치과용 글라스 아이오노머 시멘트의 압축, 간접인장 및 전단 결합강도에 관한 연구

김철위,이용근,임범순 서울대학교 치과대학 치과생체재료학교실 1994 치과생체재료학 논문집 Vol.2 No.1

The purpose of this study was to evaluate the compressive strength, diametral tensile strength and shear bond strength of the glass ionomer cements and to compare strengths of the glass ionomer cements independent of their type. The present study utilized one brand of dental zinc phosphate cement and twelve brand of dental glass inomer cements. The load at failure was measured using a Instron universal testing machine (Instron Model 1122), with crosshead speed of 0.05㎝/min. for compressive and diametral tensile test, 0.02 ㎝/min. for shear bond test. From the load at failure, the strength of the specimen could be calculated. Testing of compressive strength, diametral tensile strength, and shear bond strength were carried out at 24 hours and specimens were maintained in distilled water at 37°±2℃ just prior to testing. From the experiments, the following results were obtained; 1.The glass ionomer cements presented a wide variance of compressive strengths. The light-cured glass ionomer cements showed higher compressive strength than self-cured glass ionomer cements. 2. No significant difference (P<0.05) in the diametral tensile strength was observed among self-cured glass ionomer cements. On the contrary, the light-cured glass ionomer cements showed 3∼4 times higher dimetral tensile strength than the self-cured cements. 3. The glass ionomer cements showed a good shear bond strength to dentin.

치아회분과 석고혼합제재의 물성에 관한 연구

계기성,강동완,김광수,고영무,김윤주 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.1

The purpose of this study is to evaluate the use value of tooth ash-plaster mixture as an alternative material of the synthetic hydroxyapatite. For this purpose the author performed the experimental study to investigate the physical properties of sintered tooth ash-plaster mixture. The tooth ash was made by increasing procedure at 850℃, 900℃ and 950℃ for 20min, 40min and 60min respectively. The composition of tooth ash was analyzed using ICPSE and X-ray diffraction was done. The experimental specimens were molded to the cylindrical from 10mm high, 5mm diameter under the pressure of 1,000kg/㎠ for test of compressive strength values and 3mm high, 6mm diameter for test of diametral tensile strength values and surface microhardness values. Mixtures of tooth ash-plaster mixture was vacuum fired at 1,000℃ for 60min. The physical properties of the sintered specimen were examined and their microstructures were observed under the scanning electron microscope. The results were as follows: 1. x-ray diffraction showed the crystallization of tooth ash was developed as the incinerating temperature and time were increased, but the phase transformation following the incinerating temperature and time was not occurred. 2. The values of compressive strength of the sintered tooth ash-plaster mixture were the highest in case of incinerating temperature 950℃, the incinerating time 60min, and the tooth ash-plaster mixing weight ratio of 4:1. The higher tge incineration temperature and the longer the incineration time was, the more increased the compressive strengths were(p<0.01). 3. The values of diametral tensile strength of the sintered tooth ash-plaster mixture were the highest in case of the incinerating temperature 950℃, the incinerating time 60min, and the tooth ash-plaster mixing weight ratio of 4:1. The higher incineration temperature and the longer the incineration time was, the more increased the diametral tensile strengths were (p<0.01). The more decreased tooth ash-plaster mixing ratio was, the more increased the diametral tensile strength was, but there was not a significant difference statistically (p<0.01). 4. The values of surface microhardness of the sintered tooth ash-plaster mixture were also the highest in case of the incinerating temperature 950℃, the incinerating time 60min, and the tooth ash-plaster mixing weight ratio of 4:1. The higher the incineration temperature was, the more increased the surface microhardness values were, but there was not a significant difference statistically(p<0.01). The longer the incineration time was and the more decreased the tooth ash-plaster mixing ratio was, the more increased the surface microhardness values were. 5. The porosity and absorption of the sintered tooth ash-plaster mixture were the highest in case of the incinerating temperature 850℃, the incinerating time 20min, and the tooth ash-plaster mixing weight ratio of 3:1. The lower the incineration temperature was and the shorter the incineration time was, the more increased the porosity was. 6. There was a good wettability in the sintered tooth ash-plaster mixture under the scanning electron microscope.

