• Macromolecular Research
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• 제10권4호
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• pp.194-203
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• 2002

In resin infusion process(RIP), the fiber and the resin are in contact with each other for an impregnation step and often results in flow-induced defects such as poor fiber wetting and void formation. Resin flow characteristics in transverse direction and process modeling for woven fabric were studied, and the process modeling was applied to the manufacturing of hybrid composite materials. This study also considered the compressibility of woven fabrics in a series of compression force, and it was fitted well to an elastic model equation. Void formation was varied with the processing conditions in the stage of manufacturing composites using RIP. It was concluded from this study that proper combination of pressure build-up and dynamic heating condition makes important factor for flow-induced composite processing.

• Restorative Dentistry and Endodontics
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• 제19권2호
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• pp.513-533
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• 1994

The smooth surface after polishing of composite resin contributes to the patient's comfort, and appearance and longevity of the restoration. This study was performed for the quantitative analysis of the effects of the various finishing and polishing instruments on the surface roughness and reflectivity of the microfill, and hybrid composite resins. Cylindrical specimens 2mm thick and 10mm in diameter of Silux Plus, Durafill VS ; Z100, Prisma TPH, Brilliant, and Herculite XR composite resin were polymerized under the matrix strip. 18 specimens for each composite resin materials were divided into 6 groups ; 5 experimental groups were abraded with # 600 sand paper to remove resin-rich layer, except control. Thereafter, using diamond bur(Mani Dia-Burs), carbide bur(E. T. carbide set 4159), rubber point(Composite polishing kit), aluminum-oxide disk(Sof-Lex disk), polishing paste(Enhance system) ; each specimen was polished to its best achievable surface according to manufacturer's directions. Final polished surfaces were evaluated for the surface roughness with profilometer(${\alpha}$-step 200, Tencor instruments, USA) and for the reflectivity with image analyser(Omniment Image Analyser, Buehler, USA). The results were as follows. 1. Polishing paste or aluminum-oxide disk finish in the microfill, and hybrid composite resins was as smooth as matrix strip finish on the surface roughness test. 2. Polishing paste or aluminum-oxide disk finish in the microfill ; polishing paste finish in the hybrid composite resins was as reflective as matrix strip finish on the refectivity test. 3. For the polishing paste, there were no significant differences between the composite resin materials on the surface roughness and refectivity tests. 4. For the aluminum-oxide disk, the best result was obtained with the microfill composite resin on the surface roughness and reflectivity test. 5. Diamond bur, carbide bur, and rubber point were inappropriate for the final polishing instruments.

• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.194-204
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• 1994

The purpose of this study was to evaluate the surface hardness of composite resins according to heat treatment. storage condition and storage time. In this study. two kinds of composite resin inlays and one kind of conventional posterior composite resin were used as experimental materials. One hundred eighty composite resin specimens were constructed from composite resin inlays and conventional posterior composite resin. The conditions of this study were heat treatment. storage condition and storage time. Hardness readings were taken from the top surface of each samples using the Vickers microhardness tester(MHT-l. Matsuzawa. Japan}. The following results from this study were obtained: 1. Regardless of storage condition. both composite resin inlay and conventional posterior composite resin have a higher surface hardness under heat treatment than not. 2. Composite resins with heat treatment have a higher surface hardness under dry storage than under water immersion. 3. In case of Clearfil Photo Posterior and Brilliant Enamel with heat treatment. there was no significant difference with time. but Clearfil CR Inlay with heat treatment. there was statistical difference after 24 hours. 4. Surface hardness of composite resins with coarse hybrid type was higher than that of composite resin with fine hybrid type.

