Evaluation of Microhardness and Compressive Strength of Mineral Trioxide Aggregate Modified by Addition of Short Glass Fibers and Shredded Polyglycolic Acid Sutures

The purpose of this study was to test the microhardness and compressive strength of mineral trioxide aggregate (MTA) modified by the addition of short glass fibers (SGFs) and shredded polyglycolic acid (PGA) sutures. Encapsulated MTA (MM-MTA, MicroMega, Besançon, France), modified using either SGF or shredded PGA sutures, was used for the experiment. Four experimental groups (n = 120) were as follows: control group (MTA) (n = 30), MM MTA + 5%SGF (n = 30), MM MTA + 10%SGF (n = 30), and MM MTA + 1%PGA (n = 30). For the modified materials, MM MTA powder was removed from the capsule by 1%, 5% and 10% of weight and 1% PGA, 5%, or 10% SGF were added, respectively. The microhardness of the samples (n = 20 per group) was measured using a Vickers microhardness testing machine, while compressive strength (n = 10 per group) was measured according to ISO 9917-1:2007. The highest microhardness value was measured for MTA + 10%SGF (14.73 ± 3.09) with a statistically significant difference in comparison to the other three groups (<i>p</i> < 0.05). Statistically significant higher compressive strength was measured in the groups with the addition of 5% and 10% SGF compared to MM MTA (<i>p</i> = 0.047 for both comparisons). There were no statistically significant differences between the groups (<i>p</i> = 0.784) regarding the compressive modulus. The addition of SGF significantly increased both the microhardness and compressive strength of MM MTA.