• The Journal of Advanced Prosthodontics
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• 제10권4호
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• pp.315-320
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• 2018

PURPOSE. Fractures, occlusal adjustments, or marginal corrections after removing excess composite cements result in rough surfaces of all-ceramic FPDs. These have to be polished to prevent damage of the surrounding tissues. The aim of this study was to evaluate the roughness of zirconia, silicate-ceramic, and composite after polish with different systems for intraoral use. MATERIALS AND METHODS. Each set of 50 plates was made of zirconia, silicate-ceramic, and composite. All plates were ground automatically and were divided into 15 groups according to the treatment. Groups Zgrit, Sgrit, and Cgrit received no further treatment. Groups Zlab and Slab received glaze-baking, and group Clab was polished with a polishing device. In the experimental groups Zv, Sv, Cv, Zk, Sk, Ck, Zb, Sb, and Cb, the specimens were polished with ceramic-polishing systems "v", "k", and "b" for intraoral use. Roughness was measured using profilometry. Statistical analysis was performed with ANOVA and $Scheff{\acute{e}}$-procedure with the level of significance set at P=.05. RESULTS. All systems reduced the roughness of zirconia, but the differences from the controls Zgrit and Zlab were not statistically significant (P>.907). Roughness of silicate ceramic was reduced only in group Sv, but it did not differ significantly from both controls (P>.580). Groups Cv, Ck, and Cb had a significantly rougher surface than that of group Clab (P<.003). CONCLUSION. Ceramic materials can be polished with the tested systems. Polishing of interface areas between ceramic and composite material should be performed with polishing systems for zirconia first, followed by systems for veneering materials and for composite materials.

• 대한치과의사협회지
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• 제47권9호
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• pp.585-595
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• 2009

Purpose : The aim of this study was to compare surgical complications between simple implant placement and implant placement combined with complicated surgical procedures. We also evaluated prosthetic complications according to the specific types of prosthesis. Material and Method : A retrospective analysis of dental chart of patients who was performed implant therapy during the period from June 2003 to December 2005 was carried out. This study was performed on 408 patients (208 male, 200 female). In addition, 1671 implants were performed. Based on their medical record and radiographs, the authors evaluated surgical and prosthetic complications, surgical procedures accompanied at the time of implant, risk factors of implant failure etc. Result : Surgical complications were developed on 358 implants(21.4% on total placed implants) and wound dehiscence was most prevalent complication. On maxillary posterior area, surgical complications developed more frequently on implants with major surgery and showed a significant difference. And complication rate of implants accompanied with GBR was higher than that of simple implants placement and also showed significant difference. The implant supported prosthesis showed no statistical difference in the occurrence of complications according to the types of prosthesis, and food retention was the most common post-prosthetic complication. Also we speculated that length and width of implant showed significant correlation to the failure of implant primary osseointegration. Conclusion : Based on the result, clinician should provide more careful maintenance for patients with implant placement accompanied by complicated surgical procedure. And periodic maintenance for the patient is requested for long-term survival of implant therapy.

• The Journal of Advanced Prosthodontics
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• 제13권6호
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• pp.343-350
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• 2021

PURPOSE. The success of an implant-prosthetic rehabilitation is influenced by good implant health and an excellent implant-prosthetic coupling. The stability of implant-prosthetic connection is influenced by the rotational tolerance between anti-rotational features on the implant and those on the prosthetic component. The aim of this study is to investigate the rotational tolerance of a conical connection implant system and its titanium abutment counterpart, in various conditions. MATERIAL AND METHODS. 10 preparable titanium abutments, having zero-degree angulation (MegaGen, Daegu, Korea) with an internal 5-degree conical connection, and 10 implants (MegaGen, Daegu, Korea) were used. Rotational tolerance between the connection of implant and titanium abutments was measured through the use of a tridimensional optics measuring system (Quick Scope QS250Z, Mitutoyo, Kawasaki, Japan) in the as-received condition (Time 0), after securing with a titanium screw tightening at 35 Ncm (Time 1), after tightening 4 times at 35 Ncm (Time 2), after tightening one more time at 45 Ncm (Time 3), and after tightening another 4 times at 45 Ncm (Time 4). RESULTS. The group "Time 0" had the lowest values of rotational freedom (0.22 ± 0.76 degrees), followed by the group Time 1 (0.46 ± 0.83 degrees), the group Time 2 (1.01 ± 0.20 degrees), the group Time 3 (1.30 ± 0.85 degrees), and the group Time 4 (1.49 ± 0.17 degrees). CONCLUSION. The rotational tolerance of a conical connection is low in the "as received" condition but increases with repetitive tightening and with application of a torque greater than 35 Ncm.

