Hee-Moon KYUNGDDS, MS, Ph.D Hyo-Sang PARKDDS, MS, Ph.D Seong-Min BAEDDS, MS, Ph.D Oh-Won KWONDDS, MS, Ph.D Jae-Hyun SUNGDDS, MS, Ph.DSince 2001 www.dentos.co.krDevelopment of the Orthodontic Microimplant (AbsoAnchor )Dept. of Orthodontics, Dental School, Kyungpook National University, 188-1, Sam Duk 2 Ga,Jung Gu, Daegu, KOREA, 700-412 (*corresponding author contact : hmkyungknu.ac.kr)DDS, MS, Ph.D*Hee-Moon KYUNGDDS, MS, Ph.DHyo-Sang PARKDDS, MS, Ph.DSeong-Min BAEDDS, MS, Ph.DOh-Won KWONDDS, MS, Ph.DJae-Hyun SUNG1. Introduction42. Terms used in skeletal anchorage73. Types of AbsoAnchor Microimplant74. Terms used in Microimplant surgical procedures95. Selection of Microimplants116. Various clinical sites for Microimplant placement147. Surgical Procedures218. Advice for Microimplant driving269. Avoiding root damage2910. Orthodontic Force application3011. Postoperative patient management3012. Explanation for possibility of failure3013. Microimplant removal3014. Concluding remarks32References33CONTENTSBrochure for the AbsoAnchorOrthodontic Microimplant -6th ed, 20084Brochure for the AbsoAnchor Orthodontic Microimplant -6th ed, 20081. IntroductionThe control of anchorage is one of the most critical factors in orthodontic treatment. The reinforcement of an anchorage usually needs a a complete understanding of biomechanics and a patient compliance. Unfortunately, there are many orthodontic treatments during which absolute anchorage is needed. However, considering Newtons Third Law, it is virtually impossible to achieve absolute anchorage condition in which reactional force produces no movement at all, especially with intraoral anchorage. Thus, extraoral anchorage, such as head gear, is traditionally used to reinforce anchorage. However, the use of extraoral anchorage demands full cooperation of patient as well as 24 hours of continuous wear which cannot always be done. Therefore, it is extremely difficult to attain excellent result without compromising treatment in some way.Hence, to treat patients without patient compliance, clinicians and researchers have tried to use skeletal anchorage. Gainsforth and Higley (1945) placed metallic vitallium screws in dog s ramus as anchors and applied elastics to the maxillary arch wire for distalization of maxillary dentition as long ago as 1945. However, all screws failed within one month. There were no more published reports of attempts to use skeletal anchorage to move teeth until the clinical case report of Linkow (1969, 1970), who used mandibular blade-vent implants in a patient to apply class II elastics.After Br nemark and co-workers reported successful osseointegration of prosthodontic implants in bone, osseointegrated implants (Sherman, 1978; Roberts et al., 1994; Wehrbein et al, 1999) have been used as intraoral orthodontic anchorage, but their usage has many limitations for routine orthodontic practice. First of all, it is difficult to select a proper insertion site for a conventional implant in orthodontic patients due to the large diameter of implant. Also, waiting time for osseointegration, high cost, severity of surgery, etc. are known problems for both patients and orthodontists. Thus, a smaller diameter miniscrew has been developed for orthodontic anchorage rather than bulky conventional dental implants. Creekmore Park et al, 2001; Bae et al, 2002; Bae et al, 2002) have started to use surgical micro-screws (1.2mm in diameter) to retract maxillary anterior teeth after placing them between the roots of upper 2nd premolars and 1st molars. The treatment was very successful without any complications. They also showed that almost all kinds of tooth movement were possible including molar intrusion, molar protraction and whole dentition retraction using small diameter of micro-screws. These micro-screws were inserted into many areas of maxilla and mandible such as in between roots of adjacent teeth and midpalatal suture which were previously unavailable for conventional dental implants. In addition, they showed that micro-screw head can be exposed when it is placed on the attached gingival area. Originally, micro-screw was used to fix mini-plate into bone in surgical fields. So, it was difficult to apply orthodontic elastomers onto the screw head without forming connectional ligature wire loop on the cervical portion of the screw. Thus, there was periodontal involvement which was caused by the location of ligature wire that is under the screw and towards gingival, even though the screw itself was located on the attached gingival area. This micro-screw location allowed gingival embedment of ligature wire producing steady irritation on soft tissue and also caused difficulty for patients in keeping good oral hygiene around the screw.To compensate for these drawbacks, we developed orthodontic Microimplant (AbsoAnchor ), which has been designed specifically for orthodontic purpose and has a button-like head with a small hole. Also, by giving inclination on cervica