• Restorative Dentistry and Endodontics
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• 제24권3호
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• pp.473-481
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• 1999

This study evaluated the shear bond properties of IPS Empress glass ceramic to enamel and dentin surfaces with three ceramic surface treatments, and three resin cements. The influence of thermocycling was also investigated. The purpose of this study was to investigate the influences of resin cements, ceramic surface treatments, and thermocycling on shear bond properties. Ninety freshly extracted, noncarious human molars were selected for this study. The surface treatments of ceramic were etching <5.0% hydrofluoric acid, application of silane coupling agents(Tokuso Ceramic Primer, Clearfil porcelain bond, Monobond-S), and the combination of the two methods. Empress cylinders were bonded to enamel and dentin surfaces with three kinds of resin cements(Bistite resin cement, Panavia 21, Variolink). The specimens were aged in $37^{\circ}C$ distilled water for 24 hours. Half of the specimens were then thermocycled 500times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 15 seconds. Each specimen was debonded in shear mode and measured shear bond properties by using the universal testing machine(Zwick 020, Germany). The data were analyzed by SPSS/PC+(one-way ANOVA, Scheffe' s test and t-test). The results were as follows : 1. Without thermocyling, there was significant difference of shear bond strength to enamel surface between Bistite Resin Cement and Panavia 21 in case of etched and silane-treatment(p<0.05). 2. Without thermocyling, the shear bond strength of a group treated with silane and etching was significantly higher than that of a group treated with silane or etching with the application of Panavia 21 and Variolink(p<0.05). 3. A group treated with etching with the application of Variolink only showed a decrease of shear bond strength after thermocycling(p<0.05).

• 대한치과보철학회지
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• 제51권2호
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• pp.99-106
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• 2013

연구 목적: 본 연구의 목적은 다이의 수렴각과 치관길이의 차이와 시멘트 종류의 차이가 전부주조관의 유지력에 미치는 영향을 비교한 것이다. 연구 재료 및 방법: 치관 길이 5 mm와 10 mm의 금속다이를 각각 5, 10, 15, 25도의 수렴각을 갖도록 제작한 후 전부주조관을 치과용 시멘트 중, 인산아연 시멘트(Fleck's Zinc Phosphate Cement, Mizzy Co., Cherry Hill, NJ, USA), 레진-변형 글래스 아이오노머 시멘트(Vitremer, 3M Dental Products, St, Paul, MN, USA), 레진 시멘트(Panavia 21, Kuraray Co., Osaka, Japan)로 합착하고 500회 thermocycling을 시도한 후, Instron Universal Testing Machine (Instron Corp., Canton, MA, USA)에 장착시켜, 인장력을 가하여 전부주조금관이 분리될 때 까지 인장력을 측정하여 분리되는 순간의 최대하중값(N)을 측정, 비교하였다. 통계분석은 측정된 각 군간 유지력의 상호관계를 알아보기 위하여 one-way 및 two-way ANOVA를 시행하였고 동일 길이를 가진 시멘트 군 사이에서의 수렴각 차이에 따른 영향, 다이 길이 증가에 따른 영향 및 유지력 차이를 검정하기 위해 t-test를, 수렴각 증가 에 따른 유의성을 살펴 보기 위해서는 Tukey's HSD test를 시행하였다(${\alpha}$=0.05). 결과: 동일 수렴각에서 평균 유지력은 레진 시멘트, 인산아연 시멘트, 레진-변형 글래스 아이오노머 시멘트 순으로 높게 나타났으며 모든 시멘트에서 수렴각의 증가에 따 라서 평균 유지력은 유의차를 보이면서 감소하였다(P<.05). 동일 수렴각에서 10 mm 실험군은 다이 길이 5 mm 실험군과 비교해보았을 때 길이 증가에 따른 유지력의 증가가 통계학적으로 유의차를 나타내면서 증가된 결과를 보였다. 5 mm 실험군에서 유지력은 수렴각의 변화와 시멘트의 종류, 수렴각과 시멘트의 상호영향(interaction)에서 모두 유의성 있는 차이를 보였다(P=.001). 각 시멘트 군에서의 유지력은 10 mm 길이 금속 다이의 수렴각이 증가할수록 유의한 차이를 보이면서 감소한 것으로 나타났다 (P=.0001). 결론: 임상에서 사용되고 있는 특정 치과용 시멘트의 적용시 유지력은 지대치의 기하학적 형태에 영향을 받고 있으며 서로 다른 치관 길이와 수렴각을 가지는 경우 유지 력 증가를 위해 시멘트 선택에 있어 주의가 요망된다.

