Introduction

Pulpotomy (partial pulpectomy) involves the surgical amputation of the coronally inflamed pulp. The wounded surface of the amputated pulp is then treated with medicaments that stimulate Odontoblasts (which line the pulp). These stimulated Odontoblasts start to lay down reparative dentine.
This layer allows the remaining pulp to maintain its vitality and allow for continuing maturation of the tooth and laying down of more dentine with strengthening of the tooth.

Medicaments that have been used for pulpotomy include:

Calcium hydroxide (CaOH2) in either of two forms can be used. Either a hard setting (Life, Dycal CaOH2 powder) or non setting (pulpdent) calcium hydroxide can be used.
A new product into the market, namely Mineral trioxide Aggregate (MTA) can be used to stimulate Odontoblasts to lay down reparative dentine. MTA consists of Tricalcium silicate, aluminate oxide & silicate oxide and is radiopaque. The main disadvantage of MTA is that it takes several hours to set.
Unfilled resins have also been used to cover the pulp. Their use has been shown to be no better than CaOH2 and if some instances, resins have been toxic to the pulp causing inflammation.
The ideal medicament should be non toxic, antibacterial and biocompatible, able to seal the pulp and stimulate a dentinal bridge. MTA and CaOH2 do meet these requirements.

Indications for pulpotomy (canine tooth)

• Traumatic complicated crown fracture
• Canine Crown height reduction- disarming procedures
• Traumatic malocclusion: lingually displaced mandibular canines
• Others including abrasion, erosion of tooth

Success rates for pulpotomy

Vital pulpotomy has a high success rate (88%) if performed within 48 hours of the time of the pulp exposure.
The success rate does decrease when treatment is delayed longer than 48 hours.
In one study all the teeth that were treated > 7 days post exposure became necrotic at 6 months to 6 years post vital pulpotomy (Clarke J Vet Dent 2001 18 117-121).
In primates, there was a 21% failure rate for crown reduction of canine teeth (disarming procedure) (Lommer & Verstraete Comp Med 2001 51 70-74).

Prognosis for pulpotomy procedure

To determine the success rate of the vital pulpotomy procedure, the treated tooth needs to be re-radiographed at approximately 6 months post treatment. On the radiograph, you would like to see the formation of a dentinal bridge (reparative dentine), continued maturation of the tooth, and no evidence of apical periodontitis (bone loss around the apex of the tooth).
It is important to periodically monitor the coronal restoration for signs of fracture or leakage. Owners need to be warned re chewing on bones/rocks/other hard objects.
The veterinarian needs to consider tooth extraction or full pulpectomy (root canal therapy) if a more serious coronal or root fracture is found. Significant tooth structure loss is also an indication for extraction.
If bleeding doesn’t stop from amputated pulp- consider a further 1-2 mm of pulp amputation. If bleeding still continues after this extraction or full pulpectomy must be performed. Also, if treatment is delayed > 48-72 hours or client compliance with after care is an issue then extraction or root canal therapy must be performed.

Steps involved in Pulpotomy Procedure
NB: Treat the procedure as a sterile surgical procedure

• Preoperative radiograph
• Use of rubber dam or sterile glove isolating the affected tooth from rest of oral cavity
• Use Sterile instruments including burs (straight fissure diamond bur)
• Amputate approximately 5mm of pulpal tissue with the high speed hand piece and diamond bur
• Arrest haemorrhage with 4-5% sodium hypochlorite (NaoCl) or adrenaline or local anesthetic agent with adrenaline. Can use sterile paper points to stop bleeding
• Place a layer of CaOH2 (Life or Dycal) or MTA over pulpal stump (1mm)
• Place an intermediate layer of Resin Modified Glass Ionomer Cement (Vitrebond) and light cure this (1mm)
• Acid etch 937% phosphoric acid), rinse for 30 seconds and then apply a bonding agent (unfilled resin)
• Place a low viscosity (flowable) Composite Resin cement (1mm)
• Place a layer of hybrid Composite Resin cement (2mm)
• Place an unfilled  resin over this to protect dentinal tubules
• Use of pre/peri/post operative antimicrobials (Clavulox) and Non Steroidal Anti- Inflammatory Drugs (NSAIDs)
• Postoperative radiograph

Summary

With some further knowledge and the correct equipment, the vital pulpotomy procedure is easy to master and offers the client a good option compared to extraction or full root canal therapy when a fresh pulp exposure is observed in a pet’s tooth.