• 대한치과보철학회지
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• 제52권3호
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• pp.246-251
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• 2014

CAD/CAM을 이용하여 보철물을 제작할 경우 교합 접촉점의 위치, 면적, 형태를 원하는 대로 조절할 수 있으므로 보다 기능적인 교합의 부여가 가능하다. 또한 전통적인 Casting 기법을 이용한 주조금속 보철물이나, Porcelain의 축성을 통해 제작된 보철물에 비하여 제작과정 중의 오차가 감소하여 우수한 교합 정확도를 얻을 수 있을 것으로 기대되고 있다. 그리고 최근 소개되고 있는 CAD/CAM system에는 가상 교합기 기능이 추가되어 단일 수복물의 설계에서도 상악에 대한 하악의 운동을 재현함으로써 폐구 운동 뿐만 아니라 전/측방 운동시의 교합간섭을 고려할 수 있게 되었다. 그 동안 zirconia를 이용한 보철물의 변연 및 내면 적합도에 대한 연구는 많이 이루어졌으나 CAD/CAM을 이용해 설계된 zirconia crown의 교합 적합도에 대한 연구는 많이 이루어지지 않았다. 따라서 본 증례에서는 총 5명의 환자에서 CAD/CAM을 이용하여 제작된 7개의 지르코니아 크라운을 대상으로, 처음 설계된 zirconia crown의 교합 접촉점과 조정과정을 거쳐 구강 내 시적 후에 제작된 모델을 스캔하여 획득된 교합 접촉점을 비교하여 보철물의 정확도를 평가하고 교합조정의 양상을 파악해 보고자 하였다. 지르코니아 크라운에서 이루어진 교합조정은 대부분 기능교두 및 사면부위에서 이루어졌으며 15 - $60{\mu}m$의 분포를 보였다. CAD/CAM을 이용하여 제작된 지르코니아 크라운에서 어느정도의 교합조정은 불가피한 과정이며 이에 따른 물성저하를 보상하기 위한 추가적인 과정이 필요할 것이다.

• The Journal of Advanced Prosthodontics
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• 제7권6호
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• pp.454-459
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• 2015

PURPOSE. To determine whether the fracture strengths and failure types differed between metal and zirconia frameworks veneered with pressable or layering ceramics. MATERIALS AND METHODS. A phantom molar tooth was prepared and duplicated in 40 cobalt-chromium abutments. Twenty metal (IPS d.SIGN 15, Ivoclar, Vivadent, Schaan, Liechtenstein) and 20 zirconia (IPS e.max ZirCAD, Ivoclar) frameworks were fabricated on the abutments. Each framework group was randomly divided into 2 subgroups according to the veneering material: pressable and layering ceramics (n=10). Forty molar crowns were fabricated, cemented onto the corresponding abutments and then thermocycled ($5-55^{\circ}C$, 10,000 cycles). A load was applied in a universal testing machine until a fracture occurred on the crowns. In addition, failure types were examined using a stereomicroscope. Fracture load data were analyzed using one-way ANOVA and Tukey HSD post-hoc tests at a significance level of 0.05. RESULTS. The highest strength value was seen in metal-pressable (MP) group, whereas zirconia-pressable (ZP) group exhibited the lowest one. Moreover, group MP showed significantly higher fracture loads than group ZP (P=.015) and zirconia-layering (ZL) (P=.038) group. No significant difference in fracture strength was detected between groups MP and ML, and groups ZP and ZL (P>.05). Predominant fracture types were cohesive for metal groups and adhesive for zirconia groups. CONCLUSION. Fracture strength of a restoration with a metal or a zirconia framework was independent of the veneering techniques. However, the pressing technique over metal frameworks resisted significantly higher fracture loads than zirconia frameworks.

• 대한치과기공학회지
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• 제31권2호
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• pp.45-52
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• 2009

