This case report describes the non-surgical root canal treatment (RCT) of two cases with a periapical lesion associated with maxillary and mandibular anterior teeth of male patients who complained of swelling associated with pus drainage and pain. The obturation of both maxillary and mandibular central incisors was done by using lateral condensation and epoxy resin-based sealer, followed by composite resin filling as a permanent restoration. Clinical and radiographic re-evaluations at 4 months and 7 months for maxillary and mandibular teeth respectively revealed progressing bone healing, particularly in a maxillary region. This case report shows that an appropriate diagnosis in combination with RCT as a conservative non-surgical approach can lead to the complete healing of a large lesion without invasive treatments.