Pulpotomy for primary teeth
Pulpotomy for primary molars (vital pulp therapy)
Suitable for:
- pulpitis with irreversible symptoms (vital pulp)
- a primary molar with an advanced carious lesion with no clear band of dentine visible radiographically that separates the lesion and pulp
Aim: To enable a vital primary molar with pulpal disease to be retained free from pain and infection until exfoliation.
Where there are symptoms of pain that may be due to food packing or pulpitis with reversible symptoms, but the diagnosis is uncertain, a temporary dressing can be placed into the cavity and the patient reviewed 3-7 days later to check symptoms. Resolution of the symptoms at review will indicate that the pulpitis was reversible and a pulpotomy is not necessary. When symptoms resolve, a permanent restoration or Hall crown can then be placed. If symptoms do not resolve or worsen then a pulpotomy or extraction should be carried out.
These techniques can be demanding both for the child and the clinician as they require local anaesthesia and immediate placement of a preformed metal crown (PMC) to maximise effectiveness. Contraindications for pulp therapy include teeth that are close to exfoliation or are unrestorable, children who are pre-cooperative or immunocompromised and cases requiring multiple pulp therapies where extraction is indicated. As roots of primary teeth resorb, conventional endodontics is contraindicated. Instead, removal of irreversibly diseased pulp tissue from the pulp chamber alone, followed by placement of a PMC to achieve a good coronal seal can resolve symptoms.
Photograph (left) and radiograph (right) of a symptomatic upper left D in a 5-year-old which requires pulp therapy.
Note from the radiograph above and model below:
- how much higher the pulp horns are relative to the central part of the pulp chamber roof in primary molars
- how divergent the root canals are when leaving the pulp chamber
Care is needed to avoid perforating the floor of the pulp chamber, which is very thin in primary molars (photo below right).
Model showing pulp morphology of upper D (left) and photograph showing perforated pulp chamber floor (right)
Technique
Give local anaesthetic and consider the use of rubber dam.
Cut a large access cavity using a high-speed handpiece, ensuring the entire roof of the chamber is cleared.
Remove the contents of the pulp chamber using a slow-speed handpiece, or sharp excavator.
Images show access cavity (left) and removal of pulp chamber contents using a slow-speed handpiece (centre) and sharp excavator (right)
Thoroughly irrigate the pulp chamber with sodium hypochlorite or sterile saline.
- Rubber dam should be in place if sodium hypochlorite is used.
- Avoid the use of compressed air, which could cause surgical emphysema.
Identify entrances to root canals, which will be in the corners of the pulp chamber.
- Maxillary primary molars have three canals (two buccal and one palatal).
- Mandibular primary molars have just two canals (mesial and distal).
If still bleeding, arrest haemorrhage by placing a pellet of cotton wool dampened in ferric sulphate (commonly found as the haemostatic agent in gingival retraction kits) into the pulp chamber, place another pellet on top, and then have the child bite on a cotton wool roll placed over the tooth for ~2 minutes.
- Formocresol should not be used due to concerns about its safety.76
Images show cotton wool pellet being dampened with ferric sulphate (left) and pellet placed into the pulp chamber (right)
If haemorrhage cannot be arrested or if any of the root canals are found to be necrotic, consider pulpectomy (if no physiological resorption is present) or extraction.
Remove the cotton wool and place a calcium silicate cement (e.g. mineral trioxide aggregate) in the pulp chamber. Alternatively, zinc oxide-eugenol cement may be placed on pulp stumps and the floor of the pulp chamber.76
Images show pulp chamber after haemorrhage has been arrested (left) and placement of calcium silicate cement in pulp chamber (right)
Fill the cavity with zinc oxide-eugenol cement, then place a PMC (see Preformed metal crown technique) at the same appointment.
- There is evidence that placing a PMC at the same appointment as the pulpotomy improves the prognosis of the tooth.92-94
Images show the cavity filled with zinc oxide-eugenol cement (left) and final restoration with pre-formed metal crown (right)
Aftercare
Advise the child and the parent/carer that the tooth might be a little uncomfortable when the anaesthetic wears off, and that the child may need analgesia.
Conduct a radiographic review of pulpotomised primary molars annually.