John Libbey Eurotext

L'Orthodontie Française


Material and methods: Volume 79, issue 3, Septembre 2008

1 Département d'Orthopédie Dento-Faciale, Faculté
d'Odontologie, rue Guillaume Paradin, 69372 Lyon Cedex 08, France

Various factors participate to lower third molar eruption included premolar extractions. In Class II division 1 malocclusion, premolar extractions are sometimes decided to correct antero-posterior malocclusion. Alternative therapies without extractions exist such as DAC appliance. What is the influence on third molar eruption of extractions and non extractions in Class II division 1 malocclusion? We made a study with 60 subjects with Class II division 1 malocclusion: 30 were treated without extractions and 30 were treated with 4 extractions (included second lower premolars). We observed the evolution rate of third lower molars, the movement in the mandible and the modifications on lower arch. Results: Extractions of second lower premolars increase the possibilities of third lower molars eruption (that increase from 10% to 50%). Discussion: Like in others publications, extractions of second lower premolars, more than the first, may increase significantly the evolution rate of third molars. Nevertheless, inclusion risk is not reduced and is still important (50% in our study) with the probability that the treatment leads at the end to extractions of a quart of dental capital of the patients.