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Porrelli D, Berton F, Camurri Piloni A, Kobau I, Stacchi C, Di Lenarda R, Rizzo R. Evaluating the stability of extended-pour alginate impression materials by using an optical scanning and digital method. J Prosthet Dent 2020; 125:189.e1-189.e7. [PMID: 33129498 DOI: 10.1016/j.prosdent.2020.06.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 10/23/2022]
Abstract
STATEMENT OF PROBLEM The dimensional stability of alginate dental impressions is a key factor for the reliability of delayed gypsum pouring and digital scanning. However, studies of the dimensional stability of alginates with conventional methods that consider the dimensional variations of large impressions are lacking. PURPOSE The purpose of this in vitro study was to investigate and compare 2 digital methods for the analysis of dimensional stability of large impressions made with 5 different extended-pour alginates and to assess dimensional stability up to 5 days. MATERIAL AND METHODS Impressions of a simplified master maxillary model were made with Alginoplast, Blueprint, Hydrogum 5, Orthoprint, and Phase Plus and then analyzed at different time points. Digital scans of the alginate impression surfaces were obtained with a desktop scanner and analyzed by evaluating the linear measurements between reference points and by using a novel method that consists of the analysis of the entire scanned surface to evaluate the expansion and contraction of the impressions. RESULTS The first method revealed that the dimensional changes did not exceed 0.5%, with the exception of Phase Plus at day 3 (-0.6 ±0.7%), and the average dimensional variation was always lower than or equal to 0.2 mm. Blueprint was the most stable material (-0.2 ±0.6%). The second method revealed dimensional variations always lower than 0.03 mm and confirmed Blueprint as the best performing material (0.001 ±0.006 mm) and Phase Plus the worst (-0.019 ±0.006 mm). CONCLUSIONS Both the methods used to evaluate alginate stability showed that the analyzed materials remain stable over time; the dimensional variations showed a similar trend, with differences in the absolute values depending on the applied method. Linear measurements are affected by the operator and choice of reference points; however, by evaluating the average variations of the entire structure surfaces, local variations should be minimized. The evaluation of the average variations with the second method offers the advantage of a rapid visual representation of these variations.
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Affiliation(s)
- Davide Porrelli
- Researcher, Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.
| | - Federico Berton
- PhD student in Nanotechnology, Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
| | - Alvise Camurri Piloni
- Post-Graduate student, Department of Medicine, Surgery and Health Sciences, Specialization School in Oral Surgery, University of Trieste, Trieste, Italy
| | - Ivana Kobau
- Post-Graduate student, Department of Medicine, Surgery and Health Sciences, Specialization School in Oral Surgery, University of Trieste, Trieste, Italy
| | - Claudio Stacchi
- Doctor and Researcher, Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
| | - Roberto Di Lenarda
- Professor, Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
| | - Roberto Rizzo
- Professor, Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
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Virard F, Millet C, Bienfait A, Ducret M. Improving digital scans by using a peripheral custom tray: A dental technique. J Prosthet Dent 2020; 126:173-177. [PMID: 32800578 DOI: 10.1016/j.prosdent.2020.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 05/12/2020] [Accepted: 05/12/2020] [Indexed: 10/23/2022]
Abstract
A digital dental technique is described for registering functional borders of immediate complete dentures, by using an intraoral scanner, a dental computer-aided design software program, and a peripheral custom tray. This article also illustrates how to virtually match the recorded information in order to transform the initial intraoral scan into definitive digital scans.
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Affiliation(s)
- François Virard
- Associate Professor, Department of Oral Biology, Faculty of Dentistry, Lyon 1 University, Lyon, France; Associate Professor, Odontology Center, Lyon Civils Hospices, Lyon, France
| | - Catherine Millet
- Professor, Department of Prosthetic Dentistry, Faculty of Dentistry, Lyon 1 University, Lyon, France; Professor, Oral Manifestations of Rare Diseases Center, Lyon Civils Hospices, Lyon, France
| | - Alexandre Bienfait
- Master Dental Technician, Laboratoire Bienfait, Francheville, Lyon, France
| | - Maxime Ducret
- Associate Professor, Department of Prosthetic Dentistry, Faculty of Dentistry, Lyon 1 University, Lyon, France; Associate Professor, Odontology Center, Lyon Civils Hospices, Lyon, France; Visiting Professor, Faculty of Dentistry, McGill University, Montreal, Canada.