Esthetic restorations have been widely used in dental practice, although many studies have focused on the development and improvement of all ceramic restorations. The success of esthetic restorations depends primarily on an optimal bond strength between various veneered ceramics and core materials for esthetic restorations. The purpose of this study was to compare the shear bond strength between various veneered ceramics and core materials for esthetic restorations. 30 metal cores and 20 zirconia cores were fabricated and divided into five groups according to veneered ceramic materials such as Creation porcelain powder, Cercon Ceram Kiss, and IPS e.max ZirPress. Thirty spacimens were prepared using Creation porcelain powder, veneered 3mm height and 3mm in diameter, over the metal cores (n=10). Twenty specimens were prepared using Cercon Ceram Kiss and Zirpress, veneered 3mm height and 3mm in diameter, over the zirconia cores (n=10). The shear bond strength test was performed in a universal testing machine with a crosshead speed of 1mm/min. Ultimate shear bond strength data were analyzed with One-way ANOVA and the Scheffe's test (p=.05). Within the limits of this study, the following conclusions were drawn: The mean shear bond strengths (MPa) were: 18.44 for Uni metal VH/Creation (NCUC); 18.72 for Heraenium/Creation (NCHC); 16.23 for Wirobond C/Creation (NCWC); 13.88 for Zirconia core/$110{\mu}m$ $Al_2O_3$ sandblasting/Cercon Ceram Kiss (ZS110P); 14.61 for Zirconia core/No surface treatment/IPS e.max ZirPress (ZNTH). The mean shear bond strength for NCUC (Uni metal VH/Creation), NCHC (Heraenium/Creation) and NCWC (Wirobond C/Creation) were significantly superior to ZS110P (Zirconia core/$110{\mu}m$ $Al_2O_3$ sandblasting/Cercon Ceram Kiss) and ZNTH(Zirconia core/No surface treatment/IPS e.max ZirPress) (p<0.05).

• 대한치과기공학회지
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• 제34권2호
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• pp.95-103
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• 2012

Purpose: Fracture strength of all-ceramic 3-unit fixed partial dentures manufactured by CAD/CAM and copy-milling systems were evaluated. Methods: Zirconia cores were made by milling the pre-sintered zirconia block by CAD/CAM or copy milling method followed by subsequent sintering. By building-up the corresponding porcelains on the core, all-ceramic bridges were fabricated, and those were evaluated in comparison with PFM fixed partial denture. Results: During the flexural test of the 3-unit PFM bridge, the porcelain started to chip or break at 507.28(${\pm}62.82$)kgf and the metal framework did not break until the maximum load level of 800kgf which was set in the testing instrument of this study. However, among all-ceramic restoration test groups, Everest(EV) group showed a peeling off or breakage of the porcelain from 365.64(${\pm}64.96$)kgf and the core was broken at 491.77(${\pm}55.62$)kgf. Those values of Zirkonzahn(ZR) were 431.03(${\pm}58.47$)kgf and 602.74(${\pm}48.44$)kgf, respectively. The break strength of the porcelain of PFM(PM) group was significantly higher than that of EV (p<0.05) group and there was no significant difference when comparing to that of ZR (p>0.05). ZR group showed higher break strength than that of EV group however there was no significant difference (p>0.05). The break strength of cores were in the increasing order of EV < ZR < PM (p<0.05). Conclusion: We could find that even though the PM group fractured at much higher value than all-ceramic cores, the breakage values of the porcelain of PM group with crack formation or delamination, which will be regarded as clinical failure, was significantly higher than that of EV group and not significantly higher than that of ZR group at p-values of 0.05. The break strength of ZR group was higher than that of EV group at an insignificant level(p>0.05).

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.424-432
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• 1998

To get a satisfactory result in the composite resin restorations, it is necessary to choose correct shade. At present, most of the commercial composite resins are based on the Vita Lumin shade guide or Bioform shade guide, but color differences might be expected even using the same shade in various materials. In this study, five kinds of light-cured composite resins with A2 and B3 shade were used to measure and compare the color each other while one porcelain served as a control. All composite resins (Spectrum TPH (SP), VeridonFil- Photo (VE), Z100 (Z100), Charisma (CH), Prodigy (PRO)) were filled in to the metal mold (12 mm diameter, 2 mm depth), followed by compression, polymerization and polishing with wet sandpaper. The specimens of porcelain were fabricated by using the refractory mold for porcelain. After 24 hours, the specimens were placed on the spectrocolorimeter and spectral reflectance were measured under CIE illuminant D65. After measuring the values of $L^*$, $a^*$, $b^*$ and ${\Delta}E^*$, following results were obtained; 1. The $L^*$, $a^*$ and $b^*$ values of both shade of porcelain specimens showed significantly higher than those of resin specimens(p<0.05). 2. In comparing the resin specimens of the A2 shade, differences were significant except $L^*$ values of SP-CH and PRO-VE, $a^*$ values of the VE-SP and $b^*$ values of the VE-Z100 and SP-PRO(p<0.05), 3. In comparing the resin specimens of the B3 shade, differences were significant except $L^*$ values of PRO-SP, $a^*$ values of the SP-PRO and Z100-VE and b* values of the PRO-SP(p<0.05). 4. In comparing the resin specimens of the A2 shade, color differences between materials (${\Delta}E^*$) showed the lowest value of 1.66, and the highest was 5.16. ${\Delta}E^*$ values of the materials of VE-PRO, CH-PRO, SP-PRO, SP-Z100 and SP-CH were lower than 3.3. 5. In comparing the resin specimens of the B3 shade, the lowest value of the ${\Delta}E^*$ was 0.57 and the highest was 5.92. ${\Delta}E^*$ values of Z100-CH and SP-PRO were lower than 3.3. The present study revealed there was perceptible color difference between materials even if they have the same designated shade based on Vita shade guide. The results of the present study suggested that it would be necessary to establish the reproducible and constant color specification system for an esthetic restoration.

