• 제목/요약/키워드: resin adhesive liners

검색결과 10건 처리시간 0.027초

The effect of denture base surface pretreatments on bond strengths of two long term resilient liners

  • Kulkarni, Rahul Shyamrao;Parkhedkar, Rambhau
    • The Journal of Advanced Prosthodontics
    • /
    • 제3권1호
    • /
    • pp.16-19
    • /
    • 2011
  • PURPOSE. Purpose of this study was to evaluate effect of two surface treatments, sandblasting and monomer treatment, on tensile bond strength between two long term resilient liners and poly (methyl methacrylate) denture base resin. MATERIALS AND METHODS. Two resilient liners Super-Soft and Molloplast-B were selected. Sixty acrylic resin (Trevalon) specimens with cross sectional area of $10{\times}10$ mm were prepared and divided into two groups of 30 specimens each. Each group was surface treated (n = 10) by sandblasting (250 ${\mu}$ alumina particles), monomer treatment (for 180 sec) and control (no surface treatment). Resilient liners were processed between 2 poly(methyl methacrylate) surfaces, in the dimensions of $10{\times}10{\times}3$ mm. Tensile strength was determined with Instron Universal testing machine, at a crosshead speed of 5 mm/min; and the modes of failure (adhesive, cohesive or mixed) were recorded. The data were analyzed using one-way ANOVA, followed by Tukey HSD test (${\alpha}$= 0.05). RESULTS. Monomer pretreatment of acrylic resin produced significantly higher bond strengths when compared to sandblasting and control for both resilient liners (P < .001). Sandblasting significantly decreased the bond strength for both the liners when compared to monomer pretreatment and control (P < .001). Mean bond strength of Super-Soft lined specimens was significantly higher than Molloplast-B in various surface treatment groups (P < .05). CONCLUSION. Surface pretreatment of the acrylic resin with monomer prior to resilient liner application is an effective method to increase bond strength between the base and soft liner. Sandblasting, on the contrary, is not recommended as it weakens the bond between the two.

Influence of ozone and paracetic acid disinfection on adhesion of resilient liners to acrylic resin

  • Ekren, Orhun;Ozkomur, Ahmet
    • The Journal of Advanced Prosthodontics
    • /
    • 제8권4호
    • /
    • pp.290-295
    • /
    • 2016
  • PURPOSE. The aim of this study was to evaluate the effect of paracetic acid (PAA) and ozone disinfection on the tensile bond strength (TBS) of silicone-based resilient liners to acrylic resins. MATERIALS AND METHODS. One hundred and twenty dumbbell shaped heat-polymerized acrylic resins were prepared. From the mid segment of the specimens, 3 mm of acrylic were grinded off and separated parts were reattached by resilient liners. The specimens were divided into 2 control (control1, control7) and 4 test groups of PAA and ozone disinfection (PAA1, PAA7, ozone1 and ozone7; n=10). While control groups were immersed in distilled water for 10 min (control1) and 7 days (control7), test groups were subjected to PAA (16 g/L) or ozone rich water (4 mg/L) for 1 cycle (10 min for PAA and 60 min for ozone) per day for 7 days prior to tensile tests. Measurements of the TBS were analyzed using 3-way ANOVA and Tukey's HSD test. RESULTS. Adhesive strength of Mollosil decreased significantly by application of ozone disinfection. PAA disinfection had no negative effect on the TBS values of Mollosil and Molloplast B to acrylic resin. Single application of ozone disinfection did not have any negative effect on TBS values of Molloplast B, but prolonged exposure to ozone decreased its adhesive strength. CONCLUSION. The adhesion of resilient liners to acrylic was not adversely affected by PAA disinfection. Immersion in ozonated water significantly decreased TBS of Mollosil. Prolonged exposure to ozone negatively affects adhesion of Molloplast B to denture base materials.

