Maxillary Mandibular Plane Angle (MMPA): Ideally 27 degrees +-4 – Orthodontics MnemonicsBy Hiba Al-Shawa / April 7, 2022 Back to: Orthodontics Mnemonics I like this! Let me join! Previous Lesson Frankfort Horizontal Plane: a Line connecting Porion with Orbitale Next Lesson Herbst Appliance