ◽  
Before And After ◽  
Indirect Composites ◽  
Colour Changes ◽  
Indirect Composite ◽  
The Mean ◽  
One Way Anova

Objectives: To investigate the colour stability of four indirect composite restorative materials after accelerated aging.Methods: Four indirect composites (Gradia, Signum+, HFO and Adoro) were used. For each material, six specimens were prepared and subjected to accelerated aging (Suntest CPS+, Atlas, Chicago, IL, USA) according to ISO 7491. A Dr. Lange Microcolor Data Station colorimeter (Braive Instruments, Liege, Belgium) was used to measure specimen colour before and after aging. Measurements were performed according to the CIE L*a*b* system, and the mean L*, a* and b* values for each material were calculated. The equation ΔΕ = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2 was used to measure the total colour change (ΔΕ), where ΔL*, Δa* and Δb* are the differences in the respective values before and after aging. One-way ANOVA were used to determine statistically significant differences in ΔL*, Δa*, Δb* and ΔΕ.Results: No statistically significant differences were found in ΔL*, Δa*, Δb* and ΔΕ among the materials tested (PΔL*=.063; PΔa*=.521; PΔb*=.984 and PΔE=.408). After aging, Gradia specimens showed an increase in lightness (ΔL*=0.36) and a green-yellow shift (Δa*=-1.18, Δb*=0.6), while Signum+ specimens exhibited an increase in lightness (ΔL*=0.5) and a green-blue shift (Δa*=-0.9, Δb*=- 0.45). HFO specimens exhibited an increase in lightness (ΔL*=0.75) and a green-yellow shift (Δa*=- 1.3, Δb*=0.06), and Adoro specimens exhibited an increase in lightness (ΔL*=2.07) and a green-yellow shift (Δa*=-1.3, Δb*=0.68).Conclusions: Colour changes were found to be within accepted values of perceptibility and clinical acceptance after accelerated aging, and no statistically significant differences were found in ΔL*, Δa*, Δb* and ΔΕ among the materials tested. (Eur J Dent 2010;4:137-142)

scholarly journals Enamel Thickness before and after Orthodontic Treatment Analysed in Optical Coherence Tomography

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Julia Seeliger ◽  
Monika Machoy ◽  
Robert Koprowski ◽  
Krzysztof Safranow ◽  
Tomasz Gedrange ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Orthodontic Treatment ◽  
Adhesive Bonding ◽  
Orthodontic Brackets ◽  
Optical Coherence ◽  
Two Dimensional ◽  
Enamel Thickness ◽  
Bonding System ◽  
Before And After

Despite the continuous development of materials and techniques of adhesive bonding, the basic procedure remains relatively constant. The technique is based on three components: etching substance, adhesive system, and composite material. The use of etchants during bonding orthodontic brackets carries the risk of damage to the enamel. Therefore, the article examines the effect of the manner of enamel etching on its thickness before and after orthodontic treatment. The study was carried out in vitro on a group of 80 teeth. It was divided into two subgroups of 40 teeth each. The procedure of enamel etching was performed under laboratory conditions. In the first subgroup, the classic method of enamel etching and the fifth-generation bonding system were used. In the second subgroup, the seventh-generation (self-etching) bonding system was used. In both groups, metal orthodontic brackets were fixed and the enamel was cleaned with a cutter fixed on the micromotor after their removal. Before and after the treatment, two-dimensional optical coherence tomography scans were performed. The enamel thickness was assessed on the two-dimensional scans. The average enamel thickness in both subgroups was not statistically significant.

scholarly journals Color stability of composites subjected to accelerated aging after curing using either a halogen or a light emitting diode source

2007 ◽  
Vol 18 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Fernanda de Carvalho Panzeri Pires-de-Souza ◽  
Lucas da Fonseca Roberti Garcia ◽  
Hisham Mohamad Hamida ◽  
Luciana Assirati Casemiro
Keyword(s):  
Color Change ◽  
Light Emitting Diode ◽  
Accelerated Aging ◽  
Color Stability ◽  
Composite Resins ◽  
Significance Level ◽  
Light Emitting ◽  
Before And After ◽  
Qth Light

The purpose of this study was to evaluate, in vitro, the color stability of three composite resins of two different shades (A3 and C3) cured with either a quartz tungsten halogen (QTH) or a light emitting diode (LED) source. Forty specimens (20 x 2 mm) were prepared for each composite (Tetric Ceram®, Heliomolar® and Esthet-X®), being 20 for each shade. In each group, 10 specimens were light-cured using the QTH unit and 10 with the LED source. The shade of the materials was evaluated before and after submitting the specimens to artificial accelerated aging (4 h UV-B/4 h condensing vapor), using a reflection spectrophotometer. deltaE means were calculated and analyzed statistically by 2-way ANOVA and Tukey's test at 5% significance level. Both A3 and C3 shades of Esthet-X composite resin showed the lowest color change when cured with the QTH light, while Tetric C3 cured with the QTH light showed the highest color change.

