Preformed metal crown technique

Give local anaesthetic.

Radiograph of lower right E showing mesial advanced caries

Protect the airway. 

Consider the use of rubber dam. 

Remove caries. 

• If at risk of pulpal exposure, place an indirect pulp cap, before placing a glass ionomer cement dressing. Note the use of a distal wedge prior to preparing the distal slice.

Images show lower right E with mesial advanced caries (left), placement of a distal wedge (centre) and preparation of distal slice (right)

Carry out occlusal reduction sufficient to allow a straight probe to be passed across the tooth surface when the teeth are in occlusion. Complete before cutting mesial and distal slices. 

• The bur should pass through the crown cervically in order to avoid creation of a cervical ledge, as this will impede the seating of the crown. The wedge protects the gingivae during distal preparation.
• Note the wall of enamel left while cutting the slice to ensure there is no iatrogenic damage to the adjacent tooth. The wall will then fall away as the cut is completed cervically. 
• Once the wedge is removed a probe can pass freely from buccal to lingual through the contact. 

Images show a probe being passed through the contact (left), the tooth prepared for placement of the PMC (centre) and crown contouring pliers (right)

Select the correct size of PMC and adjust to fit with crown contouring pliers as shown, or with root/tooth forceps.

Cement the PMC in place with glass ionomer cement, remove excess cement and clear contacts using floss. 

Images show placement of PMC using glass ionomer cement (left) and final restoration (right)