Comparative evaluation of microleakage among three different glass ionomer types

This study compared the microleakage and adaptation of Class V cavity preparations restored with three types of glass-ionomer materials as a function of time.

A total of 144 sound, freshly-extracted human premolars were used for the study. One clinician prepared all the teeth for Class V-type cavities on the buccal surface of each tooth. The preparations measured 3 mm long, 2 mm wide and 1.5 mm deep, with the gingival margin in dentin and the occlusal margin in enamel. All the prepared teeth were randomly divided into three groups of 48 teeth, according to the type of glass-ionomer material used: Group (A): Ketac N100 glass ionomer, Group (B): Vitremer glass ionomer and Group (C): Photac Fil Quick glass ionomer. The restorative materials were used according to their manufacturers' recommendations. The teeth were placed in one increment and photocured for 40 seconds. All of the restored teeth were then stored in artificial saliva. Each group was subdivided into three subgroups according to the testing periods (7, 30, 60 days). Next, they were thermocycled at 5°C–55°C for 100 cycles. The teeth used for the dye penetration test were immersed in 1%methylene blue solution for eight hours. They were then sectioned longitudinally in a bucco-lingual direction. The extent of dye penetration at the occlusal and gingival margins of each restoration was studied under a stereomicroscope at 25× magnification. Randomly selected samples from each group were prepared for scanning electron microscopic evaluation. Dye penetration scores were analyzed using the SAS program, cross tabulation and Chi square test.

The difference among the three groups was significant after immersion for 30 days at the occlusal margin. Statistical analysis also revealed significant differences between group (A) and the other groups at the occlusal margin after immersion for 60 days (p<0.05). At the gingival margin, statistical analysis revealed significant differences between group (C) and the other groups at the gingival margin after immersion for 60 days (p<0.05).

The light-curing nanofilled glass ionomer (Ketac N100) showed the least microleakage.