• Proceedings of the KACD Conference
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• 2001.11a
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• pp.558.1-558
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• 2001

Flowable resin composite is a relatively new restorative material. It has been reported that a low viscosity, low modulus intermediate resin applied between the bonding agent and restorative resin act as an "elastic buffer" that can relieve contraction stress. This in-vitro study aimed to evaluate the effect of flowable composite resin as a restorative material on regional tensile bond stredgth to cervical wedge shaped cavity walls. (omitted)

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.447-459
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• 1994

The purpose of this study is to evaluate of shear bond strength of light-curing composite resin to light-curing glass ionomer cement. Composite resin and glass ionomer cement have been widely used as an esthetic filling materials in dental clinics. To achieve better clinical results, sandwich technic was developed with conpensating for disadvantages of these two materials. Especially, light-curing glass ionomer cement provided greately improved bonding strength of teeth or composite resin, and then excellent clinical results can be acquired. In this study, 6 commercial light-curing glass ionomer cements(3 commercial restorative materials : Fuji II LC, Variglass VLC, Vitremer, and 3 commercial lining materials : Fuji Lining LC, Baseline VLC, Vitrebond) were devided two groups. According to manufacturer's appointment, no surface treatment was referred to N groups. Supposing. of clinical practice, surface grinding with water spray at 320 grit sand paper, 40 seconds etching with 37% phosphoric acid, 20 seconds washing, 20 seconds air drying was referred to N groups. Totally 12 experimental groups were devided, and all 120 specimens from 10 specimens of each groups were made. After light-curing composite resin was bonded to light-curing glass ionomer cement, shear bond strength was tested by Instron universal testing machine between glass ionomer cement and composit resin. The data were analyzed statistically by Student's t-test and ANOVA. The obtained results were as follows; 1. In light-curing glass ionomer cement, restorative materials showed higher shear bond strength to composite resin than lining materials(p<0.05). 2. Variglass VLC of restorative material group and Baseline VLC of lining material group have highest shear bond strength to composite resin(p<0.001). 3. In light-curing glass ionomer cement, surface grinding and acid etching reduced shear bond strength to composite resin(p<0.001)}. 4. VGN group 1s highest shear bond strength to composite resin, VBE group is lowest shear bond strength to composite resin(p<0.001).

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.3
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• pp.313-327
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• 1999

The aim of this study was to compare wear resistance of resin denture teeth opposing various restorative materials. The wear resistance of conventional acrylic resin teeth(Trubyte Biotone) and three high-strength resin teeth(Bioform IPN, Endura, SR-Orthosit-PE) opposing different restorative materials(gold alloys, dental porcelain, composite resin) was compared. Wear tests were conducted with a sliding-induced wear testing apparatus which applied 100,000 strokes to the specimen in a mesio-distal direction under conditions of 100 stroke/min and constant loading of 1Kgf/tooth. Wear resistance of the resin denture teeth was evaluated by the following criteria : 1) wear depth, 2) weight loss, and 3) SEM observation. Results were as follows. 1. When opposed to gold alloys and composite resin, high-strength resin teeth showed superior wear resistance compared to acrylic resin teeth. But, in cases opposing dental porcelain, differences between the wear of the high-strength and acrylic resin teeth were not statistically significant (p<0.05). 2. When comparing wear resistance among high-strength resin teeth, opposing gold alloys, Endura was slightly more resistant and while in cases opposing dental porcelain, SR-Orthosit-PE was showed to be slightly resistant(p<0.05). 3. The wear of high-strength resin teeth was greater by 5 to 7 times when opposing porcelain and 2 to 3 times when opposing composite resin compared to gold alloys(p<0.05). 4. SEM observations of the wear surface showed that wear of resin teeth opposing gold alloys is a fatigue type of wear and wear of resin teeth opposing dental porcelain is fatigue and abrasion type of wear. Trubyte Biotone showed more severe fatigue type of wear than high-strength resin teeth. In conclusion, the use of dental porcelain should seriously be considered as restorative material in cases opposing resin denture teeth and improvement seems to be needed on resin teeth in the areas of wear resistance.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.313-320
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• 2000

