OJ Reduction

Question 1

Define Overjet

Answer 1

• Horizontal overlap of maxillary central incisors to Mandibular incisors
• Average 2-4mm
• IOTN a

Question 2

Risk of Trauma

Answer 2

• OJ more than 9mm = 2x trauma risk

Question 3

To Reduce increased OJ consider:

Answer 3

• Aetiology
• Growth
• Anchorage

Question 4

Aetiology of Increased OJ

Answer 4

• Skeletal- AP and vertical relationship
• Dental- ULS Proclined / LLS Retroclined / Both
• Habits- Digit / thumb sucking
• Soft tissues - lower Lip trap

Question 5

How growth aid reduction of OJ

Answer 5

• In most children AP- maxilla stop growth and Mandible grow which helps to reduce OJ

Question 6

Define Anchorage

Answer 6

• Resistance of unwanted tooth movement

Question 7

Reducing OJ by ?

Answer 7

• Retracting upper incisors
• Proclination of lower incisors
• Retrain maxilla growth
• enhance mandibular growth

Question 8

Headgear to reduce OJ

Answer 8

• Restrain maxillary growth
• Allow mandibular growth

Question 9

Inter maxillary elastics

Answer 9

• Retrouclination of ULS + Proclination LLS

Question 10

Extraction methods -upper extraction only

Answer 10

• Extraction of upper first premolars only
• Creating space anteriorly for OJ reduction
• Maintaining Increased posterior anchorage block
• What molar relationships ends?

Question 11

Extraction Choice Upper and lower extraction

Answer 11

• Upper first premolars and lower second premolars
• Creating space anteriorly for OJ reduction
• Forward movement of lower molars
• What would be molar relationship?

Question 12

In non growing patient

Answer 12

• Camouflage
• Orthognarhic depend on severity of SK Base

Question 13

OJ reduction - Working archwire

Answer 13

• Retract ULS or retract canine separately first
  E.g closing loops

Question 14

Sliding mechanism

Answer 14

• Teeth are made to slide along the arch wire by energy stored in Elastic or wire coil spring
• Pre adjusted appliances facilitates sliding mechanism

Question 15

Sliding mechanism - Closing loops
Adv/ disadvantage

Answer 15

• Advantages :
• Minimal wire bending.
  -Less time consuming
• Easier to maintain arch form with closing loops
  Disadvantages:
• High friction with closing loop
  -loss of anchorage
• Can= uncontrolled tipping (if on light wire )

Question 16

Method of force application for space closer

Answer 16

• Powerchain
• Bennett’s modules
• E-links
• Niti coil spring

Question 17

Overjet reduction - Sandusky loops

Answer 17

• Sometime loops are required for space closer / OJ reduction
• Adv - No friction , Precise control of space closer
  Dis adv- Lots of wire bending, mucosal trauma, OH issue, Difficult control activation

Question 18

Reinforcing anchorage to Reduce OJ?
How many methods

Answer 18

• Headgear
• Tranpalatal arch TPA
• TPA with nance button
• TADs
• Class II maxillary elastics
• Retract canine before incisor