My rules in Orthodontics Mohammed AlMuzian. Episode 76. February 10th 2021

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Hosted by
Farooq Ahmed

Join me for Mohammed Al Muzian’s rules in orthodontic practice

Part 1 we will cover half of the 32 tips the following topics: Knowledge Vs confidence, space requirements and creation, IPR, expansion, inclination changes and treatment planning

Knowledge Vs confidence

·      We tend to be overconfident at the beginning of our careers, and underconfident in the middle. Kruger’s curve

Space assessment

Calculate space requirements in the lower arch Use T-SCOTAR

o   Torque

o   Spee curve

o   Crowding

o   Overjet

o   Teeth size discrepancy

o   Angulation of teeth

o   Rotation

Space creation 

Use SPEEDAR for space provision

o   Stripping

o   Proclination of incisors

o   Extraction

o   Expansion

o   Distalisation

o   Angulation

o   Rotation


·      A maximum of 0.75mm of IPR per tooth can be tolerated depending on the shape and size

·      Up to 4-6mm can be achieved sometime, but you need to balance that with the opposing to avoid TSD

Inclination change and effects

o   2 mm of crowding= 50 of proclination =1 mm change in the overjet and overbite (draw bridge effect)

o   2 mm of spacing= 50 of retroclination=1 mm change in the overjet and overbite Eberhart et al (1990), Sangcharearn and Hob (2007), Kapoor 2014, Aziz et. al 2011

o   All cases can be retroclined or proclined by 5 degrees without affecting the PDL..

o   Some may accept 10 degrees if I have good gingival biotype, thick symphasis, no recession, no PDL problem and Avoid Jiggling forces.

o   Do not procline the uppers more than 1200

o   Do not retrocline the lowers to less than 800


·      Lower arch: Cannot expand (unless  Class II/2 and canines trapped )

·      Upper arch: Can expand

o   Maximum 0.5mm of space per 1mm expansion

o   Why do you lose half of the expanded space? Due to the backward movement of the anterior teeth.

·      Expansion retainer:– wire reinforcement of essix retainer

·      Bonded RME

o   Design with big hole in housing:  to easily remove the RME

o   Expansion amount guided by lower arch ideal alignment (Andrews plane)

o   Use Monoject or Water jet (flosser) with CORSYDOL to clean under the RME


Treatment planning

o   Plan around the lower arch

o   Rationale:

§  Limited labio-lingual alveolar bone

§  Upper arch labio-palatal bone can be remodelled

o   MOOH – planning around the lower arch

o   Midline

o   Overjet

o   Overbite

o   Health of PDL

§  If ALL above cannot be achieved non-extraction = extractions required

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