Restorative Dentistry & Endodontics

Hyuk-Choon Kwon

5 Articles

The polymerization rate and the degree of conversion of composite resins by different light sources: Joo-Hee Ryoo, In-Bog Lee, Hyun-Mee Yoo, Mi-Ja Kim, Chang-In Seok, Hyuk-Choon Kwon; J Korean Acad Conserv Dent 2004;29(4):386-398. Published online July 31, 2004; DOI: https://doi.org/10.5395/JKACD.2004.29.4.386

Objectives

The purpose of this study was to observe the reaction kinetics and the degree of polymerization of composite resins when cured by different light sources and to evaluate the effectiveness of the blue Light Emitting Diode Light Curing Units (LED LCUs) compared with conventional halogen LCUs.

Materials and Methods

First, thermal analysis was performed by a differential scanning calorimeter (DSC). The LED LCU (Elipar Freelight, 320 mW/cm²) and the conventional halogen LCU (XL3000, 400 mW/cm²) were used in this study for curing three composite resins (SureFil, Z-250 and AEliteFLO). Second, the degree of conversion was obtained in the composite resins cured according to the above curing mode with a FTIR. Third, the measurements of depth of cure were carried out in accordance with ISO 4049 standards. Statistical analysis was performed by two-way ANOVA test at 95% levels of confidence and Duncan's procedure for multiple comparisons.

Results

The heat of cure was not statistically different among the LCUs (p > 0.05). The composites cured by the LED (Exp) LCUs were statistically more slowly polymerized than by the halogen LCU and the LED (Std) LCU (p < 0.05). The composite resin groups cured by the LED (Exp) LCUs had significantly greater degree of conversion value than by the halogen LCU and the LED (Std) LCU (p = 0.0002). The composite resin groups cured by the LED (Std) LCUs showed significantly greater depth of cure value than by the halogen LCU and the LED (Exp) LCU (p < 0.05).

Citations

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Features of polymerization kinetics and heat realize of epoxy resin modified with silicone, silane and siloxane additives
Sergey Savotchenko, Ekaterina Kovaleva
Polymer Bulletin.2024; 81(15): 13419. CrossRef
Kinetic features of polymerization of epoxy resin modified by silicon‐containing additives and mineral fillers
Ekaterina G. Kovaleva, Sergey E. Savotchenko
Polymer Engineering & Science.2022; 62(1): 75. CrossRef
Characterization of curing behavior of UV-curable LSR for LED embedded injection mold
Joon-Sung Tae, Kyung-Gyu Yim, Byung-Ohk Rhee, Jae B. Kwak
Korea-Australia Rheology Journal.2016; 28(4): 247. CrossRef

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Effect of pH and storage time on the elution of residual monomers from polymerized composite resins: Cheol-Min Jeon, Hyun-Mi Yoo, Hyuk-Choon Kwon; J Korean Acad Conserv Dent 2004;29(3):249-266. Published online May 31, 2004; DOI: https://doi.org/10.5395/JKACD.2004.29.3.249

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Objectives

The purpose of this study was to determine whether pH and time has any influence on the degradation behavior of composite restoration by analyzing the leached monomers of dental composites qualitatively and quantitatively after storage in acetate buffer solution as a function of time using high performance liquid chromatography (HPLC) / mass spectrometer.

Materials and Methods

Three commercial composite restorative resin materials (Z-250, Heliomolar and Aeliteflo) with different matrix structure and filler composition were studied. Thirty specimens (7mm diameter×2mm thick) of each material were prepared. The cured materials were stored in acetate buffer solution at different pH (4, 7) for 1, 7 and 45days. As a reference, samples of unpolymerized composite materials of each product were treated with methanol (10 mg/ml). Identification of the various compounds was achieved by comparison of their mass spectra with those of reference compound, with literature data, and by their fragmentation patterns. Data were analysed statistically using ANOVA and Duncan's test.

