• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권2호
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• pp.94-99
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• 2008

The replica of silicone mold which can produce the test samples and the market-displayable products without making expensive metallic patterns is advantageous because it incurs less cost than the ordinary method that manufactures the products from the metallic patterns. However, the production of the products using silicone mold should require a technician with professional knowledge about the metallic patterns every time. Thus we tried to judge whether a forming analysis software for iron molding can be applied to silicon molding in this paper. In other words, this paper suggests a method to use a computer simulator from the designing step of the silicone mold, which is the most important part in making replica using simple silicone molds to the step of pouring the cast. The paper shows that if the know-how of a professional worker is provided in advance, an amateur worker can easily produce silicone molds of the best quality, the defective rate of the products will be decreased, and the replica will have a more complete status. By doing so, we suggested a possibility for reducing the delivery time at the production sites and for improving the product quality.

• The Journal of Advanced Prosthodontics
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• 제9권5호
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• pp.358-363
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• 2017

PURPOSE. The purpose of this study was to evaluate the reliability of computer-aided replica technique (CART) by calculating its agreement with the replica technique (RT), using statistical agreement analysis. MATERIALS AND METHODS. A prepared metal die and a metal crown were fabricated. The gap between the restoration and abutment was replicated using silicone indicator paste (n = 25). Gap measurements differed in the control (RT) and experimental (CART) groups. In the RT group, the silicone replica was manually sectioned, and the marginal and occlusal gaps were measured using a microscope. In the CART group, the gap was digitized using optical scanning and image superimposition, and the gaps were measured using a software program. The agreement between the measurement techniques was evaluated by using the 95% Bland-Altman limits of agreement and concordance correlation coefficients (CCC). The least acceptable CCC was 0.90. RESULTS. The RT and CART groups showed linear association, with a strong positive correlation in gap measurements, but without significant differences. The 95% limits of agreement between the paired gap measurements were 3.84% and 7.08% of the mean. The lower 95% confidence limits of CCC were 0.9676 and 0.9188 for the marginal and occlusal gap measurements, respectively, and the values were greater than the allowed limit. CONCLUSION. The CART is a reliable digital approach for evaluating the fit accuracy of fixed dental prostheses.

• The Journal of Advanced Prosthodontics
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• 제9권3호
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• pp.159-169
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• 2017

PURPOSE. The purposes of this study were to evaluate the marginal and internal gaps, and the potential clinical applications of three different methods of dental prostheses fabrication, and to compare the prostheses prepared using the silicone replica technique (SRT) and those prepared using the three-dimensional superimposition analysis (3DSA). MATERIALS AND METHODS. Five Pekkton, lithium disilicate, and zirconia crowns were each manufactured and tested using both the SRT and the two-dimensional section of the 3DSA. The data were analyzed with the nonparametric version of a two-way analysis of variance using rank-transformed values and the Tukey's post-hoc test (${\alpha}=.05$). RESULTS. Significant differences were observed between the fabrication methods in the marginal gap (P < .010), deep chamfer (P < .001), axial wall (P < .001), and occlusal area (P < .001). A significant difference in the occlusal area was found between the two measurement methods (P < .030), whereas no significant differences were found in the marginal gap (P > .350), deep chamfer (P > .719), and axial wall (P > .150). As the 3DSA method is three-dimensional, it allows for the measurement of arbitrary points. CONCLUSION. All of the three fabrication methods are valid for measuring clinical objectives because they produced prostheses within the clinically acceptable range. Furthermore, a three-dimensional superimposition analysis verification method such as the silicone replica technique is also applicable in clinical settings.

