Various types of temporary implants have been introduced to serve as orthodontic anchorage. The hypothesis of this study is that microimplants of 1.2 mm diameter can be used as orthodontic anchors, and that their success is related to their length. The aim of this study is to determine the incidence of anchor retention after orthodontic force application for moving teeth, and to determine the relationship of microimplant length to retention rate.
Methods
Fifty-nine microimplants (diameter: 1.2 mm) were placed in 29 patients as orthodontic anchorages. After 2 weeks of microimplant placement, a force of 100 to 200 g was loaded with an elastometric chain or NiTi coil spring. Risk factors were characterized as to why a microimplant may fail, and Fisher’s exact test was used for statistical analysis.
Results
Nine microimplants were removed and the overall success rate was 84.7%. Exploring the causes for failure, we found significant differences between the length of microimplants and success rate; 6 mm was 72.2% and 8 mm was 90.2%.
Conclusions
The results suggest that microimplants are suited as an alternative orthodontic anchorage. We recommend that 8-mm microimplants are preferable to 6-mm.
⁎Associate Professor, Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University, Kaohsiung, Taiwan.
†Assistant Professor, Department of Orthodontics, Kaohsiung Medical University, Kaohsiung, Taiwan.
‡Graduate Student, Graduate Institute of Dental Sciences, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
§Visiting Staff, Department of Orthodontics, Kaohsiung Medical University, Kaohsiung, Taiwan.
‖Instructor, Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University, Kaohsiung, Taiwan.
¶Instructor, Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University, Kaohsiung, Taiwan.
#Visiting Staff, Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University, Kaohsiung, Taiwan.
⁎⁎Assistant Professor, Department of Oral and Maxillofacial Surgery, Kaohsiung Medical University, Kaohsiung, Taiwan.
Address correspondence and reprint requests to Dr C-M Chen: Department of Oral Maxillofacial Surgery, Kaohsiung Medical University, No. 100, Shih-chuan 1st Road, Kaohsiung 807, Taiwan
ABSTRACT