A 48 year old male patient was referred to a private endodontic practice for evaluation and treatment of a maxillary left lateral incisor. He complained of pain on biting and palpation in the area. Medical history was non-contributory. In his dental history, he reported that the tooth had been treated non-surgically 12 months earlier. Clinical examination revealed moderate percussion sensitivity. Periodontal probing and mobility were within normal limits when compared to contralateral and adjacent teeth. The radiographic examination revealed periapical radiolucency 7 - 8 mm in diameter along the distal surface of the root, indicative of either an accessory canal or a possible apical fracture (Figure 1a). The radiograph also showed a titanium screw that was used for fixation of the membrane during a previous implant placement procedure performed two years before presentation. The tooth had porcelain fused to a metal crown with good margins and esthetics. On the basis of the history and clinical and radiographic examination, a diagnosis of a previous root canal treatment with symptomatic apical periodontitis was established. The patient was offered all treatment options; he opted for microsurgical retreatment. Written consent was obtained.

The micro-surgical technique, as suggested by Kim and Kratchman,4 was performed in addition to creation of a bony window osteotomy. After rinsing with 0.12% chlorhexidine solution (Peridex, Zila Pharmaceuticals Inc., Phoenix, AZ, USA) for 60 seconds, the patient was administered 2 carpules of 4% articaine with 1:100,000 epinephrine (3M ESPE, Seefeld, Germany) buccal and palatal infiltration. After ensuring profound anesthesia, a full thickness sulcular flap was elevated, with one release incision distal to the left canine. The exposed site was considered a candidate for the bony window osteotomy as the cortical plate was found to be intact. The osteotomy was performed using a piezoelectric device (Piezotome 2, Acteon Satelec, Acteon Germany GmbH, Mettmann, Germany). The BS5 Tip (Acteon Satelec, Acteon Germany GmbH) was used to make an outline on the exposed cortical plate based on the measurement made on the digital radiograph and the topography of the exposed bone. Two vertical and two horizontal grooves were joined to create a bony window of approximately 6 mm by 12 mm, at the recommended setting mode of 3 with 60 mL/minute irrigation of sterile saline (Figure 1e). The average width of the cut was approximately 1 mm. The carved bony window was lifted off with a curved osteotome (Figure 1f). The bone block was stored in Hanks Balanced Salt Solution (Life Technologies, Grand Island, NY, USA) in order to keep it hydrated. The granulation tissue at the surgically exposed site was removed by curettage with bone and curved periodontal curettes until healthy bone margins were encountered and the root tip was clearly visible. A biopsy sample was sent for histologic evaluation. The denuded root was stained with methylene blue and inspected under high magnification (×16) with a surgical operating microscope (Carl Zeiss OPMI Pico, Carl Zeiss, Oberkochen, Germany) for a vertical root fracture or perforation. Upon curettage, the root presented with a fracture line extending from the root tip to about 4 mm along the length on the distal surface. The fractured portion of the root was eliminated during apical resection with a high-speed carbide Lindemann surgical bur (Hu-Friedy, Chicago, IL, USA) at a zero degree bevel. The resected root surface was then stained again for inspection under high magnification (×16). The root-end preparation was achieved using ultrasonic surgical JetTips (B&L Biotech USA Inc., Fairfax, VA, USA), and the root-end cavity was filled with white mineral trioxide aggregate (MTA, ProRoot MTA, Dentsply Tulsa Dental, Tulsa, OK, USA) (Figure 1g). The bony window was repositioned (Figure 1h). Care was taken not to depress it into the osteotomy site but instead place it in alignment with the remaining bone in its original alignment. As the insert used with the piezoelectric to create the bone window was very thin, the bone flap was re-approximated firmly. 6-0 propylene nylon sutures (Supramid, S. Jackson Inc., Alexandria, VA, USA) were used for suturing the soft tissue. A postoperative radiograph was taken (Figure 1b). The patient was prescribed an oral analgesic (ibuprofen 600 mg) and instructed to rinse twice daily with a 0.2% chlorhexidine mouth rinse for 1 week. The sutures were removed 7 days after surgery.

The patient presented for follow-up at 9 (Figure 1c) and 18 (Figure 1d) months with radiographic signs of complete healing and no clinical signs or symptoms.

A 16 year old male patient with a history of dental trauma 4 years prior was referred for treatment of the maxillary right lateral incisor. Mild percussion and pain on palpation was observed during clinical examination. The radiographic examination revealed a previously treated root canal with an 8 - 9 mm periapical radiolucency, extending apically and along the distal surface of the incisor with signs of a disto-lateral resorptive defect at the mid-root (Figure 2a). On the basis of a history, clinical examination, and radiograph, a diagnosis of a previous root canal treatment with symptomatic apical periodontitis was established. The previous operator had restored the access with radiolucent flowable composite, the coronal portion of which was removed and light cure composite (Filtek Supreme XT, 3M ESPE, St Paul, MN, USA) was placed. In discussion with the patient, apicoectomy was selected as the treatment of choice. Upon flap elevation, as the cortical plate was found to be intact, the surgical procedure as described above was implemented (Figure 3a). The bone window measured about 9 mm horizontally and 18 mm vertically. The lesion in this case was found to have a cyst-like appearance, which was confirmed by histopathological evaluation of the biopsy sample sent to the laboratory. Other than the apical root-end preparation, the lateral perforation was also exposed after curettage. Both areas were carefully prepared with JetTips ultrasonic tips (B&L Biotech USA Inc.) and sealed with white MTA (ProRoot MTA, Dentsply Tulsa Dental) (Figures 2b, 3b, and 3c). Upon completion of the microsurgery, the bone flap was replaced and held in position with some CollaCote collagen material (Zimmer Dental, Carlsbad, CA, USA), as there was a break seen along the approximated bone margins (Figure 3d). The flap was sutured with 6-0 propylene nylon sutures (Supramid, S. Jackson Inc.) and the surgical procedure was completed. The patient presented for follow-up at 12 months with radiographic signs of complete healing and no clinical signs or symptoms (Figure 2c).