Accuracy of Conventional and Digital Methods for Obtaining Dental Impressions and 3D Printed Models

Abstract Background: Different sizes of arch could influence in digital methods to obtaining dental impressions and 3D models. The purpose of this study was to evaluate and compare the accuracy of two intra-oral scanners and conventional impression methods for the fabrication of working casts. Methods: Conventional impressions of a reference cast were obtained. Digital impressions were obtained with two intra-oral scanners: Cerec Omnicam (CO) and 3Shape Trios (ST). The obtained digital stereolithographic casts were printed on Zenith D 3D printer. The reference cast and fabricated casts were scanned with a bench top scanner and saved in STL format. All STL records were analyzed in specific software: complete arch (CA), partial arch (PA) and prepared teeth area (PT). One-way and two-way analyses of variance were performed to compare the accuracy, followed by the Tukey test. Results: No significant intergroup differences in trueness and precision were observed for the two intra-oral scanners. 3D printed casts had the lowest trueness when complete arch was analyzed and differed statistically from the stone cast. For complete arch precision, stone cast presented better results, however statistically different only from the CO. Conclusions: The two intraoral scanner systems had similar accuracy. Stone casts had higher trueness than 3D printed casts for CA. For CA precision, 3D printed cast presented similar results to the stone cast.

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Elastic deformation of the mandibular jaw revisited—a clinical comparison between digital and conventional impressions using a reference

Clinical Oral Investigations ◽

10.1007/s00784-021-03777-z ◽

2021 ◽

Author(s):

Alexander Schmidt ◽

Leona Klussmann ◽

Maximiliane A. Schlenz ◽

Bernd Wöstmann

Keyword(s):

Statistical Analysis ◽

Elastic Deformation ◽

Clinical Relevance ◽

Mouth Opening ◽

Reference Structure ◽

Intraoral Scanner ◽

Digital Impressions ◽

Normal Vectors ◽

Mandibular Deformation ◽

Conventional Impression

Abstract Objectives Due to the partly strongly differing results in the literature, the aim of the present study was to investigate a possible deformation of the mandible during mouth opening using an intraoral scanner (IOS) and a conventional impression for comparison with a reference aid. Materials and methods Four steel spheres were reversibly luted in the mandibular (n = 50) with a metallic reference aid at maximum mouth opening (MMO). Two digital impressions (Trios3), at MMO and at slightly mouth opening SMO and a conventional impression (Impregum), were taken as the measuring accuracy of the reference structure was already known. Difference between MMO-SMO for digital impressions and deviations between digital and conventional (SMO) were calculated. Furthermore, the angle between the normal vectors of two constructed planes was measured. Statistical analysis was performed with SPSS25. Results Deviations for linear distances ranged from −1 ± 3 μm up to 17 ± 78 μm (digital impressions, MMO-SMO), from 19 ± 16 μm up to 132 ± 90 μm (digital impressions, SMO), and from 28 ± 17 μm up to 60 ± 52 μm (conventional impressions, SMO). There were no significant differences for digital impressions (MMO-SMO), and there were significant differences between the conventional and digital impressions at SMO. Conclusions Based on the results of the present study, no mandibular deformation could be detected during mouth opening with regard to the digital impressions. The results were rather within the measuring tolerance of the intraoral scanner. Clinical relevance Based on the present study, no deformation of the mandibular during mouth opening could be observed at the level previously assumed. Therewith related, dental techniques related to a possible mandibular deformation therefore should be reconsidered.

