Vertical Play of Straight Wire Appliance Aids Correction of Gummy Smile and Bimaxillary Incisor Proclination with Mini Implant Anchorage

This report aimed to describe an effective biomechanics to control the upper incisors inclination during the correction of gummy smile with bimaxillary proclinations. A 14-year-old female presented with a Class II division I incisor relationship complicated with bimaxillary proclination on a Class 2 skeletal base. The lips were incompetent, showing 7 mm of upper incisors at rest and 5mm maxillary gingival display on smiling with normal upper lip length. Treatment involved extraction of all first permanent premolars followed by upper and lower fixed appliances. Intrusion of the upper incisors with controlled labial crown torque was accomplished with mini-implant anchorage placed bilaterally on the infrazygomatic crests with the retraction forces above the centre of resistance using 0.019x0.025-in stainless steel archwire in 0.022-in slot. The 0.019x0.025-in stainless steel archwire in 0.022-in slot provided the vertical play to favour lingual crown tipping despite having forces above the centre of resistance for concurrent anterior segment intrusion.