Abstract
Limited visibility of the operating field can lead to difficulties in relation to adequate retrograde filling during periapical surgery in specific clinical situations. Solid and homogenic root filling material that does not need to be removed after apicoectomy could be used as an alternative to retrograde filling. This study aims to compare the micro-hardness of mineral trioxide aggregate (MTA) considering retrograde vs. orthograde obturation during root end resection in vitro. Methods: 20 roots of maxillary incisors were chemo-mechanically prepared and divided into 2 groups: group A (n = 10)-retrograde filling and group B (n = 10)-orthograde filling. The specimens of group A were filled with gutta-percha and resin-based sealer, 3 mm of the apical area were removed after the incubation period. Retrograde cavities of a depth of 3 mm were made and filled with MTA. In group B, apical 7 mm of the roots was filled with MTA in an orthograde manner. After the incubation, 3 mm of the root ends were removed. Vickers microhardness test was applied to the MTA No statistically significant difference in micro-hardness between groups was found (p > 0.05). The assessment of retrograde filling did not reveal significant differences of MTA micro-hardness in different parts of the material (p > 0.05). The assessment of orthograde filling revealed that MTA micro-hardness 3 mm from the apex was significantly higher when compared to the distance of 1 and 2 mm from the root apex (p > 0.05). The obturation method did not affect the hardness of MTA during root end resection in vitro.