scholarly journals Breaking the Third Wall: Implementing 3D-Printing Technics to Expand the Complexity and Abilities of Multi-Organ-on-a-Chip Devices

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 627
Author(s):  
Yoel Goldstein ◽  
Sarah Spitz ◽  
Keren Turjeman ◽  
Florian Selinger ◽  
Yechezkel Barenholz ◽  
...  
Keyword(s):  
Cell Culture ◽  
Cfd Simulation ◽  
Cost Effective ◽  
In Vitro Models ◽  
3D Print ◽  
Biological Compatibility ◽  
3D Printed ◽  
Organ On A Chip

The understanding that systemic context and tissue crosstalk are essential keys for bridging the gap between in vitro models and in vivo conditions led to a growing effort in the last decade to develop advanced multi-organ-on-a-chip devices. However, many of the proposed devices have failed to implement the means to allow for conditions tailored to each organ individually, a crucial aspect in cell functionality. Here, we present two 3D-print-based fabrication methods for a generic multi-organ-on-a-chip device: One with a PDMS microfluidic core unit and one based on 3D-printed units. The device was designed for culturing different tissues in separate compartments by integrating individual pairs of inlets and outlets, thus enabling tissue-specific perfusion rates that facilitate the generation of individual tissue-adapted perfusion profiles. The device allowed tissue crosstalk using microchannel configuration and permeable membranes used as barriers between individual cell culture compartments. Computational fluid dynamics (CFD) simulation confirmed the capability to generate significant differences in shear stress between the two individual culture compartments, each with a selective shear force. In addition, we provide preliminary findings that indicate the feasibility for biological compatibility for cell culture and long-term incubation in 3D-printed wells. Finally, we offer a cost-effective, accessible protocol enabling the design and fabrication of advanced multi-organ-on-a-chip devices.

scholarly journals 3D Printed Model of Extrahepatic Biliary Ducts for Biliary Stent Testing

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4788
Author(s):  
Joanna Thomas ◽  
Sagar Patel ◽  
Leia Troop ◽  
Robyn Guru ◽  
Nicholas Faist ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Computer Aided Design ◽  
Bile Ducts ◽  
Biliary Stent ◽  
Metal Stents ◽  
In Vitro Testing ◽  
Stent Deployment ◽  
3D Print ◽  
3D Printed

Several inflammatory conditions of the bile ducts cause strictures that prevent the drainage of bile into the gastrointestinal tract. Non-pharmacological treatments to re-establish bile flow include plastic or self-expanding metal stents (SEMs) that are inserted in the bile ducts during endoscopic retrograde cholangiopancreatography (ERCP) procedures. The focus of this study was to 3D print an anatomically accurate model of the extrahepatic bile ducts (EHBDs) with tissue-like mechanical properties to improve in vitro testing of stent prototypes. Following generation of an EHBD model via computer aided design (CAD), we tested the ability of Formlabs SLA 3D printers to precisely print the model with polymers selected based on the desired mechanical properties. We found the printers were reliable in printing the dimensionally accurate EHBD model with candidate polymers. Next, we evaluated the mechanical properties of Formlabs Elastic (FE), Flexible (FF), and Durable (FD) resins pre- and post-exposure to water, saline, or bile acid solution at 37 °C for up to one week. FE possessed the most bile duct-like mechanical properties based on its elastic moduli, percent elongations at break, and changes in mass under all liquid exposure conditions. EHBD models printed in FE sustained no functional damage during biliary stent deployment or when tube connectors were inserted, and provided a high level of visualization of deployed stents. These results demonstrate that our 3D printed EHBD model facilitates more realistic pre-clinical in vitro testing of biliary stent prototypes.

scholarly journals Physical and chemical mechanisms involved in adhesion of orthodontic bonding composites: in vitro evaluations

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
R. Condò ◽  
G. Mampieri ◽  
A. Cioffi ◽  
M. E. Cataldi ◽  
I. Frustaci ◽  
...  
Keyword(s):  
Bond Strength ◽  
Accelerated Aging ◽  
In Vitro Study ◽  
Adhesive System ◽  
Human Saliva ◽  
Chemical Compositions ◽  
Adhesive Systems ◽  
In Vitro Aging ◽  
Before And After

