• The Journal of the Korean dental association
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• v.56 no.3
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• pp.167-174
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• 2018

The development of dental materials has widened the scope of materials by changes in processing methods. CAD/CAM processing enables the use of zirconia as a dental material. Recent esthetic materials development has been made. For aesthetic purposes, a block for CAD/CAM processing by mixing polymer and ceramic materials are fabricated. However there is no guideline of how these materials should be used in actual clinical practice. Mechanical properties, wear and clinical studies were reviewed.

• Journal of Technologic Dentistry
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• v.42 no.3
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• pp.281-289
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• 2020

Purpose: This study analyzes the self-efficacy and CAD/CAM practice of dental technology students with the aim of providing data that will be useful for improving CAD/CAM education. Methods: A questionnaire survey on self-efficacy and CAD/CAM practice was given to students who participated in face-to-face classes in the Department of Dental Technology at a college in Daegu and Gyeongsangnam-do. The survey period was two weeks long (June 15, 2020 to July 2, 2020), and 84 students completed the questionnaire. Results: The higher the self-efficacy, the fewer difficulties or mistakes students made in CAD/CAM practice. The most difficult parts of the scanning process were the top and bottom arc operation and the bite match arc insertion. The most difficult part of the design work was the use of (multiple) tools. The difference between the degree of difficulty and the degree of mistakes during the practical course was shown as the margin line setting in the design work. Setting the margin line was not difficult, but the degree of mistakes was nonetheless high. In the CAM process, height control was the most difficult part, but the degree of mistakes did not differ according to students' self-efficacy. Conclusion: Given that higher self-efficacy correlated with fewer difficulties or mistakes in CAD/CAM practice, students should be encouraged to enhance their self-efficacy. This may be done by improving their satisfaction with their major course of study, forming friendly relations with their colleagues, and increasing the ratio of performance rather than observation in CAD/CAM practice.

• The Journal of Advanced Prosthodontics
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• v.11 no.6
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• pp.305-312
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• 2019

PURPOSE. The purpose of this study was to compare computer-aided design/computer-aided manufacturing (CAD/CAM) abutment and prefabricated abutment in Morse taper internal connection type implants after cyclic loading. MATERIALS AND METHODS. The study was conducted with internal type implants of two different manufacturers (Group Os, De). Fourteen assemblies were prepared for each manufacturer group and divided into 2 groups (n=7): prefabricated abutments (Os-P, De-P) and CAD/CAM abutments (Os-C, De-C). The amount of axial displacement and the removal torque values (RTVs) were measured before and after cyclic loading (10⁶ cycles, 3 Hz with 150 N), and the tensile removal force to dislodge the abutments was measured after cyclic loading. A repeated measures ANOVA and a pattern analysis based on the logarithmic regression model were conducted to evaluate the effect of cyclic loading on the axial displacement. The Wilcoxon signed-rank test and the Mann-Whitney test was conducted for comparison of RTV reduction% and tensile removal forces. RESULTS. There was no significant difference between CAD/CAM abutments and prefabricated abutments in axial displacement and tensile removal force; however, significantly greater RTV reduction% after cyclic loading was observed in CAD/CAM abutments. The correlation among the axial displacement, the RTV, and the tensile removal force was not significant. CONCLUSION. The use of CAD/CAM abutment did not significantly affect the amount of axial displacement and tensile removal force, but presented a significantly greater removal torque reduction% than prefabricated abutments. The connection stability due to the friction at the abutment-implant interface of CAD/CAM abutments may not be different from prefabricated abutment.

• The Journal of the Korean dental association
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• v.50 no.3
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• pp.118-125
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• 2012

CAD/CAM systems (computer-aided design / computer-aided manufacturing) used for decades in restorative dentistry have its application to implant dentistry. This study aimed to overview CAD/CAM systems used implant dentistry, especially emphasizing custom implant abutments manufacturing. CAD/CAM custom abutments present the advantages of being specific to each patient and providing a better fit than the stock and cast custom abutments. This cutting edge technology of virtual-designed and computer-milled implant abutments will likely replace traditional implant restorative protocols and become the standard for implant dentistry in the foreseeable future.

• The Journal of the Korean dental association
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• v.57 no.7
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• pp.380-391
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• 2019

In recent years, with the introduction of various restorative materials, restorations using CAD/CAM equipment have been increasing in the esthetic dentistry. The critical steps in the fabrication of indirect restorations with CAD/CAM equipment are proper cavity preparation and making accurate impressions. The process of tooth preparation for CAD/CAM restoration should include a mechanical understanding of milling. In addition, during tooth preparation, the clinician should be familiar with additional equipment and techniques for obtaining the convenience. In order to obtain an accurate oral scan, the clinician should understand the limitations of the oral scan and be skilled at techniques for obtaining a successful image when making oral scans. This article focused clinical guidelines for the preparation of CAD/CAM restorations and introduced clinical methods for making successful impression of oral scans in narrow and deep tooth cavity areas.

