Displaying publications 1 - 20 of 65 in total

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  1. Mohan D, Khairullah NF, How YP, Sajab MS, Kaco H
    Polymers (Basel), 2020 Apr 23;12(4).
    PMID: 32340327 DOI: 10.3390/polym12040986
    Drug delivery constitutes the formulations, technologies, and systems for the transport of pharmaceutical compounds to specific areas in the body to exert safe therapeutic effects. The main criteria for selecting the correct medium for drug delivery are the quantity of the drug being carried and the amount of time required to release the drug. Hence, this research aimed to improve the aforementioned criteria by synthesizing a medium based on calcium carbonate-nanocellulose composite and evaluating its efficiency as a medium for drug delivery. Specifically, the efficiency was assessed in terms of the rates of uptake and release of 5-fluorouracil. Through the evaluation of the morphological and chemical properties of the synthesized composite, the established 3D printing profiles of nanocellulose and CaCO3 took place following the layer-by-layer films. The 3D printed double laminated CaCO3-nanocellulose managed to release the 5-fluorouracil as an effective single composition and in a time-controlled manner.
    Matched MeSH terms: Printing, Three-Dimensional
  2. Abdul Wahit MA, Ahmad SA, Marhaban MH, Wada C, Izhar LI
    Sensors (Basel), 2020 Jul 27;20(15).
    PMID: 32727150 DOI: 10.3390/s20154174
    Trans-radial prosthesis is a wearable device that intends to help amputees under the elbow to replace the function of the missing anatomical segment that resembles an actual human hand. However, there are some challenging aspects faced mainly on the robot hand structural design itself. Improvements are needed as this is closely related to structure efficiency. This paper proposes a robot hand structure with improved features (four-bar linkage mechanism) to overcome the deficiency of using the cable-driven actuated mechanism that leads to less structure durability and inaccurate motion range. Our proposed robot hand structure also took into account the existing design problems such as bulky structure, unindividual actuated finger, incomplete fingers and a lack of finger joints compared to the actual finger in its design. This paper presents the improvements achieved by applying the proposed design such as the use of a four-bar linkage mechanism instead of using the cable-driven mechanism, the size of an average human hand, five-fingers with completed joints where each finger is moved by motor individually, joint protection using a mechanical stopper, detachable finger structure from the palm frame, a structure that has sufficient durability for everyday use and an easy to fabricate structure using 3D printing technology. The four-bar linkage mechanism is the use of the solid linkage that connects the actuator with the structure to allow the structure to move. The durability was investigated using static analysis simulation. The structural details and simulation results were validated through motion capture analysis and load test. The motion analyses towards the 3D printed robot structure show 70-98% similar motion range capability to the designed structure in the CAD software, and it can withstand up to 1.6 kg load in the simulation and the real test. The improved robot hand structure with optimum durability for prosthetic uses was successfully developed.
    Matched MeSH terms: Printing, Three-Dimensional
  3. Pandey M, Choudhury H, Fern JLC, Kee ATK, Kou J, Jing JLJ, et al.
    Drug Deliv Transl Res, 2020 08;10(4):986-1001.
    PMID: 32207070 DOI: 10.1007/s13346-020-00737-0
    The involvement of recent technologies, such as nanotechnology and three-dimensional printing (3DP), in drug delivery has become the utmost importance for effective and safe delivery of potent therapeutics, and thus, recent advancement for oral drug delivery through 3DP technology has been expanded. The use of computer-aided design (CAD) in 3DP technology allows the manufacturing of drug formulation with the desired release rate and pattern. Currently, the most applicable 3DP technologies in the oral drug delivery system are inkjet printing method, fused deposition method, nozzle-based extrusion system, and stereolithographic 3DP. In 2015, the first 3D-printed tablet was approved by the US Food and Drug Administration (FDA), and since then, it has opened up more opportunities in the discovery of formulation for the development of an oral drug delivery system. 