共查询到16条相似文献,搜索用时 15 毫秒
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There are 7 categories of additive manufacturing (AM) technologies, and a wide variety of materials can be used to build a CAD 3D object. The present article reviews the main AM processes for polymers for dental applications: stereolithography (SLA), digital light processing (DLP), material jetting (MJ), and material extrusion (ME). The manufacturing process, accuracy, and precision of these methods will be reviewed, as well as their prosthodontic applications. 相似文献
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《Journal of prosthodontic research》2020,64(2):120-127
PurposeTo investigate the adhesion strength and bonding interface of layered porcelain to powdered cobalt–chromium (CoCr) processed by two different computer-aided manufacturing methods.MethodsSixteen specimens were manufactured from each of Three-dimensionally -printed/laser-sintered (LS) CoCr and milled pre-sintered (SM) CoCr. The specimens were layered with porcelain and 4-point bending was carried out. Nanoindentation was used to calculate changes in elastic modulus and hardness before and after porcelain firing along with adhesion energy. Fracture surface and microstructural changes were examined before and after porcelain firing observed using scanning electron microscopy.ResultsThe adhesion energy of the LS specimens bonded porcelain were higher than the SM specimens (P < 0.05). Analysis of the fracture surfaces showed a predominantly adhesive mode of failure. Elastic-modulus and hardness of the CoCr specimens increased post porcelain firing. Examination using electron-backscatter diffraction (EBSD) showed a fine grain structure for both manufacturing methods. Significant localized changes in the crystal structure post firing were only observed at the surface of the SM specimens.ConclusionsBoth manufacturing methods showed regular microstructures prior to porcelain firing. Laser-sintered CoCr had stronger bonding to porcelain than milled pre-sintered CoCr and was also more stable microstructurally post-ceramic firing. However, both manufacturing methods were deemed to have satisfactory adhesion strength to porcelain. It was also found that increased hardness of CoCr had an inverse relationship with bonding strength. High strength porcelain bonding and stability following multiple ceramic firings indicate suitability for use of these CoCr materials with implant or tooth supported long-span frameworks. 相似文献
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K. Vijay Venkatesh V. Vidyashree Nandini 《Journal of Indian Prosthodontic Society》2013,13(4):389-392
Dental technology is undergoing advancements at a fast pace and technology is being imported from various other fields. One such imported technology is direct metal laser sintering technology for casting metal crowns. This article will discuss the process of laser sintering for making metal crowns and fixed partial dentures with a understanding of their pros and cons. 相似文献
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Ülkü Tuğba Kalyoncuoğlu DDS PhD Simel Ayyıldız DDS PhD Emine Odabasi Tezer 《Journal of prosthodontics》2023,32(8):714-720
Purpose
The aim of this study was to evaluate the impact of the print orientation of direct metal laser sintering (DMLS) posts and cores on the fracture resistance and failure patterns of endodontically treated mandibular premolar teeth.Materials and Methods
Sixty intact human mandibular premolars were endodontically treated. The teeth were then randomly divided into four groups (n = 15). Cobalt-chromium (Co-Cr) metal posts were fabricated by traditional casting (Group C), and DMLS method in 0-, 45-, and 90-degree print orientations (Group DMLS 0, Group DMLS 45, and Group DMLS 90). The posts and cores were cemented with composite resin cement and subjected to compression test at a crosshead speed of 1 mm/min. Data was analyzed by using one-way analysis of variance ANOVA and multiple comparison post hoc Tukey tests (α = 0.05). Specimens were viewed under a stereo microscope with x20 magnification to evaluate the fracture types.Results
No significant differences were found among the groups tested in terms of fracture resistance (p > 0.05). Group C and Group DMLS 0 group exhibited similar fracture patterns.Conclusions
It is possible to produce post and core restorations with the DMLS technique and use them clinically. Print orientation did not influence the fracture resistance. However, fracture patterns were different. Group C outperformed all DMLS groups in terms of fracture patterns. 相似文献9.
Marta Revilla‐Len Joshua Fountain Wenceslao Piedra‐Cascn Amirali Zandinejad Mutlu
zcan 《Journal of prosthodontics》2019,28(8):855-860
The present article describes the resin infiltration technique to address white spots lesions presented on anterior and premolar teeth of a young patient after orthodontic treatment and the digital workflow for planning a diastema closure on the maxillary anterior teeth using facial photographs, an intraoral scanner, a facially driven diagnostic waxing using a dental computer‐aided design (CAD) software, and 3‐piece additive manufactured (AM) clear silicone indices. The virtual design of the silicone indices was completed using an open‐source CAD software and included a flexible clear buccal piece, flexible clear lingual piece, and rigid clear custom tray. The unique 3‐piece index design allows a horizontal path of insertion, controlled uniform thickness of the indices, flexible and rigid material properties combination, accurate translation of the diagnostic waxing into the patient´s mouth, and digital storage of the designs. 相似文献
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CAD/CAM‐Assisted Auricular Prosthesis Fabrication for a Quick,Precise, and More Retentive Outcome: A Clinical Report
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Sushma Yadav BDS Aparna Ichangod Narayan BDS MDS Archit Choudhry BDS Dhanasekar Balakrishnan BDS MDS 《Journal of prosthodontics》2017,26(7):616-621
