Odontogenic cysts are one of the most common lesions of the jaws that develop from odontogenic remnants of epithelial origin, with great biological behaviour, growth potential, and clinical manifestations.[1] Odontogenic cysts made up 84.53% of the 19,352 jaw cyst cases that were reported in a large-scale retrospective study, of which the most common types were radicular cysts (52.74%), dentigerous cysts (38.35%), and odontogenic keratocysts (7.11%).[2] The incidence of odontogenic cysts by location (mandible, maxilla, or both) was approximately 59% for the mandible, which is clinically significant.[3]

Primary enucleation and decompression are two well-established surgical methods used to treat odontogenic cysts.[4] Primary enucleation allows the complete removal of the lining of the cyst in one surgical procedure, thus avoiding the need to maintain a decompression device for a long time and allowing definitive histopathological examination.[5] However, extensive removal might result in excessive surgical manipulation around the inferior alveolar neurovascular bundle and large bony defects that would require slow regeneration.[6] On the other hand, decompression lowers the intracystic pressure by creating a sustained opening, which allows the shrinkage of the lesions over time, formation of peripheral bone, and safe subsequent enucleation.[7] Shi et al. (2024) conducted a comparative study of medium-sized odontogenic cysts and found that the advantages of decompression were that it could maintain the function of the teeth and reduce the neurosensory impairment, but it required more frequent follow-up visits and longer postoperative treatment.[5]

Neurosensory recovery is an important measure of functional outcome after surgery, as damage or compression of the inferior alveolar nerve might lead to long-term numbness, tingling, altered sensation, or dysesthesia of the lower lip and chin.[8] Prognosis may be related to the amount of time the nerve has been compressed preoperatively, the size of the lesion, the displacement of the anatomical location of the mandibular canal, and the amount of surgical manipulation.[8].

Previous comparative studies focus on reduction in cyst size, radiographic healing and recurrence, while assessment of combined outcomes of neurosensory recovery and bone regeneration is limited, especially with regard to large odontogenic cysts of the mandible.[9] Comparative evaluation with both functional and radiographic parameters, therefore, may give a more relevant guide to treatment choice. The study aims to provide evidence which can support the process of surgical planning for individual patients, reduce morbidity associated with the surgery, and enhance long-term treatment outcomes. Therefore, the goal of the present study was to compare the neurosensory recovery and bone regeneration between decompression and primary enucleation of large mandibular odontogenic cysts.

