The Forsus Fatigue Resistant Device in Premolar-Extraction Treatment.

An 11-year-old male presented with the chief complaint of anterior crowding. He displayed minor lip incompetency and reported an open-mouth posture while sleeping. Excessive overjet (4mm), mild Class II molar and canine relationships, and a slight facial asymmetry were also observed (Fig. 1). The diagnosis was a Class II, division 1 malocclusion with moderate crowding. Considering the patient’s crowding and lip protrusion, we recommended premolar extractions. Treatment with the Forsus Fatigue Resistant Device (FRD)* was planned to improve the intermolar relationship and chin retrusion. Because the force vector of the FRD can distalize the upper molars while proclining the lower incisors, the upper second and lower first premolars were chosen for compensation. After the upper second deciduous molars were extracted, second-premolar eruption was observed for five months. The upper second and lower first premolars were then extracted, and .022" MBT* brackets were placed. Following six months of leveling and alignment, the extraction space was closed using elastomeric chain. A the percentage of orthodontic cases treated with extractions has declined in recent years,1 extraction is still used in some patients to relieve crowding and improve soft-tissue profiles.2 This article shows how a fixed “noncompliant” appliance can be used in a Class II premolar-extraction case to improve the occlusal relationship through forward positioning of the mandible.3