Corrosion Resistance of Dental Crowns Fabricated of Co–Cr Alloys by Casting and CAD/CAM Milling Methods

Subject. Modern digital technologies allow us to significantly automate the process of creating prosthetic devices. First, digital images of the patient's dental rows are obtained, then the future prosthesis is virtually modeled and made using a subtractive method using CAD/CAM, or an additive method using a 3D-printer. Objective ― conducting a comparative assessment of the time spent by an orthopedic dentist and a dental technician for the production of artificial dental crowns obtained using digital and traditional technologies. Methodology. The patients were divided into four groups according to the method of manufacturing temporary artificial crowns-from a composite material Protemp 4 using a silicone key, using the CAD/CAM-system KaVo ARCTIC from polymethylmethacrylate VITA CAD-Temp multicolor, using a 3D-printer Asiga Max UV from a biologically compatible photopolymer material NextDent C&B MFH and a laboratory method of cold plastic polymerization. For statistical analysis of the results obtained, the Kraskel―Wallis H-test and the Mann―Whitney W-test were used. In total, 40 medicinal artificial crowns were made, 10 in each group. Results. Based on the data obtained, it was found that for the manufacture of a dental artificial crown using the 3D-printer Asiga Max UV dentist orthopedist and dental technician should spend 38.8 ± 4.104 minutes, using CAD/CAM KaVo ARCTICA-29.0 ± 3.162 minutes, using the laboratory method ― 71.6 ± 4.502 and using a silicone key ― 62.8 ± 5.613. Conclusions. The obtained data allowed us to conclude that the production of a temporary artificial crown with the use of modern digital technologies (CAD/CAM-systems, intraoral laser scanning and 3D-printer) requires less time compared to traditional methods of manufacturing a prothesis (p<0.0166667).

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Anatomical Shaping for Zirconia Custom Implant Abutment to Enhance Anterior Esthetic: A Clinical Technique

International Journal of Dentistry ◽

10.1155/2020/8857410 ◽

2020 ◽

Vol 2020 ◽

pp. 1-5

Author(s):

Mohammed Alshehri ◽

Mohammed Alghamdi ◽

Abdullah S. Alayad

Keyword(s):

Computer Aided Design ◽

Innovative Technology ◽

Dental Crowns ◽

Incisal Edge ◽

Custom Implant ◽

Optical Effects ◽

Computer Aided ◽

Cad Cam ◽

The One ◽

Aided Design

Abutments are used in dentistry to attach dental crowns to dental implant. Currently, zirconia custom abutment is the one which is mostly used in restorations, since it offers several advantages, especially better esthetics and prevention from infection. Several innovations are done in the implant designs and procedures to achieve better esthetics. Computer-aided design & computer-aided manufacturing (CAD/CAM) system is widely used innovative technology in dentistry. This technology offers custom implants that help to achieve better esthetics and good internal fit. This procedure used a novel technique of anatomical modification of the final abutment incisal edge from straight anatomical edge to irregular one with a mamelon-incisal effect to enhance esthetic, shade matching, and anatomical replication of incisal structure that resembles the natural incisor. Usually, dental technicians will perform facial and incisal cut-back and apply porcelain layers to the crown in order to reproduce the translucency and the other optical effects that most closely match that of natural dentin and enamel, especially at the incisal edge. These optical effects will make the prosthetic crown look more natural and esthetically pleasant. By this presented technique will help the dental technician to achieve highly esthetic crown with completely digital workflow without the need for porcelain layering. The procedure was also followed up to 3, 6, and 12 months after the surgery and found no complications or complaints from the patient and esthetically satisfied.

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Additive vs. Subtractive CAD/CAM Procedures in Manufacturing of the PMMA Interim Dental Crowns. A Comparative in vitro Study of Internal Fit

Revista de Chimie ◽

10.37358/rc.20.1.7866 ◽

2020 ◽

Vol 71 (1) ◽

pp. 405-410

Author(s):

Kamel Earar ◽

Alexandru Andrei Iliescu ◽

Gabriela Popa ◽

Andrei Iliescu ◽

Ioana Rudnic ◽

...