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A LITHOPHANE MODEL MAKING PROCESS TO 3D PRINTERS

10.31224/osf.io/e8ubh ◽

2020 ◽

Author(s):

Siddavatam Rammohan Reddy

Keyword(s):

Melting Point ◽

Acrylonitrile Butadiene Styrene ◽

3D Models ◽

3D Printer ◽

Layer By Layer ◽

3 Dimensional ◽

3D Objects ◽

3D Printers ◽

3D Printed ◽

Butadiene Styrene

This paper focuses on to convert photographs into embossed 3D models and then bring them to life using a 3D printer. A Lithophane is a 3-dimensional generation of a 2-dimensional image and 3D representation of a photo can be seen only when it is illuminated from behind. Turning images into 3D objects give us more feeling and literally adds a new dimension. The lithophane can be manufactured by the way of an automated additive manufacturing process, such as 3-D printing. lithophanes are a simple way to enhance your favourite photos. 3D printed photos also known as 3D Printed lithophanes, are an extremely unique and creative application. The process adopted in lithophane is FDM technology, in which different the materials like PLA (polylactic acid), ABS (acrylonitrile butadiene styrene), etc. By heating the filament material to its melting point and it is deposited layer by layer. Combination of many layers will give us a final 3D Printed model.

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Study of the dimensional accuracy of jaw models obtained by 3d printing using stereolithography

Kuban Scientific Medical Bulletin ◽

10.25207/1608-6228-2020-27-1-40-48 ◽

2020 ◽

Vol 27 (1) ◽

pp. 40-48

Author(s):

Evgeny N. Zhulev ◽

Yuliya A. Vokulova

Keyword(s):

Digital Images ◽

Digital Technologies ◽

Dimensional Accuracy ◽

High Dimensional ◽

Rank Test ◽

3D Printer ◽

Intraoral Scanner ◽

Digital Impressions ◽

Plaster Models ◽

Wilcoxon Rank Test

Aim. To study the dimensional accuracy of dentition models produced by digital and conventional methods using an experimental model and digital technologies.Materials and methods. This article presents an assessment of the dimensional accuracy of jaw models created using an Asiga Max UV 3D printer from digital images of dentition created by an iTero Cadent intraoral scanner and plaster jaw models obtained from one-stage two-layer A-silicone impressions. The DentalCAD software and the Meshlab computer program were used to study the dimensional accuracy of the as-obtained digital images. The nonparametric Wilcoxon rank test was used for statistical analysis of the obtained data.Results. It is established that jaw models made of DETAX Freeprint model UV photopolymer using an Asiga Max UV 3D printer, based on digital impressions obtained by an iTero Cadent intraoral scanner, have a greater dimensional accuracy in comparison with plaster jaw models obtained from single-stage double-layer A-silicone impressions by 31.6% with a signifi cance level p < 0.05.Conclusion. Jaw models created using an Asiga Max UV 3D printer are characterized by high dimensional accuracy as compared to plaster models.

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Conventional Vs Digital Impressions: Acceptability, Treatment Comfort and Stress Among Young Orthodontic Patients

The Open Dentistry Journal ◽

10.2174/1874210601812010118 ◽

2018 ◽

Vol 12 (1) ◽

pp. 118-124 ◽

Cited By ~ 19

Author(s):

Alessandro Mangano ◽

Matteo Beretta ◽

Giuseppe Luongo ◽

Carlo Mangano ◽

Francesco Mangano

Keyword(s):

State Anxiety ◽

The State ◽

Anxiety Scale ◽

Previous Experience ◽

Intraoral Scanner ◽

Impression Material ◽

Impression Technique ◽

Digital Impressions ◽

Orthodontic Patients ◽

Conventional Impression

Objective: The objective of the present study was to compare patients’ acceptability, comfort and stress with conventional and digital impressions. Materials and Methods: Thirty young orthodontic patients (15 males and 15 females) who had no previous experience of impressions were enrolled in this study. Conventional impressions for orthodontic study models of the dental arches were taken using an alginate impression material (Hydrogum®, Zhermack Spa, Badia Polesine, Rovigo, Italy). Fifteen days later, digital impressions of both arches were acquired using an intraoral scanner (CS3600®, Carestream Dental, Rochester, NY, USA). Immediately after impression taking, patients’ acceptability, comfort and stress were measured using two questionnaires and the State anxiety scale. Results: Data showed no difference in terms of anxiety and stress; however, patients preferred the use of digital impressions systems instead of conventional impression techniques. Alginate impressions resulted as fast as digital impressions. Conclusions: Digital impressions resulted the most accepted and comfortable impression technique in young orthodontic patients, when compared to conventional techniques.