The purpose of this study was to evaluate on the interfacial morphology between dentin and restorative materials. In this in vitro study, the cavity wall restorated with 3 different kinds of tooth colored restorative materials [resin-modified Glass Ionomer cement (Fuji II LC), composite resin (Z-100), compomer (Dyract)]. The thirty extracted human molar teeth without caries and/or restorations are used. The experimental teeth were randomly divided into three groups of ten teeth each. In each group, Wedge shaped cavities (width: 3mm, length: 2mm, depth: 1.5mm) were prepared at the cementoenamel junction on buccal and lingual surfaces. The adhesive of composite resin were mixed with rhodamine B. Primer of composite resin, Prime & Bond 2.1 of Dyract and liquid of Fuji II LC were mixed with fluorescein. In group 1, the cavity wall was treatment with dentin conditioner, and then restorated with Fuji II LC. In group 2, the cavity wall was treatment with Prime & Bond 2.1 and then restorated with Dyract. In group 3, the cavity wall was etching with 10% maleic acid, applied with primer and bonding agent and then restorated with Z-100. The interface between dentin and restorative materials was observed by fluoresence imaging with a confocal laser scanning microscope. The results were as follows : 1. In Glass ionomer group, adaptation of resin modified Glass-ionomer restoration against cavity wall is tight, but the crack formed inside of restoration were observed. 2. In Dyract group, the penetration of resin tag is shorter and the width of hybrid layer is narrower than composite resin group. 3. In Z-100 group, primer penetrated deeply through dentinal tubule. Also bonding agent was penetrated along the primer, but the penetration length is shorter than primer part, and in 3-D image, the resin tag is conical shape and lateral branch is observed.

• Restorative Dentistry and Endodontics
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• v.47 no.1
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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.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.469-481
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• 2006

Among the etiologic factors of enamel corrosion, daily intake has been considered with a profound interest, especially the intake of acidic drinks. It is thought that the rapid consumption of acidic drinks will not only results in the affection to the teeth but also to the surface of the tooth-colored restorative materials. Therefore, the puopose of this study is to examine the alterations occurred in the surface of the tooth-colored materials according to the exposed time, with 3 most common acidic drinks in contact with daily life. Resin-modified glass-ionomer, polyacid-modified composite resin, composite resin were immersed on 0.9% NaCl, Coke, orange juice, sports beverages as 4 groups in each. The surface hardness and the surface roughness of specimens were measured with following methods: before immersion, 1 day after immersion, 1-,2-,3-,4- weeks after immersion. Results were as follows. 1. Tooth-colored restorative materials, with the exception of composite resin, showed statistically significant changes in surface hardness and roughness when immersed on acidic drinks(p<0.05). 2. The degree of change in surface hardness and roughness occurred as follows, in order of severity from greatest to least resin-modified glass-ionomer, polyacid-modified composite resin, composite resin 3. Sports beverages resulted in greater alterations to surfaces than Coke and orange juice. 4. In the SEM image of the groups immersed in acidic drinks, resin-modified glass-ionomer and polyacid-modified composite resin showed loss of filer. Severe cracks were observed, especially on the resin-modified glass-ionomer.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.2
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• pp.436-448
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• 1997

Topical fluoride application for children is a widely performed procedure in the field of Pediatric Dentistry for its dental caries prevention effects. However, it is recently recognized as having some unwanted effects on several esthetic restorative materials as it roughens the surfaces of the restorative materials. In order to evaluate the surface changes in esthetic restorative materials, the author immersed composite resin, glass ionomer cement, and resin-modified glass ionomer cement specimens in various topical fluoride agents and measured the weight loss and also, examined the specimens under the scanning electron microscope. The followings are the results : 1. All the specimens immersed in APF gel for 4 minutes showed statistically significant weight loss. (paired t-test, P<0.05). 2. There was no statistically significant weight loss for the resin-modified glass ionomer cement and composite resin groups immersed in sodium fluoride solution (paired t-test, P>0.05). 3. When the glass ionomer cement group was immersed in APF gel for 1 and 4 minutes, there was a statistically significant weight loss compare to other esthetic restorative materials (ANOVA, P<0.05). 4. In the resin-modified glass ionomer cement group and the composite resin group, weight loss in the APF gel 4 minutes immersion group was greater than the 1 minute immersion group, and it was statistically significant (ANOVA, P<0.05). 5. When the specimens were examined under scanning electron microscope, the surface changes were greatest in the order of glass ionomer cement, resin-modified glass ionomer cement, composite resin and also in the order of APF gel 4 minute immersion group, 1 minute immersion group, sodium fluoride immersion group, and control group.