Keyword(s):

In Vitro Study ◽

Dimensional Accuracy ◽

Vitro Study ◽

Dental Crowns ◽

S 100 ◽

Cad Cam ◽

Dental Models ◽

3D Printed ◽

Internal Fit

CAD/CAM procedures are increasingly used to the manufacturing of 3D-designed PMMA interim dental crowns. The aim of this in vitro study was to compare the internal fit of interim PMMA crowns fabricated by subtractive versus additive CAD/CAM procedures. Starting from a Co-Cr CAD/CAM master abutment model, 20 standardized dental models of dental stone were done by double impression technique. Subsequently two groups of interim PMMA interim crowns, each of them having 10 specimens, were CAM obtained either by milling or 3D printing, using Exocad software package, milling machine Rolland DWX-50, and the 3D printer MoonRay S 100 respectively. An electronic digital caliper Powerfix Profi+ was used for measurements of the chrome cobalt abutment and crowns inner diameter in 4 directions (mesial-distal gingival, buccal-lingual gingival, mesial-distal occlusal, and buccal-lingual occlusal). The null hypothesis that the internal dimensional accuracy of interim PMMA crowns fabricated by DLP additive method would not be different compared to those obtained by milling procedure was rejected since the printed PMMA interim crowns were more accurate. This study concluded that the milled PMMA interim crowns show larger internal dimensional variations than the 3D printed ones. However, the fit variation among interim crowns fabricated by both procedures was statistically non significant, so that both CAM technologies may be equally used in manufacturing process.

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Corrosion Resistance and Ion Release of Dental Prosthesis of CoCr Obtained by CAD-CAM Milling, Casting and Laser Sintering

Metals ◽

10.3390/met10060827 ◽

2020 ◽

Vol 10 (6) ◽

pp. 827 ◽

Cited By ~ 1

Author(s):

Roberto Padrós ◽

Luís Giner-Tarrida ◽

Mariano Herrero-Climent ◽

Miquel Punset ◽

Francisco Javier Gil

Keyword(s):

Corrosion Resistance ◽

Current Density ◽

Manufacturing Systems ◽

Chemical Elements ◽

Artificial Saliva ◽

Laser Sintering ◽

Dental Restoration ◽

Ion Release ◽

Cr Content ◽

Cad Cam

Corrosion resistance and ion release behavior have been evaluated for thirty dental restoration samples obtained by three different manufacturing systems: computer-aided design and manufacturing (CAD-CAM), traditional casting and laser sintering. The alloy used was the CoCr alloy (same batch) generally used in clinical dentistry. Corrosion resistance has been evaluated by electrochemical testing in an artificial saliva medium at 37 °C. Corrosion parameters such as critical current density (icr), corrosion potential (Ecorr), and passive current density (ip), have been determined. Cobalt and Chromium ions released from the different samples have also been analyzed in an artificial saliva medium at 37 °C by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) at different immersion times. The casted samples showed higher corrosion rates and ion-release levels. The CAD-CAM milled samples presented lower ion-release levels and better corrosion resistance due to the total solubility of the chemical elements in only one phase with the same chemical composition. This homogeneity avoids the formation of electrochemical corrosion. Moreover, the absence of defects and residual stresses increases the corrosion resistance. Casted and laser sintered prostheses have shown the presence of Cr, W, and Nb rich-precipitates which are detrimental to the corrosion resistance. These precipitates produce a decrease in the Cr content on the surface. It is well known that the corrosion resistance increases with the Cr content by the formation of Chromium oxide on the surface that increases passivation. Consequently, the decrease in Cr induces an increase in corrosion and ion release.

