Acrylic Resin Crowns

The importance of maintaining occlusion: Inadequate occlusal contacts allow overeruption. This is (vertical movement). Missing proximal contacts can cause migration – horizontal movement – of the abutment under the influence of mastication forces.

This migration can make the adjustment of the final restoration quite difficult. Orthodontic movement is sometimes indicated to shift the abutment to its initial position. The temporary crown protects the abutment from fracture, because tooth mechanical stability has been reduced as a result of its preparation.

Mechanical Requirements:

1. The first one is to withstand functional loading.

2. The temporary crown should not be easily separated from the abutment. This means to have good retention to the abutment tooth. Important factors for good retention of the crown to the abutment are: height of the abutment, surface area, inclination of axial walls, thickness of cement layer, type of cement and mix.

3. Another requirement is to prevent the abutment from migration, including the maintenance of the abutment positions in fixed bridge restoration.