Effect Of Different Light Curing Strategies On Compressive Strength Of Bulk-Fill Composite Resin- An In-Vitro Experimental Study

Abstract

Background

The incremental layering procedure, which involves the deposition of composite resins in increments of thickness not exceeding 2mm, is one such protocol recommended to combat polymerization shrinkage. Another strategy apart from the incremental layering technique is by varying the light intensity which is used to cure the resin such as step cure polymerization, pulse delay curing, and ramp curing by allowing some time for the release of stresses associated with Polymerization when compared to the classic and recommended uniform continuous curing technique. So, it might be logical to assume that by controlling polymerization shrinkage we can also improve the mechanical properties of composites.

Objective:

The objective of the study is to compare the compressive strength of bulk-fill composite in Megapascals using different light cure strategies such as Uniform continuous cure, Step cure, Ramp cure, and Pulse delay cure.

Materials and methodology:

In this Invitro study, 160 bulk-fill composite samples were fabricated and they were randomly divided into 4 groups with each group containing 40 samples Each sample was cured with different light-curing strategies. GROUP 1-Uniform continuous cure, GROUP 2- Step cure, GROUP 3- Pulse delay cure, GROUP 4- Ramp cure. Universal testing machine at a crosshead speed of 0.5 cm/min was used to measure the compressive strength.

Results :

The order of compressive strength reported was as follows (Based on p-value)GROUP 1> GROUP 2 = GROUP 3> GROUP 4

Conclusion:

Bulkfill composite cured by uniform continuous cure showed the highest Compressive strength value. The ramp cure method showed the lowest compressive strength value among all the samples tested. In all of the test results, there were no discernible differences between step cure and pulse delay cure