Comparative analysis of microhardness of two bulk-fill composites at varying depths, photo-activated with two different light curing units

Aim: The aim of this study is to evaluate and compare the differences of the Micro hardness of two Bulk-fill Composites (Tetric N-ceram Bulkfill and Filtek Bulkfill) and a Conventional composite (Filtek Z350XT) at varying depths (0mm, 2mm, 4mm) and to evaluate the effect of two different light curing systems (LED and QTH) on the micro hardness of bulk-fill and conventional composite. Methods and Materials: 60 specimens of composite resin disks (8x4mm) will be prepared. The Teflon mould will be placed on a glass slab with an intervening mylar strip and the composite resin will be placed at once as a bulk, slightly over packed into the mould space. A second mylar strip and glass slab will be placed on top of the Teflon mould and a uniform weight of 500gms will be placed above the glass slab for 30 seconds in order to compactly pack the resin thus preventing the formation of any voids. Then, the weight along with the glass slab above the composite will be removed and the composite will be cured as per the manufacturer’s instructions. All the specimens will stored for 24 hours in distilled water at for completion of the polymerization process. Statistical Analysis used: Mean and Standard Deviation will be used for Descriptive statistics, t test - Independent samples., ANOVA – One way (Analysis of Variance), Scheffe’s Post hoc test. Results: Highest micro hardness values regardless of light sources were observed in Tetric N- Ceram bulk fill composite and Light emitting diode showed better hardness values compared to Quartz tungsten halogen unit. Conclusion: Highest micro hardness values regardless of light sources were observed in Tetric N- Ceram bulk fill composite. Filtek Z350XT Conventional composite Showed the least Hardness when placed in Bulk fill technique. Light Emitting diode (LED) showed better results when compared to Quartz tungsten Halogen (QTH) unit.