The goal of endodontic treatment is to obtain effective cleaning of the root canal system and removing the smear layer, bacteria and their byproducts. The apical third of root canal (apical 3 mm) is the most critical area to clean due to complex anatomy like apical deltas, accessory canals, and fins (1). Clinically, traditional endodontic techniques use mechanical instruments as well as ultrasonic and chemical irrigation to shape, clean and completely decontaminate the endodontic system, but still fall short of successfully removing all the infective microorganisms and debris. It was shown that after rotary instrumentation, only 35% of the canal space walls have been touched by the instruments (2). Therefore, clinician needs to rely on the chemical and antibacterial actions of irrigants like sodium hypochlorite to penetrate into the hard-to-reach areas and kill the microbes. The traditional syringe irrigation technique (positive pressure needle irrigation) is dispensing of solution into the pulp chamber or coronal/middle third of the root canal with a syringe tip. This method does not allow the solutions to reach the full working length of the canal effectively. Even in the instance of placement of the irrigating syringe into the apical third of the canal, the presence of the apical vapor lock is problematic. The apical vapor lock is a bubble that forms apically blocking the flow of the solution from reaching the working length of the canal (3). Another irrigation system is apical negative pressure. This technique uses negative pressure to pull the irrigating solution dispensed in the pulp chamber to the working length by using high-speed suction through small cannulas placed in the apical third of the canal. Studies have shown better results for this technique than syringe irrigation, however, sizes of 35 or greater are advocated for proper cannula placement at the apex (3), which does not comply with minimally invasive endodontics (4). Laser assisted irrigation is one of the most recent techniques for root canal irrigation. The laser fiber tip is placed in the coronal portion of the pulpal chamber, and left stationary. It generates photon-induced photoacoustic streaming of the irrigant throughout the complex three-dimensional root canal system (Fig.1). SWEEPS (Shock Wave Enhanced Emission Photoacoustic Streaming) is a new method for cleaning and disinfecting the root canal system, utilizing the power of the Er:YAG laser to create powerful, deeply penetrating shockwaves within the cleaning and debriding solutions in the root canal (5). It allows for smaller root canal preparation and it is in accordance with the minimally invasive endodontics (4). Laser assisted irrigation successfully addresses the major goals of endodontic treatment: to clean, debride, and disinfect anatomically complex root canal systems, including lateral canals and dentinal tubules (5).

Case presentation: A 40-year old female was referred for upper second premolar (tooth 1.5) endodontic consultation. The patient was on sertraline. Pain on chewing initially started last week. There was no initiating factor. The referring dentist has prescribed antibiotics which reduced her symptoms. She was not a grinder and has never cracked a tooth. Original root canal treatment was performed 10 years ago. There was no swelling and the soft tissue was normal. Palpation and percussion were negative. Adjacent teeth responded to cold WNL. Bite test on 15 was positive. Mobility was WNL. Periodontal probing was B 425 & P 425. The radiograph showed a curved root, and an inadequate previous root canal treatment (Fig.2). The middle and apical part of the root canal system was seemed totally calcified on the radiograph (Fig.2). The diagnosis was previous root canal treatment and symptomatic apical periodontitis. Treatment plan was to perform re-treatment through the crown. The prognosis was good provided that the apical third of the canal(s) would be accessible for cleaning and disinfection.

The re-treatment was completed in one visit. A ledge was encountered where the previous gutta percha terminated; at the initiation of the curve (Fig.2). The ledge was bypassed (Fig.3). Laser assisted irrigation was used during the opening of the blocked segments of the canals and at the end to remove smear layer. Two canals were joining. The canals were obturated by warm vertical compaction of gutta percha and a resin sealer (Figs.4 &5). The final radiograph showed a hidden anatomy which I was not aware of (Fig.5)! Laser assisted irrigation allowed for a minimal root canal preparation (ProTaper Ultimate, 20/04, Dentsply Sirona). The patient returned to her dentist for restoration.

Conclusion:
Laser activated irrigation can help overcome the limitations of previous traditional irrigation systems and contribute to minimally invasive endodontics.

Reference:

  1. Modern endodontic surgery concepts and practice: a review. Syngcuk Kim , Samuel Kratchman. J Endod 2006 Jul;32(7):601-23.
  2. Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography. Peters OA, Schönenberger K, Laib A. Int Endod J. 2001 Apr;34(3):221-30.
  3. Comparison of the EndoVac System to Needle Irrigation of Root canals. J Baumgartner JC, Nielsen B. J Endod. 2010 Mar; 36(3):509-11.
  4. Minimally Invasive Endodontics: Challenging Prevailing Paradigms. Gluskin, A.H., Peters C.I., Peters, O.A. British Dental Journal 2014;216:347-353
  5. SSP/SWEEPS Endodontics with the SkyPulse Er:YAG Dental Laser. Tomaz Ivanusic et al Journal of the Laser and Health Academy Vol. 2019, No.1: 1-10

We use laser assisted irrigation at our offices!

Disclaimer:
No financial gain for preparing this news letter was intended.