유구치 아말감 수복물에서 레진 접착성 이장재의 미세 변연 누출에 관한 비교 연구 (AN EXPERIMENTAL STUDY FOR MICROLEAKAGE OF AMALGAM USING RESIN ADHESIVE LINERS IN PRIMARY MOLAR TOOTH)

  • 김종태;최병재;이제호;이종갑
    • 대한소아치과학회지
    • /
    • 제23권2호
    • /
    • pp.401-414
    • /
    • 1996
  • The purpose of this study was to compare the marginal leakage of resin liner which was used as a liner to amalgam restoration. Control group composed of no liner group, copalite group and experimental group composed of All-bond 2, Vitrebond, Superbond D-liner applied groups were evaluated. Cl.V preparation with a size of $3{\times}2{\times}1.5mm$ on 70 extracted primary molars were made and applied appropriate liners for each groups. After amalgam filling and polishing, polished specimens underwent temperature changed from $5^{\circ}C\;to\;55^{\circ}C$ a thousand times. After thermocycling, specimens were placed in 2% methylene blue dye solution for 72 hours in an incubator set at $37^{\circ}C$. The teeth were sectioned buccolingually and the degree of dye penetration was observed with a spectroscopy. (${\times}30$) The following results were obtained. 1. Vitrebond, All-bond 2, Superbond D-liner group exhibited a statistically significant lower degree of dye penetration than no liner and copalite group. (Kruskal-Wallis analysis, P<0.05) 2. No liner group and copalite group exhibited a similar degree of dye penetration. (Mann-Whitney analysis, P>0.05) 3. All-bond 2 group exhibited a statistically significant lower degree of dye penetration than Vitrebond group, (Mann-Whitney analysis, P<0.05) Superbond D-liner group also exhibited a lower degree of dye penetration than Vitrebond group but was statistically insignificant. (Mann-Whitney analysis, P>0.05)

  • PDF

영구 연성 의치상 이장재의 물리적 성질에 관한 연구 (THE STUDY ON THE PHYSICAL PROPERTY OF THE PERMANENT SOFT DENTURE LINERS)

  • 김연미;배정식
    • 대한치과보철학회지
    • /
    • 제37권6호
    • /
    • pp.809-818
    • /
    • 1999
  • This study was performed to evaluate the tensile bond strength and modulus of elasticity of three permanent soft denture liners (Molloplast $B^{(R)}$, Ufi Gel $C^{(R)},\;Tokuyama^{(R)}$) before and after thermocycling. And their water sorption were also evaluated. Each soft denture liner was bonded to PMMA denture base resin blocks and the tensile bond strength and modulus of elasticity were measured by using universal testing machine. For the water sorption, weight measured after immersion of sea denture liners in $37{\pm}1^{\circ}C$ water bath for 4 weeks. The results were as follows : 1. Molloplast $B^{(R)}$ had the highest tensile bond strength, while Tokuyama had the lowest tensile bond strength. There was no significant difference between $Tokuyama^{(R)}$ and Molloplast $B^{(R)}$ in the both nonthermocycling and thermocycling. There was significant difference in tensile strength of $Tokuyama^{(R)}$ before and after thermocycling(p<0.05). 2. For the modulus of elasticity, there was no significant difference between Ufi Gel $C^{(R)}\;and\;Tokuyama^{(R)}$ in the both nonthermocycling and thermocycling. There was significant difference in modulus of elasticity of $Tokuyama^{(R)}$ before and after thermocycling(p<0.05). 3 The failure modes of Molloplast $B^{(R)}$ and Ufi Gel $C^{(R)}$ were mainley adhesive type and that of $Tokuyama^{(R)}$ was mainly mixed type in case of nonthermocycling and cohesive type after thermocycling. 4. The water sorption of each soft liners was within ${\pm}2%$ in times (p<0.05) but. there was no significant difference among the soft liners in times.

  • PDF

Effect of liners and primers on tensile bond strength between zirconia and resin-based luting agent

