粘结层厚度对纤维桩在根管内剪切粘结强度的影响

摘要

目的:研究3种不同粘结层厚度在不同根管部位对纤维桩粘结强度的影响.方法:取18个离体上颌单根管前牙,常规根管治疗后根据不同桩道预备直径随机分为3组.I组:直径1.2 mm的RTD纤维桩配套钻头预备桩道;Ⅱ组:直径1.4 mm的RTD纤维桩配套钻头预备桩道;Ⅲ组:直径1.6 mm的RTD纤维桩配套钻头预备桩道.桩道预备后使用酸蚀加自粘结材料(320g/L磷酸+RelyXUnicem)对纤维桩进行粘结,之后将粘结有纤维桩的牙根切割成1 mm厚度的薄片,标记根管冠部、中部和尖部.用金相显微镜对每个薄片上粘结层的厚度进行测量,然后进行薄片推出测试,记录薄片推出力值并在光学显微镜下观察薄片的破坏方式.结果:不同粘结层厚度在不同根管段内均对纤维桩粘结强度有影响,在根管各段均以I组粘结强度最大,Ⅱ组次之,Ⅲ组最小,组间比较差异有统计学意义(P<0.05).结论:粘结层的厚度对纤维桩在根管内的粘结强度有影响,纤维桩直径与桩道相匹配,即粘结层厚度较薄时粘结强度最高.%AIM: To evaluate the effect of cement film thickness and the different root region on the bond strength of the fiber post in the root canal by the push-out test method. METHODS: Eighteen intact human maxillary central incisors were treated endodontically and divided into three groups in accordance with different drill's diameter; group I with diameter 1.2 mm, group Ⅱ with diameter 1.4 mm and group Ⅲ with diameter 1.6 mm drill. 32% phosphoric etching and RelyX Unicem were used to cement diameter 1.2 mm posts . Then, six thin - slice specimens with thickness 1 mm( ±0.05 mm) were made, indented as coronal, middle, and apical region. The thickness of the cement film in thin - slice specimens was measured with metalloscope before push-out test was performed. And the damage mode of thin-slice specimens was observed with optical microscope . RESULTS; The test showed that different groups with different cement film thickness achieved significantly different results (P <0. 05). For the variable "root region" , the coronal region resulted in statistically significant difference with middle or apical region (P < 0. 05) in each group. CONCLUSION:The thickness of resin cement film influences the bond strength of the fiber post. Coronal root region has the highest bond strength.