Clinician's Corner
Surgical positioning of orthodontic mini-implants with guides fabricated on models replicated with cone-beam computed tomography

https://doi.org/10.1016/j.ajodo.2006.01.027Get rights and content

Introduction

This article illustrates a new surgical guide system that uses cone-beam computed tomography (CBCT) images to replicate dental models; surgical guides for the proper positioning of orthodontic mini-implants were fabricated on the replicas, and the guides were used for precise placement. The indications, efficacy, and possible complications of this method are discussed.

Methods

Patients who were planning to have orthodontic mini-implant treatment were recruited for this study. A CBCT system (PSR 9000N, Asahi Roentgen, Kyoto, Japan) was used to acquire virtual slices of the posterior maxilla that were 0.1 to 0.15 mm thick. Color 3-dimensional rapid prototyping was used to differentiate teeth, alveolus, and maxillary sinus wall. A surgical guide for the mini-implant was fabricated on the replica model. Proper positioning for mini-implants on the posterior maxilla was determined by viewing the CBCT images.

Results

The surgical guide was placed on the clinical site, and it allowed precise pilot drilling and accurate placement of the mini-implant.

Conclusions

CBCT imaging allows remarkably lower radiation doses and thinner acquisition slices compared with medical computed tomography. Virtually reproduced replica models enable precise planning for mini-implant positions in anatomically complex sites.

Section snippets

Methods for locating the proper position

There have been various efforts to standardize the proper positioning of mini-implants.4, 5, 7, 13 The placement site is critical to ensure a successful outcome, but the more important point is the implant guide itself. Bae et al13 reported on a guide wire that provides a reference in the x-rays. However, wire guide systems require several x-rays for determining the proper position; this limits accuracy during drilling. The wires can be deformed or bent in the oral cavity during x-ray taking.

SURGICAL GUIDE FABRICATION AND IMPLANTATION PROCEDURE

Three-dimensional CBCT images were taken of the posterior maxilla by using a new type of CBCT system (PSR 9000N, Asahi Roentgen, Kyoto, Japan) that delivers 0.1 mm in voxel size. An advantage of this model was improved reproducibility of anatomical structures with acquisition of a 0.15-mm slice. A CBCT record that was transformed into DICOM format was changed into 3D images (Fig. 2, Fig. 3). A replica model of the right posterior maxilla was fabricated by using the SLA method (Fig 4).

A

DISCUSSION

A CBCT guide is recommended for mini-implant placement for the following reasons.

CONCLUSIONS

The benefits of CBCT include its low radiation dose and higher resolution in 3 dimensions, and it has been gaining popularity for diagnosis and treatment. Placement of mini-implants is easier and safer with a CBCT guide.

Further study is needed to construct the guide directly without the additional process of making a cast, just as the prosthetic implant guides were made with computed analysis.

ACKNOWLEDGEMENT

This study was partly supported by the Korean Society of Speedy Orthodontics, Alumni fund of the Department of Dentistry, and Graduate School of Clinical Dental Science, The Catholic University of Korea. We also thank Dr Hyun-A Heo, Su-Hyun Park, Woon-kyung Seo, and Mr Chang-Uk Kim in the Uijongbu St Mary's Hospital for preparing this manuscript and Mr Jong-Min Yoon from the Humobot Company for technical assistance for replica model fabrication.

REFERENCES (24)

  • SM Parel et al.

    Interactive imaging for implant planning, placement, and prosthesis construction

    J Oral Maxillofac Surg

    (2004)
  • WC Scarfe

    Imaging of maxillofacial trauma: evolutions and emerging revolutions

    Oral Surg Oral Med Oral Pathol Oral Radiol Endod

    (2005)
  • R Kanomi

    Mini-implant for orthodontic anchorage

    J Clin Orthod

    (1997)
  • HM Kyung et al.

    Development of orthodontic microimplants for intraoral anchorage

    J Clin Orthod

    (2004)
  • HS Park et al.

    Microimplant anchorage for treatment of skeletal Class I bialveolar protrusion

    J Clin Orthod

    (2001)
  • A Carano et al.

    Clinical application of the mini-screw-anchorage-system (M.A.S.) in the maxillary alveolar bone

    Prog Orthod

    (2004)
  • BG Maino et al.

    Spider screw: skeletal anchorage system

    Prog Orthod

    (2005)
  • BG Maino et al.

    The spider screw for skeletal anchorage

    J Clin Orthod

    (2003)
  • A Carano et al.

    Implants in orthodontics

    Prog Orthod

    (2005)
  • SJ Lee et al.

    The effect of early loading on the direct bone-to-implant surface contact of the orthodontic osseointegrated titanium implant

    Korean J Orthod

    (2001)
  • KR Chung et al.

    C-orthodontic microimplant as a unique skeletal anchorage

    J Clin Orthod

    (2004)
  • Chung KR, Kim SH, Kook YA. C-orthodontic microimplant. In: Cope JB, editor. Temporary anchorage devices in...
  • Cited by (95)

    • Effect of a digital guide on the positional accuracy of intermaxillary fixation screw implantation in orthognathic surgery

      2022, Journal of Plastic, Reconstructive and Aesthetic Surgery
      Citation Excerpt :

      Subsequently, the necrotic tissues and inflammation around IMFSs stimulate root absorption, causing tooth loosening and even loss.29,35,36 Measures introduced to minimize the risk of the root damage during IMFS implantation include a steel wire guide, a guide with a transparent resin model, and a C-tube mini-plate guide using a new 2.5D program designed to reduce the incidence of the root damage.16,37–39 Although the steel wire guide has the advantages of simple manufacturing and low cost,37 it can only roughly estimate the implantation position of the screws in 2D and cannot accurately predict the specific implantation position.

    View all citing articles on Scopus
    View full text