Results

1. Amounts of leached TEGDMA in Aeliteflo were significantly larger than those of UDMA in Z-250 and Heliomolar at experimental conditions of different storage time and pH variation (p < 0.001).

2. As to comparison of the amounts of leached monomers per sorage time, amounts of leached TEGDMA in Aeliteflo and UDMA in Z-250 and Heliomolar were increased in the pH 4 solution more significantly than in the pH 7 solution after 1day, 7days and 45days, respectively (p < 0.001).

3. In total amounts of all the leached monomers with storage times, the overall amounts of pH 4 extracts were larger than those of pH 7 extracts for all resin groups, but there was no significant difference (p > 0.05).

Citations

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Release of Bisphenol A from Pit and Fissure Sealants According to Different pH Conditions
Eun-Deok Jo, Sang-Bae Lee, Chung-Min Kang, Kwang-Mahn Kim, Jae-Sung Kwon
Polymers.2021; 14(1): 37. CrossRef
Comparison of polymerization shrinkage of dual-cure core build-up resin according to shade and curing mode
Yoorina Choi, Karl Lee, Hoon-Sang Chang
Oral Biology Research.2019; 43(4): 243. CrossRef

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Microleakage of posterior packable composite resin at the gingival margins of class II cavities: Su-Jin Choi, Mi-Ja Kim, Hyuk-Choon Kwon; J Korean Acad Conserv Dent 2002;27(3):249-256. Published online May 31, 2002; DOI: https://doi.org/10.5395/JKACD.2002.27.3.249

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The use of flowable composite resins as liners in class II packable composite restoration has been suggested by some manufacturers. However, the contributions of this technique are unproven. The purpose of this study was to compare the gingival microleakage in class II packable composite restorations with or without the use of flowable composite resins as liners.

Slot cavities were prepared on both proximals of 80 extracted human molars and randomly assigned to 8 groups of 20 each. The gingival margins were located at 1mm above CEJ in 80 cavities (group1-4) and 1mm below CEJ in 80 cavities (group5-8). The prepared teeth were mounted in the customized tray with adjacent teeth to simulate clinical conditions and metallic matrix band (Sectional matrix) and wooden wedges were applied. After acid etching and application of Single Bond, each group was restored with the following materials using incremental placement technique: Group 1,5 (Filtek P60), group 2, 3, 4 and group 6, 7, 8 (AeliteFlo, TetricFlow, Revolution/Filtek P60). All specimens were thermocycled 500 times between 5℃ and 55℃ with 1 mimute dwell time, immersed 2% methylene blue dye for 24 hours and then rinsed with tab water. The specimens were embedded in clear resin and sectioned longitudinally through the center of restoration with a low speed diamond saw. Dye penetration at gingival margin was viewed at 20 magnification and analyzed on a scale of 0 to 4. Kruscal-Wallis One way analysis and Mann-Whitney Rank sum test were used to analyze the results.

The results of this study were as follows.

1. The leakage values seen at the enamel margin were significantly lower than those seen at the dentin margin(P<0.05).

2. On the enamel margin, packable composite resins with flowable liners showed lower leakage than those without flowable liners, but there were no significant differences among the four groups(P>0.05).

3. On the dentin margin, four groups demonstrated moderate to severe leakage, and there were no significant differences in leakage values(P>0.05).

