• Title/Summary/Keyword: 레진 기질

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POLYMERIZATION SHRINKAGE KINETICS OF SILORANE-BASED COMPOSITES (Silorane 복합레진의 중합수축의 동력학)

  • Kwon, Young-Chul;Lee, In-Bog
    • Restorative Dentistry and Endodontics
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    • v.35 no.1
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    • pp.51-58
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    • 2010
  • Dental composites have improved significantly in physical properties over the past few decades. However, polymerization shrinkage and stress is still the major drawback of composites, limiting its use to selected cases. Much effort has been made to make low shrinking composites to overcome this issue and silorane-based composites have recently been introduced into the market. The aim of this study was to measure the volumetric polymerization shrinkage kinetics of a silorane-based composite and compare it with conventional methacrylate-based composites in order to evaluate its effectiveness in reducing polymerization shrinkage. Five commercial methacrylate-based (Beautifil, Z100, Z250, Z350 and Gradia X) and a silorane-based (P90) composites were investigated. The volumetric change of the composites during light polymerization was detected continuously as buoyancy change in distilled water by means of Archemedes' principle, using a newly made volume shrinkage measurement instrument. The null hypothesis was that there were no differences in polymerization shrinkage, peak polymerization shrinkage rate and peak shrinkage time between the silorane-based composite and methacrylate-based composites. The results were as follows: 1. The shrinkage of silorane-based (P90) composites was the lowest (1.48%), and that of Beautifil composite was the highest (2.80%). There were also significant differences between brands among the methacrylate-based composites. 2. Peak polymerization shrinkage rate was the lowest in P90 (0.13%/s) and the highest in Z100 (0.34%/s). 3. The time to reach peak shrinkage rate of the silorane-based composite (P90) was longer (6.7 s) than those of the methacrylate-based composites (2.4-3.1 s). 4. Peak shrinkage rate showed a strong positive correlation with the product of polymerization shrinkage and the inverse of peak shrinkage time (R = 0.95).

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.

Behavior of Polymerization Shrinkage Stress of Methacrylate-based Composite and Silorane-based Composite during Dental Restoration (Methacrylate 기질 복합레진과 Silorane 기질 복합레진의 치아 수복 시 중합수축응력거동)

  • Park, Jung-Hoon;Choi, Nak-Sam
    • Composites Research
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    • v.28 no.1
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    • pp.6-14
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    • 2015
  • Polymerization shrinkage stress analysis of dimethacrylate-based composite (Clearfil AP-X, Kuraray) and silorane-based composite (Filtek P90, 3M ESPE) used for dental composite restorations was performed using strain-gage measurement and FEM analysis. A theoretical equation based on Young's modulus and polymerization shrinkage of the composite resin was proposed to predict the polymerization shrinkage stress. Experimental results showed that the maximum shrinkage stress of Clearfil AP-X was about 2.8 times higher than Filtek P90. FEM analysis agreed with such experimental stress behaviours and showed that the maximum Von-Mises stress appeared near the margin of the filled resin adhered with PMMA ring. The stress concentration at the interface on the specimen surface was higher than that in the interior. The maximum error of shrinkage stress by the theoretical equation was reasonable within 5% in comparison to FEM results under plane stress.

Evaluation of polymerization shrinkage stress in silorane-based composites (Silorane계 복합레진의 중합수축응력의 평가)

  • Ryu, Seung-Ji;Cheon, Ji-Hoon;Min, Jeong-Bum
    • Restorative Dentistry and Endodontics
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    • v.36 no.3
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    • pp.188-195
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    • 2011
  • Objectives: The purpose of this study was to evaluate the polymerization shrinkage stress among conventional methacrylate-based composite resins and a silorane-based composite resin. Materials and Methods: The strain gauge method was used for the determination of polymerization shrinkage strain. Specimens were divided by 3 groups according to various composite materials. Filtek Z-250 (3M ESPE) and Filtek P-60 (3M ESPE) were used as a conventional methacrylate-based composites and Filtek P-90 (3M ESPE) was used as a silorane-based composites. Measurements were recorded at each 1 second for the total of 800 seconds including the periods of light application. The results of polymerization shrinkage stress were statistically analyzed using One way ANOVA and Tukey test (p = 0.05). Results: The polymerization shrinkage stress of a silorane-based composite resin was lower than those of conventional methacrylate-based composite resins (p < 0.05). The shrinkage stress between methacrylate-based composite resin groups did not show significant difference (p > 0.05). Conclusions: Within the limitation of this study, silorane-based composites showed lower polymerization shrinkage stress than methacrylate-based composites. We need to investigate more into polymerization shrinkage stress with regard to elastic modulus of silorane-based composites for the precise result.

