• Title/Summary/Keyword: light curing

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DEGREE OF COLOR CHANGE AND DYE DEPOSITION ONTO COMPOSITE RESINS AFTER OFFICE BLEACHING IN VITRO (표백술에 의한 복합 레진의 색변화와 색소 침착 정도)

  • Choi, Nak-Won;Son, Ho-Hyun
    • Restorative Dentistry and Endodontics
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    • v.25 no.4
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    • pp.599-605
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    • 2000
  • Among the effects of tooth bleaching on composite resins, degree of color change and dye deposition onto composite resins after office bleaching were investigated in vitro. Seventy two disc-shaped resin samples were fabricated with hybrid type composite resin, Z-100 under 3 different environments(24 samples for each environment) characterized by 3 kinds of light-curing intensity and duration($250mW/cm^2$-20sec., $250mW/cm^2$-40sec., $550mW/cm^2$-20sec.). As control, one-third samples of each group were not treated with bleaching agent. The remaining two-thirds samples of each group were treated with bleaching agent(bleaching group). Then, before thermocycling procedure in coffee bath, the half of the samples treated with bleaching agent were polished(polishing group) with polishing system. SofLex, but the other half(not-polishing group) and control group were not polished. Another 72 samples were also made with microfilled type composite resin. Sillux Plus and treated according to the experimental procedures mentioned above. The color of each resin sample was measured before bleaching, after bleaching, and after thermocycling preceded by bleaching. And color difference was evaluated. It was concluded as follows: 1. The amount of color change of resin samples after office bleaching was not statistically significant(p>0.05). But the samples which were treated with bleaching agent showed more color change than that of control group. 2. After thermocycling in coffee bath, the amount of color change of resin samples between control and bleaching group was not statistically significant(p>0.05). 3. After thermocycling in coffee bath, the polishing procedure of resin samples showed no statistically significant difference(p>0.05) between polishing and not-polishing group in the aspect of color change.

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Filling and Wiping Properties of Silver Nano Paste in Trench Layer of Metal Mesh Type Transparent Conducting Electrode Films for Touch Screen Panel Application (실버 나노분말을 이용한 메탈메쉬용 페이스트의 충전 및 와이핑 특성)

  • Kim, Gi-Dong;Nam, Hyun-Min;Yang, Sangsun;Park, Lee-Soon;Nam, Su-Yong
    • Journal of Powder Materials
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    • v.24 no.6
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    • pp.464-471
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    • 2017
  • A metal mesh TCE film is fabricated using a series of processes such as UV imprinting of a transparent trench pattern (with a width of $2-5{\mu}m$) onto a PET film, filling it with silver paste, wiping of the surface, and heat-curing the silver paste. In this work nanosized (40-50 nm) silver particles are synthesized and mixed with submicron (250-300 nm)-sized silver particles to prepare silver paste for the fabrication of metal mesh-type TCE films. The filling of these silver pastes into the patterned trench layer is examined using a specially designed filling machine and the rheological testing of the silver pastes. The wiping of the trench layer surface to remove any residual silver paste or particles is tested with various mixture solvents, and ethyl cellosolve acetate (ECA):DI water = 90:10 wt% is found to give the best result. The silver paste with 40-50 nm Ag:250-300 nm Ag in a 10:90 wt% mixture gives the highest electrical conductance. The metal mesh TCE film obtained with this silver paste in an optimized process exhibits a light transmittance of 90.4% and haze at 1.2%, which is suitable for TSP application.

A Study on the Alternative Method for Weathering Test of Military Coated Fabrics (군용 도포직물의 내후성시험 대체에 대한 연구)

  • Son, Chanyoung
    • Journal of Korean Society for Quality Management
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    • v.44 no.3
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    • pp.509-526
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    • 2016
  • Purpose: We would like to find the alternative method for the weathering test on rubber coated fabrics and adhesive-coated fabrics for the military products, KS M 0706 (Sunshine carbon arc) to KS M ISO 4892-2 (Xenon arc). Methods: We measured the tensile strength of adhesive-coated fabrics and adhesive products treated with sunshine carbon arc and xenon arc during 100, 150 and 200 hours, respectively. All of the results were treated with statistical test, ANOVA method. We also validate the surface modifications caused by treatment method and time by using FT-IR ATR and, SEM. Results: In case of the thick adhesive-coated fabrics (app. 1 mm), there was no distinctive difference on tensile strength by treatment method and time. In case of the thin mask hood (app. 0.22 mm) and TENT (app. 0.5 mm), there was distinctive difference on tensile strength. Especially, carbon arc showed a huge lowering properties. We could validate the curing from light and moisture, and the functional group change from cross-linking and oxidation using FT-IR ATR. In case of IBS, there was a surface cracks on SEM images. In case of mask hood, there was no distinctive differences, except for a particle falling from decreased affinity between rubber and particles caused by carbon arc. Conclusion: We concluded that there was no problems for changing xenon arc weathering test with same treatment time on IBS, KM7, K21 and adhesive products. In case of TENT and mask hood, there was a difference in tensile strength in accordance with the change of the treated time and method.

