离体牙储存方式对牙本质黏结剂微拉伸强度的影响

目的：对比研究不同的离体牙储存方法和时间对牙本质黏结剂Single Bond微拉伸强度的影响。方法：选用30颗因正畸拔除的第一前磨牙,随机分为5组。拔除后立即分别放人4℃的0．02％麝香草酚水溶液、10％甲醛溶液、1％氯胺溶液、蒸馏水中储存,以及用湿纱布包裹-20℃冰箱中储存。分别在储存的第10天、90天取出,在牙冠殆面表层牙本质上使用牙本质黏结剂Single Bond,复合树脂Z250黏结修复,测定牙本质黏结剂的微拉伸强度值。选用新鲜拔除的前磨牙作为对照组。用体视显微镜和扫描电子显微镜观察微拉伸强度测试样本的断裂类型。用SPSS11．5软件对牙本质黏结剂的微拉伸强度值做双因素方差分析。结果：不同的储存方法对牙本质黏结剂微拉伸强度有显著影响(P=0．01),与新鲜拔除的牙比较,蒸馏水中4℃储存(P=0．024)和0．02％麝香草酚水溶液4℃储存(P=0．008)的离体牙的微拉伸强度显著降低;不同的储存时间对牙本质黏结剂的微拉伸强度影响无统计学差异(P=0．279)。所有微拉伸强度测试样本的断裂均发生在黏结界面。结论：离体牙储存方法对牙本质黏结剂Single Bond的黏结强度有重要影响,建议使用离体牙评价牙本质黏结剂的黏结强度时,选用新鲜拔除的牙、-20℃冷冻的牙或1％氯胺溶液4℃储存的牙,以减小不必要的实验误差。     

Influence of moisture conditions on dentin bond strength of single-step self-etch adhesive systems

This study was conducted to clarify the influence of dentin surface moisture on bond strength of single-step self-etch adhesive systems. The adhesive systems used were Adper Prompt L-Pop (AP), Clearfil tri-S Bond (CT), Fluoro Bond Shake One (FB), G-Bond (GB), and One-Up Bond F Plus (OF). Bovine mandibular incisors were wet-ground with #600 SiC to expose the labial dentin. After rinsing with tap water, the dentin surface was dried with air for 10 sec (Dry condition) or blotted (Wet condition). Adhesives were applied according to each manufacturer's instructions, followed by resin composite polymerization. Ten samples per test group were stored in distilled water at 37 degrees C for 24 h, then shear tested at a crosshead speed of 1.0 mm/min. The data were analyzed by Student's t test and Tukey HSD test at a probability level of 0.05. The mean bond strengths for Dry condition ranged from 13.9 MPa to 18.2 MPa, and those for Wet condition ranged from 7.1 MPa to 18.4 MPa. Significantly lower bond strengths were obtained for the Wet condition for GB, FB, and OF. Failure after the test was commonly due to adhesive breakdown associated with partial cohesive failure in the dentin. These data suggest that air-drying of the dentin surface is appropriate for the adhesive systems tested.     

Influence of disinfectants on dentin bond strength of different adhesive systems

The influence of water disinfectants used in dental unit waterlines on the dentin bonding of different adhesive systems was investigated by using push-out tests. Three hundred and twenty dentin disc specimens were prepared from caries-free human molars. In each specimen, a standardized conical cavity was prepared while cooling with water from a dental unit containing one of three different disinfectants (n=80 each group; A=control: water without disinfectant, B: Alpron neutral, C: Alpron mint, D: Dentosept P). Subsequent rinsing of the cavities was performed With the respective disinfectant. The cavities were filled with the following combinations of dentin adhesives and composites, resulting in 16 subgroups (n=20): Syntac Classic/Tetric Ceram, Clearfil Liner Bond 2V/Luxacore, OptiBond FL/Prodigy and Prime&Bond NT/Spectrum. After polishing the fillings, one half of each subgroup (n=10) was stored in water (37 degrees C) for 24 hours. The other half was stored in water (37 degrees C) for 180 days and additionally thermocycled (2000 cycles at 5/55 degrees C). The bond strength was then measured by push-out tests. Statistical analysis of the data was carried out using ANOVA and pairwise t-tests (Significance level p < or = 0.01). The disinfectants showed no significant influence on the loads required for debonding of Syntac Classic/Tetric Ceram, Clearfil Liner Bond 2V/Luxacore and OptiBond FL/Prodigy as compared to the controls. However, the use of disinfectants in the water supply of a dental unit decreased dentin bond strength in the specimens filled with Prime&Bond NT/Spectrum. Disinfectants in the water of dental unit waterlines may have an influence on dentin bonding, depending on the adhesive system used.     

