Apical Surgery of Mandibular Molar - Clinical Handling of Cystic Lesion Adjacent to the Inferior Alveolar Nerve: a Case Report

Objectives: Endodontic microsurgery in the mandibular molar region is associated with significant clinical challenges when large periapical cystic lesions are located near the inferior alveolar nerve. The purpose of this case report is to describe the clinical management and outcomes of a patient presenting with a cystic lesion in close proximity to the inferior alveolar nerve, illustrating the importance of advanced imaging in treatment planning and risk assessment.

Material and Methods: A 45-year-old female with persistent pain related to mandibular first molar previously treated with root canal therapy and restored with a metal-ceramic crown underwent radiographic and cone beam computed tomography examinations. A well-defined cystic lesion in direct contact with the inferior alveolar nerve was identified. Preoperative planning guided the surgical approach, which included elevation of a full-thickness mucoperiosteal flap, osteotomy, root-end resection, removal of a separated instrument, careful cyst enucleation to avoid nerve injury, ultrasonic root-end preparation, and retrograde obturation using a calcium silicate-based material. The surgical site was closed with 4-0 polypropylene sutures (Prolene^® - Ethicon, Inc.).

Results: At the three-month follow-up, the patient reported resolution of pain and absence of neurosensory disturbances. Radiographic imaging indicated favourable early bone healing of the surgical site.

Conclusions: Careful preoperative evaluation with cone beam computed tomography and meticulous microsurgical techniques are essential for mitigating risks and achieving successful outcomes in the management of periapical cysts adjacent to the inferior alveolar nerve. Clinicians should consider ongoing clinical and radiographic monitoring to evaluate long-term success following surgical intervention.

J Oral Maxillofac Res 2026;17(2):e5

doi: 10.5037/jomr.2026.17205

Accepted for publication: 30 June 2026

Keywords: cone-beam computed tomography; cysts; endodontics; inferior alveolar nerve; microsurgery.

INTRODUCTION

Apical surgery, also known as endodontic microsurgery, is a well-established treatment modality for persistent periapical pathology in cases where conventional root canal retreatment is not feasible or has failed [1]. Advances in surgical instruments, magnification, and biomaterials have significantly improved the prognosis of apical surgery, particularly in posterior teeth [2]. However, the management of periapical cystic lesions in mandibular molars presents unique clinical challenges, especially when the lesion is situated in close proximity to the inferior alveolar nerve (IAN) [3].

The risk of iatrogenic injury to the IAN during surgical intervention necessitates careful preoperative planning, precise surgical technique, and judicious decision-making to avoid postoperative neurosensory disturbances. Cone-beam computed tomography (CBCT) imaging has become indispensable in diagnosing the extent of periapical lesions and their relation to adjacent anatomical structures, allowing for a tailored surgical approach [3].

Despite the prevalence of apical surgery in dental practice, literature addressing the management of mandibular molars with cystic lesions in direct contact with the IAN remains limited. Most reports focus primarily on technique or outcomes, with few emphasizing the anatomical complexities and technical modifications required in such challenging cases [2,3].

This manuscript presents a case of endodontic microsurgery performed on a mandibular first molar with a large periapical cystic lesion adjacent to the inferior alveolar nerve. The purpose of this case report is to describe the clinical management and outcomes of a patient presenting with a cystic lesion in close proximity to the inferior alveolar nerve, illustrating the importance of advanced imaging in treatment planning and risk assessment. The detailed surgical approach and early healing outcomes are discussed, highlighting considerations for preserving neurovascular integrity and optimizing patient recovery.

CASE DESCRIPTION AND RESULTS

This case report adheres to the Preferred Reporting Items for Case reports in Endodontics (PRICE 2020) guidelines [4]. Case description and results according to PRICE 2020 guidelines are showed in Table 1.

Written informed consent was obtained from the patient for publication of this report.

A 45-year-old female was referred to the Department of Dental and Oral Pathology, Lithuanian University of Health Sciences, with the chief complaint of pain in the left mandibular region during mastication in February 2025. The patient’s dental history revealed that tooth 36 (mandibular left first molar) had undergone endodontic and prosthetic treatment approximately five years ago.

Clinical examination

The initial clinical examination revealed that tooth 36 was restored with a metal-ceramic crown (Figure 1A). The tooth was tender to percussion, whereas palpation elicited no pain. Periodontal probing depths were within normal limits, measuring 2 to 3 mm on all aspects. The prosthetic crown was assessed as adequate with no apparent defects or marginal discrepancies.

Radiographic and imaging assessment

A panoramic radiograph (orthopantomogram) (Figure 1B) revealed a well-defined, cyst-like radiolucency associated with the mesial roots of tooth 36 (FDI World Dental Federation notation, ISO 3950). Given the size of the lesion and it’s ambiguous relationship to adjacent anatomical structures, a CBCT scan via Carestream CS 8100 3D (Carestream Dental LLC; Atlanta, GA, USA) was conducted for further evaluation. CBCT imaging (Carestream Dental LLC) demonstrated a well-circumscribed, cystic-like lesion in direct contact with IAN (Figure 1C and 1D), with only a thin bony plate remaining between the lesion and the neurovascular bundle. The lesion was located around the mesial roots, approximately 15 mm below the cementoenamel junction.