  • Jo, Eun-Hye;Huh, Yoon-Hyuk;Ko, Kyung-Ho;Park, Chan-Jin;Cho, Lee-Ra
    • The Journal of Advanced Prosthodontics
    • /
    • 제10권5호
    • /
    • pp.374-380
    • /
    • 2018
  • PURPOSE. The effect of silica-based glass-ceramic liners on the tensile bond strength between zirconia and resin-based luting agent was evaluated and compared with the effect of 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing primers. MATERIALS AND METHODS. Titanium abutments and zirconia crowns (n = 60) were fabricated, and the adhesive surfaces of the specimens were treated by airborne-particle abrasion. The specimens were divided into 5 groups based on surface treatment: a control group, 2 primer groups (MP: Monobond Plus; ZP: Z Prime Plus), and 2 liner groups (PL: P-containing Liner; PFL: P-free Liner). All specimens were cemented with self-adhesive resin-based luting agent. After 24-hour water storage and thermocycling (5,000 cycles, $5^{\circ}C/55^{\circ}C$), the tensile bond strength was measured using a universal testing machine. Failure mode analysis and elemental analysis on the bonding interface were performed. The data were analyzed using Kruskal-Wallis test, Dunn's post hoc test, and Fisher's exact test. RESULTS. The liner groups and primer groups showed significantly higher tensile bond strengths than that of the control group (P<.05). PFL showed a significantly higher tensile bond strength than the primer groups (P<.05). The percentage of mixed failure was higher in the primer groups than in the control group (P<.001), and all the specimens showed mixed failure in the liner groups (P<.001). A chemical reaction area was observed at the bonding interface between zirconia and liner. CONCLUSION. The application of liner significantly increased the tensile bond strength between zirconia and resin-based luting agent. PFL was more effective than MDP-containing primers in improving the tensile bond strength with the resin-based luting agent.

연성 의치상 이장재의 인장결합 강도와 탄성계수에 관한 연구 (THE TENSILE BOND STRENGTH AND ELASTIC MODULUS OF THE SOFT DENTURE LINING MATERIALS)

  • 김병진;고준원;이용근;조혜원
    • 대한치과보철학회지
    • /
    • 제35권3호
    • /
    • pp.458-469
    • /
    • 1997
  • This study was to compare the tensile bond strength and flexibility of four different soft liners(Coe-Soft, Soft Relining, Soft-Liner, Dura Base Soft) before & after thermocycling. Each soft liner was bonded to denture base resin block, and measured the tensile bond strength and modulus of elasticity using Universal testing machine. The mean value of tensile bond strength and modulus of elasticity for each experimental groups were statistically processed by SPSS(Statistical Package of Social Science). The obtained results were as follows : 1. Dura Base Soft had the highest tensile bond strength and Coe-Soft had the lowest tensile bond strength. 2. Coe-Soft had the lowest modulus of elasticity, and Dura Base Soft had the highest modulus of elasticity. 3. Thermocycling had no effects on the tensile bond strength and modulus of elasticity of all the soft liners. 4. The failure modes of Coe-Soft, Soft Relining, Soft Liner were mainly cohesive failure, and that of Dura Base Soft were mainly adhesive failure.

  • PDF

애크릴릭 및 실리콘 계열 연성 의치상 이장재의 결합력에 관한 연구 (A Study for Bond Strengths of Acrylic and Silicone Based Soft Lining Materials)

  • 남은주;임주환
    • 구강회복응용과학지
    • /
    • 제16권1호
    • /
    • pp.27-36
    • /
    • 2000
  • One of the methods to improve the softness and comfortness of denture base is the use of soft denture liners. In this study, specimens were made by 2 kinds of acrylic based soft lining materials and 2 kinds of silicone based soft lining materials, and bonded to acrylic resin(Lucitone $199^{(R)}$). Then they were tested the differences of tensile bond strengths according to the materials, thickness, surface treatment and failure mode. 1. Tensile bond strength according to soft lining materials was increased in order of Coe-$soft^{(R)}$, $Mollosil^{(R)}$, $Trusoft^{(R)}$, Ufi-Gel $C^{(R)}$. The differences between groups were statistically significant at level of 0.05. 2. Tensile bond strength according to thickness of soft lining materials was increased in order of 3mm, 2mm, 1mm. The differences between groups were not statistically significant. 3. Tensile bond strength of treated surface showed higher bond strength than nontreated surface. The difference between groups was not statistically significant. 4. The failure mode of Coe-$soft^{(R)}$, $Trusoft^{(R)}$, $Mollosil^{(R)}$ were mainly cohesive failure, and that of Ufi-Gel $C^{(R)}$ were mainly adhesive failure.