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Comparative Study on the Corrosion Resistance of CAD/CAM and Conventional Processed Co-Cr Dental Alloys in NaCl Solutions

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/416/1/012047 ◽

2018 ◽

Vol 416 ◽

pp. 012047

Author(s):

L-V Costea ◽

M L Dan ◽

C E Savencu ◽

L Porojan

Keyword(s):

Corrosion Resistance ◽

Comparative Study ◽

Dental Alloys ◽

Cad Cam

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CAD-CAM assisted investment casting for preparation of dental crowns

Materials Today Proceedings ◽

10.1016/j.matpr.2019.10.169 ◽

2020 ◽

Vol 26 ◽

pp. 223-228

Author(s):

Ranvir Singh ◽

Rupinder Singh ◽

Jasminder Singh Dureja

Keyword(s):

Investment Casting ◽

Dental Crowns ◽

Cad Cam

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The Micromorphological Research of the Internal Structure of Chairside CAD/CAM Materials by the Method of Scanning Impulse Acoustic Microscopy (SIAM)

The Open Dentistry Journal ◽

10.2174/1874210601812010125 ◽

2018 ◽

Vol 12 (1) ◽

pp. 125-132 ◽

Cited By ~ 1

Author(s):

Kristina E. Goryainova ◽

Egor S. Morokov ◽

Marina V. Retinskaja ◽

Fedor S. Rusanov ◽

Samvel V. Apresyan ◽

...

Keyword(s):

Internal Structure ◽

Glass Ceramic ◽

Acoustic Microscopy ◽

Polymer Materials ◽

Material Defects ◽

Dental Crowns ◽

Ceramic Samples ◽

Internal Structures ◽

Cad Cam ◽

Hybrid Ceramic

Aim:The aim of the present work was to compare the elastic properties and internal structure of 4 different CAD/CAM chairside materials, by the method of Scanning Impulse Acoustic Microscopy (SIAM).Methods:Four chairside CAD/CAM materials with different structures from hybrid ceramic (VITA Enamic, VITA Zahnfabrik), feldspatic ceramic (VITABlocs Mark II, VITA Zahnfabrik), leucite glass-ceramic (IPS Empress CAD, Ivoclar Vivadent) and PMMA (Telio CAD, Ivoclar Vivadent) were examined by Scanning Impulse Acoustic Microscope (SIAM).Results:The results of micromorphological research of CAD/CAM chairside materials using SIAM method showed differences between the internal structures of these materials. The internal structure of feldspatic and glass-ceramic samples revealed the presence of pores with different sizes, from 10 to 100 microns; the structure of polymer materials rendered some isolated defects, while in the structure of hybrid material, defects were not found.Conclusion:Based on the results obtained from the present study, in cases of chairside production of dental crowns, it would be advisable to give preference to the blocks of hybrid ceramics. Such ceramics devoid of quite large porosity, glazing for CAD/CAM crowns made from leucite glass-ceramic and feldspatic ceramic may be an option. For these purposes, commercially available special muffle furnace for clinical and laboratory individualization and glazing of ceramic prostheses were provided. Further studies are needed to confirm the evidence emerging from the present research.

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Multivariate Assessment of Marginal Fit of Three Types of Dental Crowns Using Three Scanning Systems for CAD-CAM Technology - in vitro Pilot Study

Materiale Plastice ◽

10.37358/mp.18.3.5033 ◽

2018 ◽

Vol 55 (3) ◽

pp. 376-379

Author(s):

Smaranda Buduru ◽

Anca Mesaros ◽

Cristian Culcitchi ◽

Marioara Moldovan ◽

Doina Prodan ◽

...

Keyword(s):

In Vitro Study ◽

Marginal Fit ◽

Dental Crowns ◽

Intraoral Scanning ◽

Different Types ◽

Cad Cam ◽

Scanning Systems ◽

Conventional Impression ◽

Hybrid Ceramic

The objective of this in-vitro study was to compare if there are any differences in the marginal fit of crowns fabricated by CAD/CAM technique. We used three different types of materials (two types of polymethylmetacrylate (PMMA) provided by two different manufacturers and one type of hybrid ceramic) and three different types of impressions: intraoral scanning, model scanning and conventional impression scanning. The crowns were subsequently measured with an electronic microscope at 1000X. Our results showed better results for the hybrid ceramic. The differences between the PMMA were not significant. There were no statistic differences with the ANOVA analysis between the scanning methods. Best combination in terms of marginal fit was found with hybrid ceramic and intraoral scanning.

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