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RAPID prototyping, ACCURACY, ORTHODONTICS, STEREOLITHOGRAPHY, and THREE-dimensional printing

Objective: To determine the accuracy (trueness and precision) of two different rapid prototyping (RP) techniques for the physical reproduction of three-dimensional (3D) digital orthodontic study casts, a comparative assessment using two 3D STL files of two different maxillary dentitions (two cases) as a reference was accomplished. Materials and Methods: Five RP replicas per case were fabricated using both stereolithography (SLA) and the PolyJet system. The 20 reproduced casts were digitized with a highly accurate reference scanner, and surface superimpositions were performed. Precision was measured by superimposing the digitized replicas within each case with themselves. Superimposing the digitized replicas with the corresponding STL reference files assessed trueness. Statistical significance between the two tested RP procedures was evaluated with independent-sample ttests (P , .05). Results: The SLA and PolyJet replicas showed statistically significant differences for trueness and precision. The precision of both tested RP systems was high, with mean deviations in stereolithographic models of 23 (66) lm and in PolyJet replicas of 46 (613) lm. The mean deviation for trueness in stereolithographic replicas was 109 (64) lm, while in PolyJet replicas, it was 66 (614) lm. Conclusions: Comparing the STL reference files, the PolyJet replicas showed higher trueness than the SLA models. But the precision measurements favored the SLA technique. The dimensional errors observed in this study were a maximum of 127 lm. In the present study, both types of reproduced digital orthodontic models are suitable for diagnostics and treatment planning. [ABSTRACT FROM AUTHOR]

RAPID prototyping, COMPUTER-aided design, NEW product development, ENGINEERING education, ENGINEERING students, ENGINEERING laboratories, and UNIVERSITIES & colleges

Rapid prototyping technologies (RP) enable solid models to be obtained from designs generated using CAD applications. Their increasing popularity in industry is due to the reductions in cost and time associated with the use of these models when verifying product development stages and improvements in end quality. However, these technologies can also be applied to enhance students' active learning in the teaching of multiple subjects connected with product development. Students can bring their designs to fruition and check any decisions taken in an economically acceptable way. This work shows how RP technologies can be exploited for teaching, using the full development of a gear pump. The work has been carried out with educational aims in the Product Development Laboratory of Madrid Polytechnic University (UPM), for the subject Design and Manufacturing with Polymers. [ABSTRACT FROM AUTHOR]

THREE-dimensional printing, 3-D printers, STEREOLITHOGRAPHY, RAPID prototyping, and DESIGN software

Purpose: This study aimed to evaluate the trueness and precision of complete-arch models printed with three-dimensional printers via three different printing technologies. Methods: An arch-shaped master model was designed using software (RapidForm XOR2, 3D Systems Inc., USA), and the digital master model was printed 10 times with three-dimensional printers using stereolithography (SLA), direct light processing (DLP), and Polyjet technology (n = 30). The printed models were then scanned with an industrial scanner to create the respective digital models. All digital models were compared with the master model, and an evaluation of the trueness was performed by model superimposition with Geomagic Control software (3D Systems, Rock Hill, SC, USA). Precision was determined for each case by superimposing some combination of the 10 datasets in each group. Results: The trueness of the printed models was 46.2 µm for the DLP printer, 51.6 µm for the SLA printer, and 58.6 µm for the Polyjet printer. The DLP models were significantly better than the Polyjet models (p = .005). However, the Polyjet models (30.4 µm) were more precise than the SLA (37.6 µm) and DLP (43.6 µm) models (p < .001, p = .016). Furthermore, the SLA (11.8 µm) was the most accurate printer in the Z-direction (p = .016, p = .002). Conclusions: The 3D printing technologies showed significant differences in the precision and trueness of complete-arch measurements. Although DLP was more accurate other tested 3D printers, the accuracy of all 3D printed models was within clinical tolerance, and they were clinically acceptable and could be used for the production of fixed restorations. [ABSTRACT FROM AUTHOR]

DENTAL implants, STEREOLITHOGRAPHY, COMPUTER-assisted surgery, RAPID prototyping, and SURGICAL complications

Objective This study investigates the usefulness of a navigation method using a reference frame directly fixed to the mandible compared to the stereolithographic (STL) surgical guide template method in dental implant surgery. Materials and methods Twenty rapid prototyping (RP) mandibular models were divided into two groups. Simulation surgery was performed using SimPlant software for both groups. The actual dental implants were placed in the RP models using a real-time navigation system or the surgical guide template, which was fabricated based on STL data by a 3-dimensional printer. Positional implantation errors were measured by comparing the simulation surgery implant positions to the actual postoperative implant positions. Results The vertical distance error of the top surface area in the first molar region was not significantly different between groups. Otherwise, the implantation method using real-time navigation showed greater errors except for the horizontal and vertical errors in the apical area of the canine region. Conclusion The STL surgical guide template was associated with fewer errors than the real-time navigation method in dental implant surgery. [ABSTRACT FROM AUTHOR]

RAPID prototyping, PILOT projects, SIMULATION methods & models, CAD/CAM systems, DENTISTRY, and STEREOLITHOGRAPHY

