Micro-surgical management of a long-standing radicular cyst

Histopathology Findings

Histopathological examination revealed a cystic cavity lined by non-keratinized stratified squamous epithelium arranged in an arcading pattern, interspersed with intense inflammatory cell infiltration consisting chiefly of lymphocytes and plasma cells. The histopathological findings confirmed the provisional diagnosis of radicular cyst.

Final diagnosis - Radicular cyst secondary to trauma in relation to the left maxillary central incisor.

III.Prosthetic Phase

Tooth preparation was done in accordance with new core position in alignment. Post-space preparation was done with Peeso Reamer #2 and the canal was circumferentially filed for even and smooth inner surface receptive of taking a wax pattern. An impression of the canal was taken with the help of #40 K file and inlay wax which was then given for casting. The file was angulated to the future position of the core to straighten the tooth in alignment with the rest of the arch.

The custom cast post was then cemented and an impression was taken for the final crown which was then cemented in line with the rest of the teeth in the arch. Although the angulation was severe, we were able to achieve decent esthetic results.

Follow Up

• Post-operative instructions were given to the patient and patient was kept on antibiotics and analgesics
• After six months, both clinical and radiographic evaluation was very satisfying with complete resolution of all clinical symptoms

Currently, the patient is asymptomatic and he is under follow-up for the past 2 years

Discussion

Radicular cysts are thought to be formed from epithelial cell rests of Malassez (ERM), which are remnants of Hertwig’s epithelial root sheath, present within the periodontal ligament. Proliferation of these epithelial cell rests is frequently associated with stimuli from periapical periodontal inflammation secondary to pulpitis. The treatment modalities of radicular cyst are either root canal therapy when lesion is localized or surgical treatment like cystic enucleation, marsupialization or decompression when lesion is large. In our case, we preferred enucleation and endodontic treatment and saw good results after the 2 year follow up. Formation & growth: During periapical inflammation, host cells in the periapical tissues release many inflammatory mediators, proinflammatory cytokines, and growth factors which induce proliferation of the ERM in all directions to form a three-dimensional ball mass. As the epithelial mass grows, the central cells move further away from their source of nutrition and undergo necrosis and liquefaction degeneration, forming central cystic cavity lined by epithelial wall. Following its formation, radicular cysts grow by periapical bone resorption mediated by prostagladins and cytokines. It is interesting to note that most inflammatory mediators which induce proliferation of epithelial cell rests also mediate bone resorption in inflammatory periapical lesion. Differential diagnosis between periapical granulomas and radicular cysts is an important subject to decide on the treatment. Radiometric analysis of radiographs of periapical granuloma and radicular cysts are used to differentiate the two lesions; according to the current literature, size of radiolucencies of periapical granulomas could differentiate these lesions. It has been reported that radicular cysts could be distinguished from periapical granulomas based on the larger size of radicular cysts (more than 5.9 mm). Periapical abscess was ruled out due to the absence of drainage from the canal on initiating root canal treatment. Given the dimensions of the lesion as reported by CBCT analysis, our provisional diagnosis was a radicular cyst, which was confirmed by histopathological analysis. Provisional & final diagnosis:Radiological analysis is important for provisional diagnosis, in this case, we decided to go radiology beyond the conventional IOPA. Cone beam computed tomography was preferred because the surgeon can assess the exact extension of the lesion, plan the surgical protocol and monitor the results. Since lesion was extensive, CBCT also allowed a check for proximity or any involvement of lesion with nasal floor. Histopathology is essential for final diagnosis. Microscopy gives the exact picture of the lesion, showing its true characteristics. The histopathological findings confirmed the provisional diagnosis of radicular cyst in this case. Need of Endo-surgery: Proper endodontic therapy of the involved teeth removes irritants in the canals by chemo-mechanical instrumentation. As the root canal is completely sealed, all cell components participating in inflammatory reaction gradually resolve. But if the irritants and inflammatory mediators are in abundance in the periradicular area, treatment of this area directly by curettage and graft placement becomes necessary. This is where micro-surgery or apicectomy comes into play. When the flap is raised, the lesion can be viewed directly and treated completely. In this case, we used sticky bone to fill the osseous defect. The use of an osseograft combined with concentrated growth factors (CGF) has numerous advantages owing to the formation of sticky bone. The product thus formed can be molded, prevent both macro and micro movements, also the network is proven to contain platelets and growth factors thereby contributing to accelerated soft-tissue healing and bone regeneration. Furthermore, the fibrin interconnection prevents the ingrowth of soft tissue into the bone graft as well. Studies recommend the placement of root-end filling especially when an unsuccessful root canal therapy was corrected by an apicectomy rather than by re-treatment. In this case, since it was the non-vitality of the tooth due to the long-standing trauma that caused the cyst, it was decided to simply remove the overextended gutta percha, clean and burnish the root apex.

Conclusion

Radicular cyst is one of the most common lesions seen in dental practice . It is most identified incidentally, following radiographic examination. Since there is a high chance of neoplastic transformation, it is advised to carry out proper treatment and follow up patients diagnosed with radicular cyst.

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