Almeida Júlio C F, Osorio Raquel, Garcia Fernanda C P, Osorio Estrella, Carvalho Ricardo M, Toledano Manuel
Division of Dentistry, University Hospital of Brasilia, University of Brasilia-UnB, Brazil.
Am J Dent. 2010 Jun;23(3):137-41.
To evaluate the effect of oxalate during total-etch bonding, under different dentin moisture conditions, over time. The null hypothesis tested was that microtensile bond strength (microTBS) was not affected by oxalate treatment and dentin moisture during two evaluation periods.
Extracted human third molars had their mid-coronal dentin exposed flat and polished with 600-grit SiC paper. The surfaces were etched with 35% phosphoric acid for 15 seconds, washed and blot dried. After etching, a 3% potassium oxalate gel was applied for 120 seconds, except for the control group (no desensitizer). The surface was then washed and left moist (Wet bonding) or air-dried for 30 seconds (Dry bonding). The surfaces were bonded with: (1) two 2-step etch-and-rinse adhesives: Single Bond (SB); Prime & Bond NT (PBNT) and (2) one 3-step etch-and-rinse adhesive: Scotchbond Multi Purpose (SBMP). Composite buildups were constructed incrementally with Tetric Ceram resin composite. Each increment was cured for 40 seconds. After storage in water for 24 hours or 1 year at 37 degrees C, the specimens were prepared for microTBS testing with a cross-sectional area of approximately 1 mm2. They were then tested in tension in an Instron machine at 0.5 mm/minute. Data were analyzed by ANOVA and Student-Newman-Keuls at alpha = 0.05.
Application of potassium oxalate had no significant effect on the bond strengths of SBMP and PBNT, regardless of the surface moisture condition (P > 0.05). Conversely, reduced bond strengths were observed after oxalate treatment for SB in both moisture conditions, that being significantly lower when using a dry-bonding procedure (P < 0.05). Lower bond strength was obtained for PBNT when a dry-bonding technique was used, regardless of the oxalate treatment (P < 0.05). After aging the specimens for 1 year, bond strengths decreased. Smaller reductions were observed for SBMP, regardless of moisture conditions. For the WB technique, smaller reductions after 1 year were observed without oxalate treatment for SB and after oxalate treatment for PBNT.
评估草酸盐在不同牙本质湿度条件下，随时间推移在全酸蚀粘结过程中的作用。所检验的零假设为，在两个评估期内，微拉伸粘结强度（microTBS）不受草酸盐处理和牙本质湿度的影响。
提取的人类第三磨牙将其牙冠中部牙本质暴露并磨平，用600目碳化硅砂纸抛光。表面用35%磷酸酸蚀15秒，冲洗并吸干。酸蚀后，除对照组（未使用脱敏剂）外，应用3%草酸钾凝胶120秒。然后冲洗表面，使其保持湿润（湿粘结）或风干30秒（干粘结）。表面用以下材料粘结：（1）两种两步酸蚀冲洗粘结剂：单组分粘结剂（SB）；预粘结剂和粘结剂NT（PBNT），以及（2）一种三步酸蚀冲洗粘结剂：多功能 Scotchbond（SBMP）。用Tetric Ceram树脂复合材料逐层构建复合树脂堆积体。每层固化40秒。在37℃水中储存24小时或1年后，制备用于微拉伸粘结强度测试的试样，其横截面积约为1平方毫米。然后在Instron试验机上以0.5毫米/分钟的速度进行拉伸测试。数据采用方差分析和Student-Newman-Keuls检验，显著性水平α = 0.05。
无论表面湿度条件如何，草酸钾的应用对SBMP和PBNT的粘结强度均无显著影响（P > 0.05）。相反，在两种湿度条件下，SB经草酸盐处理后的粘结强度均降低，在采用干粘结程序时显著更低（P < 0.05）。无论是否进行草酸盐处理，采用干粘结技术时PBNT的粘结强度均较低（P < 0.05）。试样老化1年后，粘结强度降低。无论湿度条件如何，SBMP的降低幅度较小。对于湿粘结技术，SB未进行草酸盐处理和PBNT进行草酸盐处理后，1年后观察到的降低幅度较小。
