The influence of different light curing systems with different curing depth on the microhardness of packable composites

Abstract EN

Background : adequate polymerization of resin composite is considered to be very important factor.

The aim of this study was to evaluate and compare the influence of different light curing system (conventional QTH, LED and PAC units) with different polymerization depth (0-1, 1-2, 2-3, 3-4 and 4-5 mm) on micro hardness of two types of packable composite (Filtek p60 and Surefil).

Materials and Methods : Two types of packable composites (Filtek p60 and Surefil) were tested.

Thirty hemi cylindrical specimens (5mm diameter x 6mm height) were made for each material.

Photo-activation was performed using conventional QTH, light emitting diodes (LED) or plasma arc (PAC).Exposure times were 40 seconds for QTH and LED lights, and 12 seconds for the PAC light.

After one day of storage, the micro hardness test was measured at 5mm depth intervals (0-1, 1-2, 2-3, 3-4 and 4-5 mm).

Results : the micro hardness of packable composite resins (Filtek p60) showed a significantly higher micro hardness than packable composite (Surefil) in all light activation systems and in all depth intervals.

The LED light curing system produced superior mean micro hardness value followed by conventional QTH and PAC light curing systems respectively.

And all of the tested composite resins groups with the three different types of light activation systems showed a significant decrease in the micro hardness with the increase of depth.

Conclusion : the micro hardness of packable composite is affected by the type of materials, light curing systems and curing depths.