Polymerization Shrinkage Behavior Measured by Digital Image Correlation for Methacrylate-based and Silorane-based Composites During Dental Restoration (디지털 이미지 상관법을 이용한 Methacrylate기질과 Silorane기질 복합레진의 치아 수복 시 중합수축거동)

  • Park, Jung-Hoon;Choi, Nak-Sam
    • Composites Research
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    • v.33 no.3
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    • pp.125-132
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    • 2020
  • The polymerization shrinkage behavior of dimethacrylate-based composite (Clearfil AP-X, Kuraray) and silorane-based composite (Filtek P90, 3M ESPE) used for dental composite restorations was measured using digital image correlation method. The stress distribution on the surface of specimen was calculated by finite element analysis with equivalent elastic modulus and was compared with the measured shrinkage distribution. Camera images were monitored by a CCD camera during and after the irradiation of light. As a result of the DIC analysis, a non-uniform shrinkage distribution was observed in both composite resins, and the resin core inside the ring specimen had free flowability, leading to in greater shrinkage strain than the resin/ring interfacial region. It was observed that as the distance from the center of the resin increased, the radial average shrinkage strain decreased. The radial average shrinkage strain during light irradiation occurred to be 33% for P90 and 57% for AP-X of the entire strain at the end of the test. The shrinkage behavior of P90 and AP-X was measured to be significantly different from each other during light irradiation. In the resin near the resin/ring interface, it was confirmed that the tensile strain rapidly formed to increase after light irradiation, causing a tensile stressed, interface weak.

Polymerization Shrinkage Distribution of a Dental Composite during Dental Restoration Observed by Digital Image Correlation Method (디지털 이미지 상관법을 이용한 치과용 복합레진의 수복 시 중합수축분포 관찰)

  • Park, Jung-Hoon;Choi, Nak-Sam
    • Composites Research
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    • v.30 no.6
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    • pp.393-398
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    • 2017
  • The shrinkage distribution of a dental composite (Clearfil AP-X, Kuraray, Japan) used for dental restoration was observed using a digital image correlation method. In order to analyze the shrinkage distribution formed during and after light irradiation, digital images were taken with different photographing conditions for each period. Optimal photographing conditions during LED irradiation were obtained through a preliminary experiment in which the exposure time was applied from 0.15 ms to 0.55 ms in 0.05 ms intervals. The DIC analysis results showed that the strain was non-uniform. For the initial 20 s of light irradiation the composite resin shrank to the level of 50~60% of the final curing shrinkage. Such large shrinkage amount of the composite resin lump affected the tensile stress concentration near the adhesive region between the composite resin and the substrate.

A NEW METHOD TO MEASURE THE LINEAR POLYMERIZATION SHRINKAGE OF COMPOSITES USING A PARTICLE TRACKING METHOD WITH COMPUTER VISION (컴퓨터 시각과 입자 추적 방법을 이용한 복합레진의 선형중합수축 측정의 새로운 방법)

  • Lee, In-Bog;Min, Sun-Hong;Seo, Deog-Gyu;Kim, Sun-Young;Kwon, Young-Chul
    • Restorative Dentistry and Endodontics
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    • v.35 no.3
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    • pp.180-187
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    • 2010
  • Since the introduction of restorative dental composites, their physical properties have been significantly improved. However, polymerization shrinkage is still a major drawback. Many efforts have been made to develop a low shrinking composite, and silorane-based composites have recently been introduced into the market. In addition, many different methods have been developed to measure the polymerization shrinkage. In this study, we developed a new method to measure the linear polymerization shrinkage of composites without direct contact to a specimen using a particle tracking method with computer vision. The shrinkage kinetics of a commercial silorane-based composite (P90) and two conventional methacrylate-based composites (Z250 and Z350) were investigated and compared. The results were as follows: 1. The linear shrinkage of composites was 0.33-1.41%. Shrinkage was lowest for the silorane-based (P90) composite, and highest for the flowable Z350 composite. 2. The new instrument was able to measure the true linear shrinkage of composites in real time without sensitivity to the specimen preparation and geometry.

Solid-phase refolding of immobilized enterokinase for fusion protein cleavage

  • Kim, Min-Young;Na, Sea-Jin;Suh, Chang-Woo;Kim, Chang-Ho;Lee, Na-Hyun;Lee, Eun-Kyu
    • 한국생물공학회:학술대회논문집
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    • 2003.10a
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    • pp.555-559
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    • 2003
  • EK를 고정화하기 위해 니켈 친화결합 방법과 공유 결합형 고정화 방법을 수행하였으며 니켈 친화결합이 공유 결합형 고정화보다 높은 고정화 수율과 activity를 나타냈다. 풀림과 재접힘을 이용한 효소의 활성 회복은 공유결합형 고정화가 니켈 친화결합보다 높은 결과를 나타내었다. 또한 기질의 분자량 크기에 따른 절단율의 차이가 없었으므로 레진 공극 내부로의 확산도 차이에 의한 절단반응의 차이는 없는 것으로 나타났고, 기질 종류에 따른 EK의 활성은 작은 기질이 큰 기질보다 높은 활성을 보였다.

