A Study on Light-cured Type II Glass-ionomer Cement for Repair

在某些情况下，当需要对老化的修复体进行修复时，使用光固化玻璃离子聚合物水泥（LCGIC）。据报道，通过减少老化水泥，然后使用粘结剂，可以获得最高的粘结强度。本研究的目的是研究热循环对不同粘结剂对老化LCGIC与新添加LCGIC粘结强度的影响。同时测定了修复水泥的抗弯强度。采用富士IILC型离子聚合物（GC）和Vitremer （3M）两种lcgic，以及5种市售粘结剂。热循环10000次后，在水泥试件上涂上粘结剂。经过表面处理后，LCGIC被浓缩成模具，放置在老化水泥上并进行光活化。制备完成的样品分别进行1000、3000和10000次热循环，模拟口腔环境中降解的过程。样品在37℃水中保存24小时，然后使用Instron试验机（4204型，Instron），以1.0 mm/min的十字速度进行剪切粘结强度试验和弯曲强度试验。实验结果如下：1.实验结果表明：热循环降低了老化lcgic与新增lcgic之间的结合强度。填充的粘结剂比未填充的粘结剂具有更小的这种倾向。粘结强度试验后，充填粘结剂试件的破坏模式为混合破坏或内聚破坏。随着热循环次数的增加，胶粘剂的破坏趋于增加。热循环降低了修复后LCGIC的抗弯强度。填充的粘结剂比未填充的粘结剂的这种趋势要小。

There are some occasions in the use of light-cured glass-ionomer cements (LCGIC) when it is necessary for repairs to be made to aged restorations. It has been reported that the highest bond strength was obtained with the reduction of aged cements followed by bonding agent application. The purpose of this study was to examine the effect of thermal cycling on bond strength between aged LCGIC and newly added LCGIC using various bonding agents. Also, the flexural strength of repaired cements was measured.Two LCGICs, Fuji Ionomer Type IILC (GC) and Vitremer (3M), and five commercially available bonding agents were employed. After thermal cycling for 10,000 cycles, bonding agents were applied on the cement specimens. After surface treatment, LCGIC was condensed into molds placed on the aged cement and light activated. The finished specimens were subjected to thermal cycling for 1,000, 3,000, and 10,000 cycles to simulate the degradation occurring in oral environment. These samples were stored in 37℃ water for 24 hours, then shear bond strength test and flexural strength test were carried out using an Instron testing machine (Type 4204, Instron) at a crosshead speed of 1.0 mm/min. The results were as follows :1. Thermal cycling decreased the bond strengths between aged and newly added LCGICs. This tendency was less for the filled bonding agents than non-filled bonding agents.2. After the bond strength tests, the failure modes of the specimen made with filled bonding agents revealed mixed or cohesive failure. Adhesive failure tended to increase with increasing thermal cycles .Thermal cycling decreased the flexural strengths of repaired LCGIC.This tendency was less for the filled bonding agents than non-filled bonding agents.