• 한국콘텐츠학회논문지
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• 제12권8호
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• pp.240-247
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• 2012

보철물이 구강 내 제 기능을 하기 위해 가장 중요한 요소 중 하나는 적합도이다. 본 연구의 목적은 그 동안 시도되지 않았던 광간섭단층영상기를 이용하여 비파괴적인 방법으로 적합도를 측정해보고, 측정된 값을 기존의 방법으로 측정된 값과 비교하여 보고자 한다. 실험을 위해 상악 우측 중절치가 지대치인 석고모형 10개를 제작하고 치과용 캐드캠으로 각각의 모형에 해당하는 지르코니아 코어를 10개 제작하였다. 시편 당 5부위 씩 광간섭단층영상기로 적합도를 측정하고, 같은 부위를 기존의 방법인 실리 복제본 기술로 측정하였다. 두 집단 간의 평균 값에 유의한 차이가 있는지 알아보기 위해 독립표본 t-검정을 실시하였다(${\alpha}$=0.05). 그 결과 측정된 두 집단 간의 평균 값에는 유의한 차이를 보이지 않았고(P>0.05), 이러한 결과로 미루어 볼 때 앞으로 광간섭단층영상기를 이용한 보철물의 적합도 측정이 가능할 것으로 사료된다.

• The Journal of Advanced Prosthodontics
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• 제7권3호
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• pp.199-206
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• 2015

PURPOSE. The present study investigated the influences of various gypsum materials on the precision of fit of CAD/CAM-fabricated prostheses and analyzed their correlation with surface roughness. MATERIALS AND METHODS. The master model of the mandibular right first molar was replicated, and four experimental groups based on two types of Type IV stone (GC Fujirock EP, Die keen) and two types of scannable stone (Aesthetic-Basegold, Everest Rock) were created to include a total of 40 specimens, 10 in each group. The surface roughness of the working models for the respective experimental groups was measured. Once the zirconia cores had been fabricated, the marginal and internal fits were measured with a digital microscope using the silicone replica technique. The mean and standard deviation of the respective points of measurement were computed and analyzed through the one-way ANOVA and Tukey's HSD test. The correlation between surface roughness and the precision of fit of the zirconia core was analyzed using the Pearson correlation analysis (${\alpha}$=.05). RESULTS. The zirconia cores fabricated from the scannable stone working models exhibited a superior precision of fit as compared to those fabricated from the Type IV stone working models. The correlation analysis results showed a clear positive correlation between surface roughness and the precision of fit of zirconia cores in all of the experimental groups (P<.05). CONCLUSION. The results confirmed that the surface roughness of dental working models has a decisive influence on the precision of fit of zirconia cores.

• 대한치과기공학회지
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• 제41권4호
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• pp.271-278
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• 2019

Purpose: To quantify the effect of the crystallization process on lithium disilicate ceramic crowns that are fabricated using a computer-aided design/computer-aided manufacturing(CAD/CAM) system, and to determine whether they are clinically acceptable by comparing values before and after the crystallization process. Methods: The maxillary first molar was selected as the abutment for the experiments. Ten working models were prepared. Marginal and internal gap of 4 groups of lithium disilicate crowns(n=10) fabricated with conventional method. Comparison was performed using the silicone replica technique and 3D superimposition analysis. The marginal and internal gaps of the restoration were measured before and after the crystallization process of this prosthesis. The average value of each part(the average of values measured before and after the crystallization) was statistically analyzed using paired t-test(α=0.05). Results: The results from the second phase of this research, which compared the average value of the gap between the marginal and internal fits of the lithium disilicate single crown before and after the crystallization process, indicated that the marginal gap was larger and the internal gap was smaller after the crystallization process, and this difference was statistically significant (P<0.05) in all the parts evaluated. Conclusion: While the shrinkage that occurs during crystallization does affect the marginal and internal fit of the prosthesis, it cannot be concluded to be a major effect because the resultant distortion was within the clinically acceptable range.

