Primary molar root morphology, physiological resorption and the proximity of the permanent tooth are all complicating factors in the root treatment of primary molar teeth. However, in a select group of patients, pulpectomy can be successfully completed.

The aim of a pulpectomy is to entirely remove irreversibly inflamed or necrotic radicular pulp tissue and gently clean the root canals followed by obturating with a filling material that will resorb at the same rate as the primary tooth.

Indications for a pulpectomy:

• Tooth shows signs/symptoms of irreversible pulpitis and therefore unsuitable for pulpotomy.
• Non-vital radicular pulp with/without pathology
• Compliant patient

How to Carry Out a Pulpectomy:

• A periapical radiograph showing all roots and apices is essential prior to beginning pulpectomy.
• Administer local analgesia and place a rubber dam.
• Remove caries and identify the site of pulp exposure. If there isn’t a pulp exposure, access to the pulp chamber is made from the base of the cavity.
• Identify root canals and irrigate using normal saline, chlorhexidine or sodium hypochlorite.
• Estimate working length keeping 2mm short of radiographic apex
• Insert up to file size 30 into canals and gently file
• Dry using paper points, again keeping 2 mm short of radiographic apex
• Obturate using pure zinc oxide eugenol/sterile water paste, non-setting calcium hydroxide or Vitapex (calcium hydroxide and iodoform paste).
• Restore with SSC.

Remember:

Pulpotomy – VITAL (removal of some of the pulp)

Pupectomy – NON-VITAL (removal of all the pulp)

Stainless steel crown (also known as preformed metal crowns) are the gold standard restoration for primary molar teeth and are simple to place. They come in a range of sizes from 2-7 with 2 being the smallest size and 7 the largest.

Indications for SSC:

• Restoration of primary molars requiring large, multisurface restorations
• Restoration of primary molars in children with high caries risk
• Restoration of teeth after pulp therapy
• Restoration of teeth with developmental defects, e.g. dentinogenesis imperfecta and amelogenesis imperfecta
• Abutments for space maintainers
• Restoration of fractured primary molars
• Protection of primary molars with non-carious tooth surface loss
• Restoration of hypomineralised young permanent molars

Contra-indications for SSC:

• Inability to fit one – this may be due to insufficient coronal tooth remaining but more likely is lack of cooperation
• If the primary molar is close to exfoliation with more than half the roots resorbed
• A patient with a known nickel allergy or sensitivity

Technique for the placement of SSC:

Appropriate local analgesia should be obtained and the tooth should be isolated with a rubber dam. Caries removal and pulp therapy should be completed as necessary.

1. Occlusal reduction – using a rugby ball shaped diamond bur or a diamond wheel. Follow the occlusal anatomy of the tooth and reduce the crown until it is completely out of occlusion.

2. Reduction of mesial and distal proximal surfaces – Use a tapered diamond to reduce the mesial and distal surfaces to ensure sufficient clearance for the placement of the SSC. This is the most crucial part of the crown preparation. No gingival step should be left otherwise the crown will not fit properly. When the mesial and distal reduction has been completed, a check should be made with a probe that no step exists.

3. Selection of size – With experience, an estimate can be made of the appropriate size crown to select. The crown is gently placed on the tooth and pressed into place from palatal to buccal. It should snap onto the tooth with only a reasonable amount of pressure. Crimping the crown margins with an Adams pliers can be used to adjust the crown margins to ensure a tight fit. This is important to prevent the buildup of plaque on the crown and lessen the risk of gingivitis.

4. Cementing the crown – The crown should be filled with suitable cement–usually glass ionomer. The crown should be seated and pressure applied until the cement has set. Excess cement can be removed using an excavator. In order to ensure that no excess cement is left at the mesial and distal gingival margins, a piece of dental floss is passed backwards and forwards through the contact point.

5. Final result – Following the placement of a SSC blanching of the gingiva is often noted and occlusion may be high. It is important to reassure the patient and parent that both are normal and blanching will disappear/occlusion will adjust.

The Hall technique is a technique whereby decay is sealed under preformed metal crowns without local analgesia, tooth preparation of any caries removal.

Clinical trials have shown the Hall technique to be effective and acceptable to most children and parents.

Indications for a SSC using the Hall technique:

1. Proximal carious lesions in primary molars

2. Class I lesions in primary molars if patient unable to accept conventional restoration

Contraindications for a SSC using the Hall technique:

1. Signs or symptoms of irreversible pulpitis or sepsis

2. Clinical or radiographic signs of pulpal involvement or pathology

3. Unrestorable crown of tooth

4. Child at risk of bacterial endocarditis

Technique for the placement of a SSC using the Hall technique:

Placement of orthodontic separators – If there is insufficient space for the seating of a crown, orthodontic separators may be placed a week before the fitting of the SSC.

Placing the crown – the patient is not supine as there is a risk of aspiration of the crown. Seat the child in an upright position and place some gauze lingual to the tooth being restored to protect the airway.

Choosing the size – the size selected will usually be bigger than with conventional crowns as you will not be preparing the tooth.

Choose a crown and try it on the tooth – it should feel as if it would seat between the contact points. Do not seat the crown fully as it will be difficult to take off for cementation. When you have chosen the appropriate crown, cement it using a luting cement in the same manner as conventional SSC. Ask the patient to bite the crown on using a cotton roll.

Carrotte, P., 2005. Endodontic treatment for children. British Dental Journal, 198(1), pp.9-15. https://www.nature.com/articles/4811946/

Howley, B., Seale, N.S., McWhorter, A.G., Kerins, C., Boozer, K.B. and Lindsey, D., 2012. Pulpotomy versus pulpectomy for carious vital primary incisors: randomized controlled trial. Pediatric Dentistry, 34(5), pp.112E-119E.

Ludwig, K.H., Fontana, M., Vinson, L.A., Platt, J.A. and Dean, J.A., 2014. The success of stainless steel crowns placed with the Hall technique: a retrospective study. The Journal of the American Dental Association, 145(12), pp.1248-1253.

Innes, N., Evans, D. and Hall, N., 2009. The Hall Technique for managing carious primary molars. Dental update, 36(8), pp.472-478.