Clinical suitability of titanium microscrews for orthodontic anchorage-preliminary experiences

The future of orthodontic anchorage implants may well belong to micro-implants, developed in varying designs, lengths and diameters by different manufacturers. The aim of the present clinical study was to investigate whether titanium microscrews manufactured by Jeil Medical Corp. (South Korea) are suitable for orthodontic anchorage purposes.

At the Department of Orthodontics, University of Aachen, 36 micro-implants with diameters of 1.4, 1.6 and 2 mm and lengths of 6, 8 and 10 mm were inserted in 17 patients. The implants served predominantly as anchorage for premolar distalization, molar uprighting and molar mesialization.

The mean age of the patients was 29 +/- 14 years. The implantation sites were evenly divided between the upper and lower jaw. The main insertion sites were buccal interradicular, retromolar, and palatal interradicular. Most implants used were 8 mm in length and 1.6 or 2 mm in diameter. The mean in situ time was 158 +/- 97 days. Eleven fixtures failed before the end of treatment, corresponding to a failure rate of 30%.

The tested miniscrews with a diameter of 1.6-2 mm and a length of 8-10 mm proved suitable for orthodontic anchorage purposes. Whereas larger implants need a relatively extensive bone supply and the insertion sites are limited, microscrews offer a more flexible range of applications. They also offer crucial advantages such as simple, atraumatic insertion and removal, minimum patient stress, and a favorable cost-benefit ratio.