A dental laser assembly is disclosed for use in eradicating carious lesions in teeth, the treatment of sensitive teeth, as well as the removal of soft tissue, the incising of the frenum, opurculum, anestesia of the tooth, etching enamel for restorations or orthodontic appliance fixation, the welding of fixed prosthesis, removal of bacterial flora periodontal pockets, removal and/or vaporization of healthy or necrotic pulp, the vertical and/or horizontal condensation of gutta percha or any other root canal sealant, the cauterization of blood vessels in the oral cavity, vaporizing bone tissue, removing tartar, apical fusion of foramina, enlarging and shaping root canal, removing carbon from surface of teeth, removal of enamel, bleaching teeth, etching dentin, separating orthodontic brackets, merging hydroxyapatite to bone and enamel, amalgam removal and undercutting of carious and/or healthy dentin and/or cementum. The laser assembly of Root Canal treatment includes a housing having a cavity in which a pulsed laser in contained. The laser is excited so that the laser emits a laser beam along a predetermined axis that is in line with a fiber optic delivery system and at a pulse rate of one to 10,000 pulses per second and an average power variable from one tenth to 50 watts. A handpiece is dimensioned to be inserted into a human mouth while an optical fiber optically connects the laser output to the handpiece. The laser assembly also includes a continuous output aiming laser which, upon activation, provides a continuous laser aiming beam coaxial to the treatment beam. Both beams are then introduced into a fiber optic delivery system.