Documentational Study and Observation from the View of Hyungsang Medicine on Bangpungtongseong-san (방풍통성산(防風通聖散)의 문헌(文獻) 및 형상의학적(形象醫學的) 고찰(考察))

  • Suck, Min-Hee;Kim, Jun-Hong;Lee, Yong-Tae
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.1
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    • pp.51-59
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    • 2008
  • The following conclusions were obtained from the studies on Bangpuntongseongsan both from the documents and Hyungsang medicine. Bangpungtongseong-san was created by Yu Wan-so to relieve both interior and exterior of disease from the pathogenic fire, and it cures wind syndrome and dry syndrome. Bangpungtongseong-san is of light herbal combination and it works in the upper part of the body and is mainly applied to skin disease. Perspiration without harming the exterior and purgation without hurting the interior shows that it is not a severe prescription belonging to meditation therapy. It is mostly used for curing the disease of internal heat caused by over drinking and consuming heavy food, and it has special relationship with Yangmyung meridian. It is mentioned in the chapters of spirit, head, face, eye, ear, nose, throat, skin, hair, prescription, wind, dryness, fire, internal damage, epidemic infectious disease, carbuncle and cellulitis, ulceration, and pediatrics of ${\ulcorner}$Donguibogam${\lrcorner}$. It is usually applied to those who belong to Yangmyung type of the six meridian types or wind type, who has excessive heat, people with red complexion, reddened nose, pimples over the face and nose, coarse heel, loss of hair due to wind-heat, and to those who tend to have dandruff. Through examination over the cases treated with Hyungsan medicine, Bangpungtongseong-san was found efficacious in bloodshot eyes, brandy nose, loss of hair, various skin problems, tetanus, acute alcoholism, paralysis of hand and foot, deafness, and tinnitus.

Shear Bond Strength of Porcelain Repair Systems (도재 수리 시스템의 전단결합강도에 관한 연구)

  • Woo, Soo;Shin, Soo-Youn;Cho, In-Ho
    • Journal of Dental Rehabilitation and Applied Science
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    • v.22 no.3
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    • pp.211-220
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    • 2006
  • Need of porcelain-repair system is largely demanding as dental porcelain restorations are increased in clinical dentistry. This study investigated shear bond strength of commercial porcelain-repair systems on dental porcelain and their reliability. Experimental groups were as follows; Group A Super Bond C&B, Group B Porcelain repair kit, Group C Ceramic repair, and Group D Spectrum system as a control. Porcelain disks were fired and embedded in epoxy resin. Porcelain surface were ground using 220 grit SiC disk, then cleaned in ultrasonic bath. Then porcelain specimens were treated with each repair system. A clear polystyrene cylinder 3.5 mm in internal diameter was filled with composite resin. Then the resin cylinder was polymerized with a visible light curing unit. Thirty one specimens at each group were prepared and stored at $37^{\circ}C$ distilled water for 48 h. Specimens were tested in an Instron testing machine according to ISO TR 11405. Mean shear bond strength and standard deviation of each group was $15.7{\pm}4.1MPa$ (Group A), $12.8{\pm}4.9MPa$ (Group B), $7.2{\pm}3.0MPa$ (Group C) and $9.6{\pm}2.2MPa$ (Group D). ANOVA and Tukey HSD post-hoc test showed that there were significant differences between groups (p<0.05). Data of bond strength were analyzed with two-parameter Weibull distribution. Confidence interval of Weibull modulus (m-parameter) at 95% of Group A (3.5-6.3) and Group D (3.6-6.0) were significantly higher than Group B (2.2-3.7) and Group C (2.0-3.4). There was little correlation between mean shear bond strength and Weibull modulus. Results indicated that acid-etching of porcelain surface increased porcelain-resin shear bonding strength.

