Table 2 Protocol for carrying out Hall Technique restorations, following the Innes et al. [27] protocol

First visit:

• Assess the tooth shape, contact points/areas and the occlusion.

• Use orthodontic separators to create space for fitting a Hall crown, unless there are no contact points. In order to protect the airway, the child will be sat upright

• Thread two lengths of dental floss through the separator. Stretch the separator and floss taught and floss through the contact point briskly and firmly until the leading edge only is felt “popping through” the contact point. Remove the floss and make a second appointment with the patient 3 to 5 days later.

Second visit:

• Remove the separator with an excavator.

• Gently remove loose plaque and food debris only from the cavity.

• Assess the occlusion: measure the patient’s occlusal-vertical dimensions (OVD) with a millimeter probe using the distance between the most coronal points of the primary canines in order to assess the degree of overbite after mounting of the crown.

• Protect the airway by placing a gauze swab square between the tongue and the tooth to be crowned.

• Select the correct crown size (Stainless Steel Crowns, 3 M™ ESPE™, St. Paul, MN, USA). The crown should covers all the cusps and approaches the contact points, with a slight feeling of “spring back.” You should aim to fit the smallest size of crown which will seat.

• Keep the treatment area free from saliva by isolating the tooth with cotton wool rolls.

• Dry the inside of the crown with dry cotton pellets.

• Mix the encapsulated glass ionomer cement (GIC) (Fuji I, GC Europe, Leuven, Belgium) for 10 seconds, according to the manufacturer’s instructions.

• Load the crown generously with GIC (at least two thirds full). Avoid air blows and voids.

• Place the crown over the tooth and seat the crown into place by finger pressure or ask the child to bite it into place.

• Check the crown position as soon the crown is fitted.

• Wipe away the excess GIC with a cotton wool roll or the gauze swab used to protect the airway.

• Place a cotton wool roll between the crown and the opposing tooth and ask the child to bite firmly on the crown for another 2–3 minutes.

• Remove excess cement, flossing between the contacts.

• Blanching usually disappears within minutes. The occlusal discrepancy should resolve in a few weeks.

• Measure the degree of bite opening and record in the notes. If excessive, then consider removing the entire crown.

• Check the buccal relationship of the crowned tooth with its opposing number. If there is a displacing contact, resulting in a cross bite, then manage as for excessive bite propping.