The principal objective of caries removal is to eliminate the infected and necrotic tissues and microorganisms that may cause a persistent inflammation and treatment failure. Thus, thorough removal of the infected dentin has a direct influence and impact on the clinical success of a restoration. A number of studies have demonstrated that the bacteria left in the dentin of a cavity due to any of the above mentioned infection sources could maintain their activities for a long time. Although cavity preparation is an operative procedure that attempts to remove all infected dentin prior to placing a restorative material, the bacterial remnants during and after the cavity preparation are considered as one of the major problems in restorative dentistry. This can lead not only to increase pulp sensitivity and pulpal inflammation, but also to secondary caries. For these reasons, the elimination of the bacteria from the cavity surfaces is of a major importance, and a disinfectant solution that eliminates these residual bacteria could be useful after cavity preparation. This book describes the use of laser and CHX to disinfect coronal cavity infected with Streptococcus mutans.