응축형 복합레진의 기계적 성질에 관한 비교연구

정지아,문주훈,고영곤 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.6

The purpose of this study was to compare the mechanical properties of three condensable composite resins and one hybrid composite resin. The compressive strength, diametral tensile strength, Vicker's microhardness were tested for mechanical properties of condensable composite resins (SureFil, Ariston pHc, Synergy compact), and hybrid composite resin (Z 100). The tested materials were divided into four groups : control group - Z 100 (3M Co, USA), experimental group I- Ariston pHc, (Vivadent, Co., Liechtenstein) , experimental group II - SureFil (Dentsply, Co., U.S.A.) , experimental group III- Synergy Compact (Coltene, Co., Swiss) . According to the above classification, we made samples of SureFil, Ariston pHc, Synergy Compact, Z 100 with separable cylindrical metal mold. And then, we measured and compared the value of compressive strength, diametral tensile strength and Vicker's microhardness of each sample. The results were as follows : 1. In compressive strength, control group (Z 100) revealed the highest value (398.85±19.61MPa), and followed by SureFil (381.65±31.24MPa), Synergy compact (354.85±12.22MPa), Ariston pHc (308.60±36.88MPa). There were no significant differences between SureFil group and Z 100 group, whereas there were significant differences between SureFil group and Ariston pHc group (P<0.05) . 2. In diametral tensile strength, Synergy compact revealed the highest value (86.54±3.44MPa) and followed by SureFil (84.54±3.53MPa), Z100 (76.91±1.63MPa), Ariston pHc(60.34±6.95MPa). There were no significant differences between SureFil group and Synergy compact group 3. In microhardness, control group (Z 100)revealed the highest value (223.7 ±58.0Hv), and followed by SureFil (117.5±10.2Hv), Ariston pHc (116.2±11.9Hv), Synergy Compact (101.9±10.8Hv). There were no significant differences between Ariston pHc group and Synergy compact group Key words : Condensable composite resin, Compressive strength Diametral tensile strength, Vicker's microhardness

Comparison of polymer-based temporary crown and fixed partial denture materials by diametral tensile strength

Ha, Seung-Ryong,Yang, Jae-Ho,Lee, Jai-Bong,Han, Jung-Suk,Kim, Sung-Hun 대한치과보철학회 2010 The Journal of Advanced Prosthodontics Vol.2 No.1

PURPOSE. The purpose of this study was to investigate the diametral tensile strength of polymer-based temporary crown and fixed partial denture (FPD) materials, and the change of the diametral tensile strength with time. MATERIAL AND METHODS. One monomethacrylate-based temporary crown and FPD material (Trim) and three dimethacrylate-based ones (Protemp 3 Garant, Temphase, Luxtemp) were investigated. 20 specimens (Ø 4 mm × 6 mm) were fabricated and randomly divided into two groups (Group Ⅰ: Immediately, Group Ⅱ: 1 hour) according to the measurement time after completion of mixing. Universal Testing Machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed using one-way ANOVA, the multiple comparison Scheffe′test and independent sample t test (α= 0.05). RESULTS. Trim showed severe permanent deformation without an obvious fracture during loading at both times. There were statistically significant differences among the dimethacrylate-based materials. The dimethacrylate-based materials presented an increase in strength from 5 minutes to 1 hour and were as follows: Protemp 3 Garant (23.16 - 37.6 MPa), Temphase (22.27 - 28.08 MPa), Luxatemp (14.46 - 20.59 MPa). Protemp 3 Garant showed the highest value. CONCLUSION. The dimethacrylate-based temporary materials tested were stronger in diametral tensile strength than the monomethacrylate-based one. The diametral tensile strength of the materials investigated increased with time.

