Regardless whether you do a 4 year or 6year/MD track of OMFS residency the $$$$$$$$$$$$$ is in staying in your office AS MUCH AS POSSIBLE and avoiding the hospital as much as possible.
Most OMFS'ers whether they are 4 year or 6 year/MD get on staff at a hospital and attain full hospital privileges for at least the traditional scope of OMFS (Orthognathic, Cranio-Maxillofacial Trauma, and related OR time for dentoalveolar procedures). Often times, new grads find themselves working as associates in practices where they have to pick up part of the office-call and hospital trauma call. They do it for various reasons, but mostly because they have to, and its a way to get your name out in the community as well.
The beauty of OMFS is that you have the power to pick and chose your course. Some start out with more hospital procedures as they build a private referral base, others flat out avoid it from the get-go. Some keep the hospital privileges for life, while others slowly phase them out as their private practices and bank-accounts grow.
Most OMFS would be happy to do more hospital and expanded scope procedures (just like back in residency), but they quickly lose interest in it when you factor in:
1) Minimal or NO reimbursement for technically demanding, high-risk procedures (as in the case of facial trauma, head & neck cancer).
2) Irregular Hours, time away from family & friends
In my humble opinion, I think as a specialty we have an obligation to provide care for facial trauma, but that obligation should not be such that it completely over-rides and destroys our private practice/elective surgery lifestyle. To that end, facial trauma call must be negotiated and arranged in a FAIR manner with other practicing OMFS as well as any Plastics and ENT's that may do facial trauma. That's a lot easier said than done! Where I grew up, the OMFS/Plastics and ENTs get along pretty well at the Level 1 trauma hospital... they have it split in such a way that they average a trauma call schedule of about 1 week out of every 10-12 weeks.