• The Journal of Advanced Prosthodontics
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• 제3권3호
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• pp.119-125
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• 2011

PURPOSE. The aim of this study was to evaluate the influence of resin cement thickness on the microtensile bond strength between zirconium-oxide ceramic and resin cement. MATERIALS AND METHODS. Thirty-two freshly extracted molars were transversely sectioned at the deep dentin level and bonded to air-abraded zirconium oxide ceramic disks. The specimens were divided into 8 groups based on the experimental conditions (cement type: Rely X UniCem or Panavia F 2.0, cement thickness: 40 or 160 ${\mu}m$, storage: thermocycled or not). They were cut into microbeams and stored in $37^{\circ}C$ distilled water for 24 h. Microbeams of non-thermocycled specimens were submitted to a microtensile test, whereas those of thermocycled groups were thermally cycled for 18,000 times immediately before the microtensile test. Three-way ANOVA and Sheffe's post hoc tests were used for statistical analysis (${\alpha}$=95%). RESULTS. All failures occurred at the resin-zirconia interface. Thermocycled groups showed lower microtensile bond strength than non-thermocycled groups (P<.001). Differences in cement thickness did not influence the resin-zirconia microtensile bond strength given the same resin cement or storage conditions (P>.05). The number of adhesive failures increased after thermocycling in all experimental conditions. No cohesive failure was observed in any experimental group. CONCLUSION. When resin cements of adhesive monomers are applied over air-abraded zirconia restorations, the degree of fit does not influence the resin-zirconia microtensile bond strength.

• Restorative Dentistry and Endodontics
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• 제43권3호
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• pp.27.1-27.9
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• 2018

Objectives: The aim of this in vitro study was to evaluate the effects of the thickness and shade of 3 types of computer-aided design/computer-aided manufacturing (CAD/CAM) materials. Materials and Methods: A total of 120 specimens of 2 shades (A1 and A3) and 2 thicknesses (1 and 2 mm) were fabricated using VITA Mark II (VM; VITA Zahnfabrik), IPS e.max CAD (IE; IvoclarVivadent), and VITA Suprinity (VS; VITA Zahnfabrik) (n = 10 per subgroup). The amount of light transmission through the ceramic specimens was measured by a radiometer (Optilux, Kerr). Light-cured resin cement samples (Choice 2, Bisco) were fabricated in a Teflon mold and activated through the various ceramics with different shades and thicknesses using an LED unit (Bluephase, IvoclarVivadent). In the control group, the resin cement sample was directly light-cured without any ceramic. Vickers microhardness indentations were made on the resin surfaces (KoopaPazhoohesh) after 24 hours of dark storage in a $37^{\circ}C$ incubator. Data were analyzed using analysis of variance followed by the Tukey post hoc test (${\alpha}=0.05$). Results: Ceramic thickness and shade had significant effects on light transmission and the microhardness of all specimens (p < 0.05). The mean values of light transmittance and microhardness of the resin cement in the VM group were significantly higher than those observed in the IE and VS groups. The lowest microhardness was observed in the VS group, due to the lowest level of light transmission (p < 0.05). Conclusion: Greater thickness and darker shades of the 3 types of CAD/CAM ceramics significantly decreased the microhardness of the underlying resin cement.

• Journal of Korean Dental Science
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• 제1권1호
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• pp.28-34
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• 2008

Objectives. The objectives of this study were: 1) to compare the effect of varying timing of light curing on shear bond strength, and; 2) to compare the shear bond strength of three self-adhesive cements. Materials and methods. A total of 72 extracted non-carious teeth were divided into 24 for Unicem tests, 24 for Maxcem tests, and 24 for Biscem tests; they were assigned 3 * 2 subgroups of 12 teeth each. The specimens were prepared as follows: 1) The calculus and periodontal ligament were removed from the teeth; 2) The teeth were stored in normal saline; 3) The occlusal enamel of each tooth was removed using high-speed coarse diamond burs under water cooling, and; 4) Finally, the teeth were flattened by 600-grit silicone carbide paper disks. Resin blocks were adhered using either Unicem, Maxcem, or Biscem. Light curing timing was divided into two groups: U10, M10, and B10 were exposed to light after 10 seconds, and; U150, M150, and B150 on the other side were exposed to light after 150 seconds. Shear bond strength was measured by a Universal testing machine with cross head speed of 1mm/min. T-test and One way ANOVA were used for the statistical analysis of data. Results. The shear bond strength of U150 was not significantly higher than that of U10 (U150: 20.55.7Mpa, U10: 18.73.80Mpa). On the other hand, the shear bond strength of M150 was significantly higher than that of M10. The shear bond strength of B150 was also significantly higher than that of B10 (M150:14.45.7Mpa, M10: 9.94.2Mpa, B150: 24.38.3Mpa, B10: 17.27.3Mpa). When the light curing timing was 10sec after bonding, the shear bond strength of Unicem was highest; the shear bond strength of Biscem was highest when the light curing timing was 150sec after bonding (U10: 18.73.80Mpa, B150: 24.38.3Mpa). Significance. Since Unicem is less sensitive based on light curing timing, dentists seem to use it without considering the light curing timing. Maxcem showed the lowest bonding strength (especially M10). Thus, when using Maxcem, dentists need to delay the light curing after adhesion.

