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This study tested the hypothesis that multiple sterilizations of endodontic stainless-steel and nickel-titanium files will lead to a continuous decrease in the resistance of files to separation by torsion. One hundred stainless-steel and 100 nickel-titanium #30 K-type files were divided into 20 groups of 10 and sterilized in increments of 10 cycles, using a full cycle and a fast cycle autoclave. These files were tested by twisting each of them in a clockwise direction until fracture (torque g-cm). Samples of the fractured files were embedded in an epoxy resin and polished for Knoop hardness tests. In addition, the samples were chemically etched to reveal changes in microstructure. The findings of this study indicate that neither the number of sterilization cycles nor the type of autoclave sterilization used affects the torsional properties, hardness, and microstructure of stainless-steel and nickel-titanium files.

This case report describes the clinical, radiologic, and histopathologic features of the glandular odontogenic cyst (GOC). Although a relatively rare lesion not previously reported in the endodontic literature, the GOC is recommended for inclusion in a differential diagnosis of a dentoalveolar radiolucency. The GOC is a destructive lesion that can be easily misdiagnosed microscopically as a central mucoepidermoid carcinoma.

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