• The Journal of Korean Academy of Prosthodontics
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• v.40 no.5
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• pp.525-535
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• 2002

The purposes of this study were to evaluate the adherence of bacteria on various denture base resin materials and effects of chitosan, added to denture base materials on bacterial adherence. PMMA denture base resin such as heat-cured Vertex-RS, self-cured Vertex-SC and 4-META denture base resin such as heat-cured Meta-Dent, self-cured Meta-Fast were used in this study Samples were divided into two groups the denture base resin with chitosan, without chitosan Streptococcus mutans and Lactobacillus casei were used in this study. The surface of samples was observed by SEM. When chitosan was added to M17 and MRS broth, viable cell count of bacteria was reduced. Viable cell count of Streptococcus mutans on the samples decreased as follows : Meta-Dent, Vertex-SC, Meta-Fast, Vertex-RS. Viable cell count of Lactobacillus casei on the samples decreased as follows: Vertex-RS, Meta-Dent, Meta-Fast, Vertex-SC. The resin with chitosan showed lower adherence of bacteria than without chitosan. The images of SEM showed that the surface of the resin with chitosan was rougher than that of without chitosan. These results showed that the denture base resin materials with chitosan have rougher surface than without chitosan, but less bacteria adhered on them.

• The Journal of Korean Academy of Prosthodontics
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• v.28 no.2
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• pp.29-51
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• 1990

This study was designed to compre the tensile bond strength of 4-META containging denture base resin to Co-Cr alloys after various surface treatments. Especially the surface treatment of sandblasting the mental with aluminum oxide and treating in oxidizing solution composed of 3% aqueous sulfuric acid with 1% potassium manganate were compared. Effect of surface roughness on bonding was measured after sandblasting with 50um, 300um aluminun oxide and polishing with emery pater. Also the effects of wax and wax solvent on bonding were observed. According to the type of polymerization process, heat-cured Meta-Dent resin and autopolymerizing Meta-Fast resin were used. For some specimnens, the tensile bond strength were measured agter three pre-conditions : 1day after bonding, immersed in water at $75^{\circ}C{\pm}3^{\circ}C$ for 4weeks, under normal ambient condition for 4weeks. The following results were obtained from this study : 1. The bond strengths of resins containing 4-META were significantly higher than those of conventional denture base resins(p<0.05). 2. Autopolymerizing Meta-Fast resin had higher bond strength than heat-cured Meta-Dent, resin(p<0.05). 3. The bond strengths of Biosil and Nobilium to 4-META containging resins were not significally different(p>0.05). 4. Stable adhesion can be achieved when mechanically roughen the metal surface by snadblasting with $50{\mu}m$ aluminum oxide than treating in an oxidizing soluing with potassium manganate(p<0.05). 5. Once the metal surface is contaminated with wax, the bond srtength decreased greatly in spite of wax wash with boiling water. But the bond strength recovered significantly with the use of wax solvent 6. Meta-Dent resin had higher bond strength when roughen the metal surface with $50{\mu}m$ aluminum oxide than with $300{\mu}m$ aluminum oxide(p<0.05). In case of Meta-Fast, resin, the use of $300{\mu}m$aluminum oxide was a little advantageous of bonding, but was statistically insignificant(p>0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.1
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• pp.38-49
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• 2000

The purpose of this study was to evaluate the effects of thermocycling on the shear bond strength of Co-Cr alloy to denture base resin. PMMA denture base resin such as heat-cured $Vertex-RS^{(R)}$, self-cured $Vertex-SC^{(R)}$ and 4-META denture base resin such as heat-cured $Meta-Dent^{(R)}$, self-cured $Meta-Fast^{(R)}$ was bonded to Co-Cr alloy. Samples were divided into 3 groups : no thermocycling group as control, thermocycling between $5^{\circ}C\;and\;55^{\circ}C$ with 15 second dwell time as group 1, thermocycling with 1 minute dwell time as group 2. The shear bond strength was measured and the interface between metal and resin was observed by SEM. The results were as follows. 1. The shear bond strength decreased significantly according to thermocycling and dwell time(P<0.001). 2. The bond strength of Co-Cr alloy and 4-META denture base resin was significantly higher than that of Co-Cr alloy and PMMA denture base resin(P<0.001) 3. In SEM, there was no gap in control group, but there was much and large gap in group 1, 2. The longer dwell times, the lower bond strength. PMMA denture base resin had more gap than 4-META denture base resin in the interface. These results revealed that thermocycling decreased the bond strength between Co-Cr alloy and denture base resin and dwell time of thermocycling changed the effect of thermocycling. The results suggested that oral temperature change affect the bond strength of prosthesis.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.1
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• pp.78-94
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• 1997

