Aim of the study
To evaluate the effect of flowable composite and glass ionomer liner on the marginal integrity of Class II composite resin restorations.
Materials and methods
A total of thirty non-carious human maxillary molar teeth were mounted in acrylic blocks. Simple Class II cavity with parallel walls was prepared. The cervical margin was established 1.5 mm above the cemento- enamel junction. The overall dimensions and depth of the cavities were standardized as follow: 4 mm length occlusocervically, 4 mm width buccolingulaly and 2 mm depth axially. Specimens were randomly divided into three equal groups (10 each). Group 1: The cavities were restored with Xtra Fil bulk fill composite without liner. Group 2: Xtra base flowable composite (1 mm thickness) was applied, followed by Xtra Fil bulk fill. Group 3: Ionoseal glass ionomer was applied as a base (1 mm thickness), followed by Xtra Fil bulk. Specimens were then subjected to 500 thermal cycles from 5 to 55oC with 30 s dwell time, and 15 s transfer time. Impressions of the teeth were made using a polyvinyl siloxane material, poured with epoxy resin. These replicas were left 24 h for complete setting. Then, Gold sputtered to be examined under scanning electron microscopy (SEM). Results were expressed as percentage of open margins for the total margin length for proximal and cervical margins and also the width of the gap were measured. The recorded data was collected, tabulated, and statistically analyzed using SPSS version 25.
Results
It was found that there was a significant difference in total gap length between group 1 and group 2 with P value = 0.000. Where group 1 has the biggest marginal gap length and the smallest marginal gap length belongs to Group 2. While there was no significant difference between group 1 and group 3 with P value 0.124. It was also found that there was no significant difference between groups in marginal gap widths.
Conclusions
The use of flowable composite and glass ionomer as liner could reduce microleakage of bulkfill composite restorations.
