Methods: In this experimental study, 40 intact human premolars were divided into 4 groups of 10. A round cavity measuring 3±0.2 mm in diameter and 1 mm in depth was prepared in dentine on the buccal surface of each sample according to ISO 11405-2003. The groups were as follows: group 1 : Light cure resin modified glass ionomer lining cement, group 2: Light cure resin modified glass ionomer restorative cement, group 3: A base containing hydroxylapatite applied with bonding agent, a base containing hydroxylapatite applied without bonding agent. The cavities were filled with each material according to manufacturer’s instructions. After thermocycling (5000 cycles) the specimens were immersed in AgNO3 solution for 2 hours. After sectioning the specimens, dye penetration was evaluated using a stereomicroscope. Microleakage was graded according to ISO 11405(2003) in occlusal and gingival cavity margins (0-3). Data was statistically analyzed using kruskal-wallis wilcoxon and Mann-Whitney tests.
Results: Group 3 showed the most microleakage of grade zero in gingival and occlusal cavity margins. In group 4, most microleakages of grade 3 in both margins was seen and the difference was significant (p< 0.05), but there were no significant difference among glass ionomer groups (p> 0.05).
Conclusions: It seems that the hydroxyapatite base with a bonding agent which is suggested as optional in the manufacturing instructions of the material should be followed. This causes a decrease in microleakage around the material but will not eliminate it.
Keywords: Microleakage, Liner, Resin modified glass ionomer, ClassV cavity.