Literatura científica selecionada sobre o tema "Impression 3D – Biotechnologie"

Accuracy of dental impression plays a significant role in the success of definitive restorations. This study aimed to compare the dimensional accuracy of working dies fabricated using two different impression materials and techniques. Forty working dies fabricated from 40 impressions of preprepared mandibular first molar tooth replica stabilized in a jaw model to receive full coverage crown. Two different Polyvinyl siloxane (PVS) impression materials were used; Aquasil and Virtual. Two different impression techniques were used with each type of impression material; One-step and two-step. The working dies dimensional accuracy was measured in four dimensions and compared with that of the preprepared molar tooth replica using a digital caliper and 3D scanner. Based on a 3D scanner, there were a significant difference of dies fabricated by the two tested impression materials using the two-step impression technique in Mesiodistal-Gingival dimension (IIA and IIB) groups compared to the preprepared tooth replica with an average 0.370 μm (P < .005). A significant difference was observed of the dies fabricated by the two tested impression techniques using virtual impression. material in Mesiodistal Occlusal dimensions with an average 0.135 μm (P < .03), and in Mesiodistal-Gingival dimensions with an average 0.490 μm (P < .001) and Buccolingual-Gingival dimensions with an average 0.143 μm (P < .005) using Aquasil impression material compared to the preprepared molar tooth replica. Both impression materials (Aquasil and Virtual) and techniques (One-step and Two-step) used in this study produced working dies with clinically accepted dimensional accuracy.

Biotechnologies appliquées à la médecine, nouvelles technologies de l’information avec l’e-santé, robotique chirurgicale, impression 3D…, les nouvelles technologies dans le domaine de la santé prennent des formes multiples. Derrière certaines de ces innovations, comme la modification du vivant ou l’utilisation des mégadonnées en santé, émergent de nouvelles questions éthiques .

Digital technology offers many opportunities and challenges across various domains. Aim: This comprehensive review explores the transformative impact of digitalization on dental practices, encompassing digital Imaging, 3D printing, intraoral scanners, teledentistry, Artificial Intelligence, CAD-CAM technology, and virtual reality. Methods: A rigorous search was conducted across various electronic bases, including PubMed, Google Scholar, Scopus, and the National Center for Biotechnology Information (NCBI). The search employed keywords such as “Orthodontics,” “Dental Health,” “Dental Imaging,” “CAD-CAM,” “Digital Medicine,” “Teleconsultation,” “Intraoral Scanner,” “Artificial Intelligence (AI),” “Digital Health,” “Teledentistry,” and “3D Dentistry.” Papers published between 2017 and the present were considered, focusing on peer-reviewed journals and reviews providing comprehensive insights into digital dentistry. Results: The review highlights the diverse facts of digitalization in dentistry, emphasizing its potential benefits for patient practitioners and the dental industry. Digital impressions, 3D printing, and CAD-CAM are streamlining restorative dentistry. In orthodontics, digital models enable precise simulations. Artificial Intelligence promises more efficient diagnostics and treatment planning. Conclusion: Digital technology is poised to reshape dentistry, improving efficiency, patient outcomes, and practitioner experiences. However, challenges such as data security and ethical considerations must be addressed. The successful integration of digital dentistry into dental practice will require more research and innovation, even though this review offers a thorough overview of the field.

Aim: This study aimed to compare the conventional, digital, and three-dimensional (3D)-printed casts in terms of their accuracy in quantifying arch and teeth measurements. Materials and Methods: The conventional casts were prepared using polyether dental impressions. Digital impressions of the typodont reference casts were accomplished using an intra-oral scanner. The digital casts were first converted to stereolithography (STL) files which were then edited, and printed using an SLA printer and photo-polymer resin material. The measurements of the first two groups were completed using a digital caliper, while an imaging software was used to measure digital casts. The occlusocervial (OC) height and mesiodistal (MD) width of canines, second premolars (PMs), and molars of each jaw were measured. Additionally, intercanine width (ICW) and intermolar width (IMW) were also measured. Results: Overall, the lowest OC measurement errors were observed for 3D-printed casts for the upper canine, lower canine, and lower molar (0.003±0.01 mm). Similarly, the lowest MD measurement errors were observed for 3D-printed casts for upper canine, upper PM, and lower PM (0.002±0.01 mm). The ICW and IMW measurement errors for the 3D-printed casts were significantly lower (p < 0.01) for the upper ICW (0.011±0.01 mm) and lower IMW (0.017±0.01 mm) than the other two groups. Compared to the conventional and digital casts, the lower ICW (0.013±0.01 mm) and upper IMW (0.017±0.01 mm) measurement errors observed for the 3D-printed casts were also lower, but non-significantly (p > 0.01). Conclusions: 3D-printed casts presented the lowest OC, MD, ICW, and IMW measurement errors, than the conventional and digital casts. The highest measurement errors were associated with the digital casts.