A STUDY ON SHEAR BOND STRENGTH OF COMPOSITE RESIN TO DENTIN FOLLOWING SURFACE TREATMENTS (표면처리에 따른 상아질과 콤포짓드 레진간의 전단결합강도에 관한 연구)

  • Noh, Eun-Hee;Park, Sang-Jin
    • Restorative Dentistry and Endodontics
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    • v.16 no.1
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    • pp.200-208
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    • 1991
  • The purpose of this study was to observe shear bond strength of composite resin to dentin following surface treatment. Freshly extracted forty-eight sound human molars were used in this study. They were stored at $4^{\circ}C$ physiologic saline solution before experiment. The teeth was then mounted with self curing acrylic resin in brass mold. The buccal surfaces of the teeth were grinding approximately 1.5mm by means of water-irrigated grinding wheel to expose the flattened fresh dentin surfaces. The specimens were divided into 6 groups according to preparation and treatment procedures on dentin surfaces; Group 1: Untreated after preparation with No.301 diamond point Group 2: Treated with primer for 60 seconds after preparation with No.301 diamond point Group 3: Untreated after preparation with No.700 fissure carbide bur Group 4: Treated with primer for 60 seconds after preparation with No.700 fissure carbide bur Group 5: Untreated after grinding with 600 grit silicon carbide paper Group 6: Treated with primer for 60 seconds after grinding with 600 grit silicon carbide paper Light cure dental adhesive was applicated to each specimen. Silux plus(3M) was inserted then into polyethylene tube of 3mm diameter and 3mm height, and polymerized to dentin surface. All of the specimens were stored in distilled water at $35.6^{\circ}C$ for 24 hours prior to testing. The shear bond strength was measured using an Instron Universal Testing Machine. The results obtained from this study were as follows: 1. The shear bond strength to dentin was the highest in group II. 2. The shear bond strength to dentin was the lowest in group III. 3. There was no significant difference in shear bond strength to dentin according to preparation instrument. 4. The primer treatment group showed significantly greater shear bond strength than untreated group.

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Microleakage of class II posterior composite resin filling using various light curing methods (구치부 광중합 복합레진 수복시 여러 광조사 방법에 따른 미세변연누출에 관한 연구)

  • Jong-Uk Par;Byeong-Hoon Cho;Ho-Hyun Son;Chung-Moon Um;Hyuk-Choon Kwon
    • Restorative Dentistry and Endodontics
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    • v.26 no.4
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    • pp.326-331
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    • 2001
  • 목적 - 최근 복합레진의 미세변연누출을 줄이기 위한 새로운 광중합 조사방법이 연구되고 있다. 또한 구치용 복합레진이 개발되면서 그 제조회사에서는 5mm 깊이까지 광중합이 가능하다고 소개하고 있다. 본 연구에서는 논리적 가설에 근거한 몇가지 광중합 조사방법이 구치부 class II 와동의 복합레진 충전시 미세변연누출에 어떠한 영향을 미치는지를 관찰하였다. 재료 및 방법 - 100개의 우식증이 없는 사람의 상하악 대구치를 사용했다. 각 치아에 교합-치은방향으로 4mm, 협설 4mm, 깊이 2mm의 class II 와동을 형성하여 인접치와 함께 베이스플레이트 왁스에 매몰하고 구치용 복합레진인 Surefil을 제조 회사의 지시대로 충전하였다. 이때 5가지의 광조사방법을 이용하여 5개의 군으로 나누어 중합하였다(Table 1). 수복된 치아들을 5$^{\circ}C$와 55$^{\circ}C$의 수조에서 번갈아 1분씩 총 500회의 온도변화를 주어 thermocycling을 실시한 후 근첨을 폐쇄하고 수복와동의 치은경계를 제외한 전 표면에 nail varnish를 2회 도포하였다. 2%의 methylene blue용액에 24시간 침적시키고 흐르는 물에 세척한 후 시편을 투명한 에폭시 레진에 매몰하였다. 매몰된 시편을 치아 장축에 평행하게 절단 연마하였다. 입체 현미경으로 미세변연누출을 관찰하고 Kruskal-Wallis One Way ANOVA 와 Dunn's Method로 통계처리 하였다. 결과 - 1. 미세누출은 1군, 4군과 5군, 2군 3군 순으로 증가였다. 이때 1군, 4군과 5군은 통계적 유의성이 없었다(P>0.05). 2. 2군의 경우 1군, 4군, 5군에 비교하여 유의성 있게 미세누출이 많았으며(P<0.05) 3군에 비하여 유의성 있게 적게 나타났다(P<0.05). 3. 3군의 경우 다른 방법들에 비교하여 통계적으로 유의성 있게 미세누출이 많았다(P<0.05).