  • PDF

A STUDY ON THE ADHESION OF A SOFT LINER CONTAINING 4-META TO THE BASE METAL ALLOY AND ITS VISCOELASTIC PROPERTY

  • Park Hyun-Joo;Kim Chang-Whe;Kim Yung-Soo
    • 대한치과보철학회지
    • /
    • 제41권6호
    • /
    • pp.732-746
    • /
    • 2003
  • Statement of problem. Soft lining materials, also referred to as tissue conditioning materials, tissue heating materials, relining materials, soft liners or tissue conditioners, were first introduced to dentistry by a plastic manufacturer in 1959. Since the introduction of the materials to the dental field, their material properties have been continually improved through the effort of many researchers. Soft lining materials have become widely accepted, particularly by prosthodontists, because of their numerous clinical advantages and ease of manipulation. Unfortunately, few reports have been issued upon the topic of increasing the bond strength between the base metal alloy used in cast denture bases and PMMA soft liner modified with 4-META, nor upon the pattern of debonding and material change in wet environment like a intra oral situation. Purpose. The purposes of this study were comparing the bond strength between base metal alloy used for the cast denture bases and PMMA soft liner modified with 4-META, and describing the pattern of debonding and material property change in wet environment like the intraoral situation. Material and Methods. This study consisted of four experiments: 1. The in vitro measurement of shear bond strength of the adhesive soft liner. 2. The in vitro measurement of shear bond strength of the adhesive soft liner after 2 weeks of aging. 3. A comparison of debonding patterns. 4. An evaluation the Relation time of modified soft liner. The soft liner used in this study was commercially available as Coe-soft (GC America.IL.,USA), which is provided in forms of powder and liquid. This is a PMMA soft liner commonly used in dental clinics. The metal primer used in this study was 4-META containing primer packed in Meta fast denture base resin (Sun Medical Co., Osaka, Japan). The specimens were formed in a single lap joint desist which is useful for evaluating the apparent shear bond strength of adhesively bonded metal plate by tensile loading. Using the $20{\times}20mm$ transparent grid, percent area of adhesive soft liner remaining on the shear area was calculated to classify the debonding patterns. To evaluate the change of the initial flow of the modified adhesive soft liner, the gelation time was measured with an oscillating rheometer (Haake RS150W/ TC50, Haake Co., Germany). It was a stress control and parallel plate type with the diameter of 35mm. Conclusion. Within the conditions and limitations of this study, the following conclusions were drawn as follows. 1. There was significant increase of bond strength in the 5% 4-META, 10% 4-META containing groups and in the primer coated groups versus the control group(P<0.05). 2. After 2 weeks of aging, no significant increase in bond strength was found except for the group containing 10% 4-META (P<0.05). 3. The gelation times of the modified soft liner were 9.3 minutes for the 5% 4-META containing liner and 11.5 minutes for the 10% 4-META liner. 4. The debonding patterns of the 4-META containing group after 2 weeks of aging were similar to those of immediaely after preparation, but the debonding pattern of the primer group showed more adhesive failure after 2 weeks of aging.

적층가공과 절삭가공으로 제작한 의치상과 직접 첨상용 레진 간의 인장결합강도 비교 (Tensile bond strength of chairside reline resin to denture bases fabricated by subtractive and additive manufacturing)

  • 김효성;정지혜;배지명;김정미;김유리
    • 대한치과보철학회지
    • /
    • 제58권3호
    • /
    • pp.177-184
    • /
    • 2020
  • 목적:본 연구의 목적은 절삭가공과 적층가공으로 제작한 의치상과 직접 첨상용 레진과의 인장결합강도를 열중합형 의치상과 직접 첨상용 레진의 인장 결합강도와 비교 및 평가하여 절삭가공과 적층가공으로 제작한 의치상의 직접 첨상을 임상에 활용하고자 하는 것이다. 재료 및 방법:열중합형 의치상 레진(Lucitone 199), 절삭가공용 의치상 레진(VITA VIONIC BASE), 적층가공용 의치상 레진(NextDent Base)을 이용해 가로 25 mm × 세로 25 mm × 높이 3 mm의 직육면체 형태로 제작하였다. 제작한 의치상 레진 시편을 30일간 37℃ 증류수에 보관한 뒤, 건조하여 자가중합형 polyethyl methacrylate (PEMA) 직접 첨상용 레진(REBASE II Normal)을 사용해 결합하였다. 절삭가공과 적층가공용 의치상 레진을 실험군으로, 열중합형 의치상 레진을 대조군으로 설정하고 각 군 당 10개의 시편을 제작하였다. 모든 시편을 24시간 동안 37℃ 증류수에 보관한 뒤 꺼내어 만능시험기를 이용해 10 mm/min의 cross head speed로 인장결합강도를 측정하였고, 파절 양상을 관찰하여 접착 파절, 응집 파절, 혼합 파절로 분류하였다. 의치상의 제작 방법에 따른 직접 첨상용 레진과의 인장결합강도를 일원배치 분산분석으로 분석하였고 사후검정(Bonferroni's method)을 시행하였다 (α= .05). 결과:절삭가공용 의치상 레진과 직접 첨상용 레진과의 인장결합강도(2.33 ± 0.39 MPa)는 열중합형 의치상과 직접 첨상용 레진과의 인장결합강도(2.45 ± 0.39 MPa)와 통계적으로 유의성 있는 차이가 없었다 (P > .999). 적층가공한 의치상 레진과 직접 첨상용 레진과의 인장결합강도(1.23 ± 0.36 MPa)는 나머지 두 군보다 유의성 있게 낮았다 (P < .001). 열중합형과 절삭가공한 의치상에서는 혼합 파절이 가장 많이 나타났으며, 적층가공한 의치상에서는 혼합 파절과 접착 파절이 동일한 빈도로 나타났다. 결론:직접 첨상용 레진과 다양한 방법으로 제작한 의치상의 인장결합강도를 비교하였을 때 적층가공으로 제작한 의치상은 절삭가공으로 제작한 의치상, 열중합형 의치상보다 유의하게 낮은 인장결합강도를 보였다.

