• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.4
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• pp.366-376
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• 2013

The purpose of this study is to evaluate the marginal and internal fit of coping made by CAD/CAM using different scanning methods. Zirconia coping was made by each CAD/CAM system followed by intra-oral scanning, model optical scanning and model contact scanning. It was embedded into Epoxy Resin and was cut by buccal to lingual. AMD (Absolute marginal discrepancy), MG (Marginal gap), GA (Gap of axial), GL (Gap of line angle) and GO (Gap of occlusal) of each sample were measured. The result is as followed; 1. The mean value of AMD in Group 1, Group 2, Group 3 are $141.21{\pm}42.94{\mu}m$, $140.63{\pm}31.64{\mu}m$, $109.37{\pm}28.42{\mu}m$. The averages of MG in Group 1, Group 2, Group 3 are $82.52{\pm}43.99{\mu}m$, $90.28{\pm}27.93{\mu}m$, $66.55{\pm}28.77{\mu}m$. Statistically there is no difference in AMD and MG among the three Groups (Anova, P>0.05). 2. GA of Group 2 revealed statistically difference compared with Group 1 and Group 3 (Anova, P<0.05). 3. GL and GO of Group 1 showed statistically significant differences compared with Group 2 and Group 3 (Mann-whitney test (P<0.05). Zirconia copings made by 3 ways of scanning methods have no difference with conventional ceramics in AMD and MG which are known as the most important factors.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.3
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• pp.370-378
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• 2021

Purpose. The purpose of this study was to evaluate the currently published literatures investigating the accuracy of computer-aided design and computer-aided manufacturing removable partial denture (CAD-CAM RPD) framework with different manufacturing techniques and methods. Materials and methods. A comprehensive search for literatures was conducted in PubMed database using specific keywords with the patient, intervention, comparison, and outcome (PICO) question, "Is there a difference in accuracy of RPD frameworks manufactured using digital workflow according to the manufacturing process and methods?" Results. A total of 7 articles were selected. Two studies compared intraoral scanning and laboratory scanning for RPD frameworks and had heterogenous results. In the studies using different manufacturing process, RPD frameworks had clinically acceptable accuracy in both subtractive and additive manufacturing. Polyetheretherketone (PEEK)-milled RPD frameworks showed higher fit accuracy than traditionally casted or 3D printed RPDs. Direct milling method showed a higher accuracy than indirect milling method. However, in rapid prototyping, indirect method showed higher accuracy than direct method. Conclusion. The RPD frameworks fabricated using CAD-CAM technology showed a clinically acceptable level of accuracy regardless of manufacturing process or techniques. Consistent results have not been reported regarding the digital impression methods, which were intra oral scanning or laboratory scanning, and further studies are needed.

• Imaging Science in Dentistry
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• v.50 no.1
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• pp.15-22
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• 2020

Purpose: This study was conducted to objectively and subjectively compare the accuracy and reliability of 2-dimensional(2D) photography and 3-dimensional(3D) soft tissue imaging. Materials and Methods: Facial images of 50 volunteers(25 males, 25 females) were captured with a Nikon D800 2D camera (Nikon Corporation, Tokyo, Japan), 3D stereophotogrammetry (SPG), and laser scanning (LS). All subjects were imaged in a relaxed, closed-mouth position with a normal smile. The 2D images were then exported to Mirror^® Software (Canfield Scientific, Inc, NJ, USA) and the 3D images into Proplan CMF^® software (version 2.1, Materialise HQ, Leuven, Belgium) for further evaluation. For an objective evaluation, 2 observers identified soft tissue landmarks and performed linear measurements on subjects' faces (direct measurements) and both linear and angular measurements on all images(indirect measurements). For a qualitative analysis, 10 dental observers and an expert in facial imaging (subjective gold standard) completed a questionnaire regarding facial characteristics. The reliability of the quantitative data was evaluated using intraclass correlation coefficients, whereas the Fleiss kappa was calculated for qualitative data. Results: Linear and angular measurements carried out on 2D and 3D images showed excellent inter-observer and intra-observer reliability. The 2D photographs displayed the highest combined total error for linear measurements. SPG performed better than LS, with borderline significance (P=0.052). The qualitative assessment showed no significant differences among the 2D and 3D imaging modalities. Conclusion: SPG was found to a reliable and accurate tool for the morphological evaluation of soft tissue in comparison to 2D imaging and laser scanning.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.1
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• pp.61-70
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• 2017

