Utilising R-SWEEPS laser-assisted irrigation for the treatment of chronic periapical periodontitis

Tooth #46 was tender to percussion, non-tender to palpation and had no response to the electric pulp test and cold test. Analysis of the dental panoramic tomogram showed a large mesio-occlusal amalgam restoration with recurrent caries, reaching close to the mesial pulp horn of the tooth (Fig. 1). Two roots could be observed and no visible root resorption. Slight periodontal ligament widening was evident and a periapical lesion. She was diagnosed with irreversible pulpitis of tooth #46 and chronic periapical periodontitis.

We decided to use laser-assisted irrigation with a 2,940 nm Er:YAG laser and Fotona R-SWEEPS (resonant shock wave-enhanced emission photoacoustic streaming) mode at settings suitable for treating a mandibular molar. In the first session, 4% articaine hydrochloride with 1:100,000 adrenaline (citocartin, Molteni Dental) was Administered to anaesthetise the area. The patient was properly draped with a waterproof gown to protect her clothing. The tooth was isolated with a dental dam. The old amalgam and carious tissue were removed, an access cavity was prepared and the root canal was negotiated to the apex with a #8 hand K-file. There was no spontaneous bleeding upon opening of the pulp chamber, and there was necrotic tissue present. Hence, the decision was made to complete the root canal treatment in two sessions.

A total of four canals were identified (Fig. 2). The treatment started with continuous delivery of sodium hypochlorite (NaClO) solution (3 ml) by syringe and simultaneous activation by Er:YAG laser. Laser-assisted irrigation was performed with a LightWalker AT-S (Fotona) and an Er:YAG H14 handpiece with a flat SWEEPS 400/9 fibre tip positioned safely at the entrance to the pulp orifice (Table 1). For the shaping of the root canal system, the ProTaper Gold rotary file system (Dentsply Sirona) was used. Minimally invasive root canal preparation began with the 19/0.04 SX file to relocate the coronal aspect of the canals. Cleaning and shaping of the canals were subsequently performed with the 18/0.02 S1 file and 20/0.07 F1 file to the working length.

The R-SWEEPS final irrigation protocol was performed at the end of instrumentation and consisted of two cycles of 17% EDTA activated by R-SWEEPS for 30 seconds for each activation period with 30 seconds of resting time in between, rinsing with distilled water activated by R-SWEEPS for 30 seconds, and then three cycles of 5% NaClO activated by R-SWEEPS for 30 seconds for each activation period and a resting time of at least 30 seconds in between. After drying the canals (Fig. 3), Odontopaste (Australian Dental Manufacturing), a zinc oxide-based root canal paste with 5% clindamycin hydrochloride and 1% triamcinolone acetonide, was placed, followed by a temporary filling (Fig. 4).