Before beginning the procedure, the patient will be assessed and the tooth categorized as having signs and symptoms indicative of IRP (sharp and lingering pain triggered by thermal stimulus [often 30 second or longer after stimulus removal] and presence of spontaneous pain. In order to assess preoperative vitality, the teeth will be isolated with cotton wool and dried prior to a -26ºC Endo Ice and EPT. Periapical and bitewing radiographs clearly showing the depth of caries lesion/ restoration and periapical area will be obtained as part of the diagnostic procedure. Information on previous dose duration and type of analgesic medication taken, the response to percussion and palpation tests, mobility, probing, the duration of pain with cold application, and the duration of pulpal bleeding will be recorded.

Complete pulpotomy

The clinical procedure will be completed over one visit:

• Injection of local anaesthesia and rubber dam tooth isolation.
• Disinfect the cavity prior to commencing caries excavation by wiping around the cavity with a 2-4% sodium hypochlorite solution on a cotton wool pellet.
• All remaining caries will be be non-selectively excavated and overhanging enamel will be removed to provide good access to the coronal pulp.
• Roof of the pulp chamber will be removed using a sterile fissure diamond bur and high-speed handpiece with water coolant.  No overhanging dentine from the roof of the pulp chamber or pulp horns will be retained.
• Bleeding from the exposed pulp tissue will be confirmed, if necessary, by removing the superficial layer with a sterile high-speed bur.
• If there is no bleeding from the exposed pulp, pulpectomy and root canal treatment will be initiated, and the patient will be excluded from the study.
• A blood sample will be collected from the pulp using an inverted size-60 sterile paper point.
• No attempt to control the haemorrhage will be done until the entire coronal pulp has been amputated.
• The entire coronal pulp will be amputated to the level of the root canal orifices using a high-speed bur under water coolant or a sharp clean/ sterile excavator.
• The pulp stumps will be cleanly excised with no tissue tags extending across the floor of the pulp chamber.
• The pulp chamber will be irrigated with a 2-4% sodium hypochlorite solution.
• Haemostasis at the pulp wound will be achieved by gentle pressure with a 2-4% sodium hypochlorite-moistened cotton pellet over the amputated pulps for up to 10 minutes until a blood clot forms. The wound will be checked for haemostasis every 2 minute and time required to achieve haemostasis will be recorded.
• If haemostasis at the pulp wound is not achieved within 10 minutes, pulpectomy and root canal treatment will be carried out and the patient will be excluded from the study.

• Biodentine (Septodont Ltd., Saint Maur des Fausse ́s, France) will be mixed according to the manufacturer’s instructions. The entire pulp chamber will be filled with a Biodentine cap to a minimum depth of 3-4mm. The remainder of the cavity will be filled with a definitive resin-based composite restoration. A post-operative periapical radiograph (using a parallel cone technique) will be taken of the restored tooth.

The clinical intervention for the control group

Pulpectomy and root canal treatment:

As this is a pragmatic trial, this procedure will be carried out using the methods and materials that the participating clinicians would normally use for performing root canal treatment. A contemporary root canal treatment protocol in line with standards outlined in the AAE Treatments Standards will be done. The procedure may be carried out in single or two visits.

-       Local anesthesia will be administered.

-       Rubber dam will be applied.

-       Access opening will be done and a blood sample will be collected from the pulp using an inverted size-60 sterile paper point.

-       Irrigation protocol will be done with 2.5% sodium hypochlorite.

-       Working length will be determined using radiographs and apex locator.

-       Automated instrumentation to accompany hand instrumentation will be done.

-       Preparation to apical size 2-3 larger than largest file that binds at the WL in the uninstrumented canal initial apical file (IAF) will be done.

-       Canal medicament with non setting calcium hydroxide will be done in two visits.

-       Root canal filling with gutta pecha and AH plus sealer will be done.

-       Proper coronal seal will be ensured.

-       Good quality postoperative radiograph using parallel cone technique will be taken.

-       Final post-endo restoration will be given depending upon the individual case.