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COMPARISON OF POLYMERIZATION SHRINKAGE AND STRAIN STRESS OF SEVERAL COMPOSITE RESINS USING STRAIN GUAGE (스트레인 게이지를 이용한 수종의 복합레진의 중합수축 및 수축응력의 비교)

  • Kim, Young-Kwang;Yoo, Seung-Hoon;Kim, Jong-Soo
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.3
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    • pp.516-526
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    • 2004
  • Polymerization shrinkage of photoinitiation type composite resin cause several clinical problems. The purpose of this study was to evaluate the shrinkage strain stress, linear polymerization shrinkage, compressive strength and microhardness of recently developed composite resins. The composite resins were divided into four groups according to the contents of matrix and filler type. Group I : $Denfil^{TM}$(Vericom, Korea) with conventional matrix, Group II : $Charmfil^{(R)}$(Dentkist, Korea) with microfiller and nanofller mixture, Group III : $Filtek^{TM}$ Z250(3M-ESPE, USA) TEGDMA replaced by UDMA and Bis-EMA(6) in the matrix, and Group IV : $Filtek^{TM}$ Supreme(3M-ESPE, USA) using pure nanofiller. Preparation of acrylic molds were followed by filling and curing with light gun. Strain gauges were attached to each sample and the leads were connected to a strainmeter. With strainmeter shrinkage strain stress and linear polymerization shrinkage was measured for 10 minutes. The data detected at 1 minute and 10 minutes were analysed statistically with ONE-way ANOVA test. To evaluate the mechanical properties of tested materials, compressive hardness test and microhardness test were also rendered. The results can be summarized as follows : 1. Filling materials in acrylic molds showed initial temporary expansion in the early phase of polymerization. This was followed by contraction with the rapid increase in strain stress during the first 1 minute and gradually decreased during post-gel shrinkage phase. After 1 minute, there's no statistical differences of strain stress between groups. The highest strain stress was found in group IV and followed by group III, I, II at 10 minutes-measurement(p>.05). In regression analysis of strain stress, group III showed minimal inclination and followed by group II, I, IV during 1 minute. 2. In linear polymerization shrinkage test, the composite resins in every group showed initial increase of shrinkage velocity during the first 1 minute, followed by gradually decrease of shrinkage velocity. After 1 minute, group IV and group III showed statistical difference(p<.05). After 10 minutes, there were statistical differences between group IV and group I, III(p<.05) and between group II and group III(p<.05). In regression analysis of linear polymerization shrinkage, group II showed minimal inclination and followed by group IV, III, I during 1 minute. 3. In compressive strength test, group III showed the highest strength and followed by group II, IV, I. There were statistical differences between group III and group IV, I(p<.05). 4. In microhardness test, upper surfaces showed higher value than lower surfaces in every group(p<.05).

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AN EVALUATION OF WEAR CHARACTERISTICS OF LIGHT-CURED RESTORATIVE COMPOSITES ON ENAMEL SURFACE (광중합형 복합레진과 법랑질간의 마모특성 평가)

  • Baik, Byeong-Ju;Lee, Seung-Young;Lee, Doo-Cheol;Kim, Jae-Gon
    • Journal of the korean academy of Pediatric Dentistry
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    • v.28 no.2
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    • pp.261-270
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    • 2001
  • This study was performed to evaluate wear characteristics of light-cured composites when opposed by human enamel. Seven light-cured restorative composites were selected and enamel cusps sectioned from premolars. All samples were stored in distilled water at $37^{\circ}C$ for 10 days. 68.6 N of weight was loaded during the test. The measurements of vertical loss of enamel cusps, weight loss and volume loss of composites, and SEM observations of the polished and abraded surfaces were made after 30,000 cycles. The results obtained were summarized as follows; 1. The highest hardness value of 70.4 was observed in the Spectrum group and the lowest value of 19.8 was observed in the Heliomolar group. Results of Tukey test showed that an overall significant difference was indicated except the Spectrum, Z100 and Clearfil AP-X groups(p<0.05). 2. Enamel showed the good abrasion resistance against the Heliomolar group of microfilled composite and the Palpique Toughwell group containing the submicron hybrid type spherical fillers. 3. The abrasive wear resistance of hybrid composites was improved with the decrease of mean particle size and hybrid of submicron particle fillers. 4. SEM observation of worn surfaces revealed the protrusion, attrition and missing of fillers, cracks developing and delamination in the matrix.

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