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Park JY, Kim D, Han SS, Yu HS, Cha JY. Three-dimensional comparison of 2 digital models obtained from cone-beam computed tomographic scans of polyvinyl siloxane impressions and plaster models. Imaging Sci Dent 2020; 49:257-263. [PMID: 31915610 PMCID: PMC6941835 DOI: 10.5624/isd.2019.49.4.257] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/19/2019] [Accepted: 08/30/2019] [Indexed: 11/18/2022] Open
Abstract
Purpose This study was performed to evaluate the dimensional accuracy of digital dental models constructed from cone-beam computed tomographic (CBCT) scans of polyvinyl siloxane (PVS) impressions and cast scan models. Materials and Methods A pair of PVS impressions was obtained from 20 subjects and scanned using CBCT (resolution, 0.1 mm). A cast scan model was constructed by scanning the gypsum model using a model scanner. After reconstruction of the digital models, the mesio-distal width of each tooth, inter-canine width, and inter-molar width were measured, and the Bolton ratios were calculated and compared. The 2 models were superimposed and the difference between the models was measured using 3-dimensional analysis. Results The range of mean error between the cast scan model and the CBCT scan model was −0.15 mm to 0.13 mm in the mesio-distal width of the teeth and 0.03 mm to 0.42 mm in the width analysis. The differences in the Bolton ratios between the cast scan models and CBCT scan models were 0.87 (anterior ratio) and 0.72 (overall ratio), with no significant difference (P>0.05). The mean maxillary and mandibular difference when the cast scan model and the CBCT scan model were superimposed was 53 µm. Conclusion There was no statistically significant difference in most of the measurements. The maximum tooth size difference was 0.15 mm, and the average difference in model overlap was 53 µm. Digital models produced by scanning impressions at a high resolution using CBCT can be used in clinical practice.
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Affiliation(s)
- Jin-Yi Park
- Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, Korea
| | - Dasomi Kim
- Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, Korea
| | - Sang-Sun Han
- Department of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul, Korea
| | - Hyung-Seog Yu
- Department of Orthodontics, Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
| | - Jung-Yul Cha
- Department of Orthodontics, Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
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Stuani VT, Ferreira R, Manfredi GGP, Cardoso MV, Sant'Ana ACP. Photogrammetry as an alternative for acquiring digital dental models: A proof of concept. Med Hypotheses 2019; 128:43-49. [PMID: 31203907 DOI: 10.1016/j.mehy.2019.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 04/29/2019] [Accepted: 05/12/2019] [Indexed: 11/27/2022]
Abstract
Photogrammetry is a mathematical technique that generates three-dimensional coordinates of specific points identified from multiple images of the same object obtained at different angles. This technique may be a low-cost alternative for traditional scanning. The objective of this proof of concept was to evaluate the accuracy and precision in obtaining digital models (DM) from a plaster model (PM) using photogrammetry. Five DM were generated from 50 photographs taken surrounding the PM. The photographs were taken by a single operator on five consecutive days using natural light. The images obtained were processed on 3DF Zephyr Free software. The height and width of all teeth were recorded on both PM and DM, as well as the distance between the canine cusps (C-C) and between the mesiobuccal cusps of the first molars (1 M-1 M). For the PM the measurements were taken with a digital caliper, whereas the DM was measured using the software Blender. The DM and PM measurements presented a limit of agreement between -0.433 and 0.611 mm. The accuracy of DM measurements showed a SD of ±0.171 mm and a repeatability coefficient of 0.474. In the superimposition of all DM, it was possible to notice a greater discrepancy in the posterior region of the arch and palate, but this difference decreased when the region was segmented. It can be concluded that photogrammetry appears to be a viable technique for the digitization of dental models. Further studies need to be performed to evaluate its clinical application.
