title: Recommended placement torque when tightening an orthodontic mini-implant.
abstract: To determine an adequate placement torque for obtaining a better success rate of mini-implants that are screwed into the buccal alveolar bone of the posterior region as an anchor for orthodontic treatment, implant placement torque (IPT) was measured. The subjects were 41 orthodontic patients (124 implants), with an average age of 24.9 years (SD 6.5 years), who had surgery to place titanium mini-implants. The peak value of IPT was measured using a torque screwdriver. The success rate of the mini-implant anchor for 124 implants was 85.5%. The mean IPT ranged from 7.2 to 13.5 N cm, depending on the location of the implants. There was a significant difference in the IPT between maxilla and mandible. The IPT in the mandible was, unexpectedly, significantly higher in the failure group than in the success group. Therefore, a large IPT should not be used always. According to our calculations of the risk ratio for failure, to raise the success rate of 1.6-mm diameter mini-implants, the recommended IPT is within the range from 5 to 10 N cm.
authors.affiliation: Department of Orthodontics, Division of Clinical Research, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan. motoyoshi@dent.nihon-u.ac.jp
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Motoyoshi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hirabayashi
authors.forename: Miwa
authors.initials: M
authors.lastname: Uemura
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Shimizu
mesh_terms: D000293:Adolescent; D000328:Adult; D000539:Alveolar Process; D001863:Bone Screws; D003758:Dental Implantation, Endosseous / Q000295:instrumentation*; D015921:Dental Implants; D003799:Dental Stress Analysis; D005260:Female; D006801:Humans; D008297:Male; D008904:Miniaturization; D016017:Odds Ratio; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D014025:Titanium; D019415:Torque
chemical_list: D015921:Dental Implants; D014025:Titanium