title: Safe placement techniques for self-drilling orthodontic mini-implants.
abstract: Self-drilling mini-implants are being used more frequently as an orthodontic anchorage, but the placement torque of self-drilling mini-implants can easily become excessive in the thick, mandibular cortical bone. The purpose of this study is to examine a safe self-drilling placement technique that provides adequate placement torque for orthodontic mini-implants. The mini-implants were placed using self-drilling and pre-drilling methods into the ribs of pigs. Specimens were classified into two groups, thin and thick, with cortical bone thicknesses of 1.2 ± 0.02 and 2.0 ± 0.03 mm, respectively, and used to model the human maxillary and the mandibular bones. The peak mini-implant placement torque value was measured and the surrounding cortical bone was observed histologically. In the mandible model, the torque in the self-drilling and pre-drilling groups exceeded 10 N cm, except in one case which had a 1.3 mm diameter pilot hole. Histology revealed cracks in the surrounding cortical bone in the groups whose torque value was 10 N cm or more. Therefore, when using the self-drilling technique to place a 1.6mm diameter mini-implant in the mandibular alveolar bone, it is preferable to drill a 1.3mm diameter pilot hole first.
authors: Department of Orthodontics, Nihon University School of Dentistry, Tokyo, Japan.
authors: R
authors: R
authors: Tachibana
authors: M
authors: M
authors: Motoyoshi
authors: A
authors: A
authors: Shinohara
authors: T
authors: T
authors: Shigeeda
authors: N
authors: N
authors: Shimizu
mesh_terms: D015921:Dental Implants; D006801:Humans; D052280:Orthodontic Anchorage Procedures
chemical_list: D015921:Dental Implants