31. Lingual plate appliance-indication, design, modification, mode of action

Question 1

Lingual plate appliance and mode of action

Answer 1

• Removable orthodontic device=>
• Tipping tooth around center of resistance
• The active movements=>
• Tipping (mesio-distal or labio-lingual)
• Rotation
• Bodily movement
• Extrusion or intrusion
• Anterior bite plane can also separate molars to allow vertical eruption=> reduces overbite
• Forces exerted depend on type of appliance=>
• Harness forces from adjacent soft and hard tissues, or incorporation of springs/elastics, and type of contact active component makes w/ tooth or teeth to be moved

Question 2

Design components of lingual plate appliance

Answer 2

• Force/Active Components=>Springs, screws, elastics
• Fixation/Retentive Components=>Clasps
• Base Plates or Frameworks=>acrylic
• Additional Elements=> Occlusal rest, pads

Question 3

Lingual base plate

Base plates function

Answer 3

• Withstand pressure and distribute forces to anchorage area=>
• Incorporate active and retentive components into single functional unit=>
• Resist unwanted drifting during teeth movement=>
• Anchorage and retention in mouth
• Protection=> palatal springs against distortion
• Specific requirements=>thickness 1.5-2 mm

Question 4

Wire elements used in a lingual plate

Answer 4

• Labial Bow=>0.8 mm stainless steel wire=>
• Overjet reduction and anterior fixation
• Springs=>0.5, 0.6, or 0.7 mm wire=>
• Mesial, distal, vestibular, and palatal/lingual movements
• Elements for Expansion=>coffin spring (1.2 mm) and screws=> activated by patient

Question 5

Retentive components for lingual plate appliance

Answer 5

• Clasps=>
• Retain appliance in place
• Resist displacement

Question 6

Additional elements incorporated into a lingual plate appliance

Answer 6

• Buccal tubes=>extraoral anchorage (EOA)
• Occlusal rests
• Wire clasps
• Lip pads

Question 7

Modifications for lingual plate appliance

Answer 7

• Lingual Plate w/ Inclined Plane=>
• Move lower jaw forward in class II cases=>
• Covers lower anterior teeth and facilitates protrusion and intrusion of lower anterior teeth
• Buccal Capping=>eliminates occlusal interference and allows tooth movement by placing acrylic base over occlusal surface of buccal segment
• Anterior Bite Plane=>
• Reduce overbite and can incorporate tongue guard
• Behind upper incisors on which lower incisors occlude=>