Effect of gutta-percha solvents on surface microhardness of IRM fillings

Eighty identical samples of IRM were prepared and embedded in acrylic resin , The samples were polished, rinsed, and divided into experimental groups a nd controls, 10 specimens each. Each experimental group was treated for 1 o r 5 min with one of the following gutta-percha solvents: chloroform, xylene , or halothane. Sterile saline was used as a control. Treatment consisted o f pipetting each solvent onto the external IRM surface. The specimens were then sealed in plastic assay tubes for the corresponding exposure periods. At each time period, surface microhardness of the samples was measured usin g a mini-load hardness tester with a 500 g load for 20 s, It was found that xylene and halothane caused significant reduction in surface microhardness of IRM after 5 min (p < 0.01), Chloroform caused significant reduction in surface microhardness of IRM after 1 min of treatment (p < 0.01), Chlorofor m caused total dissolution after 5 min of treatment. Saline caused only min or and nonsignificant changes in surface microhardness of IRM.