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The development of a 3D colour reproduction system of digital impressions with an intraoral scanner and a 3D printer: a preliminary study

Scientific Reports ◽

10.1038/s41598-019-56624-3 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Yushu Liu ◽

Rui Zhang ◽

Hongqiang Ye ◽

Shimin Wang ◽

Kuan-Paul Wang ◽

...

Keyword(s):

Polynomial Regression ◽

Three Dimensional ◽

3D Printer ◽

Intraoral Scanner ◽

Third Order ◽

Reproduction System ◽

Dental Prostheses ◽

Digital Impressions ◽

Preliminary Study ◽

The Aesthetic

AbstractThis study aimed to develop a three-dimensional (3D) colour reproduction system to improve the aesthetic effects of dental prostheses. The system’s colour accuracy was also evaluated. Based on the concept of colour management, 96 colour patches were selected to develop colour profiles for an intraoral scanner and a 3D printer using polynomial regression. The colour differences Δ$${E}_{ab}^{\ast }$$Eab⁎ between colour patches reproduced using different colour profiles and the original colour patches were analysed to select the best combinations of colour profiles. The 3D colour reproduction system with the best-performing (i.e. third-order polynomial regression) colour profiles was finally evaluated using tooth and gum shades. The median Δ$${E}_{ab}^{\ast }$$Eab⁎ was 6.940 ranging from 1.504 to 32.660. In terms of tooth and gum shade, the median Δ$${E}_{ab}^{\ast }$$Eab⁎ was 6.313, and half of the shade blocks were above the mismatch threshold (Δ$${E}_{ab}^{\ast }$$Eab⁎ > 6.80). In conclusion, the colour management based on polynomial regression can decrease the colour difference of the 3D colour reproduction system, but not to clinically acceptable levels. Further advances are needed to improve the methods and hardware.

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Accuracy of photogrammetry, intraoral scanning, and conventional impression techniques for complete-arch implant rehabilitation: an in vitro comparative study

BMC Oral Health ◽

10.1186/s12903-021-02005-0 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Bowen Ma ◽

Xinxin Yue ◽

Yujie Sun ◽

Lingyan Peng ◽

Wei Geng

Keyword(s):

Digital Library ◽

Intraoral Scanner ◽

Intraoral Scanning ◽

Impression Technique ◽

Digital Impressions ◽

Reference File ◽

Implant Abutment ◽

Laboratory Reference ◽

Conventional Impression

Abstract Background To compare the accuracy of photogrammetry, intraoral scanning and conventional impression techniques for complete-arch implant rehabilitation. Methods A master cast containing 6 implant abutment replicas was fabricated. Group PG: digital impressions were taken 10 times using a photogrammetry system; Group IOS: intraoral scanning was performed to fabricate 10 digital impressions; Group CNV: splinted open-tray impression technique was used to fabricate 10 definitive casts. The master cast and conventional definitive casts were digitized with a laboratory reference scanner. For all STL files obtained, scan bodies were converted to implant abutment replicas using a digital library. The accuracy of a digitizer was defined by 2 main parameters, trueness and precision. "Trueness" was used to describe the deviation between test files and reference file, and "precision" was used to describe the closeness between test files. Then, the trueness and precision of three impression techniques were evaluated and statistically compared (α = 0.05). Results The median trueness was 24.45, 43.45 and 28.70 μm for group PG, IOS and CNV; Group PG gave more accurate trueness than group IOS (P < 0.001) and group CNV (P = 0.033), group CNV showed more accurate trueness than group IOS (P = 0.033). The median precision was 2.00, 36.00 and 29.40 μm for group PG, IOS and CNV; Group PG gave more accurate precision than group IOS (P < 0.001) and group CNV (P < 0.001), group CNV showed more accurate precision than IOS (P = 0.002). Conclusions For complete-arch implant rehabilitation, the photogrammetry system showed the best accuracy of all the impression techniques evaluated, followed by the conventional impression technique, and the intraoral scanner provided the least accuracy.