2种牙本质黏结系统对不同深度牙本质微拉伸黏结强度的比较

目的:比较2种不同类型的牙本质黏结系统对深层牙本质和浅层牙本质的微拉伸黏结强度的影响.方法:20颗因正畸拔除的第一前磨牙,在釉牙本质界附近去除冠向牙体组织,暴露牙本质平面.按产品说明书要求,分别黏结全酸蚀黏结剂Prime ＆ Bond NT (PB)和自酸蚀黏结剂FL-Bond(FB),蓝色光固化复合树脂修复.黏结好的标本储于37±10℃的蒸馏水中24h后,将样本片切为0.9 mm±0.9 mm的柱状形态.测量样奉黏结界面与髓腔顶部之间的剩余牙本质的厚度(remaining dentin thickness,RDT),RDT≥3mm者为浅层牙本质组,RDT≤2mm者为深层牙本质组,进行微拉伸黏结强度测试,加载速度1mm/min.体视显微镜下观察断裂类型.采用SPSS11.5软件包对结果进行统计学分析.结果:各实验组的微拉伸黏结强度分别为浅层/FB组(22.63±5.43)MPa、浅层/PB组(28.13±7.80)MPa、深层/FB组(18.65.63±5.44)MPa、深层/PB组(26.82±4.85)MPa,全酸蚀黏结剂PB的黏结强度显著高于自酸蚀黏结剂FB(P<0.05).牙本质深度不同,对微拉伸黏结强度的影响无显著差异(P>0.05).各组的断裂类型多为黏结界面断裂.结论:在离体牙上进行微拉伸黏结强度测试时,牙本质深度不同.对全酸蚀黏结剂和自酸蚀黏结剂的黏结强度无显著影响.     

Influence of environmental conditions on dentin bond strengths of one-application adhesive systems

Resin composites are considered susceptible to environmental conditions that might affect bond strength. This study investigated the influence of relative humidity and temperature on the dentin bond strength of newly developed one-application adhesive systems. Bonding systems employed in this study were five commercial one-application adhesive systems. Labial surfaces of bovine incisors were ground wet on 600-grit SiC paper. The teeth were transferred to a controlled temperature and humidity chamber and the specimens were prepared in six different environmental conditions, A) 25 +/- 0.5 degrees C, 50 +/- 5% RH, B) 25 +/- 0.5 degrees C, 80 +/- 5% RH, C) 25 +/- 0.5 degrees C, 95 +/- 5% RH, D) 37 +/- 0.5 degrees C, 50 +/- 5% RH, E) 37 +/- 0.5 degrees C, 80 +/- 5% RH, F) 37 +/- 0.5 degrees C, 95 +/- 5% RH. The dentin surfaces were treated according to each manufacturer's instructions. Resin composites of each bonding system were condensed into a mold and light irradiated. After storage in 37 degrees C water for 24 hours, 10 specimens per group were tested in a shear mode in a testing machine at a crosshead speed of 1.0 mm/minute. Statistical analysis was carried out with one-way ANOVA followed by Duncan's multiple range tests at a p-value of 0.05. The dentin bond strengths of one-application adhesive systems decreased with increasing RH. These data suggest that the relative high humidity in the oral environment needs consideration in developing clinical procedures for management of these one-application adhesive systems.     

