Postoperative Pain After Ultrasonically and Laser-activated Irrigation During Root Canal Treatment

Patients older than 18 years who require root canal treatment of an asymptomatic tooth with vital or necrotic pulp are included. Those teeth are subjected to root canal treatment using hand and rotating/reciprocating instruments, in combination with irrigation (3% NaOCl, 17% EDTA). After chemomechanical preparation, the teeth are randomly allocated to one of the following groups, according to the final irrigant activation:

• Ultrasonically activated irrigation (UAI), with an Irrisafe file (Satelec Acteon, Mérignac, France) held 1-3mm from working length, driven by an ultrasonic device, activated for 3 x 20 seconds. In between each 20-second cycle, each canal is rinsed with 1 mL NaOCl and finally with 2 mL.
• Laser-activated irrigation (LAI), with the tip of a pulsed Er:YAG laser (2940 nm, Fidelis II, Fotona) held above the canal entrance, activated for 2 x 30s. Settings are 20 Hz, 50 μs, 20 mJ. In between each 30-second cycle, each canal is rinsed with 1 mL NaOCl and finally with 2 mL.

The canals are then dried using paper points and obturated with gutta percha and an epoxy resin sealer using warm vertical condensation. Finally, the endodontic access is sealed with a provisional or permanent filling.

The patient is asked to keep a pain diary after the treatment, indicating postoperative pain on a visual analogue scale at 6, 24, 48 and 72 hours after treatment. Pain medication (Ibuprofen 400mg) is prescribed, and the intake of analgesic tablet is recorded at the same times.

Pre-Treatment Procedure

• Medical + dental history
• Clinical examination: sensibility tests, percussion, palpation, mobility, pockets measurement
• Radiographic examination
• Pulpal and periapical diagnosis
• Intensity of pre-op pain on 100mm VAS scale
• Patient information and informed consent
• Explanation on how to complete the pain diary and how and when to return it

Endodontic Protocol

• Anesthesia
• Rubber dam, disinfection of operative field
• Removal of caries and/or defective restorations
• Access cavity
• Build-up to provide a reservoir for the irrigation if necessary
• Crown-down preparation
• Length determination
• Apical enlargement

Irrigation protocol

• 3% NaOCl
• 17% EDTA when shaping completed
• Irrigation throughout the whole procedure with 27G notched-end needle 2 - 3 mm from WL

Inclusion criteria

• subject has an asymptomatic (VAS 0-0,4mm) tooth requiring primary endodontic treatment
• subject must be able to undergo primary endodontic treatment

Exclusion criteria

• analgesic intake over the last 12h
• immunocompromised patients
• pregnant women
• tooth with incompletely formed apex/apices
• subjects with more than one tooth in need of RCT
• previously root canal treated teeth
• subjects with intolerance on NSAID's