• Journal of dental hygiene science
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• v.18 no.1
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• pp.42-49
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• 2018

The computer-aided design/computer-aided manufacturing (CAD/CAM) system was introduced to shorten the production time of all-ceramic restorations and the number of patient visits. Among these types of ceramic for dental CAD/CAM, they have been processed into inlay, onlay, and crown shapes using leucite-reinforced glass-ceramics to improve strength. The purpose of this study was to observe the mechanical properties and microstructure of leucite-reinforced glass-ceramics for dental CAD/CAM. Two types of leucite-reinforced glass-ceramic blocks (IPS Empress CAD, Rosetta BM) were prepared with diameter of 13 mm and thickness of 1 mm. Biaxial flexural testing was conducted using a piston-on-three-ball method at a crosshead speed of 0.5 mm/min. Weibull statistics were used for the analysis of biaxial flexural strength. Fracture toughness was obtained using an indentation fracture method. Specimens were observed by field emission scanning electron microscopy to examine the microstructure of the leucite crystalline phase after acid etching with 0.5% hydrofluoric acid aqueous solution for 1 minute. The results of strength testing showed that IPS Empress CAD had a mean value of $158.1{\pm}8.6MPa$ and Rosetta BM of $172.3{\pm}8.3MPa$. The fracture toughness results showed that IPS Empress CAD had a mean value of $1.28{\pm}0.19MPa{\cdot}m^{1/2}$ and Rosetta BM of $1.38{\pm}0.12MPa{\cdot}m^{1/2}$. The Rosetta BM sample exhibited higher strength and fracture toughness. Moreover, the crystalline phase size and ratio were increased in the Rosetta BM sample. The above results are expected to elucidate the basic mechanical properties and crystal structure characteristics of IPS Empress CAD and Rosetta BM. Additionally, they will help develop leucite-reinforced glass-ceramic materials for CAD/CAM.

• Journal of Technologic Dentistry
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• v.33 no.2
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• pp.137-145
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• 2011

Purpose: To evaluate the accuracy of zirconia copings in terms of clinical verified for the clinical application of CAD/CAM. Methods: Zirconia copings (n=5) were prepared using CAD/CAM system and were sintered using the relevant electrical induction furnace, which uses a 2h sintering program with a maximum temperature of $1500^{\circ}C$. The copings placed at the models and the interval values were measured. Results: The meas interval values between the die and the zirconia copings were $44.14{\mu}m$(A), $44.57{\mu}m$(B), $44.72{\mu}m$(C). 51.05 ${\mu}m$(D). Conclusion: The maximum interval values between the die and the zirconia copings were $51.3{\mu}m$ which is acceptable for clinical use. ${\mu}m$ Proper understanding of the test conditions will help enhancing the accuracy of zirconia coping.

• The Journal of the Korean dental association
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• v.54 no.8
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• pp.651-657
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• 2016

Currently with the continuous development of ceramic and cementation materials, CAD-CAM(Computer-aided design/Computer-aided manufacture) restorations are becoming increasingly popular in esthetic dentistry. Preparation design is influenced by the selected restorative material, the fabrication method, and the ability to bond the restoration. For long-lasting CAD/CAM inlay/onlay restoration, clinicians should understand the basic knowledge of CAD/CAM restoration's cavity design to obtain the fracture resistance and proper fitting margin. This article gives an overview of preparation guidelines for CAD/CAM inlay/onlay restorations.

• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.695-700
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• 2016

Objectives: The purpose of the study was to investigate the effect of CAD/CAM ceramic thickness on shade. Methods: 24 disk-shaped ceramic specimens (E.Max CAD & Empress CAD, $12mm{\times}12mm$) were prepared and divided into 4 groups (n=6). Ceramic specimens in 2 thicknesses (0.8 mm, 1.0 mm) were made low translucency(LT) shade A2. All specimens were measured as L*, a*, b* using spectrophotometer. The color differences(${\Delta}E$ values) between the specimen and a control target block ($12{\times}12{\times}1.2mm$) were calculated. Two-way ANOVA performed between 2 groups(material and thickness). Results: As the thickness increased, the $L^*$ (for all groups) and $b^*$ value (for all groups) increased and the $a^*$ value(for LR group) decreased. The mean color differences caused by thickness was acceptible (${\Delta}E$ > 2) for group LD1. But the mean color differences by thickness were not selected (${\Delta}E$ < 2) for group LD2, LR1, LR2. Conclusions: The different thickness can influence the final color of CAD/CAM ceramic.

• Journal of Technologic Dentistry
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• v.36 no.3
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• pp.159-164
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• 2014

Purpose: The purpose of this study was analysis of quality of fixed prostheses fabricated by dental CAD/CAM system. Methods: The ten same cases of stone models were manufactured by dental scannable model, and stone models were scanned using the dental scanner for changing digital model. Ten digital models were completed. The design of zirconia core for zirconia based all-ceramic crown was conducted by the dental CAD program. The samples were fabricated using the pre-sintered zirconia block by dental milling machine. Marginal gaps were analyzed using by silicone replica technique at the eight parts for quality analysis of samples. One-way ANOVA was used for statistical analysis(${\alpha}=0.05$). Results: The mean for marginal gaps were $93.2{\sim}99.1{\mu}m$ at the eight parts. One-was ANOVA didn't show significant differences(p=0.089). Conclusion: The fixed dental prostheses fabricated by dental CAD/CAM were within clinically acceptable range.