• The Journal of Advanced Prosthodontics
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• v.4 no.1
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• pp.1-6
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• 2012

PURPOSE. The aim of this study was to compare the flexural strength of polymethyl methacrylate (PMMA) and bis-acryl composite resin reinforced with polyethylene and glass fibers. MATERIALS AND METHODS. Three groups of rectangular test specimens (n = 15) of each of the two resin/fiber reinforcement were prepared for flexural strength test and unreinforced group served as the control. Specimens were loaded in a universal testing machine until fracture. The mean flexural strengths (MPa) was compared by one way ANOVA test, followed by Scheffe analysis, using a significance level of 0.05. Flexural strength between fiber-reinforced resin groups were compared by independent samples t-test. RESULTS. For control groups, the flexural strength for PMMA (215.53 MPa) was significantly lower than for bis-acryl composite resin (240.09 MPa). Glass fiber reinforcement produced significantly higher flexural strength for both PMMA (267.01 MPa) and bis-acryl composite resin (305.65 MPa), but the polyethylene fibers showed no significant difference (PMMA resin-218.55 MPa and bis-acryl composite resin-241.66 MPa). Among the reinforced groups, silane impregnated glass fibers showed highest flexural strength for bis-acryl composite resin (305.65 MPa). CONCLUSION. Of two fiber reinforcement methods evaluated, glass fiber reinforcement for the PMMA resin and bis-acryl composite resin materials produced highest flexural strength. Clinical implications. On the basis of this in-vitro study, the use of glass and polyethylene fibers may be an effective way to reinforce provisional restorative resins. When esthetics and space are of concern, glass fiber seems to be the most appropriate method for reinforcing provisional restorative resins.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.109-115
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• 2000

This study was designed to evaluate the microhardness of restorative composite resin and dual-cured composite resin cement which were light cured through the 1.5mm thickness composite overlay. For restorative materials, Z100 and Tetric Ceram were used. For dual cured composite cements, Variolink II((VL II) of three consistency (low, high, ultra high) were used. To determine the optimal microhardness of Z100, Tetric Ceram and Variolink II, each material was packed into the 1mm thickness teflon mold without composite overlay and light cured for 60 seconds. Then the microhardnesses of each sample were measured, averaged and regarded as optimal hardness of each material. To evaluate the microhardness of restorative composite resin and dual-cured composite resin cement which were light cured through the 1.5mm thickness composite overlay, the composites were packed into 1mm thickness teflon mold, coverd with celluloid strip, and then precured composite overlay which was made of Targis(Ivoclar/Vivadent, Liechtenstein) was positioned. 2 types of visible light curing machine, the power density of one of which was 400$mW/cm^2$ and the other was 900$mW/cm^2$, and one type of argon laser were used to cure the restorative composite and dual cured cement. For each group, 10 sample were assigned. The light curing tip was positioned over the composite overlay and light cured for 1min., 2min. or 3min with visible light curing machine or 15sec, 30 sec, 45sec, and 60 sec with argon laser. The Vickers hardnesses of upper and lower surface of Z100, Tetric Ceram, and 3 types of VL II cement were measured. When the 900 $mW/cm^2$ curing light was used, 2min. was needed for optimal curing of Z100 and Tetric Ceram. Variolink II did not be cured optimally even though the curing time was extended to 3min. When 400$mW/cm^2$ curing light was used, 3min. was necessary for Z100, whereas 3min. was not enough for Tetric Ceram. Variolink II was not cured optimally even though the curing time was extended to 3min. When argon laser was used, Z100, Tetric Ceram and Variolink II were not cured optimally in 60 seconds.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.321-337
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• 2000

Dental caries, one of the most frequent dental disease, become larger because it can be thought as a simple disease. Further more, it can progress to unexpected root canal therapy with fabrication of crown that needs reduction of tooth structure. Base is required in a large caries and ZOE, ZPC, glass ionomer are used frequently as base material. They, with restorative material, can affect the longevity of the restoration. In this study, we assume that the mandibular 1st molar has deep class I cavity. So, installing the 3 base material, 3 kinds of fillings were restored over the base as follows; 1) amalgam only, 2) amalgam with ZPC, 3) amalgam with ZOE, 4) amalgam with GI cement, 5) gold inlay with ZPC, 6) gold inlay with GI cement, 7) composite resin only, 8) composite resin with GI cement. After develop the 3-dimensional model for finite element analysis, we observe the distribution of stress and temperature with force of 500N to apical direction at 3 point on occlusal surface and temperature of 55 degree, 15 degree on entire surface. The analyzed results were as follow : 1. Principal stress produced at the interface of base, dentin, cavity wall was smallest in case of using GI cement as base material under the amalgam. 2. Principal stress produced at the interface of base, dentin, cavity wall was smaller in case of using GI cement as a base material than ZPC under gold inlay. 3. Composite resin-filled tooth showed stress distributed over entire tooth structure. In other words, there was little concentration of stress. 4. ZOE was the most effective base material against hot stimuli under the amalgam and GI cement was the next. In case of gold inlay, GI cement was more effective than ZPC. 5. Composite resin has the small coefficient of thermal conductivity. So, composite resin filling is the most effective insulating material.