• The Journal of Advanced Prosthodontics
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• v.4 no.3
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• pp.162-169
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• 2012

PURPOSE. Fracture of the veneering material of zirconia restorations frequently occurs in clinical situations. The purpose of this in vitro study was to compare the fracture strengths of zirconia crowns veneered with various ceramic materials by various techniques. MATERIALS AND METHODS. A 1.2 mm, $360^{\circ}$ chamfer preparation and occlusal reduction of 2 mm were performed on a first mandibular molar, and 45 model dies were fabricated in a titanium alloy by CAD/CAM system. Forty-five zirconia copings were fabricated and divided into three groups. In the first group (LT) zirconia copings were veneered with feldspathic porcelain by the layering technique. In the second group (HT) the glass ceramic was heat-pressed on the zirconia coping, and for the third group (ST) a CAD/CAM-fabricated high-strength anatomically shaped veneering cap was sintered onto the zirconia coping. All crowns were cemented onto their titanium dies with Rely $X^{TM}$ Unicem (3M ESPE) and loaded with a universal testing machine (Instron 5583) until failure. The mean fracture values were compared by an one-way ANOVA and a multiple comparison post-hoc test (${\alpha}$= 0.05). Scanning electron microscope was used to investigate the fractured interface. RESULTS. Mean fracture load and standard deviation was $4263.8{\pm}1110.8$ N for Group LT, $5070.8{\pm}1016.4$ for Group HT and $6242.0{\pm}1759.5$ N for Group ST. The values of Group ST were significantly higher than those of the other groups. CONCLUSION. Zirconia crowns veneered with CAD/CAM generated glass ceramics by the sintering technique are superior to those veneered with feldspathic porcelain by the layering technique or veneered with glass ceramics by the heat-pressing technique in terms of fracture strength.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.3
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• pp.292-299
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• 2017

Long-term alveolar bone resorption in edentulous patient causes difficulty in denture use. Applying an implant overdenture with 2 to 4 implants to edentulous patient is easily approachable. Moreover, it improves denture stability, support, and retention. Milled bar, the attachment used in implant overdenture, can be used to induce better stability and retention to the supporting structure than conventional bar. It has become convenient to use due to the development of CAD/CAM system which had allowed the simplification of dental techniques. In this case, application of conventional maxillary full denture and mandibular overdenture made of CAD/CAM milled bar with 4 implants showed satisfactory results in the patient who had used upper and lower full dentures for a long time.

• Journal of Technologic Dentistry
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• v.40 no.4
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• pp.231-237
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• 2018

Purpose: The development of the dental technology industry has digitized the dental process. Definition of Digitalization of Dental Implantation Digitalization is the process of model making and prosthodontic processing using 3D CAD and CAM. Currently, it is becoming popular due to the spread of various devices. However, precision evaluation at this stage is an important factor in precision-based dental procedures. Therefore, in this study, we want to analyze the precision of the processed body made with digital dental machine. Methods: The accuracy of digital dental pore devices was evaluated. Specimens were fabricated with 5 types of 3D printers. The external shape was measured with the prepared specimen. The surface roughness was measured. Results: As a result, precision was excellent in order of EP2 specimen, EP1 specimen, and EA2 specimen. The precision of EP3 specimen and EA1 specimen is not excellent. And the precision of the specimen processed with polymer 3D printer is excellent. The accuracy of LCPS type polymer 3D printers is considered to be excellent. Conclusion : 1. Observation of the shape The 3D printer for LCPS system and the 3D printer for SLM $40{\mu}m$ system were found to be precisely processed. 2. Surface roughness results The LCPS system polymer 3D printer has been shown to have a precise surface.

• The Journal of Advanced Prosthodontics
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• v.15 no.3
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• pp.155-170
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• 2023

PURPOSE. This study aims to clinically compare the fitness and trueness of zirconia crowns fabricated by different combinations of open CAD-CAM systems. MATERIALS AND METHODS. Total of 40 patients were enrolled in this study, and 9 different zirconia crowns were prepared per patient. Each crown was made through the cross-application of 3 different design software (EZIS VR, 3Shape Dental System, Exocad) with 3 different processing devices (Aegis HM, Trione Z, Motion 2). The marginal gap, absolute marginal discrepancy, internal gap(axial, line angle, occlusal) by a silicone replica technique were measured to compare the fit of the crown. The scanned inner and outer surfaces of the crowns were compared to CAD data using 3D metrology software to evaluate trueness. RESULTS. There were significant differences in the marginal gap, absolute marginal discrepancy, axial and line angle internal gap among the groups (P < .05) in the comparison of fit. There was no statistically significant difference among the groups in terms of occlusal internal gap. The trueness ranged from 36.19 to 43.78 ㎛ but there was no statistically significant difference within the groups (P > .05). CONCLUSION. All 9 groups showed clinically acceptable level of marginal gaps ranging from 74.26 to 112.20 ㎛ in terms of fit comparison. In the comparison of trueness, no significant difference within each group was spotted. Within the limitation of this study, open CAD-CAM systems used in this study can be assembled properly to fabricate zirconia crown.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.4
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• pp.309-315
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• 2006

The availability of high-technology systems that use computer-aided design(CAD) and computer-aided machining(CAM) is on the increase. One such system is the Procera system, which fabricates an all-ceramic crown composed of a densely sintered, high-purity aluminum oxide coping combined with a compatible veneering porcelain. Strength, precision of fit, esthetics, cementation, and biocompatibility are among the many factors that concern clinicians when fabricating all-ceramic restorations with this system. This paper reviews the long history and background development of technical, laboratory and clinical applications and presents, in summary form, the data from the many studies on the Procera system.

• Journal of Technologic Dentistry
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• v.31 no.4
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• pp.123-138
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• 2009

• Journal of Technologic Dentistry
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• v.28 no.1
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• pp.251-257
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• 2006

• Journal of Technologic Dentistry
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• v.30 no.2
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• pp.193-200
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• 2008

• Journal of dental hygiene science
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• v.11 no.4
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• pp.299-303
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• 2011

The purpose of this case report was to present an example of an esthetic and functional rehabilitation of anterior teeth with tetracycline discoloration and minor morphological abnormality of a 39-year old female. A chairside computer-aided design/computer-aided manufacturing (CAD/CAM) system with CEREC AC was applied for the prosthetic procedure and all ceramic crowns made with lithum disilicate (IPS e.max CAD) restored the esthetic and functional features of sixteen anterior teeth successfully.

• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.240-247
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• 2012

Marginal and internal fit is an important part of the longevity of dental restorations. The purpose of this study was to analysis the marginal and internal fit of zirconia core by dental CAD/CAM system using innovative and non-destructive methods such as optical coherence tomography(OCT) and compare with conventional method such as silicone replica technique(SRT). Ten dental stone models of abutment of maxillary right central incisal were manufactured and scanned. Ten zirconia cores were fabricated with commercial CAD/CAM system. To measure the marginal and internal fit of each sample, five point of fitness were measured using 2 different methods(OCT and SRT). Statistical analysis was performed using independent sample t-test(${\alpha}$=0.05). OCT and SRT groups were not significantly different(P>0.05). By this results, analysis the fitness of dental restorations using OCT were acceptable measuring method.