scholarly journals Effects of Post-Curing Time on the Mechanical and Color Properties of Three-Dimensional Printed Crown and Bridge Materials

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2762
Author(s):  
Dohyun Kim ◽  
Ji-Suk Shim ◽  
Dasun Lee ◽  
Seung-Ho Shin ◽  
Na-Eun Nam ◽  
...  
Keyword(s):  
Vickers Hardness ◽  
Color Change ◽  
Clinical Performance ◽  
Three Dimensional ◽  
Degree Of Conversion ◽  
Curing Process ◽  
Curing Time ◽  
Color Tone ◽  
Curing Conditions ◽  
3D Printed

Three-dimensional (3D) printing is increasingly being utilized in the dental field. After fabricating a prosthesis using a 3D printed resin, a post-curing process is required to improve its mechanical properties, but there has been insufficient research on the optimal post-curing conditions. We used various 3D printed crown and bridge materials in this study, and evaluated the changes in their properties according to post-curing time by evaluating the flexural strength, Weibull modulus, Vickers hardness, color change, degree of conversion, and biocompatibility. The obtained results confirmed that the strength of the 3D printed resin increased when it was post-cured for 60–90 min. The Vickers hardness, the degree of conversion, and biocompatibility of the 3D printed resins increased significantly around the beginning of the post-curing time, and then increased more gradually as the post-curing time increased further. It was observed that the color tone also changed as the post-curing time increased, with some groups showing a ΔE00 value of ≥ 2.25, which can be recognized clinically. This study has confirmed that, after the printing process of a 3D printed resin was completed, a sufficient post-curing time of at least 60 min is required to improve the overall clinical performance of the produced material.

Optimization of the Uncooked Oratosquilla Oratoria Curing Process via Response Surface Methodology

2014 ◽  
Vol 1073-1076 ◽  
pp. 1793-1797
Author(s):  
Qi Wei Mao ◽  
Jun Rui Wu ◽  
Xi Qing Yue
Keyword(s):  
Pathogenic Bacteria ◽  
Raw Materials ◽  
Curing Temperature ◽  
Curing Process ◽  
Curing Time ◽  
Optimal Process ◽  
Curing Conditions ◽  
Oratosquilla Oratoria ◽  
Sensory Score ◽  
Total Bacteria

Oratosquilla oratoria was the experimental raw materials in the paper. Design expert8.0.6 and Excel2007 was used to analyze the optimal process with the factors which were curing time, curing temperature, curing salt contention and the index which was the total bacteria. The pathogenic bacteria and sensory score under various curing conditions were determined simultaneously. After analyzing the significance of the various factors and interactions, the results showed the optimum curing conditions of oratosquilla oratoria were as follows: curing time 7.14h, curing temperature 14.34°C, curing salt contention 8.3%. Under this condition no pathogenic bacteria was detected and the sensory score was the highest.

scholarly journals Polymerization Efficiency of a Dual-Cured Resin Cement through Zirconia with Three Different Cusp Inclinations

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Chang-Yuan Zhang ◽  
Hao Yu ◽  
Yi-Ling Cheng ◽  
Wen-Zhou Wu ◽  
Liang-Jun Xu ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Vickers Hardness ◽  
Fourier Transform Infrared ◽  
Degree Of Conversion ◽  
Resin Cement ◽  
The Other ◽  
Curing Time ◽  
Fourier Transform Infrared Spectrometer ◽  
Infrared Spectrometer ◽  
Recorded Data

Assessing the polymerization efficiency of a dual-cured resin cement through zirconia with three different cusp inclinations is the aim of this study. Seventy-two resin cement (Multilink Speed) specimens were light-cured through the zirconia with three different cusp inclinations (30°, 20°, and 0°) for 20 s or 40 s (n=12). For each group, the Vickers hardness (VH) measurement was performed on half of the specimens, whereas the degree of conversion (DC) was tested for the other half with a Fourier transform infrared spectrometer. The recorded data were analyzed with a two-way ANOVA. Varied VH (32.3 ± 3.2–40.3 ± 4.8) and DC (50.5% ± 3.0%–59.6% ± 2.4%) values were obtained from different groups. The cusp inclinations significantly affect the VH (p=0.001) and DC (p<0.001) of the resin cement, and the curing time exhibited a significant effect on the DC (p=0.014) of resin cement but not on the VH (p=0.167). In conclusion, the cusp inclination of zirconia significantly affects the polymerization efficiency of dual-cured resin cement.