3DP allows the production of an oral drug delivery device that enables tailor-made formulation with customizable size, shape, and release rate. Despite the advantages offered by 3DP technology in the drug delivery system, there are challenges in terms of drug stability, safety as well as applicability in the clinical sector. Nonetheless, 3DP has immense potential in the development of drug delivery devices for future personalized medicine. This article will give the recent advancement along with the challenges of 3DP techniques for the development of oral drug delivery. Graphical abstract.
    Matched MeSH terms: Printing, Three-Dimensional*
  4. Abdullah KA, Reed W
    J Med Radiat Sci, 2018 Sep;65(3):237-239.
    PMID: 29971971 DOI: 10.1002/jmrs.292
    Three-dimensional (3D) printing technology has demonstrated a huge potential for the future of medicine. Since its introduction, it has been used in various areas, for example building anatomical models, personalising medical devices and implants, aiding in precision medical interventions and the latest development, 3D bioprinting. This commentary is provided to outline the current use of 3D printing in medical imaging and its future directions for advancing the healthcare services.
    Matched MeSH terms: Printing, Three-Dimensional/economics; Printing, Three-Dimensional/instrumentation*; Printing, Three-Dimensional/trends; Printing, Three-Dimensional/statistics & numerical data
  5. Awuah WA, Tenkorang PO, Adebusoye FT, Ng JC, Wellington J, Abdul-Rahman T, et al.
    Postgrad Med J, 2023 Dec 21;100(1179):1-3.
    PMID: 37857514 DOI: 10.1093/postmj/qgad100
    Matched MeSH terms: Printing, Three-Dimensional
  6. Sun Z, Ng CKC, Wong YH, Yeong CH
    Biomolecules, 2021 09 03;11(9).
    PMID: 34572520 DOI: 10.3390/biom11091307
    The diagnostic value of coronary computed tomography angiography (CCTA) is significantly affected by high calcification in the coronary arteries owing to blooming artifacts limiting its accuracy in assessing the calcified plaques. This study aimed to simulate highly calcified plaques in 3D-printed coronary models. A combination of silicone + 32.8% calcium carbonate was found to produce 800 HU, representing extensive calcification. Six patient-specific coronary artery models were printed using the photosensitive polyurethane resin and a total of 22 calcified plaques with diameters ranging from 1 to 4 mm were inserted into different segments of these 3D-printed coronary models. The coronary models were scanned on a 192-slice CT scanner with 70 kV, pitch of 1.4, and slice thickness of 1 mm. Plaque attenuation was measured between 1100 and 1400 HU. Both maximum-intensity projection (MIP) and volume rendering (VR) images (wide and narrow window widths) were generated for measuring the diameters of these calcified plaques. An overestimation of plaque diameters was noticed on both MIP and VR images, with measurements on the MIP images close to those of the actual plaque sizes (<10% deviation), and a large measurement discrepancy observed on the VR images (up to 50% overestimation). This study proves the feasibility of simulating extensive calcification in coronary arteries using a 3D printing technique to develop calcified plaques and generate 3D-printed coronary models.
    Matched MeSH terms: Printing, Three-Dimensional*
  7. Touri M, Moztarzadeh F, Osman NAA, Dehghan MM, Mozafari M
    Mater Sci Eng C Mater Biol Appl, 2018 Mar 01;84:236-242.
    PMID: 29519434 DOI: 10.1016/j.msec.2017.11.037
    Tissue engineering scaffolds with oxygen generating elements have shown to be able to increase the level of oxygen and cell survivability in specific conditions. In this study, biphasic calcium phosphate (BCP) scaffolds with the composition of 60% hydroxyapatite (HA) and 40% beta-tricalcium phosphate (β-TCP), which have shown a great potential for bone tissue engineering applications, were fabricated by a direct-write assembly (robocasting) technique. Then, the three-dimensional (3D)-printed scaffolds were coated with different ratios of an oxygen releasing agent, calcium peroxide (CPO), which encapsulated within a polycaprolactone (PCL) matrix through dip-coating, and used for in situ production of oxygen in the implanted sites. The structure, composition and morphology of the prepared scaffolds were characterized by different techniques. The oxygen release kinetics and biological investigations of the scaffolds were also studied in vitro. The results showed that oxygen release behaviour was sustained and dependant on the concentration of CPO encapsulated in the PCL coating matrix. It was also demonstrated that the coated scaffolds, having 3% CPO in the coating system, could provide a great potential for promoting bone ingrowth with improving osteoblast cells viability and proliferation under hypoxic conditions. The findings indicated that the prepared scaffolds could play a significant role in engineering of large bone tissue implants with limitations in oxygen diffusion.