Surgical management

After administration of local anaesthesia, a full thickness mucoperiosteal flap was elevated, with vertically releasing incisions placed mesially and distally to tooth 36 using a No. 15C surgical blade (Swann-Morton Ltd.; Sheffield, UK). Osteotomy was initiated 12 mm below the cementoenamel junction, permitting simultaneous access for root-end resection (Figure 2A). Upon resection of 3 mm of the root ends, a separated instrument fragment was identified in the mesiobuccal canal (Figure 2B).

Cystectomy was meticulously performed by circumscribing and detaching the cystic membrane coronally, avoiding curettage near the apex to minimize the risk of injury to the adjacent nerve. Once the membrane was sufficiently loosened, gentle traction with a needle holder facilitated complete enucleation of the cystic lesion. (Figure 2C and 2D). The cystic lesion was then sent for histological evaluation which showed the confirmation of a radicular cyst.

Root-end preparation of the mesial roots and the isthmus was accomplished using ultrasonic instruments: a diamond-coated tip (AS3D - Satelec Acteon Group; Merignac, France). The separated instrument and gutta-percha were removed, and the canals were obturated with a calcium silicate-based material (TotalFill^® RRM Fast Set Putty - FKG Dentaire; La Chaux-de-Fonds, Switzerland) (Figure 2E). The flap was repositioned and secured employing simple interrupted 4-0 polypropylene sutures (Prolene^® - Ethicon, Inc.; Somerville, New Jersey, USA) (Figure 2F). A periapical X-ray was taken via digital intraoral X-ray system, RVG sensor (Carestream Dental LLC; Atlanta, Georgia, USA) at 70 kVp, 7 mA, 0.16 s after the procedure to ensure the result (Figure 3A).

Follow-up

At the 3-month follow-up period, the patient was asymptomatic, reporting no pain, paraesthesia, or other neurosensory disturbances. Radiographic evaluation (periapical radiograph) demonstrated evidence of bone regeneration and favourable early healing in the periapical region of mesial root of tooth 36 (Figure 3B).

DISCUSSION

Endodontic surgical procedures in the posterior mandible can present significant clinical challenges, particularly when periapical pathology is situated near critical anatomical structures, such as the IAN. The risk of iatrogenic nerve injury during apical surgery is a genuine concern, underscoring the necessity for meticulous preoperative planning and surgical precision [5]. The success of such interventions depends on the clinician’s experience, the use of magnification, the techniques employed, and the anatomical relationship between the lesion and the neurovascular bundle [6]. Additionally the outcomes of periradicular surgery can be positively influenced by the use of bone grafts and barrier materials as demonstrated in the research by Sumangali et al. [7], Furthermore, overall success rates can be significantly reduced in cases with periodontal involvement compared to those involving endodontic lesions alone [8]. The advantages of CBCT as an important tool for microsurgical endodontic techniques are well-documented and endorsed by the European Society of Endodontology [9] for presurgical evaluation prior to complex apical surgery [6]. In the present case, CBCT imaging was indispensable in establishing the spatial relationship between the periapical cystic lesion and the IAN. The imaging revealed that a thin bony partition separated the lesion from the canal, thereby reducing the likelihood of direct nerve trauma during the surgical procedure.

While periapical surgery is a well-documented solution for persistent endodontic pathology, cases involving cystic lesions in immediate proximity to IAN are relatively rare in literature. The approach in this case was deliberately conservative. Emphasis was placed on careful manipulation and enucleation of the cystic tissue, avoiding aggressive curettage near the apex to further minimize risk to the nerve. The use of dental microscope and ultrasonic instruments facilitated controlled root-end preparation, while calcium silicate-based obturation materials were selected for their favourable healing properties and biocompatibility when using as retro fillings [10].

This treatment approach is highly predictable when modern microsurgical techniques are employed in conjunction with biocompatible and bioactive root-end filling materials, allowing for reported tooth survival rates ranging from 79% to 100% over follow-up periods of 2 to 13 years after intervention [11,12]. Follow-up after endodontic microsurgery is recommended at regular intervals, with assessment typically advised at 3 to 6 months to monitor initial healing, and then annually for at least 2 to 4 years to confirm long-term success and detect any late complications. According to a retrospective study on neurosensory disturbances following apical surgery, 12.9% of procedures performed on mandibular premolars and molars resulted in postoperative altered sensation. Notably, skin sensitivity returned to normal in all affected cases [13,14]. Although follow-up in this presented case is limited to three months, early outcomes are promising [6]. The patient reported no postoperative complications, particularly concerning sensory disturbances including paraesthesia, hypoesthesia, or anaesthesia of the lower lip and chin. Furthermore, radiographic evidence of periapical healing was observed, with bone regeneration seen at the surgical site. A longer follow-up period is essential to definitively assess the outcome and ensure long-term success. While innovative techniques were not part of this case, our report highlights the importance of careful planning and execution with conventional microsurgical methods, contributing practical knowledge for clinicians faced with similar anatomical challenges.

CONCLUSIONS

This case demonstrates that, with careful assessment, appropriate imaging, and meticulous microsurgical technique, endodontic surgery can be safely performed adjacent to the inferior alveolar nerve without compromising neural integrity.

The clinician’s ability to adapt the surgical approach based on anatomical nuances greatly contributes to a favourable prognosis. Additional case series with extended follow-up are warranted to further elucidate the best practices for managing similar cases.

ACKNOWLEDGMENTS AND DISCLOSURE STATEMENTS

The authors report no conflicts of interest related to this study.

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