Evaluation of optimal length and insertion torque for miniscrews

Makoto Suzuki, Toru Deguchi, Hisako Watanabe, Masahiro Seiryu, Masahiro Iikubo, Takashi Sasano, Koji Fujiyama, Teruko Takano-Yamamoto

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)


Introduction: The purpose of this article was to test the theory that short miniscrews will decrease the possibility of damaging the root, but the failure rate will increase. Methods: One hundred eighty-six miniscrews (diameter, 1.3 × 5 mm, n = 63; 6 mm, n = 62; 7 mm, n = 61) were placed in 105 consecutive patients. Multislice computed tomography and cone-beam computed tomography scans were taken before and after miniscrew placement. Insertion torque was measured at miniscrew placement. Results: The success rate of the miniscrews in the maxilla (93.4%) was higher than that in the mandible (70.3%). A significantly lower success rate with 5-mm miniscrews was observed compared with 6-mm and 7-mm miniscrews in the mandible. Miniscrews placed in less than approximately 3.8 mm of bone and those within 1.4 mm of the root had significantly higher failure rates. Miniscrews placed with insertion torque greater than 10 Ncm had a tendency for a lower success rate. Conclusions: The optimum lengths of miniscrews of a diameter of 1.3 mm are 5 mm in the maxilla and 6 mm in the mandible. They should be placed at a distance from the root with insertion torque less than 10 Ncm for safe orthodontic anchorage without failure.

Original languageEnglish
Pages (from-to)251-259
Number of pages9
JournalAmerican Journal of Orthodontics and Dentofacial Orthopedics
Issue number2
Publication statusPublished - 2013 Aug


Dive into the research topics of 'Evaluation of optimal length and insertion torque for miniscrews'. Together they form a unique fingerprint.

Cite this