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目的:研究四氟化钛(TiFn 4)溶液对酸蚀症牙本质粘接强度的影响。n 方法:选取24颗新鲜拔除的人第三磨牙,获取冠部近髓腔的牙本质,随机分为6组,每组4颗牙,其中4组通过酸蚀和机械力方法建立人工酸蚀症牙本质模型,另外2组为健康牙本质。随机选取1组人工酸蚀症牙本质和1组健康牙本质,使用扫描电镜和显微硬度仪测定其表面形貌与表面硬度,评价人工酸蚀症牙本质的建模效果。另外3组人工酸蚀症牙本质和1组健康牙本质用于粘接测试,按不同处理分为4组:4.0% TiFn 4处理酸蚀症牙本质组(4.0% TiFn 4-ED组)、2.5% TiFn 4处理酸蚀症牙本质组(2.5% TiFn 4-ED组)、无处理酸蚀症牙本质组(ED组)及健康牙本质组(SD组)。使用SE Bond自酸蚀粘接系统进行粘接,AP-X复合树脂分层充填,测定即刻微拉伸粘接强度并观察断裂模式。n 结果:人工酸蚀症牙本质和健康牙本质的显微硬度值分别为(56.92±5.27)HV和(60.19±4.52)HV,组间比较差异有统计学意义(n P<0.05)。扫描电镜结果证实,人工酸蚀症牙本质与自然酸蚀症牙本质的微观形貌特征相符。4.0% TiFn 4-ED组、2.5% TiFn 4-ED组、ED组和SD组的微拉伸粘接强度分别为(28.94±8.04)MPa、(46.08±8.19)MPa、(20.39±7.46)MPa和(45.16±7.86)MPa。2.5% TiFn 4-ED组和SD组的微拉伸粘接强度比较,差异无统计学意义(n P=0.529),二者均高于4.0% TiFn 4-ED组和ED组(均n P<0.05)。4组断裂模式分布比较,差异有统计学意义(n χ2=54.91,n P<0.001)。2.5% TiFn 4-ED组以内聚牙本质断裂为主,提示其粘接强度可能高于微拉伸测试均值。n 结论:酸蚀症牙本质粘接强度低于健康牙本质,2.5% TiFn 4溶液可显著提高酸蚀症牙本质的粘接强度。n “,”Objective:To investigate the effect of titanium tetrafluoride (TiFn 4) solution on bonding strength of acid-etched dentin.n Methods:Tooth crown dentin proximal to the pulp cavity was obtained from 24 freshly-extracted human third molars and randomly divided into 6 groups (n n=4 each) n . Among them, 4 groups were modeled for artificial acid-etched dentin by means of acid-etching and mechanical friction. The other 2 groups were used as sound dentin controls. One each of the artificial acid-etched dentin groups and sound dentin control groups were randomly selected and studied under scanning electron microscope and microhardness tester to measure the surface morphology and hardness, and to evaluate the effectivity of the modeling for artificial acid-etched dentin. The other 3 groups of artificial acid-etched dentin and remaining group of healthy dentin were used for bonding test, re-assigned into 4 groups according to different treatments: etched dentin treated with 4.0% TiFn 4 (4.0% TiFn 4-ED group) , etched dentin treated with 2.5% TiFn 4 (2.5% TiFn 4-ED group) , untreated etched dentin (ED group) and sound dentin control (SD group) . All dentin samples were then bonded with a self-etching system (SE bond) , layered by AP-X composite resin with light-curing. Microtensile bonding strength (μTBS) test was used to measure the immediate bonding strength and to determine the fracture pattern.n Results:The microhardness values of artificial acid-eched dentin and sound dentin were (56.92±5.27) HV and (60.19±4.52) HV, respectively, with significant difference between groups (n P<0.05) . Scanning electron microscopy confirmed that the artificial acid-etched dentin presented microscopic morphological characteristics consistent to natural acid etching. The μTBS of 4.0% TiFn 4-ED group, 2.5% TiFn 4-ED group, ED group and SD group were (28.94±8.04) MPa, (46.08±8.19) MPa, (20.39±7.46) MPa and (45.16±7.86) MPa, respectively. The μTBS did not differ significantly between the 2.5% TiF n 4-ED group and the SD group (n P=0.529) , and both were higher than those in the 4.0% TiFn 4-ED group and the ED group (all n P<0.05) . The fracture patterns differed significantly among the 4 groups (n χ2=54.91, n P<0.001) . In the 2.5% TiFn 4-ED group, cohesive dentin fracture was the main cause, suggesting that the bonding strength may be higher than the mean measurements from the micro-tensile test.n Conclusion:The bonding strength of acid-etched dentin is lower compared with sound dentin. 2.5% TiFn 4 solution can significantly improve the bonding strength of acid-etched dentin.n