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Microleakage and water stability of resin cements
Sun-Young Choi, Sun-Hyung Lee, Jae-Ho Yang, Jung-Suk Han
최선영, 이선형, 장재호, 한중석

Statement of Problem : Recently, resin cements have become more widely used and have been accepted as
prominent luting cements. Current resin cements exhibit less microleakage than conventional luting cements.
However, the constant contact with water and exposure to occlusal forces increase microleakage even in resin
cements inevitably.
Most bonding resins have been modified to contain a hydrophilic resin such as 2-hydroxyethylmethacrylate
(HEMA) to overcome some of the problems associated with the hydrophobic nature of bonding resins. By virtue
of these modifications, bonding resins absorb a significant amount of water, and there may also be significant
stresses at bonding interfaces, which may adversely affect the longevity of restorations. Therefore the reinforcement
of water stability of resin cement is indispensable in future study.
Purpose : This study was conducted to examine the influence of water retention on microleakage of two resin
cements over the period of 6 months.
Materials and Methods  : 32 extracted human teeth were used to test the microleakage of a single full
veneer crown. Two resin cements with different components and adhesive properties - Panavia F (Kuraray Co.,
Osaka, Japan) and Super-Bond C&B (Sun Medical Co., Kyoto, Japan)- were investigated. The storage medium
was the physiological saline solution changed every week for 1 month, 3 months, and 6 months. One group was
tested after storage for 1 day.
At the end of the each storage period, all specimens were exposed to thermocycling from 5? C to 55? C of 500
cycles and chewing simulation of 50,000 cycles, and then stained with 50% silver nitrate solution. The linear pen-
etration of microleakage was measured using a stereoscopic microscope at ×40 magnification and a digital trav-
eling micrometer with an accuracy of ±3 ㎛.
Values were analyzed using two-way ANOVA test, Duncans multiple range tests (DMRT).
Results :
Statistically significant difference of microleakage was shown in the 3-month group compared with the 1-day
or 1-month group in both systems (p<0.05) and there were statistically significant differences in microleakage
between the 3-month group and the 6-month group in both systems (p<0.05).
The two systems showed different tendency in the course of increased microleakage during 3 months. In Panavia
F, microleakage increased slowly throughout the periods. In Super-Bond C&B, there was no significant increase
of microleakage for 1 month, but there was statistically significant increase of microleakage for the next 2 months.
For the mean microleakage for each period, in the 3-month group, microleakage of Super-Bond C&B was sig-
nificantly greater than that of Panavia F. On the other hand, in the 6-month group, microleakage of Panavia F
was significantly greater than that of Super-Bond C&B (p<0.05).
Conclusion : Within the limitation of this study, water retention of two different bonding systems
influence microleakage of resin cements. Further studies with the longer observation periods in viro
are required in order to investigate water stability and the bonding durability of the resin cement.
Microleakage at the Cement-tooth interfaces did not necessarily result in the failure of the crowns.
But it is considered to be a major factor influening the longerity of restorations. Further clinical approach-
es for decreasing the amount of microleakage are required.

* Keywords: Resin cement, Microleakage, Water stability, Bonding interfaces, Thermocycling

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