The Use of Lasers in Disinfection and Cleaning of Root Canals: a Review

Abstract

The outcome of root canal treatment is based on efficient disinfection of the root canal system and prevention of reinfection. Current chemomechanical cleaning methods do not always achieve these goals, and insufficient root canal disinfection is the main reason for endodontic failure. Due to high energy content and specific characteristics of laser light, laser treatment has been proposed for cleaning and disinfecting the root canal system. This paper reviews the literature covering the effect of Er:YAG, Er,Cr:YSGG, Nd:YAG and diode laser on the root canal wall in the removal of smear layer and against intracanal bacteria. Recently, the use of laser energy to induce cavitation and acoustic streaming of intracanal irrigants has been investigated. Based on recent literature, it can be concluded that lasers have bactericidal effects. However, they still cannot replace sodium hypochlorite and should be considered as an adjunct to the current chemical root canal disinfection protocols. Certain lasers can help in removing the smear layer and debris and can modify the morphology of the root canal wall. Unfortunately, there have not been enough randomized clinical studies evaluating endodontic treatment outcome following the use of laser.

Comparative Evaluation of the Efficacy of Chlorhexidine, Sodium Hypochlorite, the Diode Laser and Saline in Reducing the Microbial Count in Primary Teeth Root Canals – An In Vivo Study

“…Moreover, as it is known that the laser emits a unidirectional beam which travels in a straight line from the optical fiber tip, it is hard to achieve equal irradiation of the whole root canal dentin surface. 24 This would be a probable reason why diode laser disinfection did not show a statistically significant reduction in the CFU counts over the other irrigants.…”

“…They can also be used for the removal of the layer and disruption of intracanal biofilms. 24 The potential of the diode laser for soft tissue surgeries has been studied by many. On the contrary, minimal application of the same has been studied in the antibacterial activity against the root canal bacterium.…”

“…Photodynamic therapy is a technique employed for root canal disinfection using a photosensitizer; that produces singlet oxygen out of molecular oxygen (3O2) and other free radicals when exposed to laser light which in turn causes damage to the bacterial membrane and its DNA. 3,23,24 The soft tissue dental Diode laser is a compact and portable device which is used in various areas of dentistry. The diode laser emits radiation within the visible (mostly 660 nm) and infrared (810 to 980 nm) range of the electromagnetic spectrum.…”

“…The diode laser emits radiation within the visible (mostly 660 nm) and infrared (810 to 980 nm) range of the electromagnetic spectrum. 24 Moritz et al introduced its use for disinfecting the root canal system with the help of a thin and flexible fiber delivery system. The fine diameters of optic fibers (200-320 μm) permit effective distribution of laser light in the root canal system to help with the lowering of microbial contamination.…”

The Antibacterial Efficacy and In Vivo Toxicity of Sodium Hypochlorite and Electrolyzed Oxidizing (EO) Water-Based Endodontic Irrigating Solutions

“…The removal of the pathologic pulp, cleaning, and shaping of the root canal system are essential for successful endodontic treatment to disinfect pulpal space or prevent its reinfection of reference [1]. The complex root anatomy is one of the major challenges to intracanal cleaning and disinfection; therefore, mechanical instrumentation combined with chemical irrigation is the widely accepted strategy to enhance successful debridement [2]. An ideal irrigant should be effective in removing necrotic pulp tissues, smear layers, and disinfecting dentinal tubules [3].…”