The lower third molar is the most commonly impacted tooth, with higher prevalence in the mandibular and mesioangular angulation. In orthodontic patients, the observation of third molar impaction generally entails measurement of its angulation before and after treatment. This study aimed to determine mesioangular impacted lower third molar angulation changes in subjects with fixed orthodontic treatment in Teaching Dental Hospital, Faculty of Dentistry, Universitas Indonesia. 27 samples were selected and measured before and after treatment on panoramic radiograph using the Poosti method. The result showed an increase in angulation clinically on both sides of the jaw. Based on statistical analysis, however, these angulation changes were not significant (p > 0.05). © Published under licence by IOP Publishing Ltd.