Lasers can be used to improve disinfection of the root canal space. The internal anatomy of the root canal system is very complex and web-like. This means that conventional rinsing with strong disinfectants (the best is bleach) are unable to fully penetrate and clean out these tortuous spaces.
The laser energy causes heating and bubbling of the disinfectant, pushing it into these spaces. This allows for better cleaning and is thought to improve root canal treatment success.
Other applications include root canal space preparation, partial pulp removal (pulpotomy), root canal retreatment and root-end surgery (apicoectomy).
One of the main difficulties in using lasers for non-direct cutting (as in apicoectomy) or disinfectant activation is that the laser energy is transmitted only in a straight line. Root canals are irregular and curved, so using lasers inside them can be difficult.
Currently, lasers are not considered mandatory for use in modern root canal therapy. Using a laser to improve disinfection may be useful in retreatment of heavily infected teeth. A laser may not necessarily improve the outcome for all root canal treatment cases.