• Journal of Chest Surgery
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• 제31권12호
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• pp.1165-1171
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• 1998

배경 : 인공판막치환술을 받은 환자에서 인공판막의 기능부전이나 합병증으로 재치환술의 빈도가 증가하고있는 추세이다. 본 논문은 인공심장판막에 대한 재치환술시 위험인자를 분석하여 향후 수술성적을 향상시키는데 도움을 얻고자 하였다. 대상 및 방법: 1985년 1월부터 1996년 7월까지 계명대학교 흉부외과학교실에서 인공심장판막질환에 대한 재치환술을 받은 124예에 대하여 술전 임상적 소견 및 수술성적을 중심으로 분석하였다. 이중 3예는 2차로 재치환술은 받은 경우였다. 심장판막재치환술의 원인으로 조직판막자체의 구조적 실패가 96례(77.4%)로 가장 많았고 판막혈전증 16례(12.9%), 심내막염 7례(5.6%), 판막주위누출 5례(4.1%)가 있었다. 결과: 심장판막재치환술의 병원사망률은 8.9%였고, 술후 사망원인으로는 저심박출증이 가장 많았다(70.6%). 생존군과 사망군의 비교에서는 NYHA functional class, 혈중 크레아티닌 수치, LVSD, 체외순환시간이 사망군에서 유의하게 높았다(p < 0.05). 재치환술후 병원사망의 술전 위험인자들로는 LVSD, NYHA functional class IV, 혈중 크레아티닌 수치 등이었으며( p < 0.05), 연령이나 성별, 흉부 엑스선상 심흉곽의 비 등은 위험인자가 되지 못하였다. 결론: 술전의 임상적 소견중 LVSD, NYHA functional class, 혈중 크레아티닌 수치 등이 재치환술후의 예후를 추측할 수 있는 술전 인자라는 것을 알 수 있었다. 그리하여 심장판막재치환술은 심장 및 신기능이 악화되기 이전에 가능한한 조기에 시행하는 것이 바람직하리라 생각된다.

• Journal of Periodontal and Implant Science
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• 제48권4호
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• pp.236-250
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• 2018

Purpose: Resorption of the alveolar bone is an unavoidable consequence of tooth extraction when appropriate alveolar ridge preservation (ARP) measures are not taken. The objective of this trial was to test the hypothesis that dimensional changes in the alveolar bone after tooth extraction would be reduced by inserting an equine collagen membrane and a collagen cone to fill and seal the alveolus (as ARP), in comparison to extraction with untreated alveoli. Methods: In this randomized clinical trial, 31 patients were directly treated with the collagen material after extraction of a tooth from the maxilla (the ARP group). Twenty-nine patients served as the control group. After extraction, no further treatment (i.e., no socket preservation measures) was performed in the control group. Changes in the alveolar process immediately after extraction and after an 8 (${\pm}1$)-week healing period were evaluated 3-dimensionally. Blinded analyses were performed after superimposing the data from the digitalized impressions and surfaces generated by cone-beam computed tomography. Results: Both the ARP and control groups showed a reduction of bone in the alveolar area after tooth extraction. However, significantly less bone resorption was detected in the clinically relevant buccal region in the ARP group. The median bone reduction was 1.18 mm in the ARP group and 5.06 mm in the control group (P=0.03). Conclusions: The proposed hypothesis that inserting a combination material comprising a collagen cone and membrane would lead to a difference in alveolar bone preservation can be accepted for the clinically relevant buccal distance. In this area, implantation of the collagen material led to significantly less alveolar bone resorption. German Clinical Trials Register at www.drks.de, DRKS00004769.

