Erbium, Chromium: Yttrium, Scandium, Gallium, Garnet (Er,Cr:YSGG) Laser in Root Canal Disinfection

Inclusion Criteria: * Provision of signed and dated informed consent form. * Stated willingness to comply with all study procedures and availability for the duration of the study. * Male or female (Gender is not an inclusion or exclusion criteria), aged 18 years old or above. * In good general health as evidenced by medical history or non-contributory medical history (Patient can be seen for regular dental appointment in Penn Dental Medicine; American Society of Anesthesiologists (ASA) classes I and II). * Radiographic presence of periapical radiolucency. * Negative response to thermal sensitivity testing (difluorochloromethane at -50 °C, Endo-Ice, Coltène/Whaledent Inc., Cuyahoga Falls, Ohio) or electric pulp testing. * Enough tooth structure for adequate isolation with rubber dam. * No history of previous endodontic treatment on the tooth. * Teeth with single canal, 1 distal canal of lower molar, 1 palatal canal of upper molar. Exclusion Criteria: * Patients who report they are pregnant. * Teeth affected by dental trauma. * Periodontal changes (pockets 3 mm, mobility I or gingival edema). * Radiographic presence of resorptive processes. * Per the investigator's discretion, unable or unlikely to comply with study procedure. * Presence of any condition which, in the opinion of the investigator, makes participation in the study not in the individual's best interest.