Korean J Orthod.  2008 Jun;38(3):149-158. 10.4041/kjod.2008.38.3.149.

The effect of loading time on the stability of mini-implant

  • 1Department of Orthodontics, College of Dentistry, Yonsei University, Korea.
  • 2Department of Orthodontics, College of Dentistry, Dental Science Research Institute, Yonsei University, Korea. ypark@yuhs.ac.


The purpose of this study was to investigate the stability of mini-implants in relation to loading time. METHODS: A total of 48 mini-implants (ORLUS, Ortholution, Korea) were placed into the buccal alveolar bone of the mandible in 8 male beagle dogs. Orthodontic force (200 - 250 gm) was applied immediately for the immediate loading group while force application was delayed for 3 weeks in the delayed loading group. For the subsequent loading periods (3, 6, 12 weeks), BIC (bone implant contact) and BV/TV (bone volume/total volume) and mobility test were carried out. RESULTS: The immediate loading group showed no changes in BIC from 3 to 12 weeks, while the delayed loading group showed a significant increase in BIC between 3 and 12 weeks (p < 0.05). The BV/TV of the delayed loading group significantly increased from 6 to 12 weeks of loading (p < 0.05), while the BV/TV of the immediate loading group decreased from 3 to 12 weeks of loading. However, there was no significant difference in BV/TV between experimental groups. The mobility of the immediate loading group was not significantly different from that of the delayed loading group after 12 weeks of loading (p < 0.05). CONCLUSIONS: These results showed that immediate loading does not have a negative effect on the stability of mini-implants compared to the early loading method in both the clinical and histomorphometric point of view.


Mini-implant; Immediate loading; Delayed loading; Histomorphometric analysis

MeSH Terms

Nitrogen Mustard Compounds
Nitrogen Mustard Compounds


  • Fig. 1 Implantation sites of orthodontic mini-implants (A) and intra-oral photo (B). Orthodontic forces to both immediate and delayed groups were loaded reciprocally with elastic chain.

  • Fig. 2 Timetable for installation of mini-implants. W, weeks; DL, delayed loading group; IL, immediate loading group; HC, healing control group.

  • Fig. 3 Subsequent photographs of mini-implants for each group after installation. Histological section showed well-organized vital bone in contact with the implant after loading. Mature lamellar bone was visible at 6 weeks. Toluidine blue; × 100; 3 w, 3 week; 6 w, 6 weeks; 12 w, 12 weeks; scale bar shows 100 um.

  • Fig. 4 Histological findings at week 6 of the immediate loading group. Intimate bone-implant contact was observed (left, × 100); osteoclast-like cell was shown at implant-bone surface (center) and bone marrow (right, × 200); B, alveolar bone; M, mini-implant.

  • Fig. 5 Bone implant contact (BIC, %) and bone volume/total volume (BV/TV, %) of each group for different time periods. *p < 0.05. IL, Immediate loading group; DL, delayed loading group; HC, healing control group.

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Korean J Orthod. 2011;41(5):354-360.    doi: 10.4041/kjod.2011.41.5.354.

Histomorphometric evaluation of the bone surrounding orthodontic miniscrews according to their adjacent root proximity
Hyun-Ju Oh, Jung-Yul Cha, Hyung-Seog Yu, Chung-Ju Hwang
Korean J Orthod. 2018;48(5):283-291.    doi: 10.4041/kjod.2018.48.5.283.

Microimplant mandibular advancement (MiMA) therapy for the treatment of snoring and obstructive sleep apnea (OSA)
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Korean J Orthod. 2010;40(2):115-126.    doi: 10.4041/kjod.2010.40.2.115.


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