Introduction. The purpose of this systematic review was to compare the accuracy of the three-dimensional images among different scanners, scanning techniques, and substrates. Materials and methods. Electronic databases (PubMed and Elsevier) were searched until March 2020. The systematic search was performed to identify the most precise method of obtaining a 3D image of the dentition. Results. Thirteen articles out of 221, considering the accuracy of 3D images, were selected. The main factors that are considered to have an influence on the precision are substrate type in the oral cavity, experience of the scanner’s operator, direct vs. indirect scanning, and the reproducibility of the procedure. Conclusion. Substrate type does have an impact on the overall accuracy of intraoral scans where dentin has the most and enamel the least accurately recorded dental structure. Experience of the operator has an influence on the accuracy, where more experienced operators and smaller scan sizes are made for more accurate scans. A conventional impression technique in a full-arch image provided the lowest deviation. The reproducibility of direct scanning was comparable to indirect scanning although a slight difference was noticeable (0.02 mm).

The aim of this study was to develop and evaluate a digital process for manufacturing of occlusal splints. An alginate impression was taken from the upper and lower jaws of a patient with temporomandibular disorder owing to cross bite and wear of the teeth, and then digitized using a table laser scanner. The scanned model was repaired using the 3D ata E xpert software, and a splint was designed with the V iscam RP software. A splint was manufactured from a biocompatible liquid photopolymer by stereolithography. The system employed in the process was SLA 350. The splint was worn nightly for six months. The patient adapted to the splint well and found it comfortable to use. The splint relieved tension in the patient's bite muscles. No sign of tooth wear or significant splint wear was detected after six months of testing. Modern digital technology enables us to manufacture clinically functional occlusal splints, which might reduce costs, dental technician working time and chair-side time. Maximum-dimensional errors of approximately 1 mm were found at thin walls and sharp corners of the splint when compared with the digital model.

Abstract Low-dimensional metal halide perovskites have emerged as promising alternatives to the traditional three-dimensional (3D) components, due to their greater structural tunability and environmental stability. Dion-Jacobson (DJ) phase two-dimensional (2D) perovskites, which are formed by incorporating bulky organic diammonium cations into inorganic frameworks that comprises a symmetrically layered array, have recently attracted increasing research interest. The structure-property characteristics of DJ phase perovskites endow them with a unique combination of photovoltaic efficiency and stability, which has led to their impressive employment in perovskite solar cells (PSCs). Here, we review the achievements that have been made to date in the exploitation of DJ phase perovskites in photovoltaic applications. We summarize the various ligand designs, optimization strategies and applications of DJ phase PSCs, and examine the current understanding of the mechanisms underlying their functional behavior. Finally, we discuss the remaining bottlenecks and future outlook for these promising materials, and possible development directions of further commercial processes.

AbstractThe present work addresses the limitations by fabricating a wide range of negative electrodes, including metal nitrides/sulfides on a 3D bimetallic conductive porous network (3D‐Ni and 3D‐NiCo) via a dynamic hydrogen bubble template (DHBT) method followed by vapour phase growth (VPG) process. Among the prepared negative electrodes, the 3D‐Fe3S4‐Fe4N/NiCo nanostructure demonstrates an impressive specific capacitance (Cs) of 1125 F g−1 (2475 mF cm−2) at 1 A g−1 with 80% capacitance retention over 5000 cycles. Similarly, a 3D‐Mn3P nanostructured positive electrode fabricated via electrodeposition followed by a phosphorization process exhibits a maximum specific capacity (Cg) of 923.04 C g−1 (1846.08 mF cm−2) at 1 A g−1 with 80% stability. A 3D‐Mn3P/Ni//3D‐Fe3S4‐Fe4N/NiCo supercapattery is also assembled, and it shows a notable CS of 151 F g−1 at 1 A g−1, as well as a high energy density (ED) of 51 Wh kg−1,a power density (PD) of 782.57 W kg−1 and a capacitance efficiency of 76% over 10 000 cycles. This may be ascribed to the use of a bimetallic 3D porous conductive template and the attachment of transition metal sulfide and nitride. The development of negative electrodes and supercapattery devices is greatly aided by this exploration of novel synthesis techniques and material choice.