목재(木材)파아티클과 철선(鐵線) 복합체(複合體)가 보오드의 물리적(物理的) 및 기계적(機械的) 성질(性質)에 미치는 영향(影響) (Effects of Wood Particles and Steel Wire Compositions on Physical and Mechanical Properties of the Boards)

  • 박헌;이필우
    • Journal of the Korean Wood Science and Technology
    • /
    • 제14권1호
    • /
    • pp.3-44
    • /
    • 1986
  • 목재(木材)파아티클과 성질(性質)이 전혀 다른 철선(鐵線)을 물리적(物理的)으로 결합(結合)시킴으로써 목재(木材)와 철재(鐵材)의 재료적(材料的) 특성(特性)을 서로 보완(補完)하여 목재(木材)파아티클과 철선(鐵線)의 새로운 복합체(複合體)인 목질(木質)-철선(鐵線)보오드를 제조(製造)하고 그 특성(特性)을 구명(究明)하여 기초자료(基礎資料)를 얻고자 하였다. 메란티 합판제조폐재(合板製造廢材)을 이용(利用)한 팔만칩을 12mesh를 통과하고 20mesh체에 남는 큰 파아티클과 20mesh을 통과하고 60mesh체에 남는 작은 파아티클로 구분하여 요소수지를 분무한 다음, 굵기 1mm인 철선(鐵線)을 나비방향과 길이방향으로 1, 2 및 3층(層)으로 배열하여 성형(成型)하고 시험용(試驗用) 복합(複合) 파아티클 보오드를 제조하였다. 1층(層) 철선구성(鐵線構成)보오드의 경우에는 철선간(鐵線間)의 배치간격(配置間隔)을 나비방향과 길이방향(方向)으로 각기 0.5cm, 1cm, 1.5cm, 2cm 및 2.5cm 등(等) 5가지로 하여 24가지의 철선구성방법(鐵線構成方法)으로 하였으며, 2층(層) 철선구성(鐵線構成 )보오드는 철선구성간격(鐵線構成間隔)을 1cm로 하였고 철선구성방법(鐵線構成方法)을 3가지로 하였으며, 3층(層) 철선구성(鐵線構成)보오드는 철선구성간격(鐵線構成間隔)을 1cm로 하고 철선구성방법(鐵線構成方法)을 11가지로 하여 제조(製造)한 보오드는 대조(對照)보오드를 포함(包含)하여 312개였다. 보오드를 성형(成型)한 열압온도(熱壓溫度) 160$^{\circ}C$, 악력(壓力) 35kgf/$cm^2$, 열압시간(熱壓時間) 9분(分)으로 하여 보오드를 제조(製造)하고 이 목질(木質) 철선복합(鐵線複合)보도드의 물리적(物理的) 및 기계적(機械的) 성질(性質)을 측정(測定)분석(分析)한 바 다음과 같은 결과(結果)를 얻었다. 1. 큰 파아티클과 작은 파아티클로 제조(製造)한 보오드에서 철선구성층수(鐵線構成層數) 및 구성철선(構成鐵線)의 수(數)가 많은 보오드일수록 그 비중(比重)은 컸었다. 2. 큰 파아티클로 제조(製造)한 보오드는 철선구성(鐵線構成)으로 인하여 두께팽창율(膨脹率)의 감소(減少)가 뚜렷하였으며 특히 철선구성층수(鐵線構成層數)가 많을수록 이 팽창율(膨脹率)은 더 개선되었다. 3. 