• Restorative Dentistry and Endodontics
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• 제47권1호
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• pp.5.1-5.11
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• 2022

Objectives: This study aimed to assess the clinical longevity of a bulk-fill resin composite in Class II restorations for 3-year. Materials and Methods: Patient record files acquired from the 40 patients who were treated due to needed 2 similar sizes Class II composite restorations were used for this retrospective study. In the experimental cavity, the flowable resin composite SDR was inserted in the dentinal part as a 4 mm intermediate layer. A 2 mm coverage layer with a nano-hybrid resin composite (CeramX) was placed on SDR. The control restoration was performed by an incremental technique of 2 mm using the nano-hybrid resin composite. The restorations were blindly assessed by 2 calibrated examiners using modified United States Public Health Service criteria at baseline and 1, 2, and 3 years. The data were analyzed using non-parametric tests (p = 0.05). Results: Eighty Class II restorations were evaluated. After 3-years, 4 restorations (5%) failed, 1 SDR + CeramX, and 3 CeramX restorations. The annual failure rate (AFR) of the restorations was 1.7%. The SDR + CeramX group revealed an AFR of 0.8%, and the CeramX group an AFR of 2.5% (p > 0.05). Regarding anatomical form and marginal adaptation, significant alterations were observed in the CeramX group after 3-years (p < 0.05). The changes in the color match were observed in each group over time (p < 0.05). Conclusions: The use of SDR demonstrated good clinical durability in deep Class II resin composite restorations.

• Restorative Dentistry and Endodontics
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• 제26권6호
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• pp.485-491
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• 2001

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. (omitted)

• Restorative Dentistry and Endodontics
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• 제25권3호
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• pp.446-458
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• 2000

In this study, compressive strengths of three condensable composite resins(ALERT, SureFil, Solitaire), conventional hybrid composite resin(Z-100) and amalgam(HI-Aristaloy 21) according to the 6 types of cavity design(cylinder, trapezoidal, butt-joint, round bevel, long bevel and short bevel) were measured and appearance of fracture surfaces were observed with SEM, thus evaluated clinical applications of condensable composite resins according to the cavity designs. The results were as follows; 1. Compressive strengths according to experimental materials were the highest in SureFil, and Z-100, ALERT, Solitaire, HI-Aristaloy 21 in order. 2. SureFil showed the highest compressive strength(p<0.05). compressive strengths of ALERT and Solitaire were lower than that of Z-100, hybrid composite(p<0.05). 3. Compressive strengths according to specimen design were the highest in trapezoidal shape(p<0.05) and no significant difference was detected between other specimen designs. 4. The appearance of condensable composite resin under SEM was of a diverse configuration according to component of resin matrix, shapes of filler and surface treatments between resin and filler.

• Advanced Composite Materials
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• 제17권4호
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• pp.333-341
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• 2008

A novel manufacturing method for hybrid composites filled with carbon nanotubes (CNTs) and aramid fibers is proposed. To disperse the CNTs in the epoxy matrix with the presence of aramid fibers, CNT/polyethyleneoxide (PEO) composites are prepared and utilized because PEO is miscible in the epoxy resin. After thin films are made of the CNT/PEO composite and placed together with the aramid fibers, the epoxy resin is infused to them. The PEO is dissolved in the epoxy and then the CNTs are dispersed in the PEO/epoxy matrix between aramid fibers before the pre-heated matrix is cured. It is found that the PEO is completely miscible with the epoxy resin and CNTs are dispersed well in the space between the aramid fibers.

• Restorative Dentistry and Endodontics
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• 제26권4호
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• pp.316-325
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• 2001

The purpose of this study was to evaluate the effect of adhesive curing timing on the direction of polymerization shrinkage of light-curing composite resin. In this study, the curing times of adhesive and composite resin were measured by differential scanning calorimeter(DSC). 28 extracted human molars were embedded in clear resin and box-type cavities were prepared. Based on DSC data, the experimental teeth were divided into 4 groups. Group 1: no bond; Group 2: late curing; Group 3: Intermediate curing; Group 4: Early curing. After treating with adhesive, the buccal cavities were filled with Z-100 hybrid composite resin and the lingual ones were filled with AEliteflo flowable composite resin. The depressions at the surface were measured by surface profilometer, then the specimens were embedded in clear resin and sectioned. Impressions were obtained and used to get epoxy resin replicas. The epoxy replicas were gold-coated and observed under SEM. Average Maximum Gap(AMG), Gap Proportion(GP), Average Marginal Index(AMI) were used to compare the shrinkage gap of each group. The results were statistically analyzed using the Kruskal-Wallis One Way ANOVA, Student-Newman-Keuls method. The results of this study were as follows. 1. Average Maximum Gap, Gap Proportion, Average Marginal Index and depression at the surface or Z-100 hybride composite resin were smaller than those of AEliteflo flowable composite resin(P<0.05). 2. When the bonding between composite resin and tooth structure was strong, the shrinkage gap was small, and depression at the surface was deep(P<0.05). 3. In the well-bonded group, light-curing composite resin shrank toward bonded cavity wall, not toward light source. The result suggested that the direction of polymerization shrinkage was affected by the quality of bonding in the dentin-resin interface. The strong was the bonding between composite resin and tooth structure, the smaller was the gap and the deeper was the depression at the surface. Then the flow to compensate the polymerization shrinkage proceeded from surface to bonded cavity wall.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.21-24
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• 2005

