Ortho III unit 2 Removable Appliances

Ortho III unit 2 Removable Appliances

Uses removable appliances

• Adjunct to fixed appliances

• Tipping movements

• Simple rotations

• Retention (passive retainer)

• Slow expansion

Contraindications removable appliances

• Rapid maxillary expansion

• Bodily movement

• Should not replace fixed appliances when fixed is more appropriate

Advantages

• Easy cleaning

• Less chair side time

• Good for overbite reduction

• Efficient tipping

• Occlusal interferences can be removed

Disadvantages

• Limited tooth movement

• Anchorage difficult

• Retention issues

• Patient cooperation needed

• Affects phonation

Components removable appliance

1. Retentive components (clasps)

2. Active components (bows, springs, canine retractors)

3. Base płatę

Common clasps

• C clasp

• Jackson clasp

• Adam’s clasp

• Triangular clasp

• Schwartz clasp

• Resta clasp

• Southend clasp

• Ball-end clasp

C-clasp

• Used for 1st and 2nd molar and canine

• Advantages: simple, easy, minimal occlusal interference

• Disadvantages:

  • Poor retention in active appliances,

  • Not for partially erupted teeth or deciduous molars

  • Easily distorted

Adam’s clasp parts

1. Arrow heads (2)

2. Bridge

   1. 45 degree angulations with long axis of clasped tooth

   2. Parallel with buccal cusp

   3. 2mm away from the buccal surface

3. Tags

4. Retentive parts

Adam’s clasp characteristics

• Most universal

• 0,7 mm SS wire

• Works on any tooth

• Advantages:

  • Excellent retention

  • Versatile

  • Repairable

  • Modifiable

• Disadvantages:

  • Harder to fabricate

  • More occlusal interference

Modifications

• Helix (for elastics)

• Soldered hook (for elastics)

• Traction hook (for elastics)

• Extra arrowhead (for more retention)

• Buccal tube (for face bow)

• Double Adam’s (for extra retention)

• Distal extension (for elastics and retention)

Ball-End clasp

For extra retention, but has low retention

Active components

• Bows

• Springs

• Canine retractors

Bow types

• Short labial bow

  • Canine to canine

• Long labial bow

  • PM to PM

• Split labial bow

  • Split at midline

• Modified split labial bow

  • Each side engages opposite CI

Short labial bow

• Canine to canine

• Minor overjet

• Small anterior space closure

Definition of removable orthodontic appliances

Removable appliances are orthodontic devices that can be inserted and removed by the patient, used for tipping movements, minor rotations, expansion, and adjunctive treatment

Main categories of removable appliances

• Myofunctional appliances

• Orthopedic appliances

• Active removable appliances

• Passive retainers

• Clear aligners

Indications for removable appliances

• Adjunct to fixed appliances

• Tipping movemens

• Simple rotations

• Retention

• Slow expansion

• Minor overjet reduction

Contraindications for removable appliances

• Rapid maxillary expansion

• Bodily tooth movement

• Cases requiring strong anchorage

• Poor patient compliance

Why removable appliances cannot perform bodily movement

They deliver forces primarily through springs and bows, which generate tipping moments rather than controlled root movement.

Advantages of removable appliances

• Easy cleaning

• Reduced chairside time

• Ability to remove occlusal interferences

• Efficient tipping

• Useful as retainers

Disadvantages of removable appliances

• Limited movement types

• Anchorage difficulties, retention issues

• High dependence on patient cooperation

• Phonation problems

Three essential components of removable appliances

1. Retentive components (clasps)

2. Active components (bows, springs, retractors)

3. Base plate

Purpose of retentive components

Engage undercuts to stabilize the appliance, resist dislodging forces, and maintain appliance position during activation

Advantages of the C clasp

• Simple

• Easy to fabricate

• Minimal occlusal interference

• Adequate retention for passive appliances

Disadvantages of the C clasp

• Poor retention in active appliances

• Unsuitable for partially erupted or deciduous molars

• Easily distorted

Adam’s clasp — definition and importance

A universal clasp with two arrowheads and a bridge; provides excellent retention and is adaptable for many clinical situations, for any tooth

Key parts of Adam’s clasp

Mesiobuccal and distobuccal arrowheads, connecting bridge, retentive arms, retentive tags.

Advantages of Adam’s clasp

• Excellent retention

• Versatile, modifiable

• Repairable by soldering

• Works on erupted and partially erupted teeth

Disadvantages of Adam’s clasp

Difficult to fabricate, more occlusal interference than C clasp.

Clinical adjustment points for Adam’s clasp

Retentive arms exiting acrylic, arrowheads adaptation, bridge alignment relative to buccal cusps.

Purpose of ball‑end clasp

Accessory clasp providing additional retention, especially when undercuts are limited.

Short labial bow — indications and biomechanics

• Minor overjet reduction (≤3.5 mm) and mild anterior space closure

• Less flexible, activated by reducing palatal acrylic and compressing U‑loops.

Long labial bow — indications and biomechanics

• Minor overjet reduction

• Anterior space closure

• Closure distal to canine

• More flexible due to longer span.

Split labial bow — indication

Anterior retraction; increased flexibility due to midline split

Modified split labial bow — indication

Closure of midline diastema by engaging opposite central incisors

Finger spring — design and indication

Single cantilever spring with helix and retentive arm; used for minor mesiodistal movements and midline diastema closure

Z‑spring — indication and biomechanics

Used for minor rotations and labial movement of incisors; double helices allow differential activation

T‑spring — indication

Buccal movement of premolars (and occasionally canines) by pulling the free T‑arm

Mattress spring — indication

Labial movement of upper teeth in crossbite when adequate space exists → in cross bite

Helical coil spring — indication

Regaining lost space through controlled activation of dual helices

Classification of canine retractors

Buccal vs palatal; helical vs looped; push vs pull type

U‑loop, helical, palatal, and buccal canine retractors — shared biomechanical principle

All retract canines by applying distal crown tipping forces; not suitable for bodily movement; appropriate when uprighting is needed.