The Application of "Bone Window" Technique in Endodontic Microsurgery.

Endodontic microsurgery for a tooth with a large periapical lesion and an intact cortical plate may necessitate the removal of extra bone and cause delayed or unfavorable healing. In such cases, the "bone window" technique offers excellent exposure to the operative field and preserves cortical bone without placing any additional graft material. In the reported cases, root-end surgery was performed on the maxillary and mandibular molars with a large periapical lesion. The bone window was fashioned with the aid of thin osteotomy instruments and repositioned to the original site at the end of the procedure, which resulted in minimizing bone loss and acted as an autologous graft for the surgical site. At 12- and 16-month follow-ups, clinical examinations and cone-beam computed tomographic scans revealed the healing of the lesion without symptoms or complications. Cone-beam computed tomographic imaging was used as a presurgical assessment tool for indication selection and precise design of the bone window. The use of a bone window in endodontic microsurgery, which appears to be a reliable technique, should be the method of preference when the large lesion is deeply positioned between intact buccal and lingual cortices.