Abstract Background Bond strength of orthodontic composite is strongly influenced by molecular and structural mechanisms. Aim of this in vitro study was to compare bond strength of light-cure orthodontic composites by measuring debonding forces and evaluating locations of bond failure. Investigations on chemical compositions clarified adhesive behaviors and abilities, exploring effects of ageing processes in this junction materials. Methods Twelve enamel discs, from human premolars, were randomly coupled to one orthodontic adhesive system (Transbond XT™ 3 M UNITEK, USA, Light-Cure Orthodontic Paste, LEONE, Italy and Bisco Ortho Bracket Paste LC, BISCO, Illinois) and underwent to Shear Bond Strength test. Metallic brackets were bonded to twenty-seven human premolar, with one of the adhesive systems, to quantify, at FE-SEM magnifications, after debonding, the residual material on enamel and bracket base surfaces. Raman Spectroscopy analysis was performed on eight discs of each composites to investigate on chemical compositions, before and after accelerated aging procedures in human saliva and sugary drink. Results Orthodontic adhesive systems showed similar strength of adhesion to enamel. The breakage of adhesive-adherent bond occurs in TXT at enamel-adhesive interface while in Bisco and Leone at adhesive-bracket interface. Accelerated in vitro aging demonstrated good physical–chemical stability for all composites, Bisco only, was weakly contaminated with respect to the other materials. Conclusion A similar, clinically adequate and acceptable bond strength to enamel for debonding maneuvers was recorded in all orthodontic adhesive systems under examination. No significant chemical alterations are recorded, even in highly critical situations, not altering the initial mechanical properties of materials.

scholarly journals In Vitro Comparison between Metal Sleeve-Free and Metal Sleeve-Incorporated 3D-Printed Computer-Assisted Implant Surgical Guides

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 615
Author(s):  
Kyung Chul Oh ◽  
June-Sung Shim ◽  
Ji-Man Park
Keyword(s):  
Computer Assisted ◽  
Cross Sectional ◽  
Implant Placement ◽  
Surgical Guides ◽  
Measured Weight ◽  
Before And After ◽  
3D Printed ◽  
Student’S T ◽  
The Right

The present study aims to compare the accuracy of metal sleeve-free 3D-printed computer-assisted implant surgical guides (MSF group) (n = 10) with metal sleeve-incorporated 3D-printed computer-assisted implant surgical guides (MSI group) (n = 10). Implants of diameter 4.0 mm and 5.0 mm were placed in the left second premolars and bilateral first molars, respectively, using a fully guided system. Closed-form sleeves were used in teeth on the left and open-form sleeves on the right. The weight differences of the surgical guides before and after implant placement, and angular deviations before and after implant placement were measured. Weight differences were compared with Student’s t-tests and angular deviations with Mann–Whitney tests. Cross-sectional views of the insert parts were observed with a scanning electron microscope. Preoperative and postoperative weight differences between the two groups were not statistically significant (p = 0.821). In terms of angular deviations, those along the mesiodistal direction for the left second premolars were significantly lower in the MSF group (p = 0.006). However, those along the mesiodistal direction for the bilateral molars and those along the buccolingual direction for all teeth were not significantly different (p > 0.05). 3D-printed implant surgical guides without metal sleeve inserts enable accurate implant placement without exhausting the guide holes, rendering them feasible for fully guided implant placement.

scholarly journals Color Stability of Silicone or Acrylic Denture Liners: An in Vitro Investigation

2007 ◽  
Vol 01 (03) ◽  
pp. 144-151 ◽  
Author(s):  
Gulfem Ergun ◽  
Isil Cekic Nagas
Keyword(s):  
Accelerated Aging ◽  
Color Stability ◽  
Control Group ◽  
Distilled Water ◽  
Uniform Size ◽  
Liner Material ◽  
In Vitro Investigation ◽  
Before And After ◽  
Denture Liners

ABSTRACTObjectives: The aim of this study was to compare the color stability of three acrylic based hard liners (Ufi gel hard, Dura-Liner II, Tokuso Rebase) and two silicone based soft liners (Ufi gel permanent, Molloplast B) by using the colorimeter.Methods: Sixty disc-shaped samples, with uniform size of 10 mm diameter and 2 mm in thickness were fabricated for each material. Thirty samples were made as control group in distilled water and the remaining thirty samples were weathered in accelerated aging chamber. Color measurements were made before and after distilled water and aging. Data were statistically analyzed using nonparametric Kruskal-Wallis and Mann-Whitney U tests.Results: Data showed that there are significant differences among materials in both after distilled water and aging treatments (P>.001). These results indicated that the most discolored liner material was Dura Liner II after aging (ΔE*=16.30) and the least discolored material was Ufi gel permanent after distilled water (ΔE*=0.41).Conclusions: Based on the results of this study, silicone based liner materials are considered to be more color stable than acrylic based liner materials. (Eur J Dent 2007;1:144-151)

scholarly journals Use of bioluminescence measurements for detection of artificial demineralization adjacent to orthodontic brackets