Influence of adhesive application duration on dentin bond strength of single-application bonding systems

This study examined the relationship between the bond agent application duration and the dentin bond strength of several single-application bonding systems. The restorative material/ bonding systems used were Reactmer, with its single-application bonding system Reactmer Bond (RB, Shofu Inc, Kyoto, Japan); Palfique Estelite, with its single-application bonding system One-Up Bond F (OU, Tokuyama Co, Tokyo, Japan) and F2000 Compomer, with its bonding system Primer/Adhesive in Clicker (F2,3M Dental Products, St Paul, MN 55144, USA). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. Adhesives were applied for 5, 10, 20, 30 and 60 seconds, and restorative materials were condensed into a Teflon mold (04 x 2 mm) on the dentin and light activated. Fifteen samples per test group were stored in 37 degrees C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/min. One-way ANOVA followed by Duncan test (p = 0.05) was done. SEM observations of the treated dentin surface were also conducted. The dentin bond strength ranged from 6.9 +/- 2.4 to 11.2 +/- 2.8 MPa for RB, 8.9 +/- 2.2 to 12.2 +/- 1.9 MPa for OU, and 7.8 +/- 3.1 to 11.4 +/- 2.6 MPa for F2. No significant differences were found among the 10-60 second application duration groups for the systems used. From the SEM observations, demineralization of the dentin surface was more pronounced with longer application duration. The data suggest that the duration of single-application bonding systems was not a crucial factor for determining dentin bond strength, even though morphological changes were observed on the dentin surface.     

Influence of formaline cresol on bond strength of adhesive luting agents to dentin

The present study investigates the influence of the pulpotomy agent formaline cresol (FC) on bond strength between dentin and five adhesive systems (Super-Bond C&B, Bistite II, Imperva Dual Set, Panavia 21, and Panavia 21 with AD Gel). After the dentin surfaces of 75 bovine teeth (including 25 control samples) were exposed by grinding, 25 of the samples were soaked in FC for 2 days, and 25 samples were soaked for 7 days. Samples were bonded to acrylic rods using five adhesive systems, and tensile bond strengths were determined after 1-day immersion in water. Data were analysed by analysis of variance and Duncan's new multiple range test, and the fractured surfaces were observed through a scanning electron microscope. The bond strengths were found to be influenced by the type of system, soaking period, and their combination. The bond strength values of three adhesive systems (Super-Bond C&B, Imperva Dual Set Bistite II, and Panavia 21 with AD Gel) decreased after soaking in FC. After 7 days of FC exposure, the highest bond strength (9.8+/-2.9 MPa) was obtained with the Super-Bond C&B system.     

Porcelain to dentin bond strength with a dentin adhesive.

Adhesion of porcelain to dentin may be important in those cases with little remaining enamel. The purpose of this study was to determine the bond strength of porcelain to dentin using a dentin adhesive (All-Bond) and compare it to the enamel bond strength. Sixty human molar teeth had either a dentin or enamel bonding site prepared by flat grinding to a 600 grit. The teeth were divided into three groups of 20 each. Sixty porcelain cylinders were prepared, hydrofluoric acid etched on one end and silane treated. Twenty of the cylinders were bonded to enamel, 20 bonded to dentin with a dentin adhesive to be tested at 48 hours, and 20 bonded to dentin with a dentin adhesive to be tested after 24 hours of thermocycling (800 cycles at 6 degrees C to 60 degrees C). The specimens were tested in an Instron at a crosshead speed of 0.5 mm/minute. The following bond strengths were found: enamel (19.0 +/- 2.9 MPa), dentin at 48 hours (14.4 +/- 5.4 MPa), and dentin after thermocycling (10.1 +/- 3.8 MPa). When this data was subjected to statistical analysis (ANOVA), there was a significant difference between the groups. A Scheffe's test found that the dentin-porcelain bond at 48 hours was stronger than the thermocycled group, and that the enamel bond was significantly stronger than the two dentin bonds.     