The purpose of this experiment was to determine the effects of various treatments on denture base resin to metal bond for cobalt-chromium alloy. The metal surface was treated as follows. Group 1 : Sandblasted with $50{\mu}m$ aluminum oxide. Group 2 : Sandblasted with $250{\mu}m$ aluminum oxide. Group 3 : Sandblasted with $250{\mu}m$ aluminum oxide and followed by silicoating. Group 4 : Electrochemically etched. Group 5 : treated with oxidizing solution. Group 6 : Beaded with $200{\mu}m$ retention structure and followed by silicoating. All specimens were applied with 4-META resin and were thermocycled 1000 times at temperature of $5^{\circ}C$ to $55^{\circ}C$. The effects of various surface treatments on the bond strength between 4-META resin and metal interface were measured by using the universal testing machine. All specimens were observed with SEM. The results were as follows 1. The bond strength of 4-META resin were significantly higher to Co-Cr alloy. 2. The bond strength decreased in the following orders : group 6, group 3, groups 1 and 2, group 4, group 5 and there was no statistically significant difference in bond strength among groups 1 and 2.(p>0.05) 3. The bond strength of cobalt-chromium alloy to 4-META resin were not significantly different.(p>0.05) 4. The treated surface of groups 1, 2 and 3 has more fine undercut than that of groups 4 and 5 with SEM. 5. Stable adhesion can be achieved when mechanically roughened metal surface by sandblasting than treating in an electrochemical etching and an oxidizing solution with potassium manganate.

• Restorative Dentistry and Endodontics
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• v.34 no.4
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• pp.371-376
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• 2009

We evaluated in vitro microleakage of Mineral Trioxide Aggregate (MTA) powder with 4-methacryloxyethyl trimellitate anhydride (4-META) / methyl methacrylate (MMA) & tri-n-butylborane (TBB) resin as a retrograde filling material by using methylene blue dye method. Fifty-two single rooted, extracted teeth were instrumented and obturated with gutta percha and AH plus sealer. The apical 3mm of each root was resected and 3mm deep ultrasonic root end preparation was done. External surface of roots was coated with nail varnish. Prepared teeth were randomly divided into five groups; Negative control: completely covered with nail varnish; Positive control: coated with nail varnish except for apical foramen; Group 1 (retrofilled with Portland cement); Group 2 (retrofilled with MTA); Group 3 (retrofilled with MTA powder mixed with 4-META/MMA & TBB resin). Immediately after completion of root-end filling, all specimens were submerged in methylene blue dye for 72 hours in $37^{\circ}C$incubator. The roots were longitudinally sectioned and measured for extent of dye penetration by three different examiners under microscope (${\times}$10). The results were statistically analyzed using one way ANOVA and Turkey's HSD test. No leakage was evident in negative control and complete leakage in positive control group. Group 3 showed significantly less leakage than group 1 and 2 (p < 0.01). There was no significant difference between group 1 and 2 (p > 0.01). It was concluded that MTA powder with 4-META/MMA & TBB resin was excellent in reducing initial apical microleakage.

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.41.1-41.13
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• 2019

Objectives: This paper presents a systematic review and meta-analysis of the effect of preheating on the hardness of nanofilled, nanoceramic, nanohybrid, and microhybrid resin composites. Materials and Methods: An electronic search of papers on MEDLINE/PubMed, ScienceDirect, and EBSCOhost was performed. Only in vitro studies were included. Non-English studies, case reports, clinical trials, and review articles were excluded. A meta-analysis of the reviewed studies was conducted to quantify differences in the microhardness of the Z250 microhybrid resin composite using the Comprehensive Meta-Analysis software. Results: Only 13 studies met the inclusion criteria for this systematic review. The meta-analysis showed that there were significant differences between the non-preheated and preheated modes for both the top and bottom surfaces of the specimens (p < 0.05). The microhardness of the Z250 resin composite on the top surface in the preheated mode (78.1 ± 2.9) was higher than in the non-preheated mode (67.4 ± 4.0; p < 0.001). Moreover, the microhardness of the Z250 resin composite on the bottom surface in the preheated mode (71.8 ± 3.8) was higher than in the non-preheated mode (57.5 ± 5.7, p < 0.001). Conclusions: Although the results reported in the reviewed studies showed great variability, sufficient scientific evidence was found to support the hypothesis that preheating can improve the hardness of resin composites.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.4
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• pp.500-509
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• 2000

