• The Journal of Advanced Prosthodontics
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• 제5권2호
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• pp.140-146
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• 2013

PURPOSE. The aim of this study was to investigate the destructive effects of biofilm formation and/or biocorrosive activity of 6 different oral microorganisms. MATERIALS AND METHODS. Three different heat polymerized acrylic resins (Ivocap Plus, Lucitone 550, QC 20) were used to prepare three different types of samples. Type "A" samples with "V" type notch was used to measure the fracture strength, "B" type to evaluate the surfaces with scanning electron microscopy and "C" type for quantitative biofilm assay. Development and calculation of biofilm covered surfaces on denture base materials were accomplished by SEM and quantitative biofilm assay. According to normality assumptions ANOVA or Kruskal-Wallis was selected for statistical analysis (${\alpha}$=0.05). RESULTS. Significant differences were obtained among the adhesion potential of 6 different microorganisms and there were significant differences among their adhesion onto 3 different denture base materials. Compared to the control groups after contamination with the microorganisms, the three point bending test values of denture base materials decreased significantly (P<.05); microorganisms diffused at least 52% of the denture base surface. The highest median quantitative biofilm value within all the denture base materials was obtained with P. aeruginosa on Lucitone 550. The type of denture base material did not alter the diffusion potential of the microorganisms significantly (P>.05). CONCLUSION. All the tested microorganisms had destructive effect over the structure and composition of the denture base materials.

• 대한치과의사협회지
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• 제57권12호
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• pp.747-756
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• 2019

This paper reviews the adaptation accuracy and mechanical properties of currently used denture processing systems with base resin materials and introduces the latest research on the development of antimicrobial denture base resins. Poly(methyl methacrylate) has been successfully used as a dental denture base resin material by the compress-molding method and heat polymerization for a long time, but recently, new processing techniques, injection molding-methods or fluid-resin technique are also used for fabricating denture base. However, studies indicated that there was no difference between the injectionmolding and the conventional compression-molding method in terms of adaption accuracy of denture base. The fluid-resin fabrication and one injection-molding systems exhibited better adaptation accuracy than the other processing methods. Resin denture bases in the oral cavity may undergo midline fractures due to flexural fatigue from repeated masticatory loading. For those patients, impact resistant denture base resins are recommended to prevent denture fracture during service. Thermoplastic denture base resins can be helpful for patients suffering from allergic reaction to resin monomers with a soft-fit, however, thermoplastic resins with low stiffness can irritate gum tissues and accelerate abnormal alveolar ridge resorption. Moreover, due to low chemical durability in oral cavity, those should be used for a limited period of time.

• 구강회복응용과학지
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• 제21권1호
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• pp.59-67
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• 2005

The bond strength of denture base resin and resin teeth, is an important factor in the long term prognosis of dentures. The purpose of this study is to find an appropriate combination of commercial denture base resin and artificial resin teeth according to shear bond strength. In this study, the shear bond strength of various denture base resins (Vertex $RS^{(R)}$(Dentimax Ziest, Holland), $PERform^{(R)}$(Hedent GmbH., Germany), SR $IVOCAP^{(R)}$(Ivoclar AG, Schaan, Liechtenstein)) and resin teeth (SR Orthosit PE(Ivoclar AG, Schaan, Liechtenstein), $Trubyte^{(R)}$ $Biotone^{(R)}$(Dentsply, U.S.A.)) was evaluated. 1. In comparison of denture resin, the shear bond strength increased in the order of $IVOCAP^{(R)}$, $PERform^{(R)}$, Vertex $RS^{(R)}$. 2. In resin teeth, $Trubyte^{(R)}$ $Biotone^{(R)}$ showed higher strength, but there was no statistical difference between the groups. 3. According to loading direction, the lingual showed higher strength, but there was no statistical difference. 4. When using SR Orthosit PE, SR $IVOCAP^{(R)}$ showed significantly higher shear bond strength(p<0.05). 5. Fracture tendancy showed more cohesive fractures(59) than adhesive failures(13). $IVOCAP^{(R)}$ showed the most superior results statistically. $Trubyte^{(R)}Biotone^{(R)}$ showed the highest shear bond strength. When using the SR Orthosit PE, it is thought that $IVOCAP^{(R)}$ would present the most superior results.

