The base plate consists of the bulk of the removable orthodontic appliance. It holds the active and retentive components of the appliance together into a single unit. It also aids in the retention of the appliance and renders it stable.
Base plate thickness
It should be of a minimum thickness for patient compliance. A thickness of 1.5-2 mm provides the required strength and is also tolerable. The thickness of a lower appliance is a bit thicker than its upper counterpart to compensate for decreased length.
Coverage of the base plate
The upper appliance usually covers the entire palate up to the distal side of the 1st molar. The lower base plate's extension is limited because of irritation caused in the lingual sulcus.
Materials used for the base plate
Heat cure or cold cure acrylic is used to fabricate a base plate.