surface microhardness of different thicknesses of a premixed bioceramic material with or without the application of a moist cotton pellet

background: this study was conducted to assess the effect of thickness and hydration condition on the surface microhardness of endosequence root repair material putty (errm; brasseler usa, savannah, ga), a premixed bioceramic material. materials and methods: polymethyl methacrylate cylindrical molds with an internal diameter of 4 mm and three heights of 2, 4, and 6 mm were fabricated. in group 1 (dry condition), the molds with heights of 2, 4, and 6 mm (10 molds of each) were fi lled with errm. in groups 2 and 3 (wet condition), a distilled water- or phosphate-buffered saline (pbs)-moistened cotton pellet was placed directly on the upper surface of errm, respectively. the lower surface of errm was in contact with fl oral foams soaked with human blood. after 4 days, vickers microhardness of the upper surface of errm was tested. the data were analyzed using two-way analysis of variance. signifi cance level was set at p < 0.05. results: no signifi cant difference was found between the microhardness of three thicknesses of errm (2, 4, and 6 mm) with or without placing a distilled water- or pbs-moistened cotton pellet over the material (p > 0.05). conclusion: based on the results of this study, it could be concluded that placing a moistened cotton pellet on errm putty up to 6 mm thick might be unnecessary to improve its surface microhardness and hydration characteristics. key words: dry, hardness, pellet, phosphate-buffered saline, root repair, silicates, wet condition