Auricular defects comprise a large proportion of maxillofacial deformities. Most patients with acquired deformities have psychosocial ineptness and seek cosmetic rehabilitation. Although minor defects can be corrected surgically, extensive deformities are difficult to reconstruct with plastic surgery. Contrary to that, prosthetic restoration can provide excellent esthetic results. The conventional methods of maxillofacial prosthesis fabrication are time consuming and the outcome depends on the technician's skill. The advent of CAD/CAM technology in the field of dentistry has brought enormous improvement in the quality of health care provided. In the past decade, several methods have been described employing CAD/CAM techniques for the cosmetic rehabilitation of auricular defects. This clinical report details the integration of multiple digital technologies of CT scanning, computer aided design, and rapid prototyping to construct an ear prosthesis with limited number of appointments. 相似文献
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Objective
The objectives of the present study were: (1) to analyze the dispersion and optical properties of suspensions with various volume fractions of zirconia, and (2) to assess the influence of zirconia volume fraction on the microstructure and physical properties of products produced by the additive manufacturing and sintering process.Methods
Zirconia specimens were fabricated by an additive manufacturing technique using a DLP (digital light processing) system. The zirconia suspensions were divided into six groups based on zirconia volume fraction within the range of 48–58 vol%.Results
The maximum volume fraction of zirconia in suspensions possible for printing was 58 vol%. The cure depth of the zirconia suspensions decreased as the volume fraction increased. The cure depth was greater than 100 μm after 15 s photocuring in all groups. Geometrical overgrowth tended to increase gradually as the volume fraction of zirconia increased within the range of 28.55–36.94%. The 3-point bending strength of the specimens increased as the volume fraction of zirconia in the suspension increased, reaching a maximum value of 674.74 ± 32.35 MPa for a volume fraction of 58 vol%. Cracks were observed on the surfaces of zirconia specimens and these cracks increased in number as zirconia volume fraction decreased.Significance
In this experiment, the viscosity of zirconia suspensions sharply increased from a volume fraction of 54 vol%. Because of the very high viscosity, 58 vol% was the maximum volume fraction possible for additive manufacturing. After polymerization, all specimens showed some distortion due to geometrical overgrowth. The maximum 3-point bending strength was 674.74 ± 32.35 MPa for a volume fraction of 58 vol%. But the maximum strength of sintered zirconia prepared by additive manufacturing is inferior to that of conventionally sintered zirconia. 相似文献13.
《Dental materials》2020,36(2):197-209
ObjectivesThe aim of this study was to investigate the effect of artificial aging on the Martens parameters of different 3D printed and milled polyaryletherketon (PAEK) materials.MethodsIn total 120 specimens of 4 different polyetheretherketon (PEEK) materials (Essentium PEEK, KetaSpire PEEK MS-NT1, VICTREX PEEK 450 G and VESTAKEEP i4 G) were additively manufactured via fused layer manufacturing (FLM) in either horizontal or vertical directions (n = 15 per group). 75 specimens were milled out of prefabricated PAEK blanks from the materials breCAM.BioHPP, Dentokeep, JUVORA Dental Disc 2 and Ultaire AKP ( = 15 per group). Martens hardness (HM), indentation hardness (HIT) and indentation modulus (EIT) were determined initially and longitudinally after thermocycling (5−55 °C, 10,000x) and autoclaving (134 °C, 2 bar). In each case, the surface topography of the specimens was examined for modifications using a light microscope.Data were analysed with Kolmogorov-Smirnov test, univariate ANOVA followed by post-hoc Scheffé test with partial eta squared (ηp2), Kruskal–Wallis-, Mann–Whitney-U-, Friedman- and Wilcoxon-Test. A value of p < 0.05 was considered as significant.ResultsMilled specimens showed higher Martens parameters than printed ones (p < 0.001). Artificial aging had a negative effect on the measured parameters (p < 0.001). Horizontally printed specimens presented higher Martens parameters than vertically printed ones, regardless of material and aging process (p < 0.001). Essentium PEEK and breCAM.BioHPP showed the highest and VICTREX PEEK 450G as well as Ultaire AKP the lowest values of all investigated PAEK materials initially, after thermocycling and after autoclaving (p < 0.001). Microscopic examinations showed that artificial aging did not cause any major modifications of the materials.SignificanceAdditively manufactured PEEK materials showed lower Martens parameters than milled ones, whereas horizontally printed specimens presented higher values than vertically printed ones. Artificial aging had a negative effect on the Martens parameters, but not on the surface topography. 相似文献
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《Journal of endodontics》2023,49(7):880-888
IntroductionAugmented reality (AR) is a novel visualization technique in which pregenerated virtual 3D content is superimposed on surgical sites. This study aimed to validate the viability of AR-guided endodontic microsurgery (ARG) and compare the changes in objective and subjective outcomes of surgical simulation using ARG and freehand (FH) endodontic microsurgery on customized 3D-printed models.MethodsWe created and printed a customized 3D alveolar bone model with artificial periapical lesions (APLs) based on cone-beam computed tomography. Eight models with 96 APLs were equally divided into ARG and FH groups. We planned surgical trajectories on rescanned printed models. Four inexperienced residents (IRs) performed ARG and FH on the models and completed pre and intraoperative confidence questionnaires for the subjective outcome. Postoperative cone-beam computed tomography scans of the models were reconstructed and analyzed, and all procedures were timed. We used pairwise Wilcoxon rank sum tests to compare objective outcomes. Kruskal–Wallis tests and post hoc pairwise Wilcoxon rank sum tests were used to compare subjective outcomes.ResultsCompared to the FH group, the ARG group significantly reduced deviation of the volume of bone removal, root-end resection, and deviation of bevel angle, with improved confidence of the IRs (P < .05); it also significantly increased surgical time and volume of unremoved APL (P < .05).ConclusionsWe customized an APL model through 3D printing and developed and validated a low-cost AR application framework, based on free AR software, for endodontic microsurgery. ARG allowed IRs to perform more conservative and precise surgical procedures with enhanced confidence. 相似文献