中文摘要：

目的：评价试样夹具对微拉仲黏结强度测定的影响。方法：将12个离体人磨牙的黯面釉质切除，暴露牙本质并以600^#水砂纸打磨表面，然后将牙齿分为4组，每组3个牙。在牙本质表面分别应用下面4种黏结剂：Prime＆Bond NT（ Dentsply）, Contax（ DMG）, Adper Prompt （3M/ESPE）及 Clearfil S^3 Bond（Kuraray） ，光照固化后在黏结剂上分层堆塑制作复合树脂冠。浸37℃水24h后，顺牙齿长轴分别从近远中向及颊舌向切割牙齿，制备截面为0．8mm。的条状树脂-牙本质黏结试样．将每组黏结试样的一半黏固到无导向杆的夹具A上，另一半黏固到有导向杆的夹具B上，然后在拉力试验机上以1．0mm／min的速度测定拉伸黏结强度。结果：在夹具A上测定的拉伸黏结强度均显著小于在夹具B上的测定值（P〈0．01），夹具A上的试样在测定过程中出现明显弯曲现象，而且多数试样的断裂模式为混合破坏及复合树脂内聚破坏，而夹具B测定的试样绝大多数为黏结破坏。结论：无导向杆的夹具在测定拉伸黏结强度时存在明显弯曲现象，其测定值不能准确反映试样的拉仲黏结强度，而有导向杆的夹具测定的拉伸黏结强度能准确反映试样的拉伸黏结强度。

英文摘要：

AIM： To evaluate the effects of testing jigs on micro - tensile bond strength （TBS）. METHODS： Twelve extracted human molars were sectioned to expose the mid -coronal dentin. Each surface was grounded with 600 - grit SiC paper. Four adhesives { Prime＆Bond NT （ Dentsply, USA）, Contex （ DMG, German）, Adper Prompt （3M/ESPE,USA） and Clearfil Ss Bond （Kuraray, Japan） } were applied to the polished surfaces followed by creation of composite buildups. After 24 hr storage in 37℃ water, the teeth were sectioned perpendicular to the adhesive interface to produce multiple beams of composite - bonded dentin, approximately 0.8 mm2 in cross - sectioned area. Half of the specimens was attached to the testing jig A which did not contain positioning pins, and another half of the specimens was attached to the testing jig B which contained positioning pins. All specimens were tested using a univer- sal testing machine at a crosshead speed of 1.0 mm/min. RESULTS： Specimens tested using the jig A presented lower TBS than using the jig B （ P 〈 0. 01 ）. Many specimens tested using the jig A showed mix failure or cohesive failure within composite, and most of the failures were adhesive for specimens tested using jig A. CONCLUSION： Testing jigs without positioning pins cannot accurately present TBS and the jigs with positioning pins can present TBS more accurately.