Numerous methods of root canal preparation have been recommended and used by clinicians. This study used histomorphometrics to determine the area of root canal preparations using four currently popular techniques. Clinicians that were highly skilled in each technique prepared curved canals in acrylic blocks. Each clinician described this technique and discussed the technique with regard to the use of acrylic blocks as compared with dentin. Analysis of the areas of the root canals after preparation revealed a significant difference among the groups. The mean areas after treatment were step-back technique, 17.33 mm2; Cavi-Endo technique, 15.87 mm2; Canal Master technique, 13.56 mm2; and balanced force technique, 17.31 mm2. Photographs of the blocks used in the study were included for inspection by the reader.