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Polymerization Shrinkage and Stress of Silorane-based Dental Restorative Composite (Silorane-기질 치아 수복용 복합레진의 중합수축과 중합수축응력)

  • Lee, In-Bog;Park, Sung-Hwan;Kweon, Hyun-Jeong;Gu, Ja-Uk;Choi, Nak-Sam
    • Composites Research
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    • v.26 no.3
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    • pp.182-188
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    • 2013
  • The purpose of this study was to measure the volumetric polymerization shrinkage kinetics and stress of a silorane-based dental restorative composite and compare it with those of conventional methacrylate-based dental composites. Two methacrylate-based composites (Z250, Z350 flowable) and one silorane-based composite (P90) were investigated. The volumetric polymerization shrinkage of the composites during light curing was measured using a laboratory-made volume shrinkage measurement instrument based on the Archimedes' principle, and the polymerization stress was also determined with the strain gage method. The shrinkage of silorane-based composites (P90) was the lowest, and that of Z350 flowable was the highest. Peak polymerization shrinkage rate was the lowest in P90 and the highest in Z350 flowable. The time to reach peak shrinkage rate of P90 was longer than those of the methacrylate-based composites. The polymerization shrinkage stress of P90 was lower than those of the methacrylate-based composites.

Shear bond strength of resin cement to an acid etched and a laser irradiated ceramic surface

  • Kursoglu, Pinar;Karagoz Motro, Pelin Fatma;Yurdaguven, Haktan
    • The Journal of Advanced Prosthodontics
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    • v.5 no.2
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    • pp.98-103
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    • 2013
  • PURPOSE. To evaluate the effects of hydrofluoric acid etching and Er,Cr:YSGG laser irradiation on the shear bond strength of resin cement to lithium disilicate ceramic. MATERIALS AND METHODS. Fifty-five ceramic blocks ($5mm{\times}5mm{\times}2mm$) were fabricated and embedded in acrylic resin. Their surfaces were finished with 1000-grit silicon carbide paper. The blocks were assigned to five groups: 1) 9.5% hydrofluoric-acid etching for 60 s; 2-4), 1.5-, 2.5-, and 6-W Er,Cr:YSGG laser applications for 60 seconds, respectively; and 5) no treatment (control). One specimen from each group was examined using scanning electron microscopy. Ceramic primer (Rely X ceramic primer) and adhesive (Adper Single Bond) were applied to the ceramic surfaces, followed by resin cement to bond the composite cylinders, and light curing. Bonded specimens were stored in distilled water at $37^{\circ}C$ for 24 hours. Shear bond strengths were determined by a universal testing machine at 1 mm/min crosshead speed. Data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests (${\alpha}$=0.05). RESULTS. Adhesion was significantly stronger in Group 2 ($3.88{\pm}1.94$ MPa) and Group 3 ($3.65{\pm}1.87$ MPa) than in Control group ($1.95{\pm}1.06$ MPa), in which bonding values were lowest (P<.01). No significant difference was observed between Group 4 ($3.59{\pm}1.19$ MPa) and Control group. Shear bond strength was highest in Group 1 ($8.42{\pm}1.86$ MPa; P<.01). CONCLUSION. Er,Cr:YSGG laser irradiation at 1.5 and 2.5 W increased shear bond strengths between ceramic and resin cement compared with untreated ceramic surfaces. Irradiation at 6 W may not be an efficient ceramic surface treatment technique.

Trend change of dental filling materials for permanent teeth of primary and middle school children in a city (일부 도시 초·중등 학생들의 재료별 영구치 충전율 변화)

  • Kong, Wook Sung;Kim, Cheoul Sin
    • The Journal of the Korean dental association
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    • v.55 no.5
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    • pp.339-350
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    • 2017
  • The aim of the study was to analyze the distribution of dental filling materials for carious permanent teeth of school children in a city. The study was designed as time-serial study, using the data of the dental survey for children aged 8-, 10- and 12-year children living in Gimhae city. The samples were selected by stratified clusters sampling. The number of surveyed samples in depth-analysis for types of dental filling materials were 567 in 2009 and 331 in 2013, respectively. They had dental restorations on one or more teeth. The changing pattern of used dental filling materials was analyzed between 2009 and 2013. Statistical analysis was conducted according to variables related to dental filling material type; DMFT and DMFS index, number of fissure sealed teeth and surface and surveyed year. Amalgam filling rate decreased from 27.9% in 2009 to 18.8% in 2013, while filling rate of tooth-colored materials increased from 56.1% in 2009 and 68.9% in 2013. Amalgam filling rate was a negative correlation with filling rate of tooth-colored materials or gold and number of fissure sealed teeth and a positive correlation with DMFT index. Filling rate of tooth-colored materials was a negative correlation with filling rate of amalgam or gold and DMFT index and a positive correlation with number of fissure sealed teeth. The light-curing composite resin should be included in the reimbursement range of National Health Insurance to solve an inequity of dental health care services.

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