Sung-Hoon Lim

Chosun University, Korea

The most preferred site of mini-implant placement is between 2^nd premolar and 1^st molar in the maxilla and between 1^st and 2^nd molars in the mandible. The success rate of mini-implants placed in these areas can be improved greatly by inserting mini-implants vertically, almost parallel to the tooth long axis. To place mini-implant vertically, predrilling is mandatory and head of mini-implant should be small to avoid interference between the tooth and the driver shaft. Another way of improving the success rate of mini-implant is positioning the mini-implant on the thicker and denser bone. Thick and dense bone can be found on the midpalatal area, zygomatic buttress, corpus of mandible, and distobuccal side of mandibular second molar. Mini-implants placed in these areas are rock solid and withstand greater forces. However, applying orthodontic forces from these areas can be difficult. To overcome this problem, bone plates can be used. Bone plates are usually placed submucosally. However, a supramucosal bone plate equipped with a bracket and supported by two mini-implants can be used instead in some situations. Levers can be inserted into the bracket on this plate to generate various force systems. Above applications will be illustrated with case presentations including analyses of force systems and anatomic limitations.