scholarly journals Optimization of Manufacturing Parameters of 3D Printed Solid Microneedles for Transdermal Drug Delivery

2021 ◽  
Vol 4 (1) ◽  
pp. 22
Author(s):  
Kenan Muhamedagić ◽  
Amina Tucak ◽  
Merima Sirbubalo ◽  
Ognjenka Rahić ◽  
Lamija Hindija ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Transdermal Drug Delivery ◽  
Isopropyl Alcohol ◽  
Low Cost ◽  
Curing Temperature ◽  
Curing Time ◽  
Curing Conditions ◽  
3D Printed ◽  
Fracture Tests ◽  
Manufacturing Parameters

Microneedles (MNs) have been manufactured using a variety of methods from a range of materials, but most of them are expensive and time-consuming for screening new designs and making any modifications. Therefore, stereolithography (SLA) has emerged as a promising approach for MN fabrication due to its numerous advantages, including simplicity, low cost, and the ability to manufacture complex geometrical products at any time, including modifications to the original designs. This work aimed to print MNs using SLA technology and investigate the effects of post-printing curing conditions on the mechanical properties of 3D-printed MNs. Solid MNs were designed using CAD software and printed with grey resin (Formlabs, UK) using a Form 3 printer (Formlabs, UK). MNs dimensions were 1.2 × 0.4 × 0.05 mm, arranged in 6 rows and 6 columns on a 10 × 10 mm baseplate. MNs were then immersed in an isopropyl alcohol bath to remove unpolymerized resin residues and cured in a UV-A heated chamber (Formlabs, UK). In total, nine samples were taken for each combination of curing temperature (35, 50, and 70 °C) and curing time (5, 20, and 60 min). Fracture tests were conducted using a hardness apparatus TB24 (Erweka, Germany). MNs were placed on the moving probe of the machine and compressed until fracture. The optimization of the SLA process parameters for improving the strength of MNs was performed using the Taguchi method. The design of experiments was carried out based on the Taguchi L9 orthogonal array. Experimental results showed that the curing temperature has a significant influence on MN strength improvements. Improvement of the MN strength can be achieved by increasing the curing temperature and curing time.

Development of fabrics by digital light processing three-dimensional printing technology and using a polyurethane acrylate photopolymer

2019 ◽  
Vol 90 (7-8) ◽  
pp. 847-856
Author(s):  
Seul Gi Kim ◽  
Ji Eun Song ◽  
Hye Rim Kim
Keyword(s):  
3D Printing ◽  
Layer Thickness ◽  
Three Dimensional ◽  
Curing Time ◽  
Printing Technology ◽  
Digital Light Processing ◽  
Three Dimensional Printing ◽  
3D Printing Technology ◽  
Polyurethane Acrylate ◽  
3D Printed

This study aimed to produce fabrics by the digital light processing (DLP) three-dimensional (3D) printing technology and using a polyurethane acrylate photopolymer as the printing material. The effect of the acrylate oligomer concentration on printing was evaluated. The DLP 3D printing conditions, such as the curing time and layer thickness, were controlled considering the physical properties, such as the tensile strength, elongation, and crease recovery of the 3D printed material. The optimal printing conditions were as follows: concentration of acrylate oligomer in the photopolymer: 10% (v/v); curing time per layer: 14 s; and layer thickness: 100 µm. These results are expected to guide further studies on the development of fabrics using DLP 3D printing technology.

scholarly journals Study on the Curing Process of Silver Paste of Heterojunction Solar Cells Using Response Surface Methodology

