Molar anchorage loss and its influencing factors in orthodontic cases with premolar extraction

Abstract

In orthodontic treatment for protrusion, premolar extraction is a common option. The extraction spaces are closed by the reciprocal movement of posterior and anterior teeth. However, the unclear question is, after extracting the first or second premolars in the maxilla or mandible, what amount is the“anchorage loss”(mesial movement)of the molars when the spaces closed using intra-arch reciprocal anchorage only. We reviewed a large number of clinical studies on orthodontic treatment involving the extraction of premolars to investigate the factors related to molar anchorage loss. Existing studies have explored the influence of physiological factors such as age, occlusal relationship, and vertical facial profile, as well as treatment factors such as tooth extraction site, appliance system, and gap closure method on the molar anchorage loss in orthodontic cases involving the extraction of premolars. The reported molar anchorage loss under different conditions has certain reference value for the orthodontic extraction plan making and anchorage design. More high-quality clinical studies are needed to further clarify this important clinical issue in the future.

Keywords

• |premolar extraction|orthodontic treatment|anchorage loss|molar mesialization|treatment planning