My surgeon did not use them for my MMA. He says he uses them for particular orthognathic cases but no longer for MMA, particularly when pre-op occlusal is good (like mine was). Per his report, he and other surgeons have noted that the before/after occlusal success has been similar with or without splints. Considering this in light of the significant costs in terms of patient comfort, ability to communicate, etc, more and more surgeons are foregoing them, apparently. I'm not sure this has been formally studied at this point.