도재 소성 과정에서의 고온이 지르코니아 코어의 변연적합도에 미치는 영향

김재홍 ( Jae Hong Kim ),김기백 ( Ki Baek Kim ) 한국치위생과학회 2013 치위생과학회지 Vol.13 No.2

본 연구는 치과에서 사용되는 심미 보철물 중에 하나인지르코니아 기반의 전부도재관 제작 시 지르코니아 코어 위에 상부 도재를 축성하고 소성하는 과정에서 발생되는 고온이 완성된 전부도재관의 변연적합도에 미치는 영향을 분석함으로써 임상적 허용이 가능한지 알아볼 뿐 아니라, 치과보철치료를 위한 치과의사, 치과위생사, 치과기공사의 보철물 선택 시 임상적 참고자료로 제공할 목적으로 수행되었다. 심미에 가장 많은 영향을 미치는 상악 중절치를 지대치로 선정하여 동일한 모형 10개 제작 후 각각의 지대치에 적합한 지르코니아 코어를 제작하였다. 제작된 코어의 변연적합도 측정 후 코어 위에 상부 도재를 축성하여 전부도재관을 완성한 뒤 2차 측정을 실시하였으며, 측정 후 비교 분석된 결과는 다음과 같다. 변연적합도는 지르코니아 코어 제작한 후 전부도재관으로 제작되는 과정에 따라 더 커졌으며, 통계적으로도 유의한 차이를 보였다(p<0.001). 그러나 전부도재관에서 총 80회 측정된 변연적합도의 값에서 임상적 허용 수치인 120 μm을 넘지 않는 결과를 보였으며, 이와 같은 결과를 토대로 지르코니아 코어 위에 상부 도재 소성 시 변연적합도가 커지긴 하나 임상적으로 허용이 가능하다는 결론을 도출하였다. One factor for successful prognosis of finished dental prosthesis is good marginal fit. The purpose of this study in vitro investigation was to compare the marginal fit of all-ceramic crown before and after porcelain veneering, to evaluate the influence of high temperature of the porcelain firing on the fit. For this experiment, model of abutment tooth of maxillary right central incisor was prepared. Ten working models were produced. Ten zirconia cores were made by dental computer aided design/computer aided manufacturing system. The marginal fit of specimens were examined using silicone replica technique. Silicone replicas were sectioned four times and were measured through a digital microscope (x160). Marginal fit is a distance connected between edge end part of specimen and abutment margin. Each specimens was measured twice, the first measurement was done prior to veneering porcelain firing, while the second measurement was done after the porcelain firing to evaluate this process. Statistical analyses were performed with paired t-test. Mean±SD marginal fit was 60.8±14.2 μm for zirconia core and 86.1±13.3 μm for all-ceramic crown. They were statistically significant differences (p<0.001). But all specimens showed a marginal fit where the gap widths ranged within the clinical recommendation (120 μm), all-ceramic crown production using the zirconia core was adequate.

치과용 3D 프린터를 활용해 제작된 레진 단일치관보철의 변연적합 평가

Ki-Baek Kim 대한치과기공학회 2022 대한치과기공학회지 Vol.44 No.4

Purpose: The purpose of this study is to evaluate the quality of dental fixed prostheses fab-ricated by 3DP (three-dimensional printing). Methods: Ten main models were prepared for the study. Ten specimens were printed by 3DP (3DP group). Ten specimens were fabricated by the lost wax technique and casting method to complete the control group (LWC group). The marginal fit was measured for 20 specimens. The measurement of marginal fit was performed using the silicon replica tech-nique. Finally, the marginal fit of 10 specimens from each group was calculated. An inde-pendent sample t-test was run to see if the calculated averages for the two groups were mutually significant (α=0.05). Results: According to the experimental results, the mean marginal fit of the 3DP group was 71.9 μm, and the LWC group was 55.3 μm. The means of the two groups were found to be significantly different (p<0.001) in the results of the independent sample t-test. Conclusion: The marginal fit of fixed dental prostheses produced by 3DP technology was examined with values greater than those fabricated by traditional technology. However, as it appeared to be a value within the range of clinically acceptable range recommended by nu-merous studies, it was determined that clinical application would be feasible.