    Matched MeSH terms: Printing, Three-Dimensional*
  8. Singhvi G, Patil S, Girdhar V, Chellappan DK, Gupta G, Dua K
    Panminerva Med, 2018 Dec;60(4):170-173.
    PMID: 29856179 DOI: 10.23736/S0031-0808.18.03467-5
    One of the novel and progressive technology employed in pharmaceutical manufacturing, design of medical device and tissue engineering is three-dimensional (3D) printing. 3D printing technologies provide great advantages in 3D scaffolds fabrication over traditional methods in the control of pore size, porosity, and interconnectivity. Various techniques of 3D-printing include powder bed fusion, fused deposition modeling, binder deposition, inkjet printing, photopolymerization and many others which are still evolving. 3D-printing technique been employed in developing immediate release products, various systems to deliver multiple release modalities etc. 3D printing has opened the door for new generation of customized drug delivery with built-in flexibility for safer and effective therapy. Our mini-review provides a quick snapshot on an overview of 3D printing, various techniques employed, applications and its advancements in pharmaceutical sciences.
    Matched MeSH terms: Printing, Three-Dimensional*
  9. Hosseini S, Azari P, Cardenas-Benitez B, Martínez-Guerra E, Aguirre-Tostado FS, Vázquez-Villegas P, et al.
    Mater Sci Eng C Mater Biol Appl, 2020 Apr;109:110629.
    PMID: 32228934 DOI: 10.1016/j.msec.2020.110629
    Based on the concept of LEGO toys, a fiber probe analytical platform (FPAP) was developed as a powerful diagnostic tool offering higher sensitivity in detection of infectious agents compared to established methods. Using the form and the function of LEGO toys, this protocol describes a fiber-based, 96-well plate, which suspends a new class of chemically-designed, electrospun fibers within the assay. This clamping strategy allows both sides of the developed fiber mats to interact with biomolecules within the assay thus benefiting from the tailored chemical and physical properties of these fiber-based bioreceptors in attracting the biomolecules to the surface. The fabrication method of FPAP involves one-step electrospinning of the chemically designed fibers, 3D printing of the LEGO-like probing segments, and assembly of the device followed by ELISA procedure. FPAP follows the same principles of operation as that of a conventional enzyme linked immunosorbent assay (ELISA), therefore, it can be run by lab technicians, expert in ELISA. FPAP was used for early diagnosis of Dengue fever and provided an 8-fold higher sensitivity while the limit of detection (LOD) was recorded to be in femto-gram per milliliter range which is significantly low when compared to other existing techniques or conventional assay. This platform allows different types of paper/fiber bio-receptive platforms to be incorporated within the design that promises simultaneous recognition of multiple infectious agents.
    Matched MeSH terms: Printing, Three-Dimensional*
  10. Mehboob H, Tarlochan F, Mehboob A, Chang SH, Ramesh S, Harun WSW, et al.
    J Mater Sci Mater Med, 2020 Aug 20;31(9):78.
    PMID: 32816091 DOI: 10.1007/s10856-020-06420-7
    The current study is proposing a design envelope for porous Ti-6Al-4V alloy femoral stems to survive under fatigue loads. Numerical computational analysis of these stems with a body-centered-cube (BCC) structure is conducted in ABAQUS. Femoral stems without shell and with various outer dense shell thicknesses (0.5, 1.0, 1.5, and 2 mm) and inner cores (porosities of 90, 77, 63, 47, 30, and 18%) are analyzed. A design space (envelope) is derived by using stem stiffnesses close to that of the femur bone, maximum fatigue stresses of 0.3σys in the porous part, and endurance limits of the dense part of the stems. The Soderberg approach is successfully employed to compute the factor of safety Nf > 1.1. Fully porous stems without dense shells are concluded to fail under fatigue load. It is thus safe to use the porous stems with a shell thickness of 1.5 and 2 mm for all porosities (18-90%), 1 mm shell with 18 and 30% porosities, and 0.5 mm shell with 18% porosity. The reduction in stress shielding was achieved by 28%. Porous stems incorporated BCC structures with dense shells and beads were successfully printed.