Gallium phosphate glass (GPG)를 첨가한 글라스아이오노머 시멘트의 기계적 성질과 항균효과

김동애(Dong-Ae Kim),김규리(Gyu-Ri Kim),이정환(Jung-Hwan Lee),이해형(Hae-Hyoung Lee) 대한치과재료학회 2019 대한치과재료학회지 Vol.46 No.4

This study investigated the mechanical properties and antibacterial activity of glass ionomer cement (GIC) containing 1 mol% or 5 mol% gallium phosphate glass (GPG) powder. GPG were added to conventional GIC powder in a range of 0~20 wt%. The specimens for compressive strength (4 mmØ×6 mm) and diametral tensile strength (6 mmØ×4 mm) were prepared by mixing with the cement liquid and kept in an water of 37±1℃. Mechanical properties were evaluated at an interval of 1 h, 24 h, and 7 days. Antibacterial activity of specimens against to S. mutans and S. sobrinus was evaluated using agar diffusion methods. Data were statistically analyzed by one-way ANOVA and Tukey HSD post-hoc test (p<0.05). Diametral tensile strength of GIC containing GPG were significantly higher than control GIC while compressive strength showed no statistical difference. There was an increasing tendency of antibacterial activity for GPG-GICs. Results indicated that GPG can be considered as potential reinforcing agent for increasing antibacterial and mechanical properties for conventional GIC.

탄소나노튜브 첨가에 의한 치과용 글라스아이오노머 시멘트의 기계적 특성

김동애(Dong-Ae Kim),김한샘(Han-Sem Kim),신원상(Ueon-Sang Shin),이해형(Hae-Hyoung Lee) 대한치과재료학회 2016 대한치과재료학회지 Vol.43 No.1

The aim of this study was to investigate the effect of multiwall carbon nanotube functionalized with carboxyl group (MWCNT-COOH) on the mechanical properties of dental glassionomer cement (GIC). MWCNT-COOH was prepared by the acid oxidative method. The MWCNT-COOH was incorporated into a commercial GIC powder or liquid at 0.5 wt% or 1.0 wt%. The net setting time of the cements was measured in accordance with ISO 9917 (Dental water-based cement). Specimens for compressive strength (4 mmφ × 6 mm), diametral tensile strength (6 mmφ × 4 mm) and flexure strength with modulus (2 mm × 2 mm × 25 mm) were prepared by mixing with the cement liquid and kept in water bath of (37±1)℃. Mechanical tests were conducted in 1 d, 7 d, and 14 days at a cross-head speed of 1 mm/min. Compressive strength of GIC mixed with 0.5 wt% MWCNT-COOH increased significantly at 7 d. However, overall mechanical properties of GIC modified with MWCNT were not significantly increased with a delayed setting time, in comparison with control cement. Overall results indicated that the MWCNT/GIC composite cements showed a limited strengthening effect for dental glassionomer cement.

저/고분자량 키토산에 의한 종래형 치과용 글라스아이오노머 시멘트의 강화

김동애(Dong-Ae Kim),김규리(Gyu-Ri Kim),전수경(Soo-Kyung Jun),이정환(Jung-Hwan Lee),이해형(Hae-Hyoung Lee) 대한치과재료학회 2017 대한치과재료학회지 Vol.44 No.1

The aim of this study was to investigate the effects of chitosan powder addition on the strengthening of conventional glass ionomer cement. Two types of chitosan powders with different molecular weight were mixed with conventional glass ionomer cement (GIC): low-molecular weight chitosan (CL; 50∼190 kDa), high-molecular weight chitosan (CH; 310∼375 kDa). The chitosan powders (CL and CH) were separately added into the GIC liquid (0.25-0.5 wt%) under magnetic stirring, or mixed with the GIC powder by ball-milling for 24 h using zirconia balls. The mixing ratio of prepared cement was 2:1 for powder to liquid. Net setting time of cements was measured by ISO 9917-1. The specimens for the compressive strength (CS; 4 x 6 mm), diametral tensile strength (DTS; 6 x 4 mm), three-point flexure (FS; 2 x 2 x 25 mm) with flexure modulus (FM) were obtained from cements at 1, 7, and 14 days after storing in distilled water at (37±1)℃. All mechanical strength tests were conducted with a cross-head speed of 1 mm/min. Data were statistically analyzed by one-way ANOVA and Tukey HSD post-hoc test. The mechanical properties of conventional glass ionomer cement was significantly enhanced by addition of 0.5 wt% CL to cement liquid (CS, DTS), or by addition of 10 wt% CH (FS) to cement powder. The CL particles incorporated into the set cement were firmly bonded to the GIC matrix (SEM). Within the limitation of this study, the results indicated that chitosan powders can be successfully added to enhance the mechanical properties of conventional GIC.