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Self-adhesion of low-viscosity composites to dentin surface
Tae-Hee Cho, Kyoung-Kyu Choi, Sang-Hyuk Park, Sang-Jin Park
Journal of Korean Academy of Conservative Dentistry.2003; 28(3): 209. CrossRef

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Microleakage of microfill and flowable composite resins in class V cavity after load cycling: Suk-Ho Kang, Oh-young Kim, Myung-Hwan Oh, Byeong-Hoon Cho, Chung-Moon Um, Hyuk-Choon Kwon, Ho-Hyun Son; J Korean Acad Conserv Dent 2002;27(2):142-149. Published online March 31, 2002; DOI: https://doi.org/10.5395/JKACD.2002.27.2.142

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Low-viscosity composite resins may produce better sealed margins than stiffer compositions (Kemp-Scholte and Davidson, 1988; Crim, 1989). Flowable composites have been recommended for use in Class V cavities but it is also controversial because of its high rates of shrinkage. On the other hand, in the study comparing elastic moduli and leakage, the microfill had the least leakage (Rundle et al. 1997). Furthermore, in the 1996 survey of the Reality Editorial Team, microfills were the clear choice for abfraction lesions.

The purpose of this study was to evaluate the microleakage of 6 compostite resins (2 hybrids, 2 microfills, and 2 flowable composites) with and without load cycling.

Notch-shaped Class V cavities were prepared on buccal surface of 180 extracted human upper premolars on cementum margin. The teeth were randomly divided into non-load cycling group (group 1) and load cycling group (group 2) of 90 teeth each. The experimental teeth of each group were randomly divided into 6 subgroups of 15 samples. All preparations were etched, and Single bond was applied. Preparations were restored with the following materials (n=15): hybrid composite resin [Z250(3M Dental Products Inc. St.Paul, USA), Denfil(Vericom, Ahnyang, Korea)], microfill [Heliomolar RO(Vivadent, Schaan, Liechtenstein), Micronew(Bisco Inc. Schaumburg, IL, USA)], and flowable composite [AeliteFlo(Bisco Inc. Schaumburg, IL, USA), Revolution(Kerr Corp. Orange, CA, USA)]. Teeth of group 2 were subjected to occlusal load (100N for 50,000 cycles) using chewing simulator(MTS 858 Mini Bionix II system, MTS Systems Corp., Minn. USA). All samples were coated with nail polish 1mm short of the restoration, placed in 2% methylene blue for 24 hours, and sectioned with a diamond wheel. Enamel and dentin/cementum margins were analyzed for microleakage on a sclale of 0 (no leakage) to 3 (3/3 of wall). Results were statistically analyzed by Kruscal-Wallis One way analysis, Mann-Whitney U-test, and Student-Newmann-Keuls method. (p=0.05)

Results

1. There was significantly less microleage in enamel margins than dentinal margins of all groups. (p<0.05)

2. There was no significant difference between six composite resin in enamel margin of group 1.

3. In dentin margin of group 1, flowable composite had more microleakage than others but not of significant differences.

4. There was no significant difference between six composite resin in enamel margin of group 2.

5. In dentin margin of group 2, the microleakage were R>A=H=M>D>Z. But there was no significant differences.

6. In enamel margins, load cycling did not affect the marginal microleakage in significant degree.

7. In dentin margins, load cycling did affect the marginal microleakage only in Revolution. (p<0.05)

Citations

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Effect of a new resin monomer on the microleakage of composite resin restorations
JH Bae, YK Kim, PY Yoon, MA Lee, BH Cho
Journal of Korean Academy of Conservative Dentistry.2007; 32(5): 469. CrossRef

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Effects of filler addition to bonding agents on shear bond strength: Young Oh, Myung-Hwan Oh, Byeong-Hoon Cho, Ho-Hyun Son, Hyuk-Choon Kwon, Chung-Moon Um; J Korean Acad Conserv Dent 2002;27(1):44-53. Published online January 31, 2002; DOI: https://doi.org/10.5395/JKACD.2002.27.1.044

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Hybrid Layer, Shear Bond Strength, and Fracture Patterns of Titanium Dioxide–Doped Phosphate Glass–Filled Universal Dental Adhesives
Adam bin Husein, Sana Mhd. Fouad Seoudi, Hatem Mostafa El-Damanhoury, Ibrahim Mahmood Aziz, Ensanya Ali Abou Neel
European Journal of General Dentistry.2025; 14(01): 044. CrossRef

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