A quick synthesis of mandibular expansion.

First, there are 3 main types of mandibular expansion:

1. SFOT - most cope, basically dental/dentoalveolar expansion on steroids. Magnitude is minimal, stability is dubious, but it's the most accessible and "lowest risk" although it's still a brutal surgery and quite expensive.

2. Mandibular widening as part of an MMA (i.e. Dr. Bell's 5 or 6 piece mandibular expansion) - a unicorn procedure that's hard to find, high risk. Double jaw surgery is already scary and risky, this doubles down on that.

3. MSDO - Mandibular midline split + distractor. The kind of expansion discussed by Dr. Movahed in our recent podcast, also popular with Dr. Yousefian (known as DAME)

Reasons for mandibular expansion (let's focus on MSDO)

1. bonafide skeletal change of the mandible, more stable than SFOT (cheek forces will tend to push lower teeth inward toward tongue even after expansion with SFOT)

2. allows for more maxillary expansion before hitting occlusal limit of mandible

3. simplifies post-MARPE orthodontics, since it reduces need to lingually tip uppers, and buchally tip lowers

4. also allows for more maxillary expansion before hitting the cosmetic limit of the mandible, since the mandible gets wider and balloon face is averted

5. provides some airway benefit via advancement of tongue and other tissues tethered to the mandible (a tenting-effect of these tissues occurs with expansion)