A STUDY ON THE COMPRESSIVE, DIAMETRAT TENSILE AND SHEAR BOND STRENGTH OF GLASS IONOMER CEMENTS

Kim, Cheol-We,Lee, Yong-Keun,Lim, Bum-Soon Dept. of Dental BiomaterialsCollege of Dentistry 1994 Dental materials journal, Seoul national universit Vol.4 No.1

경화방법이 치과용 경석고의 기계적 특성에 미치는 영향

임용운,황성식,김사학,최재우,정수하,김시철 대한치과기공학회 2018 대한치과기공학회지 Vol.40 No.1

Purpose: The purpose of this study was to investigate the influence of mechanical properties of various ultra-dental stone by setting methods. Methods: 240 cylinder specimens(10 mm × 20 mm) were prepared from three ultra-dental stones(Gemma, Die keen and Fuji rock; n = 80) in accordance with the manufacturers' recommendations. Half of the specimens of each stone(n= 40) were dried in open air within a room temperature; the other half(n = 40) underwent in a silicone rubber mold in open air for 30 minutes and then were dried in a microwave oven for 10 minutes to 600W. Compressive strength(CS), compressive modulus(CM) and diametral tensile strength(DTS) conducted until fracture using Instron 5966 at each of the following periods: 1 and 24 hours from mixing. One-way analysis of variance and Scheffe's post hoc test were performed for statistical comparisons at a significance level of P<.05. Results: The CS and CM values in all dental stone indicated highest after 24h(54.25 MPa < ) than the values for specimens dried in microwave method . The DTS values revealed the highest microwave method. However, in 24h, FJ(Fu-ji rock) and GM(Gemma) had lower mechanical properties than air. Conclusion : Within the limitations of this study, CS did not influence by microwave method but DTS affected according to the setting.

Development of engineering ceramics 100% from lignite fly ash and steelmaking EAFC mixtures

S. Lamprakopoulos 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.9

In the present work, the development of ceramics is examined by using two industrial solid by-products as 100% the rawmaterial mixture, a challenge with technological, environmental (sustainable waste management and earth mineral resourcesconservation) and economic benefits (utilization of largely available industrial secondary resources). Specifically, fly ashderived from lignite-fed power station and electric arc furnace-carbon slag (EAFC) from steelmaking plant, were used assecondary resources. These powdery materials were mixed in various proportions (0-70%wt. EAFC content), cold compactedat 20 tn load using an automated hydraulic press to form a series of 5 cm diam. disc-shaped specimens, and then sintered atthree different peak temperatures (1000, 1100 and 1140 oC) for 3 h. The microstructures produced were studied via SEM-EDS,and specimen physico-mechanical properties were evaluated. For a 50-50%wt. fly ash-EAFC mixture, the experimental datashow that as the firing temperature is increased from 1000 oC up to 1140oC, the produced specimens hopefully are notdeformed during the sintering process. For that mixture, the diametral tensile strength (DTS) increases from approx. 1.5 MPaat 1000 oC and 1100 oC up to 7.4 MPa at 1140 oC. The coefficient of thermal conductivity also remains practically constant upto 1100 oC, attaining its max. value at 1140 oC. At this peak temperature, max. DTS was recorded for the 100% fly ashspecimens (11.6 MPa). Nevertheless, mixtures containing up to 60%wt. EAFC (at 1140 oC) seem to maintain satisfactoryphysico-mechanical properties. SEM micrographs provide an insight in the ceramic microstructural evolution withtemperature.