丙酮及甲基丙烯酸甲酯表面处理对基托树脂与软衬材料粘接效果的影响

目的 研究丙酮及甲基丙烯酸甲酯表面处理对基托树脂与软衬材料间微渗漏、粘接强度及基托树脂抗弯强度的影响.方法 制备30 mm×30 mm×2 mm树脂块36块,根据随机数字表随机均分为3组,每组12块,丙酮组:树脂块粘接面浸泡于丙酮溶液中30 s;甲基丙烯酸甲酯组:树脂块粘接面浸泡于甲基丙烯酸甲酯溶液中180 s;对照组:不进行表面处理.两树脂块间衬以2 mm软衬材料后粘接,冷热循环5000次,浸泡于131Ⅰ溶液中24h后计数γ射线,即微渗漏数.制备36块30 mm×10 mm ×7.5 mm树脂块,分组及表面处理同上.两树脂块间衬以3 mm软衬材料后粘接,冷热循环5000次后,测试拉伸强度,即粘接强度.制备18块65 mm× 10 mm×3.3 mm树脂块,分组及表面处理同上,涂布软衬材料粘接剂后测试抗弯强度.结果 丙酮组和甲基丙烯酸甲酯组的微渗漏数(520.0±562.2和493.5±447.9)均小于对照组(1369.5±590.2,P＜0.05);丙酮组和甲基丙烯酸甲酯组粘接强度[(1.5±0.4)和(1.4±0.5) MPa]均大于对照组[(0.9±0.2) MPa,P＜0.05];两实验组间微渗漏数和粘接强度差异均无统计学意义(P＞0.05);3组抗弯强度差异均无统计学意义(P＞0.05).结论 丙酮及甲基丙烯酸甲酯表面处理可减少软衬材料与基托树脂间微渗漏,增加两者间粘接强度,未导致基托树脂抗弯强度下降.

Effect of surface pretreatment with chemical etchants on bond strength between a silicone-based resilient liner and denture base resin

Objective To evaluate the effect of denture base resin surface pretreatment with chemical etchants on microleakage and bond strength between silicone-based resilient liner and denture base resin.The initial bending strength of denture base resin after surface pretreatment was also examined.Methods Thirty-six polymethyl methacrylate(PMMA) denture base resin blocks(30 mm × 30 mm × 2 mm)were prepared and divided into three groups:group acetone,group methyl methy acrylate(MMA) and group control.Subsequently,a 2 mm silicone-based resilient liner was applied between every two blocks.After 5000 cycles in the thermal cycler ( 5 and 55 ℃ ),they were immersed in the 131 Ⅰ solution for 24 hours and γ-ray counts were measured.Another 36 PMMA resin blocks( 30 mm× 10 mm ×7.5 mm) were prepared.The blocks were divided into three groups and treated as mentioned above.A 3 mm silicone-based resilient liner was applied between every two blocks.After 5000 thermal cycles,tensile bond strength of the sample was measured in a universal testing machine.Another 18 PMMA resin blocks (65 mm × 10 mm ×3.3 mm) were prepared.They were divided into 3 groups and treated in the same way.After an adhesive was applied,the bending strength was measured with three-piont bending test.Results Two experimental groups showed lower microleakage(520.0 ±562.2 and 493.5 ±447.9) and higher tensile bond strength[( 1.5 ±0.4) and ( 1.4 ± 0.5 ) MPa]than the group control [microleakage:( 1369.5 ± 590.2 ) ; tensile bond strength:(0.9 ± 0.2) MPa,P ＜ 0.05].There was no statistically significant difference between group acetone and MMA in microleakage and tensile bond strength( P ＞ 0.05 ).There was no statistically significant difference in bending strength among the three groups ( P ＞ 0.05 ).Conclusions Treating the denture base resin surface with acetone and MMA decreased the microleakage,increased the tensile bond strength between the two materials and did not make the initial bending strength of denture base resin decline.