2021 ◽  
Author(s):  
Anahita Jablonski-Momeni ◽  
Janine Sambale ◽  
Laura Gaerttner ◽  
Romy Nothelfer ◽  
Heike Korbmacher-Steiner
Keyword(s):  
In Vitro Study ◽  
Orthodontic Brackets ◽  
Free Calcium ◽  
Orthodontic Bracket ◽  
Promising Tool ◽  
Fluorescence Measurements ◽  
Human Enamel ◽  
Demineralized Enamel ◽  
Before And After

Abstract Purpose Enamel demineralization can occur as a side effect during orthodontic treatment with fixed appliances and should be detected as early as possible. A new approach to assess demineralization is a system consisting of a photosensitive protein that binds to free calcium ions at the enamel surface. A camera is then used to visualize the bioluminescence spots. This in vitro study aimed to evaluate the ability of the bioluminescence technology to assess artificially demineralized enamel adjacent to various orthodontic brackets. Methods In all, 108 human enamel samples were allocated randomly to groups with different orthodontic bracket material: stainless steel, titanium, ceramic. Initial lesions were created adjacent to the brackets. The samples were assessed by bioluminescence before and after demineralization. Images were assessed for presence of bioluminescence spots (yes/no). To quantify the bioluminescence measurements, the images’ pixel values (P) were calculated within a defined area (F) adjacent to each bracket before and after demineralization. Quantitative light-induced fluorescence measurements (ΔF, ΔQ) were performed as the reference standard for demineralization. Results After demineralization, bioluminescence spots were visible (yes/no decision) in 87% of the samples. The pixel analysis of the bioluminescence spots showed significantly higher pixel values after demineralization compared to baseline (p < 0.0001). The bracket material had no influence on the bioluminescence measurements. All samples showed fluorescence loss with a median ΔF of −9.52% (±3.15) and a median ΔQ of −1.01% × mm2 (±3.34), respectively. Conclusion The bioluminescence technology is a promising tool to demonstrate demineralization adjacent to different orthodontic brackets in vitro.

scholarly journals Genoprotective effects of green tea (Camellia sinensis) in human subjects: results of a controlled supplementation trial

2010 ◽  
Vol 105 (2) ◽  
pp. 171-179 ◽  
Author(s):  
K. C. Han ◽  
W. C. Wong ◽  
Iris F. F. Benzie
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Green Tea ◽  
Human Subjects ◽  
Human Lymphocytes ◽  
Random Order ◽  
Whole Body ◽  
Water Control ◽  
Before And After

Green tea is rich in polyphenolic antioxidants and has widely reported but largely unsubstantiated health benefits. In the present study, genoprotective effects of two types of green tea were studied both in an in vitro and in a human supplementation trial. For the in vitro study, human lymphocytes were pre-incubated in tea (0·005–0·1 %, w/v), washed and subjected to oxidant challenge induced by H2O2. In a placebo-controlled, cross-over supplementation study, eighteen healthy volunteers took 2 × 150 ml/d of 1 % (w/v) green tea (‘Longjing’ green tea or ‘screw-shaped’ green tea) or water (control) for 4 weeks (n 6). Subjects took all the three treatments in a random order, with 6 weeks' washout between each treatment. Fasting blood and urine were collected before and after each treatment. The comet assay was used to measure the resistance of lymphocytic DNA to H2O2-induced challenge. Basal oxidation-induced DNA damage was measured using the formamidopyrimidine glycosylase (Fpg) enzyme-assisted comet assay. Urine 7,8-dihydro-2-deoxyguanosine (8-oxodG, mol/mmol creatinine), a biomarker of whole-body oxidative stress, was measured by liquid chromatography with tandem MS. In vitro testing results of tea-treated cells showed increased (P < 0·05) resistance of DNA to the challenge. In the supplementation trial, a significant (P < 0·05) increase in resistance was also observed. Furthermore, the FPg comet data showed >20 % decrease in DNA damage with tea supplementation: mean and standard deviation changes in %DNA in comet tail in the Fpg-assisted comet assay were: − 5·96 (sd 3·83) % after Longjing tea; − 6·22 (sd 3·34) % after screw-shaped tea; +0·91 (sd 5·79) % after water (P < 0·05). No significant changes in urine 8-oxodG were seen. The results indicate that green tea has significant genoprotective effects and provide evidence for green tea as a ‘functional food’.

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