• 대한치과보철학회지
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• 제45권3호
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• pp.354-361
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• 2007

Statement of Problems. The precision of fit between the bearing surfaces of implant abutments and the prosthesis framework has been considered fundamental to implant prosthodontic protocol. Purpose. The study aimed to investigate the effect of laboratory procedure on the dimensional accuracy of cast implant bars. Material and methods Thirty implant bars were fabricated on a metal master model. The gap distances were measured at the right implant abutment replica-gold cylinder interface after casting procedure. The bar length data of precasting and postcasting state were collected and analyzed. Results. The mean gap distance found after casting was $106.3{\mu}m$ for buccal side, $122.1{\mu}m$ for distal side and $117.1{\mu}m$ for the lingual side. The mean bar length was $17964.7{\mu}m$ at precasting measurement, $17891.6{\mu}m$ at postcasting measurement. The mean change of bar length was $-73.1{\mu}m$. Conclusion. Even though the techniques used in this study strictly followed the guidelines established in the literature, the 30 cast implant bars evaluated all yielded gap distances that were beyond acceptable accuracy. There was a statistically significant difference between precasting and postcasting bar length (P<0.01). There was a decreasing tendency in bar length after casting procedure. It was necessary to correct this dimensional change from laboratory procedure by some corrective methods.

• 대한치과의료관리학회지
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• 제10권1호
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• pp.84-92
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• 2022

Impression taking is one of the most frequently performed tasks within the legal scope of dental hygienists. This study aims to compare traditional impression and digital impression taking in various aspects with dental hygienists who have experience using digital intraoral scanners. A total of 61 subjects were included in this analysis. Traditional and digital impression taking were compared, and the perception of intraoral scanners was classified into four factors through exploratory factor analysis. After a normality test of the main variables was performed, a non-parametric test was performed. In terms of the adequacy of the size of the tool inserted into the oral cavity, traditional impression taking was more positive, and there was no significant difference in the precision of impression taking, fit of the prosthesis, and time efficiency. In contrast, the digital intraoral scanner was positive in terms of reducing nausea. In the comparison between the items of the digital intraoral scanner, relatively low satisfaction was shown in terms of convenience of use. This study compared traditional impression taking based on the experience of dental hygienists using oral scanners. It is hoped that this will be one step closer to universalization. In addition, appropriate training on how to use them should be provided.

• 대한치과기공학회지
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• 제41권1호
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• pp.21-27
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• 2019

Purpose: To evaluate 2D and 3D of occulsal, mesial-occlusal and mesial-occlusal-distal cavity of composite resin inlay. Methods: Abutment tooth 16, 36 of FDI system was selected for the study. Inlay prostheses classified as occlusal cavity (OC group), mesial-occlusal (MOC) and mesial-occlusal-distal cavity (MODC) were prepared using composite resin. Composite resin was injected with composite resin in prepared tooth cavity and then photopolymerized with UV light. Additional thermal polymerization was performed. Marginal gap of composite resin inlays were measured by digital microscope(x160) with silicone replica technique. The data was analyzed from statistical software for Kruskal-Wallis test (${\alpha}=0.05$). 3-dimensional analysis was analyzed through superimposition method. Results: The smallest 2D marginal fit measure of the three groups was $47.0{\pm}21.6{\mu}m$ in the MOC group. The largest 2D marginal was $69.1{\pm}33.8{\mu}m$ in the MODC group. In the trueness of the three groups, the most accurate figure was $14.4{\pm}2.3{\mu}m$ for the MODC group. In Precision, the most accurate figure was $14.5{\pm}4.3{\mu}m$ for the MODC group. Conclusion : In this study, 2D marginal fit of OC, MOC, and MODC cavities fabricated with composite resin was applicable to all clinical applications. In the 3D inner surface accuracy evaluation, the MODC group showed the accuracy results.

• 구강회복응용과학지
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• 제39권3호
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• pp.176-185
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• 2023

조절성 교합기에 모형을 부착하기 위하여 안궁이전이 필요하다. 아날로그 안궁이전에서는 장비의 정확도와 작업자의 숙련도가 모형 부착 결과에 영향을 미칠 가능성이 있다. 더불어 편차가 큰 방법으로 부착된 작업 모형에서는 정확한 치과 보철물의 제작이 어려우므로, 아날로그 안궁이전으로 부착된 작업 모형의 위치 편차를 파악하는 것이 중요하다. 본 증례에서는 아날로그 안궁이전으로 부착된 상악 모형의 위치와 cone beam computed tomography 데이터를 기반으로 위치된 상악 모형의 위치를 거리 편차와 교합 평면의 각도 편차를 평가하였다. 이를 토대로 아날로그 안궁이전으로 부착된 상악 모형의 편차를 보고하였다. 아날로그 안궁이전 방법은 3 - 16 mm의 선형 편차와 5 - 7도의 교합평면 각도 편차를 가지는 상악 모형의 부착 결과를 나타내었다. 아날로그 안궁이전은 환자별로 위치 편차가 다를 수 있음을 확인했으며, 치과 보철물 제작에서의 부정확성을 초래할 가능성이 있다. 이러한 결과는 임상에서 아날로그 안궁이전 방법이 상악 모형을 부착하는 과정에서 큰 편차가 있을 수 있음을 나타내었기에 이를 보고하는 바이다.