Effect of Rate of Third Molar Impaction on Mandibular Arch Crowding in Skeletal Class I Patients

Aim: Assessment of Effect of rate of third molar impaction on lower arch crowding in skeletal class I patients. Materials and Method: 150 Untreated subjects with different facial divergence pattern between age 16 – 25 years seeking for orthodontic treatment, crowding of lower arch calculated by using caliper and imp-action of lower 3rd molar is evaluated by Winter’s classification. Results: Mandibular anterior crowding is divided into four groups according to severity, out of which 4-6 mm of crowding most commonly found value. In Hypo-divergent facial pattern Mesio-angular impaction is most commonly found. Crowding in hypo-divergent patients is mostly moderate between 4-6 mm which is 45 % and also 20 % in 0-2 mm and more than 6 mm group while only 15 % in 2-4mm crowding. Normodivergent subjects had 30 % crowding in 2-4 mm and 0-2 mm group and 20 % in other groups. Conclusion: Disto-angular impaction and vertical impaction type has significantly less crowding severity as compared to mesio-angular and horizontal type irrespective of facial profile.