• 대한치과기공학회지
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• 제34권4호
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• pp.353-359
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• 2012

Purpose: The aim of this study measured and compared the marginal and internal fit of metal cores with two base metal alloy (Ni-Cr alloy(non-beryllium), Co-Cr alloy). Methods: Maxillary right first molar abutment fabricated by titanium was prepared for this study. Impressions(10ea) were made from titanium model, and study models were poured with improved dental stone. Wax cores of twenty were prepared for burn-out and casting. Ten wax cores cast Ni-Cr alloy(non-Be), and finally ten cast Co-Cr alloy. Marginal and internal fit of cores was evaluated using silicone replica technique and digital microscope(x160). The data were statistically analyzed with the independent samples t-test (${\alpha}$ <.05). Results: Mean(standard deviation, SD) marginal and internal fit total size of Ni-Cr alloy(non-Be) group was $73.3(14.4){\mu}m$ and of Co-Cr alloy group $65.6(17.4){\mu}m$. The marginal and internal fit total size of Ni-Cr alloy group(non-Be) was statistically significantly greater than that of Co-Cr alloy group (P=.004). Conclusion: Co-Cr alloy cores in this study had a better marginal fit than Ni-Cr alloy(non-Be) cores.

• 대한치과기공학회지
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• 제37권1호
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• pp.1-7
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• 2015

Purpose: The aim of this study was to evaluate the marginal and internal gap of wax copings fabricated from extraoral scanning with intraoral scanning. Methods: Fifteen study models(abutment of teeth 16) were made by PMMA. STL files of thirty abutment were prepared by intraoral scanning with extraoral scanning. Wax copings of thirty fabricated using CAD/CAM system. Marginal and internal gap of wax copings of thirty were measured by silicone replica technique and digital microscope(${\times}140$). Date were analyzed by using independent samples t-test. Results: Mean (SD) of two group were measured $55.61(27.42){\mu}m$ for totally gap of ES group and $60.67(33.14){\mu}m$ for totally gap of IS group. But marginal and internal gap of two group were not differences statistically significant(p>0.05). Conclusion: Evaluation of marginal and internal gap of two group showed that no differences statistically significant and clinically acceptable results.

• 대한치과기공학회지
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• 제39권4호
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• pp.235-242
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• 2017

Purpose: The aim of this study was to evaluate the marginal and internal gap of zirconia copings fabricated by CAD/CAM system and to research the effect of cement space on the fit of zirconia prosthesis. Methods: Zirconia copings were designed using 3shape software and then milled from presintered zirconia blocks by Kavo dental milling machine. The cement space was set at $0{\mu}m$ around the margins for all groups, and additional cement space appling 1 mm above the finish lines of tooth. The samples were classified into 4 groups according to the cement space setting(Cs-0, Cs-40, Cs-80, Cs-120). Replica technique used to investigate marginal and internal gap. The silicone film thickness was recorded using a optical microscope with image software analysis system at 75${\times}$magnification. The assessment performed on the six points in bucco-lingual and mesio-distal sections(4 groups, 10 copings per group, 12 measuring points per coping). The data were statistically analyzed with one-way ANOVA followed by pair-wise Tukey's post hoc tests(${\alpha}$<0.05). Results: Better marginal and internal fit values were exhibited by $80{\mu}m$ cement space. The results showed that different cement space values had statistically significant effect on the marginal and internal gap of zirconia copings(p<0.001). The gap of margin and axial wall area was smaller than that the gap of occlusal area in all groups(p<0.001). Conclusion : Effect of different cement spaces on the marginal and internal gap of zirconia copings.

• 대한치과기공학회지
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• 제38권3호
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• pp.111-117
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• 2016

Purpose: The present study was performed to investigate the effect of abutment inclined angle on the marginal fit of zirconia all-ceramic crown. Methods: The Ti abutments with 3 different inclined angle($2^{\circ}$, $4^{\circ}$ and $6^{\circ}$) were fabricated. The zirconia copings were fabricated for each abutment by using dental CAD/CAM system. The manufactured zirconia copings were duplicated through silicone replica technique, and a replicated specimen was sectioned in the center of bucco-lingual and mesio-distal axial to measure the marginal fit by using a stereo microscope. The results were analyzed using a one-way ANOVA with SPSS 22.0 for Windows(${\alpha}=0.05$). Results: On the bucco-lingual axial, marginal fit was the RL3($41.5{\pm}3.4{\mu}m$), RL2($44.3{\pm}4.3{\mu}m$) and RL1($47.5{\pm}5.7{\mu}m$), respectively. On the mesio-distal axial, marginal fit was the RL3($41.1{\pm}3.7{\mu}m$), RL2($45.7{\pm}5.3{\mu}m$) and RL1($46.2{\pm}4.5{\mu}m$), respectively. One-way ANOVA showed statistically significant difference between groups for marginal fit(p<0.05). Conclusion: For marginal fit of the abutments inclined angle, RL3 specimen was superior. The abutment inclined angle had influence on marginal fit of the zirconia copings. The marginal fit of each group were within clinically acceptable range.