    Matched MeSH terms: Printing, Three-Dimensional*
  11. Shahar FS, Hameed Sultan MT, Lee SH, Jawaid M, Md Shah AU, Safri SNA, et al.
    J Mech Behav Biomed Mater, 2019 11;99:169-185.
    PMID: 31357064 DOI: 10.1016/j.jmbbm.2019.07.020
    Since ancient Egypt, orthosis was generally made from wood and then later replaced with metal and leather which are either heavy, bulky, or thick decreasing comfort among the wearers. After the age of revolution, the manufacturing of products using plastics and carbon composites started to spread due to its low cost and form-fitting feature whereas carbon composite were due to its high strength/stiffness to weight ratio. Both plastic and carbon composite has been widely applied into medical devices such as the orthosis and prosthesis. However, carbon composite is also quite expensive, making it the less likely material to be used as an Ankle-Foot Orthosis (AFO) material whereas plastics has low strength. Kenaf composite has a high potential in replacing all the current materials due to its flexibility in controlling the strength to weight ratio properties, cost-effectiveness, abundance of raw materials, and biocompatibility. The aim of this review paper is to discuss on the possibility of using kenaf composite as an alternative material to fabricate orthotics and prosthetics. The discussion will be on the development of orthosis since ancient Egypt until current era, the existing AFO materials, the problems caused by these materials, and the possibility of using a Kenaf fiber composite as a replacement of the current materials. The results show that Kenaf composite has the potential to be used for fabricating an AFO due to its tensile strength which is almost similar to polypropylene's (PP) tensile strength, and the cheap raw material compared to other type of materials.
    Matched MeSH terms: Printing, Three-Dimensional
  12. Daphne Clemente, Nurul Amiella Abdullah, ZurianahJusmin Jasmin, Muhammad Syafiq Abdullah, Helen Benedict Lasimbang, Wendy Diana Shoesmith, et al.
    MyJurnal
    Introduction: Continuous quality improvement of system is essential to improve efficiency of working environ- ment. Limited financial allocation in low resource setting results in the vicious circle of having inadequate money to purchase a new system and print paper documents that are required for the operation of clinic. A staff-initiated system improvement with the name of “PRW UMS Staff Portal” was attempted to break-free from the vicious cycle. Methods: An online system covering different aspects of routine clinical work of healthcare workers was created in Dec 2019 and implemented in Feb 2020 using Google SiteTM by the nurses of a local university community clinic, which included: submission of daily reports of nurses and assistant medical officers, submission of reports of all programmes conducted by the clinic, surveillance of health status of working staffs, announcement and request of working roster, archiving of documents, and medication inventory. The system could only be accessed using official working email for general documents while accesses to sensitive documents were restricted to relevant staffs to pro- tect privacy and confidentiality of information. Qualitative interviews were performed with all nursing staff involved. Results: Qualitative feeling of improvement in coordination of workflow was reported by all 23 staffs working in the clinic in view of the easy access of system using smartphone and computer at workstation. It also reduced the need to move away from the working station in order to access, replenish, or submit the printed documents and reports. Significant amount of paper and printing were saved monthly. Conclusions: Despite positive feedback from the staffs, the system requires further improvement in terms of function and security. Further evaluation on cost-efficiency of the system can be done to promote the system to other universities.