• 구강회복응용과학지
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• 제29권4호
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• pp.377-383
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• 2013

이 연구의 목적은 치과임상에서 사용되는 8종의 합착용 시멘트의 방사선불투과성을 디지털 방사선 촬영술로 평가하는 것이었다. BisCem, Clearfil SA Luting, Duolink, Maxcem Elite, Multilink Speed, Panavia F 2.0, RelyX Unicem Clicker, V-link의 8종의 재료를 5개의 원형 시편 (직경: 4 mm, 두께: 1 mm)으로 제작하였고 사람 치아의 법랑질과 상아질 시편을 1 mm 두께로 준비하여 알루미늄 스텝 웨지와 함께 촬영하였다. 관전압 70kVP, 관전류 4 mA, 노출시간 0.156초, 초첨 필름간 거리는 30 cm으로 영상판을 이용하여 촬영하였으며, ImageJ 소프트웨어를 이용하여 평균 회색조 수치를 측정하고, 이를 흡수계수로 환산한 후 검량선(calibration curve)을 이용하여 각 합착용 시멘트의 등가 알루미늄 두께를 구하였다. 합착용 시멘트의 평균 방사선불투과성은 알루미늄 두께 0.71 ~ 5.66 mm로, RelyX Unicem Clicker (0.71 mm Al)을 제외하고는 등가 알루미늄 두께 보다 높은 방사선불투과성을 보여 ISO 규격을 만족하였으며, 법랑질은 1.79 mm, 상아질은 0.19 mm 두께의 알루미늄에 해당하는 방사선불투과성을 나타내었다.

• 대한소아치과학회지
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• 제36권3호
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• pp.427-432
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• 2009

본 연구의 목적은 시중에 유통되고 있는 밴드 시멘트들을 종류별로 이용하여 교정용 밴드의 결합강도를 비교하고, 각 시멘트의 파절 양상을 비교하여 교정용 밴드에 대한 사용지침을 마련하는데 도움이 되고자 하였다. 100개의 발거된 인간의 제 3대구치를 이용해 실험군은 총 5개의 군으로 하였으며, 각 군당 시편수가 20개가 되도록 임의적으로 분류하였다. 실험에 사용한 밴드 시멘트는 다음과 같다; Ormco gold, Ultra $Band-Lok^{TM}$, Fuji $Ortho^{TM}$ LC, 3M $Unitek^{TM}$ Multi-Cure Glass Ionomer, $Ketac-Cem^{TM}$. Universal testing machine(Instron Corp., Canton, MA, USA)를 사용하여 최대하중값을 측정하였고, 전단결합강도 값을 계산하였다. 밴드가 탈락한 후, 탈락 부위를 평가하여 법랑질과 시멘트, 시멘트와 밴드 사이로 구분하였다. 밴드의 전단강도는 One-way ANOVA를 이용하여 통계처리 하였으며 Tukey test를 이용하여 검정하였다. 또한 탈락 부위는 Chi-squre analysis를 이용하여 통계 처리하였고, Fisher's exact test로 군간 유의성을 검정하였다. 실험 결과 평균 파절 강도는 Ormco군이 가장 높았고(2.44${\pm}$0.57), Fuji $Ortho^{TM}$군(2.24${\pm}$0.50), $Ketac-Cem^{TM}$군(2.10${\pm}$0.57), 3M $Unitek^{TM}$군(1.82${\pm}$0.43), $Band-Lok^{TM}$군(1.73${\pm}$0.28) 순이었으며, Ormco군은 $Band-Lok^{TM}$군과 3M $Unitek^{TM}$군, Fuji $Ortho^{TM}$군은 $Band-Lok^{TM}$군과만 통계적으로 유의할만한 차이를 보였다(p<0.05). 파절 양상에서 Ormco군과 $Band-Lok^{TM}$군은 서로뿐만 아니라 다른 군과 유의할만한 차이를 보였으며, Fuji $Ortho^{TM}$, 3M $Unitek^{TM}$, $Ketac-Cem^{TM}$ 군 간에는 유의한 차이가 없었다.