2020 ◽  
Vol 10 (14) ◽  
pp. 4857
Author(s):  
Xin Li ◽  
Hongyu Dong ◽  
Shaoqing Guo ◽  
Liangfu Zhao
Keyword(s):  
Response Surface Methodology ◽  
Solar Cells ◽  
Response Surface ◽  
Adhesion Strength ◽  
Treatment Temperature ◽  
Curing Process ◽  
Curing Time ◽  
Silver Paste ◽  
Curing Conditions ◽  
Heterojunction Solar Cells

Adhesion strength is of great importance for silver paste of heterojunction solar cells (HJT silver paste). It has a close relation with the curing system, as well as the curing process or curing conditions of the paste. The interactions among all the curing conditions such as curing time (t, min), treatment temperature (T, °C), and curing agent dosage (m, wt%) are obviously complex and hard to analyze. Response surface methodology (RSM) is used to research the interactions among t, T, and m and to optimize the curing process. The results of this study indicate that an increase of curing time and treatment temperature both had a positive effect on adhesion strength. The effect of curing time is more obvious under a lower treatment temperature. 41 wt%, 199 °C, and 44 min were determined as the optimum process conditions. The quadratic model predictions fitted well with the experimental data with a deviation less than 3%. The FTIR results indicated that there were both addition and esterification processes in the reaction of E51 and ring-open MeTHPA. Scanning electron microscopy (SEM) images showed that the silver paste formed a dense interconnected network and provided a continuous pathway for current carrier transmission. This research demonstrated the effectiveness of the E51-MeTHPA system for HJT silver paste and the superiority of RSM in studying the curing process of silver paste.

Use of Three-dimensional Printing in the Development of Optimal Cardiac CT Scanning Protocols

2020 ◽  
Vol 16 (8) ◽  
pp. 967-977
Author(s):  
Zhonghua Sun
Keyword(s):  
Cardiovascular Disease ◽  
Cardiac Computed Tomography ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Aortic Diseases ◽  
Clinical Value ◽  
Three Dimensional Printing ◽  
Doctor Patient Communication ◽  
Medical Education And Training ◽  
3D Printed

Three-dimensional (3D) printing is increasingly used in medical applications with most of the studies focusing on its applications in medical education and training, pre-surgical planning and simulation, and doctor-patient communication. An emerging area of utilising 3D printed models lies in the development of cardiac computed tomography (CT) protocols for visualisation and detection of cardiovascular disease. Specifically, 3D printed heart and cardiovascular models have shown potential value in the evaluation of coronary plaques and coronary stents, aortic diseases and detection of pulmonary embolism. This review article provides an overview of the clinical value of 3D printed models in these areas with regard to the development of optimal CT scanning protocols for both diagnostic evaluation of cardiovascular disease and reduction of radiation dose. The expected outcomes are to encourage further research towards this direction.

Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core

2020 ◽  
Vol 12 (05) ◽  
pp. 2050051
Author(s):  
Khawla Essassi ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Mohamed Amine Ben Souf ◽  
Anas Bouguecha ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Shear Stiffness ◽  
Tensile Tests ◽  
Sandwich Composite ◽  
Static Behavior ◽  
Flax Fibers ◽  
Data Points ◽  
3D Printed

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

scholarly journals Investigation of the selective color-changing mechanism of Dynastes tityus beetle (Coleoptera: Scarabaeidae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiyu Sun ◽  
Wei Wu ◽  
Limei Tian ◽  
Wei Li ◽  
Fang Zhang ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Color Change ◽  
Incidence Angle ◽  
Ion Beam ◽  
Three Dimensional ◽  
Water Infiltration ◽  
Photonic Materials ◽  
Local Color ◽  
Water Contact ◽  
Color Changes