A prospective comparative observational study was conducted in the Department of Oral and Maxillofacial Surgery, Gandhara University Sardar Begum Dental College. The study was conducted over a period of one year, from 1st April 2025 to 31st March, 2026. The sample size was determined using OpenEpi for two independent proportions with a 95% CI, 80% power, and a 1:1 allocation ratio, based on guidance from Shi et al. (2024). The minimum sample size was determined as 62 patients in each of the two groups (decompression and primary enucleation) based on the uncorrected Fleiss formula, assuming that the postoperative neurosensory impairment rates are 10% and 30% in the decompression and primary enucleation groups, respectively.[5] The final sample size included 138 patients (69 individuals in each group) after accounting for a 10% anticipated loss to follow-up. Patients were recruited using a non-probability consecutive sampling technique, which met the predetermined criteria for inclusion. Included in the study were patients between the ages of 18-65 years, of both genders, who had clinically, radiographically, and histopathologically confirmed mandibular odontogenic cysts with a minimum diameter of 3 cm. Patients with radicular cysts, dentigerous cysts, and odontogenic keratocysts were included in the study if the lesions met the size criteria defined and could be treated by decompression or first enucleation. Patients had to have preoperative baseline radiologic examinations, documented pre-operative neurosensory evaluation(s), and be able to come in for the planned postoperative follow-up visits. Patients who had any of the following were excluded: Recurrent odontogenic cysts, previous surgery in the area of the mandible, or any history of trauma that resulted in damage to the inferior alveolar nerve. Patients with pre-existing neurological disorders, such as those resulting in facial sensory changes, uncontrolled diabetes mellitus, metabolic bone diseases, or systemic disorders that could compromise wound healing and bone regeneration were also excluded. Patients who were on radiotherapy treatment for the maxillofacial region, on long-term systemic cortisone, or on drugs that had a marked effect on the metabolism of bones were not selected. Exclusion criteria involved non-odontogenic cysts, cystic neoplasms other than the above eligible lesions, pathological fractures requiring reconstructive procedures in addition to immediate segmental resection, and lesions that required immediate segmental resection. Eligible patients were recruited following IRB/Ethical Review Committee approval and with written informed consent. Data were collected using a structured data collection form and included demographic characteristics, pertinent medical and dental history, presenting complaints, duration of symptoms, and clinical findings. A thorough extraoral and intraoral examination was performed to identify facial swelling, tooth displacement, and any preoperative sensory disturbances of the lower lip and chin, as well as to document any type of tenderness or cortical expansion. Baseline radiographic assessment was conducted by panoramic X-rays and cone-beam computed tomography (CBCT), if clinically indicated, to document the dimensions of the lesions, the anatomical location, the cortical bone involvement, and the nearness to the inferior alveolar canal. The final diagnosis was made by histopathological examination of the tissue samples taken at surgery or preoperative biopsy. Group A patients received decompression by making an opening through the cyst into the oral cavity and inserting a decompression tube or stent to keep the cavity in communication with the oral cavity. The cystic contents were drained, and representative tissue was taken for histopathological examination. Patients were given guidelines for frequent irrigation of the cavity and the care of the decompression device. Periodic clinical and radiographical evaluations were done to assess the extent of reduction of lesions, formation of bone, and improvement of neurosensory function. The timing of subsequent enucleation was recorded, and the decision for subsequent enucleation was made based on either lesion reduction, pathological examination, or the surgeon's clinical judgment. In Group B, the patients had primary enucleation, and the cystic lining was carefully separated and removed from the surrounding mandibular bone, careful care being taken to preserve the inferior alveolar neurovascular bundle. Pathological confirmation was requested by submitting the excised tissue. Medications, wound care, and follow-up instructions were given as per institutional protocol. Standardized clinical neurosensory testing was used to evaluate neurosensory function before surgery and at 1 month, 3 months, 6 months, and 12 months after surgery. The assessment comprised a cotton wisp test, 2-point discrimination, and pinprick sensation in the distribution of the lower lip and chin mental nerve on the affected side. Sensory responses were compared with the contralateral normal side. Two-point discrimination thresholds were measured in mm, and light-touch and pinprick responses were noted on standardized clinical assessment forms. Patients were also asked about numbness, tingling sensation, altered sensation, and discomfort. Neurosensory recovery was assessed as improvement in sensory function from baseline, and patients were judged to have complete recovery, partial recovery, or persistent sensory impairment based on predetermined clinical criteria. An examination protocol was used to reduce interobserver variability. The evaluation of bone regeneration was based on comparison of baseline and postoperative radiographs. Standardized radiographic measurements were used to assess lesion size and extent of reduction of osseous defect. If clinically appropriate and available, CBCT images were acquired at baseline and 12-month follow-up to assess three-dimensional volume of the cystic defect and regenerated bone. At 3 months and 6 months, clinically indicated radiographs were used to perform intermediate assessments. Cystic defect volume was reduced by the volume of the defect after surgery, which was subtracted from the cystic defect's volume before surgery, divided by the volume of the cystic defect before surgery, and then multiplied by 100. Lesion size, trabecular bone formation, loss of continuity of the cortex, and osseous remnants were documented. Secondary enucleation was timed in patients who received decompression to differentiate between bone regeneration during decompression and healing after definitive surgical removal. Standardized software was used for radiographic measurements, and, wherever feasible, the software was used by an examiner blinded to treatment allocation for interpretation of the images. A structured proforma was used for clinical and radiographic assessments, which were entered into a database for statistical analysis. The Statistical Package for the Social Sciences (SPSS), version 25, was used for data entry and analysis. Data were presented as means and standard deviations or medians and interquartile ranges as appropriate for the distribution of quantitative variables, such as age, lesion size, cystic defect volume, 2PD, and percentage bone regeneration. Qualitative variables, such as gender, cyst type, treatment group, neurosensory recovery category, and complications of surgery, were described in terms of frequency and percentage. Normality in quantitative variables was tested with the Shapiro–Wilk test. Normally distributed continuous variables between groups were compared using the independent-samples t-test. The chi-square test and Fisher's exact test were used to compare categorical variables, depending on the data type. A p-value below 0.05 was regarded as statistically significant.

A total of 138 patients were included in the study, with 69 patients each in the decompression and primary enucleation groups. The mean ages were 35.8 ± 11.4 years and 37.2 ± 12.1 years, respectively, for the decompression and enucleation groups. The most common lesion in both groups was the radicular cyst (39.1% and 40.6%, respectively). The baseline demographic, clinical, and radiographic data were similar for both groups, and differences were not statistically significant (p > 0.05) (Table 1).

Table 1. Baseline demographic, clinical, and radiographic characteristics

The mean operating times were significantly less for the decompression group than for the enucleation group (p < 0.001). The number of follow-up visits was, however, much higher in the decompression group than in the controls (p < 0.001). Subsequent enucleation was performed in 85.5% of decompression patients. No statistically significant differences emerged for other postoperative complications, but there was a significant decrease in temporary postoperative neurosensory symptoms after decompression (p = 0.004) (Table 2).

Table 2. Surgical management, clinical course, and complications

There was a gradual improvement in neurosensory function in both groups over the 12-month follow-up. At 12 months, they noted that the mean two-point discrimination threshold was significantly lower in the enucleation group than in the decompression group (p < 0.001). In 94.2% and 84.1% of patients, light-touch sensation was normal, respectively. The rates of complete recovery after decompression and enucleation were 80.0% and 57.9%, respectively, with no statistically significant difference (p = 0.135) (Table 3) among those with sensory impairment preoperatively.

