Relationship between dental crowding and mandibular incisor proclination during orthodontic treatment without extraction of permanent mandibular teeth

For every millimeter of crowding alleviated, 0.5° of proclination and 0.2 mm of protrusion are expected. Our results indicate that proclination is mulifactorial and cannot be explained solely by the amount of crowding alleviated during orthodontic treatment. These results may be a useful guiding principle rather than a prognostic tool.