An In-Vitro Comparison of Micro Leakage Between Two Posterior Composites Restored with Different Layering Techniques...

Composite resins have undergone various advances since their introduction, but their polymerization shrinkage remains a problem. Shrinkage can cause debonding of the restoration and can contribute to postoperative sensitivity, secondary caries, marginal staining and eventual failure of the restoration. So, our aim is to compare the effect of two different placement techniques and two different curing modes in reducing the marginal microleakage of two different composites in Class II cavities, where oblique and horizontal placement techniques and ramp & pulse curing modes of LED are used during the restoration.

Standardized slot preparations were prepared in 80 human multi-rooted teeth. The teeth were randomly divided into four groups. Group A and B: Restored with Filtek P60 (3M, ESPE), Group C and D: Restored with Filtek P90 (3M, ESPE). All groups were further divided into sub-groups on basis of placement technique and curing mode. The samples were stored in distilled water, followed by thermocycling and immersed in 2% methylene blue. The samples were sectioned and evaluated for microleakage at the gingival margin with an optical stereomicroscope.

P60 composite when placed in the cavity with oblique incremental technique and cured with ramp mode of LED showed highest mean microleakage. There is no significant difference between horizontal and oblique placement technique (p=0.80); Pulse-curing and the ramp-curing mode (p=0.62).

In restoring deep class II cavities, the use of a low-shrink composite with the oblique placement technique and ramp curing mode of LED is recommended to overcome the problem of marginal microleakage.