Farzin Mitra, Torabi Kianoosh, Ahangari Ahmad Hasan, Derafshi Reza
Associate Professor, Department of Prosthodontics Faculty of Dentistry, Shiraz University of Medical Science, Shiraz, Iran.
Associate Professor, Depatment of Prosthodontics, Biomaterial Research Center Faculty of Dentistry, Shiraz, Iran.
J Dent (Tehran). 2014 May;11(3):256-62. Epub 2014 May 31.
Provisional cements are commonly used to facilitate retrievability of cement-retained fixed implant restorations; but compromised abutment preparation may affect the retention of implant-retained crowns.The purpose of this study was to investigate the effect of abutment design and type of luting agent on the retentive strength of cement-retained implant restorations.
Two prefabricated abutments were attached to their corresponding analogs and embedded in an acrylic resin block. The first abutment (control group) was left intact without any modifications. The screw access channel for the first abutment was completely filled with composite resin. In the second abutment, (test group) the axial wall was partially removed to form an abutment with 3 walls. Wax models were made by CAD/CAM. Ten cast copings were fabricated for each abutment. The prepared copings were cemented on the abutments by Temp Bond luting agent under standardized conditions (n=20). The assemblies were stored in 100% humidity for one day at 37°C prior to testing. The cast crown was removed from the abutment using an Instron machine, and the peak removal force was recorded. Coping/abutment specimens were cleaned after testing, and the testing procedure was repeated for Dycal luting agent (n=20). Data were analyzed with two- way ANOVA (α=0.05).
There was no significant difference in the mean transformed retention (Ln-R) between intact abutments (4.90±0.37) and the abutments with 3 walls (4.83±0.25) using Dycal luting agent. However, in TempBond group, the mean transformed retention (Ln-R) was significantly lower in the intact abutment (3.9±0.23) compared to the abutment with 3 walls (4.13±0.33, P=0.027).
The retention of cement-retained implant restoration can be improved by the type of temporary cement used. The retention of cast crowns cemented to implant abutments with TempBond is influenced by the wall removal.
临时粘结剂常用于便于取出粘结固位的种植体固定修复体；但基台预备不佳可能会影响种植体固位冠的固位力。本研究的目的是调查基台设计和粘结剂类型对粘结固位种植体修复体固位强度的影响。
将两个预制基台连接到其相应的代型上，并嵌入丙烯酸树脂块中。第一个基台（对照组）保持完整，未作任何修改。第一个基台的螺丝通道用复合树脂完全填充。在第二个基台（试验组）中，部分去除轴向壁以形成一个三壁基台。通过CAD/CAM制作蜡型。每个基台制作10个铸造全冠。在标准化条件下（n=20），用Temp Bond粘结剂将制备好的全冠粘结到基台上。在测试前，将组件在37°C、100%湿度下储存一天。使用Instron机器从基台上取下铸造全冠，并记录峰值去除力。测试后清洁全冠/基台标本，并用Dycal粘结剂重复测试过程（n=20）。数据采用双向方差分析（α=0.05）进行分析。
使用Dycal粘结剂时，完整基台（4.90±0.37）和三壁基台（4.83±0.25）之间的平均转化固位力（Ln-R）没有显著差异。然而，在TempBond组中，完整基台的平均转化固位力（Ln-R）（3.9±0.23）显著低于三壁基台（4.13±0.33，P=0.027）。
使用的临时粘结剂类型可提高粘结固位种植体修复体的固位力。用TempBond粘结到种植体基台上的铸造全冠的固位力受壁去除的影响。