• The Journal of Advanced Prosthodontics
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• 제12권4호
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• pp.225-232
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• 2020

PURPOSE. This study aimed to fabricate provisional crowns at varying build directions using the digital light processing (DLP)-based 3D printing and evaluate the marginal and internal fit of the provisional crowns using the silicone replica technique (SRT). MATERIALS AND METHODS. The prepared resin tooth was scanned and a single crown was designed using computer-aided design (CAD) software. Provisional crowns were printed using a DLP-based 3D printer at 6 directions (120°, 135°, 150°, 180°, 210°, 225°) with 10 crowns in each direction. In total, sixty crowns were printed. To measure the marginal and internal fit, a silicone replica was fabricated and the thickness of the silicone impression material was measured using a digital microscope. Sixteen reference points were set and divided into the following 4 groups: marginal gap (MG), cervical gap (CG), axial gap (AG), and occlusal gap (OG). The measurements were statistically analyzed using one-way ANOVA and Dunnett T3. RESULTS. MG, CG, and OG were significantly different by build angle groups (P<.05). The MG and CG were significantly larger in the 120° group than in other groups. OG was the smallest in the 150° and 180° and the largest in the 120° and 135° groups. CONCLUSION. The marginal and internal fit of the 3D-printed provisional crowns can vary depending on the build angle and the best fit was achieved with build angles of 150° and 180°.

• 대한치과기공학회지
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• 제42권1호
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• pp.9-16
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• 2020

Purpose: The purpose of this study was to compare the marginal and internal fit of lithium disilicate ceramic inlay produced by heat pressing that inlay pattern made by subtractive manufacturing and additive manufacturing method. Methods: A mandibular lower first molar that mesial occlusal cavity (MO cavity) die was prepared. After fabricating an epoxy resin model using a silicone impression material, epoxy resin die was scanned with a dental model scanner to design an MO cavity inlay. The designed STL pile was used to fabricate wax patterns and resin patterns, and then lithium disilicate ceramic inlays were fabricated using hot-press method. For the measurement of the marginal and internal gap of the lithium disilicate, silicone replica method was applied, and gap was measured through an optical microscope (x 80). Data were tested for significant differences using the Mann-Whitney Utest. Results: The marginal fit was 103.56±9.92㎛ in the MIL-IN group and 81.57±9.33㎛ in the SLA-IN group, with a significant difference found between the two groups (p<0.05). The internal fit was 120.99±17.52㎛ in the MIL-IN group and 99.18±6.65㎛ in the SLA-IN group, with a significant difference found between the two groups (p<0.05). Conclusion: It is clinically more appropriate to apply the additive manufacturing than subtractive manufacturing method in producing lithium disilicate inlay using CAD/CAM system.

• 치위생과학회지
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• 제12권6호
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• pp.566-571
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• 2012

제한된 조건 하에서 수행된 본 연구에서는 다음과 같은 결론을 얻었다. 1. 치형과 고정성 보철물을 근 원심 방향의 단면에 8지점을 선정한 후 서로 다른 두 가지 방식으로 적합도를 측정하여 비교한 결과 8지점 모두에서 유의한 차이를 보이지 않았다(p<0.05). 2. 8지점을 변연부, 경사부, 축벽부, 교합면으로 분류하여 비교한 결과에서도 역시 두 측정 방법 간에 유의한 차이를 보이지 않았다(p<0.05). 이와 같은 결과를 바탕으로 실리콘 복제본 기술을 이용하여 적합도를 측정하는 것이 치형과 고정성 보철물을 직접 절단하여 단면을 측정하는 것만큼 정확하다는 결론을 얻었다. 따라서 고정성 보철물의 적합도 측정 시 비 파괴적인 방법인 실리콘 복제본 기술을 이용한다면 치형과 고정성 보철물 모두 파괴하지 않고 측정이 가능할 것으로 사료된다.