In this case, the impression surface of the existing denture was scanned and was inverted three-dimensionally to express the residual ridge form. Implant planning was performed on the superimposed data of the CT with the scanned image of the denture with radiopaque markers attached. At the day of surgery, customized abutments fabricated in accordance with the form of the gingival margin were linked with fixtures and temporary restorations were set. In the process of fabricating the final prosthesis after the osseointegration of implant fixture, the intraoral scan images at abutment level were merged with images of the abutments scanned and stored before implant surgery. By fabricating the final prosthesis with the abutments obtained by merging can increase the marginal fitness of the final prosthesis and simplify the clinical process.

• Journal of Dental Rehabilitation and Applied Science
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• v.40 no.3
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• pp.125-134
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• 2024

Purpose: The aim of this study was to determine which scan range would provide the most accurate bite registration when performing a bite scan after scanning an upper and lower arch using an intraoral scanner. Materials and Methods: The occlusal contact points were recorded using articulating paper for 30 adults, and the results of various ranges of buccal bite scan were compared based on this. Buccal bite scan of 5 ranges (1st premolar to 2nd premolar, 1st premolar to 1st molar, 1st premolar to 2nd molar, 2nd premolar to 1st molar, and canines to another side canine of the maxillary teeth) was performed, and then the buccal bite scan file was used in a CAD program to confirm the occlusal area in the scan file through data editing and alignment, leaving the buccal area of the teeth. Afterwards, the degree of agreement between the occlusal contact points obtained from the articulating paper and the occlusal area obtained from the scan file was compared, and statistical analysis was performed using the homoscedastic T-test (α = 0.05). Results: The alignment success and alignment failure rates among each group were 77.23% and 40.85% in canine to another side canine, 68.23% and 28.89% in bilateral first premolar to second premolar, 63.76% and 29.97% in bilateral first premolar to first molar, 61.31% and 32.04% in bilateral first premolar to second molar, 67.55% and 27.46% in second premolar to first molar. The results of the anterior scan of both canines showed higher alignment success and failure rates compared to the scan results of all maxillary posterior teeth. In the alignment success rate, statistical significance was not found depending on the scan range of the posterior teeth, but in comparing the results of the posterior teeth and both canines, statistical significance was observed except for the scan results of the second premolar to the first molar. There was no statistical significance in the alignment failure rate depending on the scan range of the posterior teeth, and statistical significance was observed in the results of the posterior teeth and both canines. Conclusion: When taking a buccal bite scan, in the case of scanning the anterior teeth, more occlusal area appear than when scanning the posterior teeth, and in the case of scanning the posterior teeth, there is no significant difference in the bite registration depending on the scan range.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.228-238
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• 2020

In order to deliver fixed partial denture to a patient successfully, dentist must take into many considerations beforehand. Patient's occlusal pattern should be fully understood before delivering any type of prosthesis, whether it's canine guidance or group function occlusion. In order to do so, movement of mandible should be recorded precisely. Introduced by Meyers in 1933, functionally generated path technique (FGP) has been successfully used to record mandibular movement with various materials, such as wax, and utilize it in fabricating precise prosthesis. In the following cases, patients showed secondary caries or endodontic-periodontic lesion on maxillary molars. Root canal treatment and subgingival curettage were done for each patient. Since the long term prognosis of each tooth was questionable, lateral force should be minimized. In order to do so, FGP technique was used to record mandibular movements precisely. Instead of using conventional plaster impression, intra-oral scanning of wax tracing was done to fabricate prosthesis efficiently. After delivery of fixed partial denture, favorable outcome was obtained.