    Matched MeSH terms: Printing, Three-Dimensional
  13. Ashammakhi N, Ahadian S, Zengjie F, Suthiwanich K, Lorestani F, Orive G, et al.
    Biotechnol J, 2018 Dec;13(12):e1800148.
    PMID: 30221837 DOI: 10.1002/biot.201800148
    Three-dimensionally printed constructs are static and do not recapitulate the dynamic nature of tissues. Four-dimensional (4D) bioprinting has emerged to include conformational changes in printed structures in a predetermined fashion using stimuli-responsive biomaterials and/or cells. The ability to make such dynamic constructs would enable an individual to fabricate tissue structures that can undergo morphological changes. Furthermore, other fields (bioactuation, biorobotics, and biosensing) will benefit from developments in 4D bioprinting. Here, the authors discuss stimuli-responsive biomaterials as potential bioinks for 4D bioprinting. Natural cell forces can also be incorporated into 4D bioprinted structures. The authors introduce mathematical modeling to predict the transition and final state of 4D printed constructs. Different potential applications of 4D bioprinting are also described. Finally, the authors highlight future perspectives for this emerging technology in biomedicine.
    Matched MeSH terms: Printing, Three-Dimensional
  14. Harnois M, Himdi M, Yong WY, Rahim SKA, Tekkouk K, Cheval N
    Sci Rep, 2020 Feb 03;10(1):1714.
    PMID: 32015444 DOI: 10.1038/s41598-020-58657-5
    Manufacturing an array of high-quality metallic pattern layers on a dielectric substrate remains a major challenge in the development of flexible and 3-D frequency selective surfaces (FSS). This paper proposes an improved fabrication solution for the 3-D FSS based on water transfer printing (WTP) technology. The main advantages of the proposed solution are its ability to transform complicated 2-D planar FSS patterns into 3-D structures while improving both manufacturing quality and production costs. WTP technology makes use of water surface tension to keep the thin metallic patterns of the proposed FSS floating flat with the absence of a solid planar substrate. This feature enables these metallic FSS patterns to be transferred onto 3-D structures through a dipping process. To test the effectiveness of the proposed technique, the FSS was designed using computer simulation software Microwave Studio to obtain the numerical performance of the FSS structure. The WTP technology was then used to fabricate the proposed FSS prototype before its performance was tested experimentally. The measurement results agreed well with the numerical results, indicating the proposed manufacturing solution would support the development of complicated 3-D electronics devices, such as conformal antenna arrays and metamaterials.
    Matched MeSH terms: Printing, Three-Dimensional
  15. Deja M, Zieliński D, Kadir AZA, Humaira SN
    Materials (Basel), 2021 Mar 09;14(5).
    PMID: 33803424 DOI: 10.3390/ma14051318
    High requirements imposed by the competitive industrial environment determine the development directions of applied manufacturing methods. 3D printing technology, also known as additive manufacturing (AM), currently being one of the most dynamically developing production methods, is increasingly used in many different areas of industry. Nowadays, apart from the possibility of making prototypes of future products, AM is also used to produce fully functional machine parts, which is known as Rapid Manufacturing and also Rapid Tooling. Rapid Manufacturing refers to the ability of the software automation to rapidly accelerate the manufacturing process, while Rapid Tooling means that a tool is involved in order to accelerate the process. Abrasive processes are widely used in many industries, especially for machining hard and brittle materials such as advanced ceramics. This paper presents a review on advances and trends in contemporary abrasive machining related to the application of innovative 3D printed abrasive tools. Examples of abrasive tools made with the use of currently leading AM methods and their impact on the obtained machining results were indicated. The analyzed research works indicate the great potential and usefulness of the new constructions of the abrasive tools made by incremental technologies. Furthermore, the potential and limitations of currently used 3D printed abrasive tools, as well as the directions of their further development are indicated.
    Matched MeSH terms: Printing, Three-Dimensional
  16. Anita Lett J, Sagadevan S, Léonard E, Fatimah I, Motalib Hossain MA, Mohammad F, et al.
    Artif Organs, 2021 Dec;45(12):1501-1512.
    PMID: 34309044 DOI: 10.1111/aor.14045