• 대한치과재료학회지
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• 제44권3호
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• pp.207-216
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• 2017

금속-세라믹용 수복물에서 하부 구조물 제작에 사용되는 합금 중 하나인 Pd-Cu-Ga-Zn계 합금은 비교적 최근에 개발된 합금인 이유로 인해 도재 용착을 위한 소성 과정을 거치면서 합금에서 일어날 수 있는 경도 변화가 아직 밝혀지지 않았다. 그러나 이와 조성이 유사한 Pd-Cu-Ga-In-Au계 금속-세라믹용 합금의 경우 모의 소성 과정에서 경도가 하강한 것으로 밝혀져 있다. 따라서 Pd-Cu-Ga-Zn계 합금 또한 소성 과정 중에 합금의 연화가 일어날 것으로 예상되었으며 금속-세라믹용 Pd-Cu-Ga-Zn계 합금의 모의 소성 시 냉각 속도가 석출 경화에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. 냉각 속도가 빠른 경우(Stage 0) 매 소성 단계에서 합금의 경도가 상승하였고, 최종 경도 값도 높게 유지되었다. 냉각 속도가 느린 경우(Stage 3) 소성 첫 단계에서는 경도가 가장 높았지만, 소성 완료 후 합금의 최종 경도는 더 낮아졌다. 매 소성 단계에서 Stage 0으로 냉각한 시편에서 소성 과정 동안 경도가 상승한 원인은 석출 경화에 기인하였다. 주조 후 매 소성 단계에서 Stage 3의 냉각 속도로 냉각한 시편에서 소성 과정 동안 경도가 하강한 원인은 기지와 판상형 석출물 내부에 생성된 점 모양의 석출물의 조대화에 기인하였다. 기지와 판상형 석출물은 CsCl-type의 $Pd_2(Cu,Ga,Zn)$ 상이며, 입자형 구조는 Cu, Ga, Zn을 고용한 면심입방(face-centered cubic) 구조의 Pd-rich ${\alpha}$ 상이었다. $1,010^{\circ}C$에서 산화처리 한 시편을 더 낮은 온도에서 여러 단계로 소성함에 따라 Pd-rich ${\alpha}$ 상으로 이루어진 입자에 고용되어 있던 Cu, Ga, Zn이 Pd와 함께 석출되어 Pd-rich ${\alpha}^{\prime}$ 입자와 $Pd_2(Cu,Ga,Zn)$으로 이루어진 ${\beta}^{\prime}$ 석출 상으로 상 분리가 진행되었다. 이상으로부터 Pd-Cu-Ga-Zn계 합금은 모의 소성 시 냉각 속도를 빠르게 함으로써 최종 보철물의 내구성을 향상시킬 수 있다고 생각되었다.

• 대한치과기공학회지
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• 제33권2호
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• pp.121-128
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• 2011

Purpose: The purpose of this study is to investigate the level of each metal in non-precious metal alloys dental casting, still used even banned for use and trade by the law, for oral health. Methods: Two kinds of metal alloys were analyzed. One was Ticonium 100 for removable prosthesis and the other was Rexillium V for dental porcelain. Two samples of each metal alloy were made in 0.5g, 1.0g, and 1.5g. Total number of samples were 12. Two kinds of lactic acid Solution, pH7 and pH4.6, were injected into each samples. After injection, each samples had been for 21days ${\pm}$ 1 hour in the water tank of which temperature was $37^{\circ}C$. The level of metal was measured in each sample by inductively couplled plasma-atomic emission spectrometer. Results: In both metal alloys, metals, chrome, nickel, beryllium, and molybdenum, were founded. In Ticonium 1000, the highest level of nickel was 2.531ppm in 1.5g pH4.6 sample while the highest level of nickel was 4.062ppm in 1.5g pH4.6 sample of Rexillium V. In chemical composition of these methal alloys, chrome(14~17%) was much more than beryllium(1.95~1.99%) and molybdenum(5.0~9.0%) but berllium and molybdenum were founded more than chrome in samples. Therefore, chrome showed better anti-corrosion than other metal alloys. In both metal alloys, more metals were founded in higher pH level and more mass. Levels of chrome was significantly different in samples of both metal alloys in each pH level(p<0.05). Levels of nickels was significantly different in samples of both metal alloys in each pH level(p<0.05). Conclusion: For oral health, further studies are needed in nickel-chrome metal alloy and cobalt metal alloy of non-beryllium in addittion to beryllium metal alloy and also long-term studies needed in various period and other non-percious metal alloys for dental casting.

