The Snodgrass Appliance incorporates a Rapid Palatal Expansion (R.P.E.) feature into the Hilgers Pendulum design and is used in the mixed and permanent dentition as an adjunct to treat Class II malocclusions that require expansion, molar rotation, and molar distalization. Heavy wires from the anterior portion of the appliance are soldered to the molar bands, making the entire appliance rigid for R.P.E.. Initial adjustments involve twice daily activation of the midline screw until the desired lateral expansion is achieved -- usually about two weeks. The appliance should then be left in place for at least one month after expansion before activating the pendulum springs. Activating the pendulum springs requires intraoral cutting (with a 557 bur) of both solder joints mesial to the six-year molars. The springs can be pre-activated by the lab, while additional activation is possible with Weingart Pliers -- usually once a month.  Addition of the “M" Pendulum Spring to the (pictured) standard Pendulum Spring design is often preferred in the interest of achieving more bodily molar distalization. Note: Once molar position is established, the bicuspids and cuspids must be brought back in the arch form --one at a time -- using fixed mechanics.