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Affiliation(s)
- Vitor T Stuani
- Department of Periodontology, Bauru School of Dentistry, University of Sao Paulo, Bauru, Brazil.
| | - Rafael Ferreira
- Department of Periodontology, Bauru School of Dentistry, University of Sao Paulo, Bauru, Brazil
| | - Gustavo G P Manfredi
- Department of Periodontology, Bauru School of Dentistry, University of Sao Paulo, Bauru, Brazil
| | - Matheus V Cardoso
- Department of Periodontology, Bauru School of Dentistry, University of Sao Paulo, Bauru, Brazil
| | - Adriana C P Sant'Ana
- Department of Periodontology, Bauru School of Dentistry, University of Sao Paulo, Bauru, Brazil
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Hategan SI, Ionel TF, Goguta L, Gavrilovici A, Negrutiu ML, Jivanescu A. Powder and Powder-Free Intra-Oral Scanners: Digital Impression Accuracy. Prim Dent J 2018; 7:40-3. [PMID: 30095881 DOI: 10.1177/205016841800700207] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aim The purpose of this study was to evaluate the accuracy of digital impressions taken with two different intra-oral scanners (with and without optical powder), by dentists with different level of experience. Material and Methods Two intra-oral scanning devices (Apollo DI and Cerec Omnicam, Sirona Dental GmbH, Germany) were used to obtain a digital cast from scanning different preparations on a maxillary typodont. Three operator groups scanned five crown preparations using both powder and powder-free scanning systems. One group consisted of fourth year dental students, a second group consisted of prosthodontic residents, and third group consisted of prosthodontic specialists. The precision of spray application and impression expertise was compared between the three groups. Results The most frequently encountered errors were non-linear powder application, inappropriate intra-oral scanner manipulation, and insufficient digital data for crown fabrication. Conclusion Experience is needed in order to achieve high quality digital impressions. A prosthodontic specialist avoided incorrect manipulation of an intra-oral camera, uneven application of powder spray and achieved a better marginal fit.
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Accuracy and reproducibility of virtual edentulous casts created by laboratory impression scan protocols. J Prosthet Dent 2018; 120:389-395. [DOI: 10.1016/j.prosdent.2017.11.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 11/22/2017] [Accepted: 11/22/2017] [Indexed: 12/14/2022]
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Darroudi AM, Kuijpers-Jagtman AM, Ongkosuwito EM, Suttorp CM, Bronkhorst EM, Breuning KH. Accuracy of a computed tomography scanning procedure to manufacture digital models. Am J Orthod Dentofacial Orthop 2017; 151:995-1003. [PMID: 28457278 DOI: 10.1016/j.ajodo.2016.12.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 12/01/2016] [Accepted: 12/01/2016] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Accurate articulation of the digital dental casts is crucial in orthodontic diagnosis and treatment planning. We aimed to determine the accuracy of manufacturing digital dental casts from computed tomography scanning of plaster casts regarding linear dimensions and interarch relationships and to test whether eventual differences in interarch relationships between plaster and digital casts would affect orthodontic diagnostics. METHODS Plaster casts with the wax bites of 2 patients were used to create digital dental casts with a computed tomography scanner. This was repeated 4 times with a 1-week interval. Linear distances were measured on plaster and digital models twice by 2 observers. Next, the 4 digital models of each patient were scored twice by 5 observers for interarch variables. RESULTS Digital vs plaster measurements showed high Pearson correlation coefficients (>0.954), whereas the mean difference was small (<0.1 mm) and not significant. The interarch scorings, however, showed significant differences for all variables, except overjet for model 1. CONCLUSIONS We found substantial interarch inaccuracies of the digital models. These inaccuracies are probably due to a lack of built-in "collision control" in the software and manual articulation of the digital models by a human operator.
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Affiliation(s)
- Amir M Darroudi
- Department of Orthodontics and Craniofacial Biology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Anne Marie Kuijpers-Jagtman
- Department of Orthodontics and Craniofacial Biology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Edwin M Ongkosuwito
- Department of Orthodontics and Craniofacial Biology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christiaan Maarten Suttorp
- Department of Orthodontics and Craniofacial Biology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ewald M Bronkhorst
- Department of Dentistry, Radboud University Medical Center, Nijmegen, The Netherlands
| | - K Hero Breuning
- Department of Dentistry, Radboud University Medical Center, Nijmegen, The Netherlands
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