Rules in orthodontic practice Mohammed Al Muzian Part 2

orthodontics In summary

Join me for part 2 where we explore Mohammed’s rules on which teeth to extract, anchorage assessment and management, Bonding 2nd permanent molars, elastics and treatment planning adults Vs children

Which to extract 4 or 5

o CAT-V principle

§ C: Clinical condition of the teeth

§ A: Anterior crowding: 8mm + extract the 4s, 8mm – 5s or 4s

§ T: Transverse: Lower 5 will help narrow the arch

§ V: Vertical: Extraction of 5s for high angle cases will improve the overbite

Molar outcomes in treatment planning

o Non-extraction or extraction of 4 premolars = class 1

o Extraction of 2 upper premolars: Class 2

o Extraction of 2 lower premolars: Class 3

o Extraction of 1stmolars: Ignore them! Will not change the final molar relationship

Anchorage

o Type A (absolute) No movement of the posterior segment

o TADs – HG – extraction pattern

o Type B posterior movement moves mesially by 25%

o Nance, sectional archwires, intermaxillary elastics, HG

o Type C posterior movement moves mesially by 50%

o Reciprocal movement of anterior retraction

o Type D posterior movement moves mesially by 75%

o Anterior anchorage (reverse HG, TADS)

o Biomechanics: intermaxillary elastics – 2nd order bends – inverted lower brackets

Anchorage loss in the lower arch is less than upper arch

· Differential alveolar bone density

· differential root surface area

· differential Buccolingual width of molar

· differential anterior palatal root torques

Bonding upper 7s

o Don’t bond to for anchorage

o Bonding results in loss of anchorage due to 7s distally tipped, uprighting results in loss of anchorage

Elastics

o Elastics = rotation of mandible

o Overjet 0.5mm correction per month with class 2 elastics

o 1:3 ratio of vertical: horizontal effects

o Unilateral intermaxillary elastics in one side only = cant

o = Use vertical part time elastics on the other side

o Elastic should be stretched 3 times its diameter to give the force

Distalisation Rule

o Don’t expect you can distalize more than 2.5 mm unless you extract 7 OR 8

o Distalization lowers without TADS is very limited

Adults Vs growing patients

· Growing patient:

o Elastics +++

o Distalisation +++

o Functional appliances +++

o Extractions +++

· Adult

o Extractions +++

o Elastics ++

o Distalisation +