• 구강회복응용과학지
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• 제16권2호
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• pp.113-122
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• 2000

The reinforced composte resin as the esthetic operative material continuously has been studied because the porcelain fused metal prosthesis is widely used for its excellent esthetics, rigidity and marginal integrity, but it has low fracture resistance against the tensile strength and stress, attrition of the opposite teeth. The reinforced composite resin is well adapt with the dental alloy but it is low the shear bond strength with the dental alloy vs the porcelain fused metal prosthesis, and then has been studied continuously. The purpose of the study was to examine how metal was the higher shear bond strength among the dental alloy was used to the reinforced composite resin and to find the effect that the particle size of sandblasting influenced the shear bond strength. We built up the reinforced composite resin with 4 mm in diameter, 3 mm in height on circular alloy with 5 mm in diameter, 2 mm in height. Type II gold, type IV gold, and Ag-Pd alloy was used as alloys and $50{\mu}m$, $110{\mu}m$, $250{\mu}m$ of the particle size was sandblasted at each alloy in bonding between alloy and resin. We made 90 secimens of 10 per each group and we measured the shear bond strength using the Instron($M100EC^{(R)}$, Mecmesin Co., England). The obtained results were as follows : 1. In comparison among each alloys, Ag-Pd alloy had the highest shear bond strength and the shear bond strength was decreased significantly in the sequence of the type II gold and type IV gold(P<0.001). 2. In comparison according to the size of sandblasting particle, (1) In Ag-Pd alloy, shear bond strength was decreased in the sequence of $110{\mu}m$, $250{\mu}m$, $50{\mu}m$ and there were significant difference in all the group. (P<0.05) (2) In type II gold, it was decreased in the sequence of $250{\mu}m$, $50{\mu}m$, $110{\mu}m$ and there were significant difference. (P<0.05) (3) In type IV gold, it was decreased in the sequence of $110{\mu}m$, $50{\mu}m$, $250{\mu}m$. There were significant difference between the group of $110{\mu}m$ and $50{\mu}m$, the group of $110{\mu}m$ and 250, but there were no significant difference in the group of $50{\mu}m$ and $250{\mu}m$. 3. The highest shear bond strength according to the size of sandblasting particle was $110{\mu}m$ in Ag-Pd alloy and type IV gold, $250{\mu}m$ in type II gold.

• 대한치과기공학회지
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• 제33권3호
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• pp.185-192
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• 2011

Purpose: This study was to evaluate the shear bond strength of the ceramic fused to Ni-Cr alloy(Bellabond plus) and Co-Cr alloy(Wirobond C) by heat treatment. Methods: Metal specimens were divided into 5 groups for each alloy according to heat treatment conditions prior to porcelain application. Fifteen specimens from each group were subjected to a shear load a universal testing machine using a 0.1mm/min cross-head speed and one specimen from each group was observed with EDX line profile. Results: The diffusion of metal oxide observed far in the specimen heat treated than no heat treated in the opaque layer. The shear bond strength measured highest to BP3(50.50MPa), WC2(50.49MPa) groups and measured lowest from BP1(35.1MPaa), WC1(39.66MPa) groups which were not treated with heat, and there was a significant difference (p<0.05). Conclusion: The shear bond strength of Ni-Cr alloy(Bellabond plus) and Co-Cr alloy(Wirobond C) measured similar 5 groups all.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.555-558
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• 2014

Focal epithelial hyperplasia (FEH) is a human papillomavirus (HPV)-induced alteration of the oral mucosa that presents with a clinically distinct appearance. While other HPV-infected lesions such as squamous papilloma, verruca vulgaris, and condyloma acuminatum involve the skin, oral mucosa, and genital mucosa, FEH occurs only in the oral mucosa. The affected oral mucosa exhibits multiple papules and nodules with each papule/nodule being flat-topped or sessile. The affected region resembles the normal color of oral mucosa rather than appearing as a white color since the epithelial surface is not hyperkeratinized. Almost all cases present with multiple sites of occurrence. This rare, benign epithelial proliferation is related to low-risk HPV, especially HPV-13 and -32, and is not transformed into carcinoma. We report a case of FEH that arose on the attached gingiva of an East Asian male adult related to prosthesis without detection of any HPV subtype in HPV DNA chip and sequencing.