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Quality Control in 3D Printing: Accuracy Analysis of 3D-Printed Models of Patient-Specific Anatomy

Materials ◽

10.3390/ma14041021 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1021

Author(s):

Bernhard Dorweiler ◽

Pia Elisabeth Baqué ◽

Rayan Chaban ◽

Ahmed Ghazy ◽

Oroa Salem

Keyword(s):

Wall Thickness ◽

Large Scale ◽

Fused Deposition Modeling ◽

Vascular Anatomy ◽

3D Models ◽

Patient Specific ◽

Stl File ◽

Fused Deposition ◽

3D Printed ◽

The Mean

As comparative data on the precision of 3D-printed anatomical models are sparse, the aim of this study was to evaluate the accuracy of 3D-printed models of vascular anatomy generated by two commonly used printing technologies. Thirty-five 3D models of large (aortic, wall thickness of 2 mm, n = 30) and small (coronary, wall thickness of 1.25 mm, n = 5) vessels printed with fused deposition modeling (FDM) (rigid, n = 20) and PolyJet (flexible, n = 15) technology were subjected to high-resolution CT scans. From the resulting DICOM (Digital Imaging and Communications in Medicine) dataset, an STL file was generated and wall thickness as well as surface congruency were compared with the original STL file using dedicated 3D engineering software. The mean wall thickness for the large-scale aortic models was 2.11 µm (+5%), and 1.26 µm (+0.8%) for the coronary models, resulting in an overall mean wall thickness of +5% for all 35 3D models when compared to the original STL file. The mean surface deviation was found to be +120 µm for all models, with +100 µm for the aortic and +180 µm for the coronary 3D models, respectively. Both printing technologies were found to conform with the currently set standards of accuracy (<1 mm), demonstrating that accurate 3D models of large and small vessel anatomy can be generated by both FDM and PolyJet printing technology using rigid and flexible polymers.

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A New Method to Evaluate Trueness and Precision of Digital and Conventional Impression Techniques for Complete Dental Arch

Applied Sciences ◽

10.3390/app11104612 ◽

2021 ◽

Vol 11 (10) ◽

pp. 4612

Author(s):

KweonSoo Seo ◽

Sunjai Kim

Keyword(s):

Intraclass Correlation ◽

Three Dimensional ◽

New Method ◽

Digital Impression ◽

Dental Arch ◽

Digital Models ◽

Digital Impressions ◽

Measuring Machine ◽

Master Model ◽

Conventional Impression

Purpose: The aim of this study was to present a new method to analyze the three-dimensional accuracy of complete-arch dental impressions and verify the reliability of the method. Additionally, the accuracies of conventional and intraoral digital impressions were compared using the new method. Methods: A master model was fabricated using 14 milled polyetheretherketone cylinders and a maxillary acrylic model. Each cylinder was positioned and named according to its corresponding tooth position. Twenty-five definitive stone casts were fabricated using conventional impressions of the master model. An intraoral scanner was used to scan the master model 25 times to fabricate 25 digital models. A coordinate measuring machine was used to physically probe each cylinder in the master model and definitive casts. An inspection software was used to probe cylinders of digital models. A three-dimensional part coordinate system was defined and used to compute the centroid coordinate of each cylinder. Intraclass correlation coefficient (ICC) was evaluated to examine the reliability of the new method. Independent two sample t-test was performed to compare the trueness and precision of conventional and intraoral digital impressions (α = 0.05). Results: ICC results showed that, the new method had almost perfect reliability for the measurements of the master model, conventional and digital impression. Conventional impression showed more accurate absolute trueness and precision than intraoral digital impression for most of the tooth positions (p < 0.05). Conclusions: The new method was reliable to analyze the three-dimensional deviation of complete-arch impressions. Conventional impression was still more accurate than digital intraoral impression for complete arches.