In-vitro evaluation of marginal and internal fit of 3-unit monolithic zirconia restorations fabricated using digital scanning technologies

Çise Özal,Mutahhar Ulusoy 대한치과보철학회 2021 The Journal of Advanced Prosthodontics Vol.13 No.6

PURPOSE. This study aimed to compare the marginal and internal fit of 3-unit monolithic zirconia restorations that were designed by using the data obtained with the aid of intraoral and laboratory scanners. MATERIALS AND METHODS. For the fabrication of 3-unit monolithic zirconia restorations using impressions taken from the maxillary master cast, plaster cast was created and scanned in laboratory scanners (InEos X5 and D900L). The main cast was also scanned with different intraoral scanners (Omnicam [OMNI], Primescan [PS], Trios 3 [T3], Trios 4 [T4]) (n = 12 per group). Zirconia fixed partial dentures were virtually designed, produced from presintered block, and subsequently sintered. Marginal and internal discrepancy values (in μm) were measured by using silicone replica method under stereomicroscope. Data were statistically analyzed by using 1-way ANOVA and Kruskal Wallis tests (P <.05). RESULTS. In terms of marginal adaptation, the measurements on the canine tooth indicated better performance with intraoral scanners than those in laboratory scanners, but there was no difference among intraoral scanners (P <.05). In the premolar tooth, PS had the lowest marginal (86.9 ± 19.2 μm) and axial (92.4 ± 14.8 μm), and T4 had the lowest axio-occlusal (89.4 ± 15.6 μm) and occlusal (89.1 ± 13.9 μm) discrepancy value. In both canine and premolar teeth, the D900L was found to be the most marginally and internally inconsistent scanner. CONCLUSION. Within the limits of the study, marginal and internal discrepancy values were generally lower in intraoral scanners than in laboratory scanners. Marginal discrepancy values of scanners were clinically acceptable (< 120 μm), except D900L.

지대치 형태에 따른 지르코니아 코어의 변연 적합도

김기백 ( Ki Baek Kim ),김석환 ( Seok Hwan Kim ),김재홍 ( Jae Hong Kim ) 한국치위생과학회 2015 치위생과학회지 Vol.15 No.1

The present study investigated the influences of various abutment teeth shapes (maxillary right canine, pre-molar, molar) on the marginal adaptation of computer aided design/computer aided manufacturing-fabricated zirconia core. In vitro adaptation of zirconia cores manufactured by three different abutments were evaluated. Thirty zirconia cores were made per each models and the adaptation was evaluated through a silicone replica technique. The measurement of the adaptation was carried out using digital microscope. The mean and standard deviation of each reference point were analyzed using the one-way (ANOVA) and Tukey’s honestly significant difference tests (α=0.05). The overall marginal fits of the zirconia cores were as follows: canine: 47.59 μm, pre-molar: 43.74 μm, molar: 40.36 μm. They were no statistically significant differences between groups for adaptation (p>0.05). This confirmed that the type of abutment teeth used does not determine the precision of fit of zirconia core.

치과용 CAD/CAM 전용 세라믹기반 하이브리드 레진 수복물의 변연 적합 연구

정창섭,박종경,Jeong, Chang-Seop,Park, Jong-Kyoung 대한치과기공학회 2020 대한치과기공학회지 Vol.42 No.3

Purpose: This study aimed to assess and compare the marginal fit of ceramic-based hybrid resin restoration (HYB) and zirconia restoration (ZIR) for dental computer-aided design/computer-aided manufacturing systems. Methods: A stainless steel master model was produced. The impression was first made with silicone, and then stone working models were produced. A total of twenty restorations were fabricated with two different materials: ZIR and HYB. The silicone film thickness of the marginal gap was measured using a digital microscope; digital photos were taken at a magnification of ×160, and then analyzed using a measurement software. The values of the result were evaluated with the independent-sample t-test (α=0.05). All statistical analyses were performed with a statistical software. Results: The mean values for the marginal gap was 37.14±2.96 ㎛ for HYB, compared with 40.37±5.26 ㎛ for ZIR. No significant difference was found between ZIR and HYB (p=0.107). Conclusion: As a result, the marginal fit of the restoration fabricated using the hybrid resin was better than that of the restoration fabricated using zirconia. Also, the marginal fit of all groups was below the clinical acceptable range of 120 ㎛. Thus, HYB for dental CAD/CAM system in this study is expected to be suitable for clinical use in dentistry.

SLM 방식으로 제작한 도재관 금속하부구조물의 변연 및 내면 적합도 평가

배성령,이하빈,노미준,김지환 대한치과기공학회 2023 대한치과기공학회지 Vol.45 No.1

Purpose: To evaluate the marginal and internal fit of metal coping fabricated by a metal three-dimensional (3D) printer that uses selective laser melting (SLM). Methods: An extraoral scanner was used to scan a die of the prepared maxillary right first molar, and the coping was designed using computer-aided design software and saved as an stereo lithography (STL) file. Ten specimens were printed with an SLM-type metal 3D printer (SLM group), and 10 more specimens were fabricated by casting the castable patterns output generated by a digital light processing-type resin 3D printer (casting the 3D printed resin patterns [CRP] group). The fit was measured using the silicon replica technique, and 8 points (A to H) were set per specimen to measure the marginal (points A, H) and internal (points B~G) gaps. The differences among the groups were compared using the Mann-Whitney U-test (α=0.05). Results: The mean of marginal fit in the SLM group was 69.67±18.04 μm, while in the CRP group was 117.10±41.95 μm. The internal fit of the SLM group was 95.18±41.20 μm, and that of the CRP group was 86.35±32 μm. As a result of statistical analysis, there was a significant difference in marginal fit between the SLM and CRP groups (p<0.05); however, there was no significant difference in internal fit between the SLM group and the CRP group (p>0.05). Conclusion: The marginal and internal fit of SLM is within the clinically acceptable range, and it seems to be applicable in terms of fit.