In general, the three major oral functions of edentulous patients-mastication, phonation, esthetics-can be rehabilitated by the complete dentures, and both the resin based complete denture and the metal based complete denture are commonly used by many clinicians today. For the sake of many advantages such as the excellent thermal conductivity, low volumetric change, high strength, low risk of fracture and the better patient's adaptation, the metal based complete dentures are indicated to the several cases. But, there are common failures of these type of dentures mainly by the fracture or the debonding between the resin structures and the metal frameworks which is caused by the discrepancies of the flexural strength and the coefficient of thermal expansion. This is aggravated by the water contamination of the interface when exposed to the oral environment and results in the failure of complete denture treatment. So, the purpose of this study is to compare the bond strength and the fracture patterns of the gold alloy based and the Co-Cr alloy based complete dentures using the PMMA resins and the 4-META adhesive resins. The results of this study were as follows. 1. Both to the PMMA resin and the 4-META resin, the flexural bond strength of gold alloy is lower than that of Co-Cr alloy(P<0.05) 2. To the Co-Cr alloy, the bond strength of the 4-META resin is significantly higher than that of PMMA resin(P<0.05). 3. The flexural strength of the group with the mechanical retention form is significantly higher than that of the group without retention form(P<0.05). 4. Comparing with the other groups, the fracture patterns of the group 3 are quite different from the group 1,2,5.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.533-542
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• 1995

The present study investigated the effectiveness of pretreatment on dentin bonding. The adhesive resin was 5% 4-methacryloyloxyethyl trimellitate anhydride (4-META) in methyl methacrylate (MMA) combined with poly-MMA powder. Polymerization of this resin was initiated by tri-n-butyl borage (TBB). Ground bovine dentin samples were etched with either an aqueous solution of 10% citric (10-0 solution) (Group I) or aqueous solution of 10% citric acid and 3% ferric chloride(10-3 solution) (Group ll ). After etching, the primer (an aqueous solution of 35% hydroxyethyl methacrylate (HEM- A) and 5% glutaraldehyde was applied on the differently etched surfaces (Group III , Group IV). The 10-0 treatment showed the lowest tensile bond strength, followed by the 10-3 treatment, primer application after the 10-0 treatment and primer application after the 10-3 treatment. The relationship among the surface morphology after pretreatment, fractured surface morphology and tensile bond strength was examined. It revealed that the surface morphology change by different pretreatment influenced the bond strength and the resulting fractured surface morphology. The correlation of tensile bond strength with the fracture morphology was explained.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.4
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• pp.510-525
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• 2000

The effects of pretreatment of Co-Cr alloy, including two adhesive primers that contain either MDP or MAC-10, and silicoating on the bond The result sobtained as follows; o Strength of 4-META/MMA-TBB resin were investigated using FT-IR, SEM, and EDAX. o In the SEM observation of surface morphologies, the sandblasted specimen exibited a very rough surface, whereas the surfaces of the two groups primed with either MDP or MAC-10 were covered with a layer of primer, and the surface morphology of the silicoated specimen remained almost the same after sandblasting. o Before the thermocycling tests, the group treated with MDP demonstrated the highest mean tensile bond strength and the sandblasted group showed the lowest bond strength. o After 20,000 thermocyling, the mean tensile bond strength of the sandblasted group exhibited a 50% reduction in bond strength, while the others showed a $20\sim30%$ reduction. o Observation of the metal-resin interface revealed that in all groups the resin permeated the rough surface formed by sandblasting thereby producing a mechanical bond between the metal and the resin. It was also found that thermocycling resulted in a gap formation at the metal-resin interface of the specimens, and the sandblasted group exhibited a larger gap width than the other groups. o In fracture mode, all specimens indicated a cohesive fracture within the resin before thermocycling. However, thermocyling produced adhesive failure at the edge of the resin-metal interface in most specimens. The sandblasted group, which exhibited the lowest bond strength after thormocycling, also demonstrated the largest area of adhesive failure.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.29 no.2
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• pp.92-102
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• 2020

Bond-Fill SB is made of powder/liquid, and the flowability can be controlled by adjusting the amount of liquid in the brush. Thanks to the strong catalyst called TBB, it has the advantage of being able to polymerize even in the presence of water and oxygen. Also, since it contains 4-META, it has the advantage of being able to adhere to metals and ceramics with appropriate surface treatment. If you fully understand these advantages, you can actively utilize them in cases where it is difficult to treat with conventional composite resin.