• 한국산학기술학회논문지
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• 제18권9호
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• pp.244-250
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• 2017

보철물의 완성도를 평가할 수 있는 요소는 여러 가지가 있으나, 그 중 가장 중요한 하나는 보철물의 적합도이다. 합금은 기계적, 물리적 성질 그리고 연마성 개선을 위해 연화열처리나 경화열처리 과정을 거치는데, 이때의 열처리 방법이 Ni-Cr 합금 core의 변연 및 내면 간격에 어떠한 영향을 미치는지 알아보고자 한다. 실험을 위해 하악 좌측 대구치가 지대치인 석고 모형 30개를 제작하고 dipping법을 이용하여, 3 group(A, B, C)으로 나누어 group당 10개, 총 30개의 Ni-Cr 합금 core를 제작 하였다. 이들을 열처리를 하지 않은 것과 연화, 경화 열처리 방법으로 열처리함에 따라 적합도를 silicone replica technique을 이용하여 측정하였다. 세 집단 간의 평균값에 유의한 차이가 있는지 알아보기 해 독립표본 t-검정으로 분석하였다(${\alpha}=0.05$). 실험 결과 변연 부위(1, 6)에서는 통계적으로 유의한 차이를 보였으나(p<0.05), 나머지 내면 부위(2, 3, 4, 5)에서는 유의한 차이를 보이지 않았다(p>0.05). 이러한 결과로 미루어 볼 때 Ni-Cr 합금은 열처리를 하지 않는 것이 적합도 측면에서 나을 것으로 사료된다. 이에 추가적인 임상적용 연구를 통해 더욱 심도 있는 평가되어야 할 것으로 판단된다.

• 대한치과기공학회지
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• 제37권4호
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• pp.229-234
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• 2015

Purpose: The purpose of this study was to analysis the internal fitness of single crown fabricated by additive method technique. Methods: Study models were fabricated. Ten crowns were manufactured by additive method technique (AM group) and another ten crowns using conventional method were manufactured (CM group). The internal fitness of specimens were measured using silicone replica technique. Silicone replicas were sectioned one times (direction: from mesial to distal). The internal fitness were evaluated using by digital microscope. Statistical analyses were performed with independent samples t-test. (${\alpha}=0.05$). Results: Mean(SD) of all internal fitness were $92.1(20.0){\mu}m$ for AM group and $69.7(12.3){\mu}m$ for CM group. Two groups were statistically significant differences (p<0.001). Conclusion: All internal gaps of AM group were ranged within the clinical recommendation ($120{\ss}{\neq}$).

• 대한치과기공학회지
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• 제38권3호
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• pp.185-191
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• 2016

Purpose: The purpose of this study were to evaluate the quality of dental prostheses printed by 3-dimensional printing system. Methods: Mater model was prepared and ten study models were fabricated. Ten single crowns were printed by 3D-printing system(Resin group) and another ten single crowns using casting method were manufactured(Metal group). The marginal adaptation of single crowns were measured using by silicone replica technique. Silicone replicas were sectioned four times. The marginal adaptations were evaluated using by digital microscope. Statistical analyses were performed with Mann-Whitney test(${\alpha}=0.05$). Results: $Mean{\pm}standard$ deviations of all marginal adaptations were $92.1(20.0){\mu}m$ for Metal group and $69.7(12.3){\mu}m$ for Resin group. Two groups were no statistically significant differences(p>0.05). Conclusion: Marginal adaptation of single crowns printed by 3D-printing system were ranged within the clinical recommendation.

• 대한치과의사협회지
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• 제56권7호
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• pp.366-374
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• 2018

Purpose : The purpose of this study was to compare the marginal fit of monolithic zirconia restorations fabricated form the conventional and the digital impression technique. Materials and methods : Ten patients were restored with monolithic zirconia restorations fabricated from the digital and the conventional impression technique. Before definitive insertion, silicone replicas were produced from all twenty crowns. The silicone replicas were cut in three sections; each section was evaluated at two points. The measurement was carried out by using a measuring microscope (Olympus BX 51) and I-Solution. Data from the silicone replica scores were analyzed by Shapiro-Wilk test for normal distribution and the t-test for equality of two population's mean. All tests were performed with ${\alpha}-level$ of 0.05. Results : The average marginal gaps of monolithic zirconia restorations were $133.81{\pm}36.46{\mu}m$ for the conventional impression technique, $90.07{\pm}9.47{\mu}m$ for the digital impression technique. No statistical differences were found between the two impression techniques Conclusion : Both prostheses presented clinically acceptable results with comparing the marginal fit.