Early complications and performance of 327 heat-pressed lithium disilicate crowns up to five years

Fabian Huettig,Ulf Peter Gehrke 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.3

PURPOSE The prospective follow-up aimed to assess the performance of lithium disilicate crowns and clinical reasons of adverse events compromising survival and quality. MATERIALS AND METHODS 58 patients were treated with 375 heat-pressed monolithic crowns, which were bonded with resin cement. Annual recalls up to five years included a complete dental examination as well as quality assessment using CDA-criteria. Any need for clinical intervention led to higher complication rate and any failure compromised the survival rate. Kaplan-Meier-method was applied to all crowns and a dataset containing one randomly selected crown from each patient. RESULTS Due to drop-outs, 45 patients (31 females, 14 males) with the average age of 43 years (range = 17–73) who had 327 crowns (176 anterior, 151 posterior; 203 upper jaw, 124 lower jaw) were observed and evaluated for between 4 and 51 months (median = 28). Observation revealed 4 chippings, 3 losses of retention, 3 fractures, 3 secondary caries, 1 endodontic problem, and 1 tooth fracture. Four crowns had to be removed. Survival and complication rate was estimated 98.2% and 5.4% at 24 months, and 96.8% and 7.1% at 48 months. The complication rate was significantly higher for root canal treated teeth (12%, P<.01) at 24 months. At the last observation, over 90% of all crowns showed excellent ratings (CDA-rating Alfa) for color, marginal fit, and caries. CONCLUSION Heat pressed lithium disilicate crowns showed an excellent performance. Besides a careful luting, dentists should be aware of patients' biological prerequisites (grade of caries, oral hygiene) to reach full success with these crowns

The use of definitive implant abutments for the fabrication of provisional crowns: a case series

Bilhan, Hakan,Geckili, Onur,Mumcu, Emre Korean Academy of Periodontology 2011 Journal of Periodontal & Implant Science Vol.41 No.5

Purpose: The anterior region is a challenge for most clinicians to achieve optimal esthetics with dental implants. The provisional crown is a key factor in the success of obtaining pink esthetics around restorations with single implants, by soft tissue and inter-proximal papilla shaping. Provisional abutments bring additional costs and make the treatment more expensive. Since one of the aims of the clinician is to reduce costs and find more economic ways to raise patient satisfaction, this paper describes a practical method for chair-side fabrication of non-occlusal loaded provisional crowns used by the authors for several years successfully. Methods: Twenty two patients (9 males, 13 females; mean age, 36,72 years) with one missing anterior tooth were treated by using the presented method. Metal definitive abutments instead of provisional abutments were used and provisional crowns were fabricated on the definitive abutments for all of the patients. The marginal fit was finished on a laboratory analogue and temporarily cemented to the abutments. The marginal adaptation of the crowns was evaluated radiographically. Results: The patients were all satisfied with the final appearance and no complications occurred until the implants were loaded with permanent restorations. Conclusions: The use of the definitive abutments for provisional crowns instead of provisional abutments reduces the costs and the same results can be obtained.

치과용 3D 프린터를 활용해 제작된 레진 단일치관보철의 변연적합 평가

김기백 대한치과기공학회 2022 대한치과기공학회지 Vol.44 No.3

Purpose: The purpose of this study is to evaluate the quality of dental fixed prostheses fabricated by 3DP (three-dimensional printing). Methods: Ten main models were prepared for the study. Ten specimens were printed by 3DP (3DP group). Ten specimens were fabricated by the lost wax technique and casting method to complete the control group (LWC group). The marginal fit was measured for 20 specimens. The measurement of marginal fit was performed using the silicon replica technique. Finally, the marginal fit of 10 specimens from each group was calculated. An independent sample t-test was run to see if the calculated averages for the two groups were mutually significant (α=0.05). Results: According to the experimental results, the mean marginal fit of the 3DP group was 71.9 μm, and the LWC group was 55.3 μm. The means of the two groups were found to be significantly different (p<0.001) in the results of the independent sample t-test. Conclusion: The marginal fit of fixed dental prostheses produced by 3DP technology was examined with values greater than those fabricated by traditional technology. However, as it appeared to be a value within the range of clinically acceptable range recommended by numerous studies, it was determined that clinical application would be feasible.

Marginal and internal fit of 3D printed provisional crowns according to build directions

Ryu, Ji-Eun,Kim, Yu-Lee,Kong, Hyun-Jun,Chang, Hoon-Sang,Jung, Ji-Hye The Korean Academy of Prosthodonitics 2020 The Journal of Advanced Prosthodontics Vol.12 No.4

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°.