An in-vitro study to compare and evaluate the compressive strength and microleakage of three hybrid composite resin restorations

Background: In an effort to combine the favorable physical and mechanical properties of conventional composites with the smooth surface typical of the microfilled composites, the hybrid composites were developed. Marginal adaptation of a restoration can be assessed by measuring the amount of microleakage at the interface area, after it has undergone contraction during polymerization. Objective: The aim of the present in-vitro study was to compare and evaluate the compressive strength and microleakage in class I cavity restored with hybrid composite. Method: Thirty freshly extracted human premolars were used. Standardized Class I cavity was prepared and randomly divided into 3 groups with 10 teeth in each group. The teeth in Group A was restored using Spectrum (Dentsply), Group B-Charisma (Kulzer) and Group C- Hybrid, LOT-FDH07U (Unicorn Den Mart) and then subjected to thermo cycling; immersion in 1% methylene blue dye for 24 hours; sectioning longitudionally; evaluation of micro leakage under a stereomicroscope and scoring on an ordinal scale (0-4). Compressive strength was measured after loading the specimen in resin blocks and subjecting them to compressive tests using universal testing machine. The results were tabulated and subjected to Kruskal- Wallis and Mann- Whitney test for statistical analysis.