• 대한치과보철학회지
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• 제35권2호
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• pp.330-343
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• 1997

Extraoral maxillofacial prostheses are essential for restoring facial structures that are lost as a result of congenital missing, injuries from accidents, surgical treatments of head and neck cancer. Recently, silicone is the most useful material for this purpose and is more advantageous than other maxillofacial prosthetic materials. However, there are some problems for long-term usage of silicone prostheses due to tear and color change. These are major contributing environmental factors to those problems that are such as ultraviolet light, cleansing agents, changes in humidity and successive adhesion and removal. The aim of this study is to evaluate the physical properties and color changes of maxillofacial prosthetic silicone material by those environmental factors using A-2186 silicone material (Factor II, USA) and two pigments, cadmium yellow medium and cosmetic red. Aluminium molds were fabricated according to the ASTM No. D412 & D624 specifications and resulted specimens from molds were fabicated and treated as follows. Control group and experimental I group were fabricated with 0.1% wt. pigment mixing in silicone elastomer and II-1 group, II-2 group of experimental II group were fabricated with 0.2%, 0.3% wt. pigment mixing in silicone elastomer, respectively. Control group was kept in darkroom at room temperature, I-1 group was kept under natural sunlight during 1week, I-2 group was soaked in 20% soap water during 1wk. I-3 group was successively adhered and removed 200 times on inner region of arm using Daro adhesive-33. Experimental II groups were kept in darkroom at room temperature. Instron universal testing machine was used to measure the % elongation, tensile strength, tear strength of control, experimental I, II groups and reflectance spectrophotometer(COLOR EYE-3000, Macbeth, USA) was used to measure the color differences between control group and experimental I group. The results were as follows : 1. When compared with control group, natural weathering group and 20% soap-water soaking group had no significant differences in % elongation(p>0.05). 2. 200 times successive adhesion and removal group, 0.2% wt. pigment group and 0.3% wt. pigment group had significant decreases in % elongation(p<0.05). 3. Natural weathering group, 20% soap-water soaking group and 200 times successive adhesion and removal group had no significant differences in tensile strength (p>0.05). 4. 0.2%, 0.3% wt. pigment groups had significant decreases in tensile strength(p<0.05). 5. Values of all experimental groups were decreased in tear strength. and 200 times successive adhesion and removal group had significant decrease in tear strength(p<0.05). 6. Natural weathering group and 20% soap-water soaking group had significant color differences(${\Delta}E$) and it could be detectable to naked eye(p<0.05). 7. Color differences between control group and 200 times adhesion and removal group were not detectable to the naked eye (${\Delta}E<1.0$).

• The Journal of Advanced Prosthodontics
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• 제13권3호
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• pp.160-171
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• 2021

Purpose. This in-vitro study evaluated and compared the color stability of 3D-printed and conventional heat-polymerized acrylic resins following aging, mechanical brushing, and immersion in staining medium. Materials and methods. Forty disc-shaped specimens (10 mm in diameter and 3 mm thick) were prepared from two 3D-printed [DentaBASE (DB) and Denture 3D+ (D3D)] and one conventional polymethylmethacrylate (PMMA) denture materials. The specimens were thermo-cycled, subjected to mechanical brushing, and were immersed in either coffee, lemon juice, coke, or artificial saliva (AS) to simulate one and two years of oral use. Color measurements of the specimens were recorded by a spectrophotometer at baseline (T0), and after one (T1) and two years (T2) of simulation. The color changes (ΔE) were determined and also quantified according to the National Bureau of Standards (NBS) units. Descriptive statistics, followed by factorial ANOVA and Bonferroni post-hoc test (α=.05), were applied for data analysis. Results. The independent factors, namely material, staining medium, and immersion time, and interaction among these factors significantly influenced ΔE (P<.009). Irrespective of the materials, treatments, and time, the highest and the lowest mean ΔEs were observed for PMMA in lemon juice (4.58 ± 1.30) and DB in AS (0.41 ± 0.18), respectively. Regarding the material type, PMMA demonstrated the highest mean ΔE (2.31 ± 1.37), followed by D3D (1.67 ± 0.66), and DB (0.85 ± 0.52), and the difference in ΔE between the materials were statistically significant (P<.001). All the specimens demonstrated a decreased color changes at T2 compared to T1, and this difference in mean ΔE was statistically significant (P<.001). Conclusion. The color changes of 3D-printed denture resins were low compared to conventional heat polymerized PMMA. All the tested materials, irrespective of the staining medium used, demonstrated a significant decrease in ΔE values over time.