Abstract3D composite electrodes have shown extraordinary promise as high mass loading electrode materials for sodium ion batteries (SIBs). However, they usually show poor rate performance due to the sluggish Na+ kinetics at the heterointerfaces of the composites. Here, a 3D MXene‐reduced holey graphene oxide (MXene‐RHGO) composite electrode with Ti─O─C bonding at 2D heterointerfaces of MXene and RHGO is developed. Density functional theory (DFT) calculations reveal the built‐in electric fields (BIEFs) are enhanced by the formation of bridged interfacial Ti─O─C bonding, that lead to not only faster diffusion of Na+ at the heterointerfaces but also faster adsorption and migration of Na+ on the MXene surfaces. As a result, the 3D composite electrodes show impressive properties for fast Na+ storage. Under high current density of 10 mA cm−2, the 3D MXene‐RHGO composite electrodes with high mass loading of 10 mg cm−2 achieve a strikingly high and stable areal capacity of 3 mAh cm−2, which is same as commercial LIBs and greatly exceeds that of most reported SIBs electrode materials. The work shows that rationally designed bonding at the heterointerfaces represents an effective strategy for promoting high mass loading 3D composites electrode materials forward toward practical SIBs applications.

La bioimpression 3D est une technologie prometteuse pour la médecine régénératrice, permettant de concevoir des structures biomimétiques à l’aide de bioencres. Cette thèse se concentre sur le développement de bioencre(s) bioactive(s), enrichie(s) par des composants de la gelée de Wharton (GW). L’hydrogel formé à partir des composants de la GW, n’étant pas imprimable, a été combiné à des polymères naturels, tels que l’alginate et la gélatine, créant une bioencre thermosensible. Les paramètres d’impression, notamment la température et la pression, ont été optimisés pour assurer une meilleure précision.Les matrices imprimées à partir de la formulation d’alginate/gélatine type B avec ou sans hydrogel de la GW décellularisée, réticulées par du chlorure de calcium et de la transglutaminase (TG), constituent un support approprié pour les cellules, mais l’ajout de la GW n'a pas stimulé le recrutement et la prolifération des cellules souches mésenchymateuses (CSM) ni des fibroblastes. En raison du risque potentiel d'immunogénicité de l'alginate et de son effet négatif sur le comportement des cellules encapsulées, une seconde formulation a été développée. Elle était à base de gélatine de type A, plus réactive à la TG. L’impression des fibroblastes dans cette nouvelle bioencre la gélatine A a montré une bonne viabilité après 21 jours, en revanche la présence de l’hydrogel GW n’a pas été bénéfique pour les fibroblastes. L’ajout de milieu conditionné issu des CSM de la GW a, en revanche, augmenté la bioactivité de la bio-encre à base de gélatine type A
3D bioprinting is a promising technology for regenerative medicine, enabling the creation of biomimetic structures using specific bioinks. This thesis focuses on the development of bioactive bioinks, enriched with components from Wharton's Jelly (WJ) matrix. The WJ hydrogel, not being printable on its own, was combined with natural polymers such as alginate and gelatin to create a thermosensitive bioink. The printing parameters, especially temperature and pressure, were optimized to ensure better precision.Printed constructs from the alginate/type B gelatin formulation with or without WJ hydrogel, crosslinked with calcium chloride and transglutaminase (TG), provided an appropriate support for cells. However, the presence of WJ did not stimulate the recruitment or proliferation of mesenchymal stem cells (MSCs) or fibroblasts. Due to the potential immunogenicity of alginate and its negative impact on the behavior of printed cells, it was removed. The newest formulation was based on type A gelatin, more sensitive to TG activity. The printed fibroblasts in type A gelatin showed good viability after 21 days, but the addition of WJ hydrogel did not support cell viability after bioprinting. However, the addition of conditioned medium from WJ-derived MSCs enhanced the bioactivity of type A gelatine bioink