Aykent Filiz, Kalkan Mustafa, Yucel Munir Tolga, Ozyesil Atilla Gokhan
Department of Prosthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey.
J Prosthet Dent. 2006 Apr;95(4):297-301. doi: 10.1016/j.prosdent.2006.02.025.
It is necessary to obtain an adequate bond at the core/dentin junction where the majority of failures occur. The effect of recently developed dentin bonding agents on the fracture resistance of endodontically treated teeth at the amalgam core/dentin junction is unclear.
The purpose of this study was to evaluate the effects of 2 dentin bonding agents and a ferrule preparation on the fracture resistance of crowned mandibular premolars incorporating prefabricated dowel and silver amalgam cores.
Sixty extracted mandibular second premolars were divided into 6 groups of 10 each. The coronal portion of each tooth was removed at the cemento-enamel junction (CEJ) in the first 3 groups. In the other groups, teeth were sectioned 1 mm above the CEJ to create a ferrule. After root canal preparations, prefabricated dowels (ParaPost) were placed. The first group served as a control and was tested without application of bonding agents and without incorporation of a ferrule design. In the second and third groups, respectively, an autopolymerizing adhesive (Superbond D-Liner) and a dual-polymerizing adhesive (Panavia F) were applied to tooth surfaces before restorative procedures. For the fourth (ferrule) group, no bonding agent was applied, but a 1-mm ferrule preparation was used. In the fifth (ferrule+D-Liner) and sixth (ferrule+Panavia F) groups, respectively, autopolymerizing and dual-polymerizing bonding agents were used in conjunction with the ferrule preparation. After amalgam core fabrication, Ni-Cr full cast crowns for each group were prepared and cemented. All specimens were stored in water for 1 week and thermal cycled 1000 times between 5 degrees and 55 degrees C. A compressive shear load was applied at an angle of 135 degrees to the crown, and the maximum load at fracture (N) was recorded. The data were analyzed with 1-way ANOVA and Tukey Honestly Significant Difference tests (alpha=.05).
Significantly higher fracture strength values were demonstrated for the ferrule+Panavia F (652.5 N), ferrule+D-liner (649.1 N) and ferrule (592.4 N) groups, respectively, than for the other groups. The next highest fracture strength values were found for the D-Liner (485.0 N) and Panavia F (486.3 N) groups. The control group (376.6 N) demonstrated the lowest fracture strength in all test groups (P<.001).
A ferrule preparation or a bonding agent designed for silver amalgam core-dentin bonding can each increase the fracture strength for teeth receiving cast crowns after endodontic therapy and dowel and amalgam core restorations.
有必要在髓核/牙本质交界处获得足够的粘结力，因为大多数失败都发生在此处。目前尚不清楚最近开发的牙本质粘结剂对根管治疗后的牙齿在汞合金髓核/牙本质交界处的抗折强度有何影响。
本研究的目的是评估两种牙本质粘结剂和一种箍套制备方法对采用预制桩钉和银汞合金髓核的下颌前磨牙全冠修复体抗折强度的影响。
60颗拔除的下颌第二前磨牙被分为6组，每组10颗。在前3组中，每颗牙齿的冠部在牙骨质-釉质界（CEJ）处被切除。在其他组中，牙齿在CEJ上方1mm处进行切割以形成箍套。根管预备后，放置预制桩钉（ParaPost）。第一组作为对照组，不使用粘结剂且不采用箍套设计进行测试。在第二组和第三组中，分别在修复程序前将自凝粘合剂（Superbond D-Liner）和双固化粘合剂（Panavia F）应用于牙齿表面。对于第四组（箍套组），不使用粘结剂，但采用1mm的箍套制备。在第五组（箍套+D-Liner）和第六组（箍套+Panavia F）中，分别将自凝和双固化粘结剂与箍套制备结合使用。制作银汞合金髓核后，为每组制备并粘结镍铬全冠。所有标本在水中保存1周，并在5℃至55℃之间进行1000次热循环。以135度角对全冠施加压缩剪切载荷，并记录断裂时的最大载荷（N）。数据采用单因素方差分析和Tukey诚实显著差异检验（α = 0.05）进行分析。
箍套+Panavia F组（652.5N）、箍套+D-Liner组（649.1N）和箍套组（592.4N）的抗折强度值分别显著高于其他组。接下来抗折强度值较高的是D-Liner组（485.0N）和Panavia F组（486.3N）。对照组（376.6N）在所有测试组中抗折强度最低（P <.001）。
对于根管治疗后接受铸造全冠修复以及桩钉和汞合金髓核修复的牙齿，箍套制备或专为银汞合金髓核-牙本质粘结设计的粘结剂均可提高其抗折强度。