• Restorative Dentistry and Endodontics
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• 제12권2호
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• pp.73-80
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• 1987

The present study was designed to help elucidate the effect of glass ionomer cements on the exposed dental pulp by means of histologic examination. A total of 40 cavities of class V were prepared on the teeth of 4 dogs with exposure of 1mm in diameter on the bases of them. 20 cavities were filled with glass ionomer cement as the experimental group and the other 20 cavities were filled with zinc oxide eugenol cement as the control group. The dogs were sacrificed at one, two, three, and four weeks after filling, and the specimens were routinely prepared and stained with Hematoxylin-Eosin. The obtained microscopic findings were as follows: Inflammatory cell infiltrations were observed in control in 1 week, which decreased markedly with time. In all control groups, hemorrhage around exposed pulp tissue and coagulation change of pulp were observed. Secondary dentin formation and thickened predentin were observed in 4 week cases, and the recovery of pulp tissue was favorable on the whole. Inflammatory cell infiltration was observed in all GIC groups. Proliferation of blood vessel and congestion were observed with coagulation changes around the exposed pulp tissue. Secondary dentin formation and thickened predentin were observed in 3 weeks. In the experimental 4 week case, secondary dentin formation was evident. On the whole, pulpal irritation of glass ionomer cement was relatively severe. Recovery of pulp tissue in GIC groups was less favorable compared with that of ZOE groups.

• The Journal of Advanced Prosthodontics
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• 제4권3호
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• pp.139-145
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• 2012

PURPOSE. To evaluate the shear bond strength of resin luting agent to dentin surfaces cleansed with different agents like pumice, ultrasonic scaler with chlorhexidine gluconate, EDTA and the influence of these cleansing methods on wetting properties of the dentin by Axisymmetric drop Shape Analysis - Contact Diameter technique (ADSA-CD). MATERIALS AND METHODS. Forty coronal portions of human third molar were prepared until dentin was exposed. Specimens were divided into two groups: Group A and Group B. Provisional restorations made with autopolymerizing resin were luted to dentin surface with zinc oxide eugenol in Group A and with freegenol cement in Group B. All specimens were stored in distilled water at room temperature for 24 hrs and provisional cements were mechanically removed with explorer and rinsed with water and cleansed using various methods (Control-air-water spray, Pumice prophylaxis, Ultrasonic scaler with 0.2% Chlorhexidine gluconate, 17% EDTA). Contact angle measurements were performed to assess wettability of various cleansing agents using the ADSA-CD technique. Bond strength of a resin luting agent bonded to the cleansed surface was assessed using Instron testing machine and the mode of failure noted. SEM was done to assess the surface cleanliness. Data were statistically analyzed by one-way analysis of variance with Tukey HSD tests (${\alpha}$=.05). RESULTS. Specimens treated with EDTA showed the highest shear bond strength and the lowest contact angle for both groups. SEM showed that EDTA was the most effective solution to remove the smear layer. Also, mode of failure seen was predominantly cohesive for both EDTA and pumice prophylaxis. CONCLUSION. EDTA was the most effective dentin cleansing agent among the compared groups.

• The Journal of Advanced Prosthodontics
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• 제13권4호
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• pp.237-245
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• 2021

PURPOSE. This study aimed to compare the microshear bond strength (µSBS) of dual-cure resin cement in CAD-CAM zirconia after different cleaning techniques. MATERIALS AND METHODS. Fifty discs of zirconia-based ceramic from Ivoclar Vivadent were embedded in acrylic resin. The discs were divided into five groups according to the cleaning methods used: Group 1: drying with spraying + sandblasting with Al₂O₃; Group 2: washed with water and dried with spraying + sandblasting with Al₂O₃;Group 3: washed with distilled water and dried with spraying + sandblasting with Al₂O₃ + zirconium oxide (Ivoclean); Group 4: washed with distilled water and dried with spraying + sandblasting with Al₂O₃ + potassium hydroxide (Zirclean); and Group 5: washed with distilled water and dried with spraying + sandblasting with Al₂O₃ + 1% NaClO. All of the groups were contaminated with artificial saliva for 1 minute and then cleaned. Statistical analyses were performed using ANOVA and Tukey's tests. RESULTS. There were statistically significant differences among all groups for µSBS (P < .05). The group treated with zirconium oxide (Group 3) showed the highest µSBS (18.75 ± 0.23 MPa). CONCLUSION. When applied to zirconia, the cleaning methods affected the bonding with resin cement differently.