Evaluation of the Max titanium alloy retentive pins

This study evaluated the Max 017 retentive pin (.019 in./.48 mm) and its twist drill (.017 in./.43 mm) along with the Max 021 pin (.024 in., .61 mm) and its twist drill (.021 in./.53 mm), in relation to shoulder stop position, space between the end of the pin and the end of the channel and the development of cracks in dentin adjacent to pin channels. A total of 20 non-carious human molar teeth were used, 10 for each size pin. Four pins were placed in each tooth for a total of 40 of each size pin. An air turbine contra-angle was used at 1,200 rpm to prepare all channels and seat all pins. Results showed that with the 017 pins, only 14 pins out of 40 (35%) were completely seated with the shoulder stop against dentin, while the 021 pins had 36 out of 38 (95%) of the shoulder stops completely seated. There was a significant difference in the two groups. Cracks were seen adjacent to only one pin. Space between the end of the pin and the end of the channel for the 017 pins whose shoulder stops were seated was an average of .55 mm, while the 021 pins had an average of .14 mm.