Table 3. Neurosensory recovery and serial sensory assessment

The radiographic assessment revealed progressive bone regeneration in both groups, and a significantly higher amount of bone volume reduction in the decompression group. The mean percentage decrease in defect volume was 75.9 ± 11.5% in the decompression group and 66.9 ± 12.1% in the enucleation group (p < 0.001). Decompression also had a significant reduction in residual defect volume (3.8 ± 2.3 versus 5.1 ± 2.7 cm³; p = 0.003). No significant differences were found in complete radiographic resolution among groups (14.5% vs. 10.1%, p = 0.433) (Table 4).

Table 4. Radiographic bone regeneration and longitudinal healing

The results of the study were shown to be good neurosensory results and more significant defect reduction on the radiographs but in both cases there was improvement after surgery. These observations were consistent with Shi et al. (2024), who compared 69 patients and reported fewer neurosensory complications following decompression-first treatment. Their investigation was, however, with medium-sized cysts, which makes direct comparison with the larger mandibular lesions in the present study difficult.[5] In terms of bone regeneration, a 12-month reduction in the defect volume was observed in the decompression group vs. the enucleation group (75.9%vs.66.9%). This was inconsistent with Dereci et al. (2021), who assessed 30 patients and found similar radiographic defect reduction after both techniques, with no significant difference between the groups at 12 months.[10] Likewise, in their study of 37 patients, Tekin et al. (2025) reported that both procedures led to progressive improvement in trabecular bone structure with no significant difference at three or six months. These differences may be accounted for in part by differences in lesion size, imaging methods, and assessment of healing.[11] Wongrattanakarn et al. (2023) reported results of the analysis of the volume of cystic defects in 41 odontogenic cysts using three-dimensional imaging, and found that initial lesion volume was an important factor that affects the reduction rate.[12] Volumetric changes were also documented by Khalifa and Alkharboush (2023) in the treatment of odontogenic keratocysts using decompression and definitive surgical technique.[13] The results of their study, however, were restricted to the study of mixed populations of odontogenic cysts and mixed odontogenic keratocysts, and not all populations of mixed odontogenic cysts were studied, so direct comparisons are difficult.[13] Zheng et al. (2025) further confirmed the effectiveness of decompression for large lesions in the mandible by analyzing 44 patients digitally.[14] Likewise, Raabe et al. (2026) found a decrease in mean cyst volume after decompression, from 3764 mm³ to 1413 mm³ in 40 patients.[15] This was generally in agreement with the significant defect decrease noted in the decompression group of the present study. However, radiographic volume reduction is just one part of the process of bone healing, and does not necessarily mean that overall mandibular strength and/or bone quality has been restored. Moreover, the progressive radiographic improvement seen after both surgical techniques was similar to Al-Qurmoti et al. (2023), who assessed the bone regeneration after enucleation of large CCF by CBCT. They concluded that the mandible can regenerate after the extraction of the tooth.[16] In addition, Cao et al. (2022) evaluated enucleation with GBR in small and medium-sized OJCs, suggesting the possible use of other regenerative procedures.[17] However, direct comparisons of the present study with the use of guided bone regeneration and differences in lesions size are restricted. In an extension study, Chaudhary et al. (2026) conducted a prospective assessment of bone remodelling after decompression in 28 patients using fractal analysis, further supporting the use of radiographic assessment of healing for conservatively treated patients. There was no significant difference between the groups in terms of complete radiographic resolution, although there was a higher percentage volume reduction after decompression in the present study. The difference indicates the need to differentiate between the effects of treatment in terms of reduction in residual defect size and complete radiographic healing.[18] The decompression group did need more follow-up visits, but the operating time was shorter in this group. This was because of the extra care required for keeping the decompression opening open and for monitoring the reduction in lesions. These results were not interpreted due to the lack of random allocation of treatment, possible variations in the nature of the lesions, secondary enucleation timing, and a follow-up period of 12 months. Furthermore, there were variations in surgical techniques and radiographical measurements among the published studies, which prevented direct comparisons. In conclusion, the results indicated that decompression may be a favorable procedure both in terms of sensory and radiographic results in selected patients with large mandibular odontogenic cysts, but primary enucleation is still an effective procedure without prolonged decompression management. Treatment choice should therefore take into account the nature of the lesion, the anatomical relationships, and the needs of the patient. Limitations There were several limitations in the present study. It may have been subject to selection bias and confounding due to its non-randomized design and its consecutive sampling. The results were not generalizable because of the single center and relatively small sample size. In addition, a 12-month follow-up period may have been too short to consider complete bone regeneration or long-term neurosensory recovery. There may have been variations in the size of the cysts, the pathological composition, location, and time interval between primary and secondary enucleations, which have also affected treatment outcomes. In addition, the majority of radiological evaluation focused on bone defect reduction rather than on the strength and quality of the bone.

Decompression demonstrated favourable neurosensory outcomes and greater radiographic bone defect reduction compared with primary enucleation in patients with large mandibular odontogenic cysts. Nevertheless, both techniques led to progressive functional and osseous healing, and there was no significant difference in complete radiographic healing. Decompression was more time-consuming and had more follow-up visits after the surgery, but it could be an appropriate treatment for lesions affecting the inferior alveolar nerve. Primary enucleation was an effective treatment option in the appropriate cases.