In vitro testing of an experimental dental composite resin and adhesive system

In vitro testing of new experimental materials has been introduced for many years as a method to evaluate them in simulated conditions, before the clinical trials. Our study has investigated a new experimental composite resin C1 and adhesive system Ad1 by scanning electron microscope (SEM) studies and microleakage tests.

Both in vitro test were performed on extracted human teeth, that were prepared for standardized class II and V restorations and restored with three composite resins (experimental C1, TetricCeram TC and Solitaire2 S2) and their total-etch adhesive systems (Ad1, Excite EX and GlumaOneBond GB). Teeth were sectioned and investigated under the SEM microscope for the interfaces created and under the optical microscope for dye penetration and microleakage.

The Romanian experimental composite C1 has shown lower alpha "ideal" interfaces than TC and S2, with no significant difference between the latter. Microleakage was significantly lower at the enamel margin and significantly higher at the gingival margin placed below the CEJ for all three compared composites. C1 presented similar dye penetration scores with the commercial available systems.

The differences in SEM analysis can be attributed to higher viscosity and handling properties in the experimental adhesive Adl and to technique sensitivity.

Further investigation is required to obtain better working properties for the experimental adhesive and higher "ideal" scores at the interfaces. Also the SEM investigation is more sensitive than the optical microscope analysis.