큰 파아티클 및 작은 파아티클로 제조(製造)한 보오드 공(共)히 철선구성층수(鐵線構成層數)가 증가(增加)함에 따라 철선(鐵線)의 강도적(强度的) 특성(特性)이 파아티클 휨강도(强度) 성질(性質)을 보강(補强)하여 파괴계수(破壞係數), 탄성계수(彈性係數), 휨 극한하중(極限荷重) 일량(量) 등(等)이 개선(改善)되었으며, 2층(層) 및 3층(層) 철선구성(鐵線構成)보오드의 경우 보오드의 하층(下層)의 철선구성방향(鐵線構成方向)이 보오드의 길이방향(方向)과 일치(一致)하는 보오드가 특(特)히 큰 휨강도(强度) 향상(向上)을 보여 인장라미네이션을 얻었다. 4. 1층(層) 철선구성(鐵線構成)보오드는 철선구성간격(鐵線構成間隔)에 따른 개구면적(開口面積)과 파아티클의 크기에 따라 파괴계수(破壞係數), 탄성계수(彈性係數), 휨 극한하중(極限荷重) 일량(量) 등(等)이 다르게 나타났으나, 큰 파아티클로 제조(製造)한 보오드의 파괴계수(破壞係數)는 개구면적(開口面積)이 1.5~3$cm^2$이고, 나비 방향(方向)의 철선구성간격(鐵線構成間隔)이 1~2cm이면서 길이방향(方向)의 철선구성간격(鐵線構成間隔)이 1.5~2.5cm인 보오드가 높은 값을 나타냈고 작은 파아티클로 제조(製造)한 보오드의 파괴계수(破壞係數)는 개구면적(開口面積)이 0.5~1.5$cm^2$ 및 3.75~6.25$cm^2$이고 나비 방향(方向)의 철선간격(鐵線間隔)이 0.5cm이거나 2.5cm인 보오드가 높은 값을 나타냈다. 5. 큰 파아티클로 제조(製造)한 1층(層) 철선구성(鐵線構成)보오드의 탄성계수(彈性係數)는 개구면적(開口面積)이 1.5~3$cm^2$이고 나비방향(方向) 및 길이방향(方向)의 철선구성간격(鐵線構成間隔)이 1~2.5cm에서 큰 값을 나타냈으며, 한편 작은 파아티클로 제조(製造)한 보오드의 탄성계수(彈性係數)는 개구면적(開口面積)이 0.75~1.25$cm^2$ 민 3~6.25$cm^2$이고, 나비방향(方向)의 철선구성간격(鐵線構成間隔)이 0.5 또는 2.5cm에서 큰 값을 나타내었다. 6. 큰 파아티클로 제조(製造)한 1층(層) 철선구성(鐵線構成)보오드의 휨 극한하중(極限荷重) 일량(量)은 개구면적(開口面積)이 1~3$cm^2$인 보오드가 큰 값을 보였고, 작은 파아티클로 제조(製造)한 보오드의 경우의 그것은 철선(鐵線)의 개구면적(開口面積)이 좁은 것이 크게 나타났다. 7. 박리저항(剝離抵抗) 및 나사못보지력(保持力)은 큰 파아티클로 제조(製造)한 3층(層) 및 2층(層) 철선구성(鐵線構成)보오드에서 대부분(大部分) 대조(對照)보오드보다 큰 값을 보였으나 작은 파아티클로 제조(製造)한 보오드에서는 뚜렷한 경향이 없었다. 큰 파아티클로 제조(製造)한 1층(層) 철선구성(鐵線構成)보오드의 박리저항(剝離抵抗) 및 나사못보지력(保持力)은 전체적으로 비슷한 수준(水準)을 보였고 작은 파아티클로 제조한 보오드에서는 개구면적(開口面積)이 증가(增加)함에 따라 박리저항(剝離抵抗)은 증가(增加)하고 나사못보지력(保持力)은 감소(減少)하는 현상(現象)을 보였다.

  • PDF