    The primary role of bone tissue engineering is to reconcile the damaged bones and facilitate the speedy recovery of the injured bones. However, some of the investigated metallic implants suffer from stress-shielding, palpability, biocompatibility, etc. Consequently, the biodegradable scaffolds fabricated from polymers have gathered much attention from researchers and thus helped the tissue engineering sector by providing many alternative materials whose functionality is similar to that of natural bones. Herein, we present the fabrication and testing of a novel composite, magnesium (Mg)-doped hydroxyapatite (HAp) glazed onto polylactic acid (PLA) scaffolds where polyvinyl alcohol (PVA) used as a binder. For the composite formation, Creality Ender-3 pro High Precision 3D Printer with Shape tool 3D Technology on an FSD machine operated by Catia design software was employed. The composite has been characterized for the crystallinity (XRD), surface functionality (FTIR), morphology (FESEM), biocompatibility (hemolytic and protein absorption), and mechanical properties (stress-strain and maximum compressive strength). The powder XRD analysis confirmed the semicrystalline nature and intact structure of HAp even after doping with Mg, while FTIR studies for the successful formation of Mg-HAp/PVA@PLA composite. The FESEM provided analysis indicated for the 3D porous architecture and well-defined morphology to efficiently transport the nutrients, and the biocompatibility studies are supporting that the composite for blood compatible with the surface being suitable enough for the protein absorption. Finally, the composite's antibacterial activity (against Staphylococcus aureus and Escherichia coli) and the test of mechanical properties supported for the enhanced inhibition of active growth of microorganisms and maximum compressive strength, respectively. Based on the research outcomes of biocompatibility, antibacterial activity, and mechanical resistance, the fabricated Mg-HAp/PVA@PLA composite suits well as a promising biomaterial platform for orthopedic applications by functioning towards the open reduction internal fixation of bone fractures and internal repairs.
    Matched MeSH terms: Printing, Three-Dimensional
  17. Shahrubudin N, Koshy P, Alipal J, Kadir MHA, Lee TC
    Heliyon, 2020 Apr;6(4):e03734.
    PMID: 32322726 DOI: 10.1016/j.heliyon.2020.e03734
    Additive manufacturing has attracted increasing attention worldwide, especially in the healthcare, biomedical, aerospace, and construction industries. In Malaysia, insufficient acceptance of this technology by local industries has resulted in a call for government and local practitioners to promulgate the development of this technology for various industries, particularly for biomedical products. The current study intends to frame the challenges endured by biomedical industries who use 3D printing technology for their manufacturing processes. Qualitative methods, particularly in-depth interviews, were used to identify the challenges faced by manufacturing firms when producing 3D printed biomedical products. This work was able to identify twelve key challenges when deploying additive manufacturing in biomedical products and these include issues related to binder selection, poor mechanical properties, low-dimensional accuracy, high levels of powder agglomeration, nozzle size, distribution size, limited choice of materials, texture and colour, lifespan of materials, customization of fit and design, layer height, and, lastly, build-failure. Furthermore, there also are six challenges in the management of manufacturing biomedical products using 3D printing technology, and these include staff re-education, product pricing, limited guidelines, cyber-security issues, marketing, and patents and copyright. This study discusses the reality faced by 3D printing players when producing biomedical products in Malaysia, and presents a primary reference for practitioners in other developing countries.
    Matched MeSH terms: Printing, Three-Dimensional
  18. Raees S, Ullah F, Javed F, Akil HM, Jadoon Khan M, Safdar M, et al.
    Int J Biol Macromol, 2023 Mar 31;232:123476.
    PMID: 36731696 DOI: 10.1016/j.ijbiomac.2023.123476
    With the advancement in 3D bioprinting technology, cell culture methods can design 3D environments which are both, complex and physiologically relevant. The main component in 3D bioprinting, bioink, can be split into various categories depending on the criterion of categorization. Although the choice of bioink and bioprinting process will vary greatly depending on the application, general features such as material properties, biological interaction, gelation, and viscosity are always important to consider. The foundation of 3D bioprinting is the exact layer-by-layer implantation of biological elements, biochemicals, and living cells with the spatial control of the implantation of functional elements onto the biofabricated 3D structure. Three basic strategies underlie the 3D bioprinting process: autonomous self-assembly, micro tissue building blocks, and biomimicry or biomimetics. Tissue engineering can benefit from 3D bioprinting in many ways, but there are still numerous obstacles to overcome before functional tissues can be produced and used in clinical settings. A better comprehension of the physiological characteristics of bioink materials and a higher level of ability to reproduce the intricate biologically mimicked and physiologically relevant 3D structures would be a significant improvement for 3D bioprinting to overcome the limitations.
    Matched MeSH terms: Printing, Three-Dimensional
  19. Mohd Tahir N, Wan Hassan WN, Saub R
    Eur J Orthod, 2019 08 08;41(4):370-380.
    PMID: 30321319 DOI: 10.1093/ejo/cjy063
    OBJECTIVES: The aim of this study was to compare vacuum-formed thermoplastic retainers (VFRs) constructed on stone models (VFR-CV) and those constructed on three-dimensional (3D) printed models (VFR-3D) based on patients' perspective and post-treatment stability.