AbstractNot only does the Dynastes tityus beetle display a reversible color change controlled by differences in humidity, but also, the elytron scale can change color from yellow-green to deep-brown in specified shapes. The results obtained by focused ion beam-scanning electron microscopy (FIB-SEM), show that the epicuticle (EPI) is a permeable layer, and the exocuticle (EXO) is a three-dimensional photonic crystal. To investigate the mechanism of the reversible color change, experiments were conducted to determine the water contact angle, surface chemical composition, and optical reflectance, and the reflective spectrum was simulated. The water on the surface began to permeate into the elytron via the surface elemental composition and channels in the EPI. A structural unit (SU) in the EXO allows local color changes in varied shapes. The reflectance of both yellow-green and deep-brown elytra increases as the incidence angle increases from 0° to 60°. The microstructure and changes in the refractive index are the main factors that influence the process of reversible color change. According to the simulation, the lower reflectance causing the color change to deep-brown results from water infiltration, which increases light absorption. Meanwhile, the waxy layer has no effect on the reflection of light. This study lays the foundation to manufacture engineered photonic materials that undergo controllable changes in iridescent color.

scholarly journals Midface Reconstruction: Planning and Outcome

2020 ◽  
Vol 53 (03) ◽  
pp. 324-334
Author(s):  
Gautam Biswas
Keyword(s):  
Digital Imaging ◽  
3D Structure ◽  
Three Dimensional ◽  
The Past ◽  
Complex Anatomy ◽  
Osseointegrated Implants ◽  
Low Profile ◽  
3D Printed ◽  
Midface Reconstruction ◽  
Reconstruction Planning

Abstract Reconstruction of the complex anatomy and aesthetics of the midface is often a challenge. A careful understanding of this three-dimensional (3D) structure is necessary. Anticipating the extent of excision and its planning following oncological resections is critical.In the past over two decades, with the advances in microsurgical procedures, contributions toward the reconstruction of this area have generated interest. Planning using digital imaging, 3D printed models, osseointegrated implants, and low-profile plates, has favorably impacted the outcome. However, there are still controversies in the management: to use single composite tissues versus multiple tissues; implants versus autografts; vascularized versus nonvascularized bone; prosthesis versus reconstruction.This article explores the present available options in maxillary reconstruction and outlines the approach in the management garnered from past publications and experiences.

scholarly journals Recurrent contracted sockets treated with personalized, three-dimensionally printed conformers and buccal grafts

2021 ◽  
pp. 112067212110000
Author(s):  
Annabel LW Groot ◽  
Jelmer S Remmers ◽  
Roel JHM Kloos ◽  
Peerooz Saeed ◽  
Dyonne T Hartong
Keyword(s):  
Three Dimensional ◽  
Case Series ◽  
Secondary Outcome ◽  
Retrospective Case ◽  
Upper Eyelid ◽  
Ocular Prosthesis ◽  
Buccal Mucosal Graft ◽  
Custom Made ◽  
3D Printed

Purpose: Recurrent contracted sockets are complex situations where previous surgeries have failed, disabling the wear of an ocular prosthesis. A combined method of surgery and long-term fixation using custom-made, three-dimensional (3D) printed conformers is evaluated. Methods: Retrospective case series of nine patients with recurrent excessive socket contraction and inability to wear a prosthesis, caused by chemical burns ( n = 3), fireworks ( n = 3), trauma ( n = 2) and enucleation and radiotherapy at childhood due to optic nerve glioma ( n = 1) with three average previous socket surgeries (range 2–6). Treatment consisted of a buccal mucosal graft and personalized 3D-printed conformer designed to be fixated to the periosteum and tarsal plates for minimal 2 months. Primary outcome was the retention of an ocular prosthesis. Secondary outcome was the need for additional surgeries. Results: Outcomes were measured at final follow-up between 7 and 36 months postoperatively (mean 20 months). Eight cases were able to wear an ocular prosthesis after 2 months. Three cases initially treated for only the upper or only the lower fornix needed subsequent surgery for the opposite fornix for functional reasons. Two cases had later surgery for cosmetic improvement of upper eyelid position. Despite pre-existing lid abnormalities (scar, entropion, lash deficiency), cosmetic outcome was judged highly acceptable in six cases because of symmetric contour and volume, and reasonably acceptable in the remaining two. Conclusions: Buccal mucosal transplant fixated with a personalized 3D-designed conformer enables retention of a well-fitted ocular prosthesis in previously failed socket surgeries. Initial treatment of both upper and lower fornices is recommended to avoid subsequent surgeries for functional reasons.

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