Three dimensional circular braided Glass/Aramid hybrid fabric/epoxy resin composite was fabricated. FBG sensor was embedded along the braid yam in order to monitor the internal dimensional changes of the 3-D braid composite. The amount of cure and thermal shrinkage of epoxy resin was also determined using FBG sensor system. FBG sensors with different grating length were embedded and their response were compared. The thermo-optic coefficient of FBG sensor was measured by several preliminary experiments. The internal strain that measured by FBG sensor and electric strain gauge was compared during compressive test. The released residual strain of the fabricated tubular composite was estimated using cutting method. The internal strain of the composite was estimated using FBG sensor system, and the result was compared with the value from electric strain gauge. It was found that FBG sensor system is a very useful technique to investigate inside region of complicated structure.

• 대한심미치과학회지
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• 제25권2호
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• pp.98-108
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• 2016

전통적인 Metal-ceramic 보철 제작 방식으로부터 All-ceramic 보철에 이르기까지 최근 신소재 개발에 영향을 주는 가장 큰 요인은 심미적인 욕구일 것이다. 우리가 사용하는 각각의 치과용 수복 재료는 재료 별로 강도, 인성, 기계 가공의 효율성 및 사용에 필요한 다양한 과정을 기반으로 임상에서 다양하게 사용되고 있다. 예를 들어 Glass ceramic과 같은 단일 소재의 경우 약한 물성을 고려하여 주로 싱글 크라운과 같은 간단한 보철에 사용하고 있으며 상대적으로 높은 파괴 인성을 가진 지르코니아 재료의 경우 싱글 크라운은 물론 브릿지의 제작에도 널리 사용하고 있다. 하지만 지르코니아 재료는 제작 과정에서 긴 Sintering 시간을 필요로 하므로 Chair side에서 빠른 보철물 제작에 쉽지 않은 부분이 있으며 주로 Lab. side에서 사용하고 있다. CAD / CAM 시스템을 이용하여 보철물을 제작하는 용도로 개발 된 Hybrid ceramic 소재는 Resin Nano Hybrid Ceramic이라고도 하며, 개선 된 물성을 포함한 나노 세라믹 요소를 기반으로 하고 있다. 이러한 특징들은 심미적이며 기능적인 보철물의 제작이 용이한 과정과 결과를 보이고 있으며 동시에 향상된 내구성을 바탕으로 보철물의 제작 과정에 유리한 조건들을 가지고 있다. 새로운 Nano Hybrid Ceramic 재료는 Composite Resin과 Glass ceramic과 같은 단일 소재들이 가진 장점들을 이용하여 술자들의 요구사항을 바탕으로 오랜 연구를 통해 개발된 치과 수복 아이템이며 Nano ceramic filler가 혼합된 구조로 되어있어 치과 수복용 복합소재로서 널리 사용하고 있다. 또한 Nano Hybrid Ceramic소재는 Composite resin의 가공 과정에서 쉽게 파절되지 않는 개선된 물성과 Glass ceramic이 가진 심미성 동시에 포함하고 있는 것이 특징이다. 따라서 Chair side와 Lab. side에서 CAD/CAM 시스템을 이용하여 보철물을 제작할 때 임상적용이 쉽고 유용한 장점을 가지고 있어 추가적인 연구가 필요하다.