    STUDY DESIGN: The research was designed as a crossover, randomized control trial.

    MATERIALS AND METHODS: Subjects comprised patients receiving fixed appliances at a teaching institution and indicated for VFRs. Post-treatment stone models were scanned with a structured-light scanner. A fused deposition modelling machine was used to construct acrylonitrile-butadiene-styrene (ABS)-based replicas from the 3D scanned images. VFRs were fabricated on the original stone and printed models. Analysis comprised independent t-tests and repeated measures analysis of variance.

    RANDOMIZATION: Subjects were allocated to two groups using Latin squares methods and simple randomization. A week after debond, subjects received either VFR-CV first (group A) or VFR-3D first (group B) for 3 months, then the interventions were crossed over for another 3 months.

    BLINDING: In this single-blinded study, subjects were assigned a blinding code for data entry; data were analysed by a third party.

    OUTCOME MEASURES: The primary outcome measured was oral health-related quality of life (OHRQoL) based on Oral Health Impact Profile-14 (OHIP-14). Secondary outcome was post-treatment stability measured using Little's Irregularity Index (LII).

    RESULTS: A total of 30 subjects (15 in each group) were recruited but 3 dropped out. Analysis included 13 subjects from group A and 14 subjects from group B. Group A showed an increase in LII (P < 0.05) after wearing VFR-CV and VFR-3D, whereas group B had no significant increase in LII after wearing both VFRs. Both groups reported significant improvement in OHRQoL after the first intervention but no significant differences after the second intervention. LII changes and OHIP-14 scores at T2 and T3 between groups, and overall between the retainers were not significantly different. No harm was reported during the study.

    CONCLUSION: VFRs made on ABS-based 3D printed models showed no differences in terms of patients' OHRQoL and stability compared with conventionally made retainers.

    REGISTRATION: NCT02866617 (ClinicalTrials.gov).

    Matched MeSH terms: Printing, Three-Dimensional
  20. Wan Hassan WN, Yusoff Y, Mardi NA
    Am J Orthod Dentofacial Orthop, 2017 Jan;151(1):209-218.
    PMID: 28024776 DOI: 10.1016/j.ajodo.2016.08.019
    INTRODUCTION: Rapid prototyping models can be reconstructed from stereolithographic digital study model data to produce hard-copy casts. In this study, we aimed to compare agreement and accuracy of measurements made with rapid prototyping and stone models for different degrees of crowding.

    METHODS: The Z Printer 450 (3D Systems, Rock Hill, SC) reprinted 10 sets of models for each category of crowding (mild, moderate, and severe) scanned using a structured-light scanner (Maestro 3D, AGE Solutions, Pisa, Italy). Stone and RP models were measured using digital calipers for tooth sizes in the mesiodistal, buccolingual, and crown height planes and for arch dimension measurements. Bland-Altman and paired t test analyses were used to assess agreement and accuracy. Clinical significance was set at ±0.50 mm.

    RESULTS: Bland-Altman analysis showed the mean bias of measurements between the models to be within ±0.15 mm (SD, ±0.40 mm), but the 95% limits of agreement exceeded the cutoff point of ±0.50 mm (lower range, -0.81 to -0.41 mm; upper range, 0.34 to 0.76 mm). Paired t tests showed statistically significant differences for all planes in all categories of crowding except for crown height in the moderate crowding group and arch dimensions in the mild and moderate crowding groups.

    CONCLUSIONS: The rapid prototyping models were not clinically comparable with conventional stone models regardless of the degree of crowding.

    Matched MeSH terms: Printing, Three-Dimensional*
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