Appliance Design and Clinical Management
Appliance families
Know the major appliance systems: fixed labial and lingual brackets, clear aligners, removable functional appliances, headgear, and palatal expanders. Understand the design features that matter clinically - bracket prescription (tip, torque, in-out), slot size, ligation type, and archwire sequence. Know the properties of archwire materials: stainless steel, nickel-titanium, beta-titanium, and cobalt-chromium, and when each is indicated.
Clinical management
Understand the principles of bracket placement, bonding and banding, and the management of common emergencies - loose brackets, wire irritation, and lost retainers. Know the rationale for archwire sequencing from light round to rectangular and the role of auxiliary appliances such as elastics, coil springs, and power chains. Know the management of oral hygiene and white spot lesions during treatment.
Traps
Questions often test whether you can match the appliance to the malocclusion - for example, using a functional appliance in a patient with no remaining growth, or choosing aligners for a case requiring significant torque control. Another trap is confusing the properties of archwire alloys: nickel-titanium delivers light continuous force with high springback, while stainless steel offers stiffness and formability. Watch for questions about bracket prescription that ignore the patient's initial angulation.
Worked example
A patient presents with a rotated upper central incisor and a tight arch. Rule of thumb: begin with a light nickel-titanium wire to align and level, then progress to a rectangular wire for torque control. Do not jump to a stiff wire before alignment is complete, or you risk bracket failure and patient discomfort.