• 대한치과기공학회지
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• 제41권3호
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• pp.187-193
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• 2019

Purpose: The purpose of this study was to compare two-dimensional fitness of the monolithic zirconia prosthesis by using different type of scanner. Methods: No. 26 abutment tooth of FDI system was selected for the study. Using the extraoral scanner and intraoral scanner, the abutment tooth was scanned 10 times and the scanned files were saved as STL files. CAD/CAM system was used to produce the monolithic zirconia prosthesis. marginal and internal gap of the monolithic zirconia prosthesis were measured by digital microscope(x160) and applied silicone replica technique was applied. t-test, a statistical software, was used to perform data analysis. Results: Marginal gap $mean{\pm}SD$ of the monolithic zirconia prosthesis was $33{\pm}7.5{\mu}m$ with extra oral scanner and $34.7{\pm}11.1{\mu}m$ with intraoral scanner. axial gap mean was $40.5{\pm}3.5{\mu}m$ with extra oral scanner and $44.6{\pm}11.6{\mu}m$ with intraoral scanner. occlusal gap mean was $110.1{\pm}25.4{\mu}m$ with extra oral scanner and $64{\pm}9.7{\mu}m$ with intraoral scanner. Conclusion: In this study, fabricating zirconia prosthesis with different type of scanner was clinically applicable.

• 한국산업융합학회 논문집
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• 제26권4_2호
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• pp.561-570
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• 2023

This study was to evaluate the effect of different rinsing times and methods on the accuracy of temporary prostheses fabricated by 3D printing method. Sixty temporary prostheses were fabricated with LCD types of 3D printer(Halot-Sky, Creality, Shenzhen, China) and divided into six groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5 and 10 min using three methods-hand washed, ultrasonic cleaning, and automated washing. All specimens were polymerized for 3 minutes under the same conditions. The marginal and internal gaps of specimens were examined using a replica technique. The light-body silicone thickness was measured at 6 reference points(Absolute marginal discrepancy, Marginal, Chamfer, Axial, Angle, and Occlusal gap). All measurements were performed by a stereomicroscope. Reference point images were taken at 100× magnification and then measured using an image analysis program. Statistical analysis was performed using Two-way ANOVA, One-way ANOVA, and the Kruskal-Wallis test (p = .05). The marginal and internal gaps were statistically different according to the rinsing methods and rinsing times(p < .001). In the rinsing time, the temporary prosthesis rinsed for 5 minutes group showed higher accuracy than 10 minutes group. In the rinsing method, the hand washing group showed higher accuracy than the automated washing group.

• 대한치위생과학회지
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• 제5권1호
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• pp.13-19
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• 2022

Background: In this study, zirconia copings were fabricated by setting clinically acceptable inner values for prostheses using computer-aided design/computer-aided manufacturing (CAD/CAM). The processed copings were evaluated for the marginal and internal fit of each abutment shape with a CAD program using the silicone replica technique. Methods A total of 20 copings was produced by selecting models commonly used in clinical practice. After injecting the sample, the minimum thickness, internal adhesion interval, and distance to the margin line were set to 0.5, 0.05, and 1.00 mm using a dental CAD program, respectively. It was measured using a 2D section function in a three-way program of the silicon replication technology. Although the positions and number of measurements of the anterior and posterior regions differed, nine parts of each pre-tube were designated and measured by referring to a previous study to compare the two samples. Results As a result, the average margin of the mesial, distal, and buccal (labial) surfaces was 59.90 ㎛ in the anterior region and 60.40 ㎛ in the posterior region. The mean axial wall margin was 67.25 ㎛ in the anterior region and 69.25 ㎛ in the posterior region. In occlusion, the anterior teeth (77.70 ㎛), posterior teeth (77.60 ㎛), and both anterior and posterior regions were within the clinically acceptable range. Conclusion The edge and inner fit of zirconia coping manufactured using the CAD/CAM system showed clinically applicable results. To reduce errors and increase accuracy, materials and machine errors that affect the manufacture of prosthetics should be investigated. Based on our results, the completeness of prosthetics could increase if the inner value and characteristics of the material are adjusted when applied in clinical practice.