29. Fixed edgewise orthodontic appliances-general description. Principles of treatment and sequencing mechanics

Question 1

Fixed orthodontic appliances, and how they work

Answer 1

• Devices bonded to teeth=>
• Facilitate tooth movement through active force exerted by orthodontic archwires=>
• Vary in type of alloy (e.g., stainless steel, copper-nickel-titanium, titanium-molybdenum) and cross-section (e.g., round, square, rectangular).

Question 2

Most popular fixed orthodontic appliance system today

Answer 2

• Multibracket system
• Conventional brackets typically made of metal alloys
• Ceramic and plastic brackets available for aesthetic purposes

Question 3

Where brackets bonded in different techniques

Answer 3

• Labial-fixed technique=>buccal surfaces of teeth
• Lingual-fixed technique=>oral surfaces of teeth

Question 4

Original system for contemporary multibracket systems, and who introduced it

Answer 4

• Universal Angle appliance=>
• In 1925, Angle introduced Edgewise technique=>
• Three-dimensional movement of teeth and dental arches=>
• Revolutionized by Andrews w/ ‘straight wire technique

Question 5

Main differences between Edgewise and Straight Wire techniques

Answer 5

• Edgewise technique=>
• Bracket slot perpendicular to base=>
• Arch wire has bends for positioning each tooth
• Straight Wire technique=>
• Bracket slot contains all information for tooth positioning=>
• Arch wire straight without bends

Question 6

Basic elements of multibracket system

Answer 6

• Brackets
• Ligatures
• Buccal tubes
• Molar bands
• Arch wires and auxiliary elements

Question 7

Design and purpose of brackets in a multibracket system

Answer 7

• Small, rectangular plates=>
• Metal alloys, ceramic, or plastic
• Most popular type=>twin bracket=>
• Wings for attaching arch wire and additional accessories
• Design varies between Edgewise and Straight Wire techniques

Question 8

Different types of ligatures, and their functions

Answer 8

• Metal ligatures=>
• Stainless steel=>
• Can come with hooks for attaching elastics
• Elastic ligatures=>
• Secure arch wire in bracket slots

Question 9

Purpose of buccal tubes in orthodontic appliances

Answer 9

• Stability of bracket system=>
• Commonly bonded to first permanent molars
• Have slots for arch wire and additional accessories like headgear

• Convertible tubes and lingual tubes are also available for specific treatment needs

Question 10

Design and function of molar bands

Answer 10

• Placed on terminal teeth=>
• Increase stability and prevent debonding in anchorage area
• Contoured to fit cervix of tooth
• Support application of heavy orthopedic forces

-are available in various sizes

Question 11

Role of arch wires in the multibracket system

Answer 11

• Exert force to move teeth=>
• Various materials=> (e.g., Ni-Ti, stainless steel, Ti-Mo), shapes, and sizes
• Choice depends on treatment phase and objectives
• Continuous or sectional

Question 12

Auxiliary elements in orthodontic appliances

Answer 12

• Hooks, lingual buttons, sheaths
• Pulling rings, cleats, eyelets
• Facilitate single tooth movements=>
• Attachment of elastic chains and intraoral elastics for additional corrective measures

Question 13

Ideal arch concept, and importance to Edgewise technique

Answer 13

• Achieving orthognathic occlusion w/ functional and aesthetic optimum
• Each tooth has exact anatomical location allowing multiple contacts between occluding teeth=>
• Requires orthodontic arch wire bending into ideal arch shape

Question 14

Intercanine width importance in mandibular arch

Answer 14

• Measured by distance between canines=>
• Remains constant after permanent canines erupt=>
• Alterations in width=>orthodontic relapse=>
• Important parameter to maintain during treatment

Question 15

First-order bends in orthodontic arch wires

Answer 15

• Horizontal plane adjustments of arch wire=>
• Contour it to buccal surfaces of teeth=>
• Accommodate variations in labiolingual thickness
• Ensure smooth curve of incisors and canines on their lingual surfaces

Specific bends=>anterior arch form bend for incisors, in-set for maxillary lateral incisors, off-set for canines, and toe-in for molars

Question 16

Second-order bends in orthodontic arch wires

Answer 16

• Adjustments in the transverse and sagittal planes=>
• Tipping and angulation=>
• Maintain final angulation of teeth
• Ideal angulation in incisal area
• Maintain distal tipping of premolars and molars
• Bite opening

• Types=> tip-back, tip-forward, step-up, step-down, artistic bends, sweep bends, gable bends, tie-back, and arch loops

Question 17

Third-order bends () in orthodontic arch wires

Answer 17

• Torsional adjustments through long axis of rectangular arch wires
• Two types=>buccal/palatal (lingual) root torque and buccal/palatal (lingual) crown torque
• Torque can be active=>affects torque movement=>
• Or passive=>maintains achieved torque w/out producing movement
• Continuous torque recommended in mandibular incisor region=>
• Progressive torque recommended in posterior region

Question 18

How torque managed in pre-adjusted Edgewise appliance systems

Answer 18

• Torque values built into brackets
• Variations of torque for a segment or individual tooth may be required to properly finish the case

Question 19

How principles of ideal arch concept apply differently in Edgewise and Straight Wire techniques

Answer 19

• Edgewise technique=>all bends formed on stainless steel, rectangular, full-size arch wires
• Straight Wire technique=> incorporates geometry of bracket slot to function as first, second and third-order bends=>
• Eliminates need for bends to be applied exclusively