Computer packages have been introduced to simulate the movements of the jaw in three dimensions to facilitate planning of treatment. After final 3-dimensional virtual planning, a rapid prototype wafer can be manufactured and used in theatre. Our aim was to assess the accuracy of rapid prototyping of virtual wafers derived from laser scanned dental models using CAD/CAM software. Upper and lower plaster models from 10 orthognathic patients, the articulated models, and the conventional wafers were scanned. The virtual wafers were made from CAD/CAM software, and printed on a stereolithographic printer. We also scanned the articulated models with rapid prototype wafers in place. The validity of the final rapid prototype wafer was measured by the accuracy with which upper and lower models related to one another. The absolute mean error of the rapid prototype wafer when aligned with the dental models was 0.94 (0.09) mm. The absolute distance of the 2 models articulated by conventional and rapid prototype wafers ranged from 0.04 - 1.73mm. The rapid prototype wafers were able to orientate the upper and lower dental models with an absolute mean error of 0.94 (0.09) mm, but it ranged from 0.04-1.73mm. [ABSTRACT FROM AUTHOR]

THREE-dimensional printing, RAPID prototyping, STEREOLITHOGRAPHY, MEDICAL sciences, MANUFACTURING processes, and PRINTING

The article focuses on the emergence of three-dimensional (3D) printing technology, also known as rapid prototyping (RP), which offers solutions for complex problems in the field of biomedical sciences. Other topics discussed include how biological and chemical engineers harness the potential of 3D printing technology, key features of the technology, and the four major 3D printing methods, namely stereo-lithography, inkjet printing, selective laser sintering, andf used deposition modeling.

DENTURES, STEREOLITHOGRAPHY, EPOXY resins, COMPUTER-aided design, RAPID prototyping, and CAD/CAM systems

The purpose of this study was to investigate, by measuring the gap, the possible clinical use of three-unit fixed dental prostheses (FDPs) manufactured using stereolithography. A total of 20 epoxy models were built with a same case (abutment teeth 14, 16). The 40 specimens were produced using the stereolithography (SLA) and wax-up (LW). The 960 gaps of the 40 specimens produced were measured by a silicone replica. The Wilcoxon rank sum test was then used to compare and analyze the data obtained from the two groups (α=0.05). The total gap, as measured from the SLA and LW groups, was 98.6 and 66.6 pm, respectively. The results indicate that the gap in the SLA group is statistically significantly greater than that in the LW group (p<0.05). Further assessment and improvement of the SLA method for the fabrication of FDPs is evidently still required. [ABSTRACT FROM AUTHOR]

POLYCAPROLACTONE, TISSUE engineering, LITHOGRAPHY, CROSSLINKING (Polymerization), RAPID prototyping, TISSUE scaffolds, and COMPUTER-aided design

Abstract: A photocrosslinkable poly(ε-caprolactone) (PCL)-based resin was developed and applied using stereolithography. No additional solvents were required during the structure preparation process. Three-armed PCL oligomers of varying molecular weights were synthesized, functionalized with methacrylic anhydride, and photocrosslinked, resulting in high gel content networks. Stereolithography was used to build designed porous scaffolds using the resin containing PCL macromer, Irgacure 369 photoinitiator, inhibitor and dye. A suitable resin viscosity was obtained by heating the resin during the curing process. The scaffolds precisely matched the computer-aided designs, with no observable material shrinkage. The average porosity was 70.5±0.8%, and the average pore size was 465μm. The pore network was highly interconnected. The photocrosslinkable, biodegradable PCL resin is well suited for the solvent-free fabrication of tissue engineering scaffolds by stereolithography. [Copyright &y& Elsevier]

ODONTOGENIC tumors, CASE studies, RAPID prototyping, ORAL surgery, MOUTH tumors, MANDIBLE, DENTAL implants, FIBULA, and TUMOR treatment

Abstract: This paper reports one case, of an ameloblastic fibro-odontosarcoma (AFOS) affecting the mandible, in a 12-year-old girl. This neoplasm is a rare odontogenic neoplasm. To the authors’ knowledge this is the fifteenth case of AFOS reported in English. The patient''s chief complaint was a swelling in the face for 6 months. An incisional biopsy was performed diagnosing the case as an ameloblastic fibroma. After radiography ameloblastic fibro-odontoma was diagnosed. Computed tomography was performed and a stereolithography model made to plan the surgical procedures. A hemimandibulectomy followed by a vascularized fibular flap was then proposed. The surgery was uneventful. Microscopic features diagnosed an AFOS. After 23 months of close follow-up there is no sign of recurrence or metastasis. Dental implants were recently placed in the fibular flap. [Copyright &y& Elsevier]

DENTAL implants, EDENTULOUS mouth, KERATINIZATION, ORAL cancer, RAPID prototyping, SURGICAL instruments, and PATIENTS

Abstract: Surgical procedures to improve the quality of peri-implant soft tissue are a routine part of dental implant practice, especially in the edentulous patient with a significant lack of attached keratinised tissue. The use of a dressing plate at the recipient site can be beneficial in supporting free, keratinised, soft-tissue grafts during the early healing phase, especially if grafting is undertaken around all aspects of the implant and not just to the facial section. This paper outlines the use of a dressing plate, constructed on a stereolithographic model, for use at second-stage implant surgery to allow for 360° peri-implant, keratinised, soft-tissue grafting. [Copyright &y& Elsevier]