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3D reconstruction of genomic regions from sparse interaction data

NAR Genomics and Bioinformatics ◽

10.1093/nargab/lqab017 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Julen Mendieta-Esteban ◽

Marco Di Stefano ◽

David Castillo ◽

Irene Farabella ◽

Marc A Marti-Renom

Keyword(s):

3D Models ◽

Genomic Region ◽

Gene Promoters ◽

Chromosome Conformation ◽

The Matrix ◽

Chromatin Structural ◽

A Cell ◽

Similar Accuracy ◽

Genomic Regions ◽

Interaction Matrices

Abstract Chromosome conformation capture (3C) technologies measure the interaction frequency between pairs of chromatin regions within the nucleus in a cell or a population of cells. Some of these 3C technologies retrieve interactions involving non-contiguous sets of loci, resulting in sparse interaction matrices. One of such 3C technologies is Promoter Capture Hi-C (pcHi-C) that is tailored to probe only interactions involving gene promoters. As such, pcHi-C provides sparse interaction matrices that are suitable to characterize short- and long-range enhancer–promoter interactions. Here, we introduce a new method to reconstruct the chromatin structural (3D) organization from sparse 3C-based datasets such as pcHi-C. Our method allows for data normalization, detection of significant interactions and reconstruction of the full 3D organization of the genomic region despite of the data sparseness. Specifically, it builds, with as low as the 2–3% of the data from the matrix, reliable 3D models of similar accuracy of those based on dense interaction matrices. Furthermore, the method is sensitive enough to detect cell-type-specific 3D organizational features such as the formation of different networks of active gene communities.

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Design and characterization of 3D printed, neomycin-eluting poly-L-lactide mats for wound-healing applications

Journal of Materials Science Materials in Medicine ◽

10.1007/s10856-021-06509-7 ◽

2021 ◽

Vol 32 (4) ◽

Author(s):

Mahima Singh ◽

Sriramakamal Jonnalagadda

Keyword(s):

Release Kinetics ◽

Biological Properties ◽

In Vitro Dissolution ◽

3D Printer ◽

Topical Antibiotic ◽

Young’S Moduli ◽

Base Polymer ◽

Potential Applications ◽

3D Printed

AbstractThis study evaluates the suitability of 3D printed biodegradable mats to load and deliver the topical antibiotic, neomycin, for up to 3 weeks in vitro. A 3D printer equipped with a hot melt extruder was used to print bandage-like wound coverings with porous sizes appropriate for cellular attachment and viability. The semicrystalline polyester, poly-l-lactic acid (PLLA) was used as the base polymer, coated (post-printing) with polyethylene glycols (PEGs) of MWs 400 Da, 6 kDa, or 20 kDa to enable manipulation of physicochemical and biological properties to suit intended applications. The mats were further loaded with a topical antibiotic (neomycin sulfate), and cumulative drug-release monitored for 3 weeks in vitro. Microscopic imaging as well as Scanning Electron Microscopy (SEM) studies showed pore dimensions of 100 × 400 µm. These pore dimensions were achieved without compromising mechanical strength; because of the “tough” individual fibers constituting the mat (Young’s Moduli of 50 ± 20 MPa and Elastic Elongation of 10 ± 5%). The in vitro dissolution study showed first-order release kinetics for neomycin during the first 20 h, followed by diffusion-controlled (Fickian) release for the remaining duration of the study. The release of neomycin suggested that the ability to load neomycin on to PLLA mats increases threefold, as the MW of the applied PEG coating is lowered from 20 kDa to 400 Da. Overall, this study demonstrates a successful approach to using a 3D printer to prepare porous degradable mats for antibiotic delivery with potential applications to dermal regeneration and tissue engineering.

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