Influence of adhesive polymerization mode on dentin bond strength of direct core foundation systems

This study examined the influence of various adhesive systems on dentin bond strength of direct core foundation resins. Two commercially available direct core foundation resin systems and 2 adhesive polymerization modes were used. Facial bovine dentin surfaces were wet ground on 600-grit SiC paper. Dentin surfaces were treated according to the manufacturers' instructions and were light polymerized (control). Chemical- and light-polymerized adhesive systems were used separately. The resin paste was condensed into a mold and bonded to the dentin surface. Ten specimens per test group were stored in water at 37 degrees C for 24 hours, and a shear test was conducted at a crosshead speed of 1.0 mm/minute using a universal testing machine. Analysis of variance (ANOVA) and Duncan's multiple comparison test were performed (alpha = 0.05). Dual polymerization of resin pastes revealed higher bond strength with the combination of light-polymerized adhesive (22.8-24.3 MPa), but significantly lower bond strength with the combination of a chemical-polymerized adhesive (4.2-5.7 MPa). The present data suggests that dentin bond strengths in direct core foundation systems can be influenced by the combination of adhesive and resin paste.     

Influence of intrapulpal pressure simulation on the bond strength of adhesive systems to dentin

The purpose of this study was to evaluate the influence of intrapulpal pressure simulation on the bonding effectiveness of etch & rinse and self-etch adhesives to dentin. Eighty sound human molars were distributed into eight groups, according to the permeability level of each sample, measured by an apparatus to assess hydraulic conductance (Lp). Thus, a similar mean permeability was achieved in each group. Three etch & rinse adhesives (Prime & Bond NT - PB, Single Bond -SB, and Excite - EX) and one self-etch system (Clearfil SE Bond - SE) were employed, varying the presence or absence of an intrapulpal pressure (IPP) simulation of 15 cmH2O. After adhesive and restorative procedures were carried out, the samples were stored in distilled water for 24 hours at 37 degrees C, and taken for tensile bond strength (TBS) testing. Fracture analysis was performed using a light microscope at 40 X magnification. The data, obtained in MPa, were then submitted to the Kruskal-Wallis test ( a = 0.05). The results revealed that the TBS of SB and EX was significantly reduced under IPP simulation, differing from the TBS of PB and SE. Moreover, SE obtained the highest bond strength values in the presence of IPP. It could be concluded that IPP simulation can influence the bond strength of certain adhesive systems to dentin and should be considered when in vitro studies are conducted.     

Influence of pressure application before light-curing on the bond strength of adhesive systems to dentin

This study evaluated the influence of defined pressure application before light-curing on the tensile bond strength (TBS) of two adhesive systems to wet and perfused dentin. Bonding sites were analyzed by scanning electron microscopy (SEM) to assess morphological changes. Dentin discs from 120 human third molars were prepared in such a way to allow simulation of intrapulpal pressure. The specimens were randomly assigned to 6 groups (n=20) according to different experimental conditions. The adhesive systems (ScotchbondTM Multi-Purpose and Syntac(R)) were applied either to wet or perfused dentin. In the latter, compression was applied before adhesive light-curing . TBS was recorded using an universal testing machine. Qualitative examination of the bonding sites was performed by SEM after dissolving the dentin with 50% nitric acid. Pressure application prior to light-curing resulted in a remarkable decrease of TBS for Syntac(R), while no significant change was observed for ScotchbondTM MP. SEM analysis showed no considerable lengthening of the resin tags after pressure application. These findings suggest that application of adhesive systems to dentin under pressure before light-curing had no positive effect on TBS.     

牙本质的表面状态对黏接剂粘接强度的影响

目的研究3种不同的表面状态对两种牙本质黏接剂的粘接强度的影响。方法选用两种牙本质粘接系统SingleBond(SB)和Prime&BondNT(PB),分别应用于干燥、湿润和过湿的离体的人牙本质表面,用Z-100树脂恢复牙冠至4mm。用低速锯片切牙齿,精细金刚砂车针修成沙漏状的粘接面积约0.8mm2的样本,测试各个样本的微拉伸粘接强度。结果两种黏接剂在湿润状态下的粘接强度均高于干燥组和过湿组(P<0.05),干燥组与过湿组的差异无显著性。在3种表面状态下,SB的粘接强度均高于PB组(P<0.05)。结论在使用全酸蚀单瓶粘接系统时,牙本质表面必须保持适度的湿润。