• The Journal of Advanced Prosthodontics
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• 제12권5호
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• pp.273-282
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• 2020

PURPOSE. To assess shear bond strengths (SBS) of resin composites on aged and non-aged prosthetic materials with various surface treatments. MATERIALS AND METHODS. Cerasmart (CE), Vita Enamic (VE), Vita Mark II (VM), and IPS e.max CAD (EC) blocks were sliced, and rectangular-shaped specimens (14 × 12 × 1.5 mm; N = 352) were obtained. Half of the specimens were aged (5000 thermal cycles) for each material. Non-aged and aged specimens were divided into 4 groups according to the surface treatments (control, air abrasion, etching, and laser irradiation; n = 11) and processed for scanning electron microscopy (SEM). The repair procedure was performed after the surface treatments. SBS values and failure types were determined. Obtained data were statistically analyzed (P≤.05). RESULTS. The material type, surface treatment type, and their interactions were found significant with regard to SBS (P<.001). Aging also had a significant effect on prosthetic material-resin composite bonding (P<.001). SBS values of non-aged specimens ranged from 12.16 to 17.91 MPa, while SBS values of aged specimens ranged from 9.46 to 15.61 MPa. Non-aged VM in combination with acid etching presented the highest score while the control group of aged CE showed the lowest. CONCLUSION. Etching was more effective in achieving durable SBS for VM and EC. Laser irradiation could be considered as an alternative surface treatment method to air abrasion for all tested materials. Aging had significant effect on SBS values generated between tested materials and resin composite.

• Journal of Chest Surgery
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• 제32권1호
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• pp.10-15
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• 1999

배경: 건삭보존 승모판 치환술이 승모판 폐쇄부전증에 있어서는 좌심실 기능의 개선 및 술후 합병증을 줄일 수 있다고 알려져 있으나 승모판 협착증에 있어서는 좌심실 유출로의 폐쇄나 기계판엽의 운동장애 없이 적당한 크기의 기계판막을 삽입할 수 없다는 점등으로 아직 논란의 대상이 되고 있다. 대상 및 방법: 본원에서는 5명의 승모판 협착증환자와 7명의 승모판 폐쇄부전증 환자를 대상으로, 융합된 교련의 절개, 두꺼워진 판첨을 얇게 박리하고, 전판첨을 전판륜으로부터 2 mm 정도에 절개를 가하고 전판첨 중앙부를 절제하여 판엽을 두 개의 분절로 분리하여 교련부에 재 부착함으로써 건삭 및 판첨을 판륜에 위치이동 하면서 승모판막 치환술을 시행하여 건삭 및 판륜의 연속성을 유지하였다. 결과: 술후 기계판엽의 운동장애나 판막주위누출, 좌심실 유출로의 폐쇄 등 합병증 및 수술 사망환자는 없었다. 결론: 결론적으로 건삭보존 승모판 치환술이 승모판 협착증에 있어서도 안전하고 효과적인 수술방법이라 할 수 있다

• 대한치과보철학회지
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• 제60권3호
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• pp.254-262
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• 2022

편악 부분 무치악 환자를 치료하는 경우, 적절한 수복 재료를 사용하는 것이 중요하다. 적절하지 않은 수복 재료는 보철 수복의 결과에 좋지 않은 영향을 줄 수 있다. 현재 널리 사용되고 있는 재료들인 지르코니아와 치과용 합금은 피질골보다 탄성 계수가 높아 외력 발생시 임플란트 및 임플란트 주위 골에 유해한 힘을 가할 수 있다. 최근 새롭게 소개된 재료인 Polyetherketoneketone (PEKK)은 피질골과 유사한 탄성계수를 가졌으며, 물리적 특성 및 생체 친화성에 있어서도 많은 이점을 가지고 있다. 본 증례에서는 PEKK를 이용한 임플란트 지지형 고정성 보철치료를 진행하였고 기능적, 심미적으로 만족할 만한 결과를 얻었기에 이를 보고하는 바이다.