• 구강회복응용과학지
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• 제32권3호
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• pp.194-201
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• 2016

목적: 본 연구는 Co-Cr, Ti-6Al-4V 합금에 Zirconium Nitride (이하 ZrN) 적용 시, 의치상 레진과의 접착력을 비교하는 것이다. 연구 재료 및 방법: Co-Cr, Ti-6Al-4V 디스크(직경 10 mm, 두께 2.5 mm)를 각각 14개씩 제작하였고, ZrN 코팅에 따라 2개의 그룹으로 나누었다. Primer로 시편 전처리 후, 의치상 레진(직경 6 mm, 두께 5 mm)을 부착하였다. 표면 측정기를 이용하여 시편의 거칠기를 측정한 후, 만능 시험기를 이용하여 전단결합강도를 측정하였으며, 이원분산분석으로 통계 분석하였다. 시편 표면과 파절 양상을 주사전자현미경을 이용하여 관찰하였다. 결과: ZrN을 코팅한 시편에서 유의하게 높은 표면 거칠기를 나타내었고(P < 0.05), 전단결합강도는 낮았다(P < 0.001). ZrN 코팅 시편에서는 혼합성 파절과 부착성 파절이 함께 나타났다. 결론: Co-Cr, Ti-6Al-4V 합금에서 ZrN 코팅 처리는 의치상 레진과의 결합력을 약화시켰다.

• 대한치과보철학회지
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• 제32권3호
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• pp.411-430
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• 1994

The denture may be fractured accidentally by an impact while outside the mouth, or may be cracked or broken while in service in the mouth. The latter is generally a fatigue failure caused by repeated flexure over a period of time. This investigation compared the flexural fatigue resistance, the impact force and the transverse strength of two denture base materials with and without the grid strengthener, the T300, the T800 and the Kevlar fiber to evaluate the fracture resistance. The distribution and behavior of fibers across fracture lines were examined by Hi-Scope Compact Microvision System. Through analyses of the data from this study, the following conclusions were obtained. 1. The flexural fatigue resistance, impact strength and transverse strength of high impact strength resin were higher than those of conventional heat polymerizing resin, but statistically there was no significant difference(p>0.05). 2. All specimens with and without the grid strengthener did not show significant differences in the flexural fatigue, the impact and the transverse strength test(p>0.05). 3. All specimens reinforced with the T300, the T800 and the Kevlar fiber showed significant increase of the fatigue resistance and the impact force(p<0.05). 4. All specimens reinforced with the T800 and the Kevlar fiber showed significant increase of the transverse strength(p<0.05). 5. All specimens reinforced with the T300, the T800 and the Kevlar fiber exhibited greenstick fractures. The fibers tended to remain enveloped in the resin, resisting pull-out.

• 구강회복응용과학지
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• 제31권4호
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• pp.378-386
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• 2015

피개 의치는 의치의 안정과 유지력 증가라는 장점을 갖지만 지대치가 우식 또는 치주질환에 이환되기 쉬우며 의치의 두께가 얇아짐으로써 의치가 파절되기 쉽다는 단점도 갖고 있다. 자성 어태치먼트 피개 의치는 수직적 유지력은 크지만 수평적 유지력은 작으므로 지대치나 임플란트에 덜 위해한 힘을 가하며, 다른 기계적 유지장치에 비해 마모나 파손 등이 적다는 장점이 있다. 피개 의치에서 나타나는 의치의 파절은 의치상의 두께가 얇아져서 발생하기도 하지만, 연조직과 경조직, 임플란트와 자연치의 압하량 차이로 인해 발생하기도 한다. 이를 보상하기 위해 silicone ball이 자석 안에 삽입되어있는 자성 어태치먼트가 개발되었으며, 이를 이용해 피개 의치를 제작한 증례에서 우수한 결과가 나타나 보고하고자 한다.

• The Journal of Advanced Prosthodontics
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• 제5권3호
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• pp.241-247
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• 2013

PURPOSE. To evaluate the effect of various metal oxides on impact strength (IS), fracture toughness (FT), water sorption (WSP) and solubility (WSL) of heat-cured acrylic resin. MATERIALS AND METHODS. Fifty acrylic resin specimens were fabricated for each test and divided into five groups. Group 1 was the control group and Group 2, 3, 4 and 5 (test groups) included a mixture of 1% $TiO_2$ and 1% $ZrO_2$, 2% $Al_2O_3$, 2% $TiO_2$, and 2% $ZrO_2$ by volume, respectively. Rectangular unnotched specimens ($50mm{\times}6.0mm{\times}4.0mm$) were fabricated and drop-tower impact testing machine was used to determine IS. For FT, compact test specimens were fabricated and tests were done with a universal testing machine with a cross-head speed of 5 mm/min. For WSP and WSL, disc-shaped specimens were fabricated and tests were performed in accordance to ISO 1567. ANOVA and Kruskal-Wallis tests were used for statistical analyses. RESULTS. IS and FT values were significantly higher and WSP and WSL values were significantly lower in test groups than in control group (P<.05). Group 5 had significantly higher IS and FT values and significantly lower WSP values than other groups (P<.05) and provided 40% and 30% increase in IS and FT, respectively, compared to control group. Significantly lower WSL values were detected for Group 2 and 5 (P<.05). CONCLUSION. Modification of heat-cured acrylic resin with metal oxides, especially with $ZrO_2$, may be useful in preventing denture fractures and undesirable physical changes resulting from oral fluids clinically.