title: Insertion torque, resonance frequency, and removal torque analysis of microimplants.
abstract: This study aimed to compare the insertion torque (IT), resonance frequency (RF), and removal torque (RT) among three microimplant brands. Thirty microimplants of the three brands were used as follows: Type A (titanium alloy, 1.5-mm × 8-mm), Type B (stainless steel, 1.5-mm × 8-mm), and Type C (titanium alloy, 1.5-mm × 9-mm). A synthetic bone with a 2-mm cortical bone and bone marrow was used. Each microimplant was inserted into the synthetic bone, without predrilling, to a 7 mm depth. The IT, RF, and RT were measured in both vertical and horizontal directions. One-way analysis of variance and Spearman's rank correlation coefficient tests were used for intergroup and intragroup comparisons, respectively. In the vertical test, the ITs of Type C (7.8 Ncm) and Type B (7.5 Ncm) were significantly higher than that of Type A (4.4 Ncm). The RFs of Type C (11.5 kHz) and Type A (10.2 kHz) were significantly higher than that of Type B (7.5 kHz). Type C (7.4 Ncm) and Type B (7.3 Ncm) had significantly higher RTs than did Type A (4.1 Ncm). In the horizontal test, both the ITs and RTs were significantly higher for Type C, compared with Type A. No significant differences were found among the groups, and the study hypothesis was accepted. Type A had the lowest inner/outer diameter ratio and widest apical facing angle, engendering the lowest IT and highest RF values. However, no significant correlations in the IT, RF, and RT were observed among the three groups.
authors.affiliation: School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Orthodontics, Dental Clinics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Yu-Chuan
authors.initials: YC
authors.lastname: Tseng
authors.affiliation: School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chun-Chan
authors.initials: CC
authors.lastname: Ting
authors.affiliation: School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Je-Kang
authors.initials: JK
authors.lastname: Du
authors.affiliation: School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Oral and Maxillofacial Surgery, Dental Clinics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Chen
authors.affiliation: Faculty of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Ju-Hui
authors.initials: JH
authors.lastname: Wu
authors.affiliation: Faculty of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. Electronic address: hosech@cc.kmu.edu.tw.
authors.forename: Hong-Sen
authors.initials: HS
authors.lastname: Chen
mesh_terms: D008855:Microscopy, Electron, Scanning; D019736:Prostheses and Implants; D018709:Statistics, Nonparametric; D019415:Torque; D014732:Vibration
keywords: Insertion torque; Orthodontic microimplant; Removal torque; Resonance frequency